Sync async_nats work with master

Signed-off-by: Alex Ellis <alexellis2@gmail.com>

gateway/vendor/github.com/nats-io/go-nats-streaming/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2016 Apcera Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

gateway/vendor/github.com/nats-io/go-nats-streaming/README.md

@@ -0,0 +1,347 @@
+# NATS Streaming
+
+NATS Streaming is an extremely performant, lightweight reliable streaming platform powered by [NATS](https://nats.io).
+
+[![License MIT](https://img.shields.io/badge/License-MIT-blue.svg)](http://opensource.org/licenses/MIT)
+[![Build Status](https://travis-ci.org/nats-io/go-nats-streaming.svg?branch=master)](http://travis-ci.org/nats-io/go-nats-streaming)
+[![Coverage Status](https://coveralls.io/repos/nats-io/go-nats-streaming/badge.svg?branch=master)](https://coveralls.io/r/nats-io/go-nats-streaming?branch=master)
+
+NATS Streaming provides the following high-level feature set:
+- Log based persistence
+- At-Least-Once Delivery model, giving reliable message delivery
+- Rate matched on a per subscription basis
+- Replay/Restart
+- Last Value Semantics
+
+## Notes
+
+- Please raise questions/issues via the [Issue Tracker](https://github.com/nats-io/go-nats-streaming/issues).
+
+## Installation
+
+```bash
+# Go client
+go get github.com/nats-io/go-nats-streaming
+```
+
+## Basic Usage
+
+```go
+
+sc, _ := stan.Connect(clusterID, clientID)
+
+// Simple Synchronous Publisher
+sc.Publish("foo", []byte("Hello World")) // does not return until an ack has been received from NATS Streaming
+
+// Simple Async Subscriber
+sub, _ := sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+})
+
+// Unsubscribe
+sub.Unsubscribe()
+
+// Close connection
+sc.Close()
+```
+
+### Subscription Start (i.e. Replay) Options
+
+NATS Streaming subscriptions are similar to NATS subscriptions, but clients may start their subscription at an earlier point in the message stream, allowing them to receive messages that were published before this client registered interest.
+
+The options are described with examples below:
+
+```go
+
+// Subscribe starting with most recently published value
+sub, err := sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, StartWithLastReceived())
+
+// Receive all stored values in order
+sub, err := sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, DeliverAllAvailable())
+
+// Receive messages starting at a specific sequence number
+sub, err := sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, StartAtSequence(22))
+
+// Subscribe starting at a specific time
+var startTime time.Time
+...
+sub, err := sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, StartAtTime(startTime))
+
+// Subscribe starting a specific amount of time in the past (e.g. 30 seconds ago)
+sub, err := sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, StartAtTimeDelta(time.ParseDuration("30s")))
+```
+
+### Durable Subscriptions
+
+Replay of messages offers great flexibility for clients wishing to begin processing at some earlier point in the data stream.
+However, some clients just need to pick up where they left off from an earlier session, without having to manually track their position in the stream of messages.
+Durable subscriptions allow clients to assign a durable name to a subscription when it is created.
+Doing this causes the NATS Streaming server to track the last acknowledged message for that clientID + durable name, so that only messages since the last acknowledged message will be delivered to the client.
+
+```go
+sc, _ := stan.Connect("test-cluster", "client-123")
+
+// Subscribe with durable name
+sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, stan.DurableName("my-durable"))
+...
+// client receives message sequence 1-40
+...
+// client disconnects for an hour
+...
+// client reconnects with same clientID "client-123"
+sc, _ := stan.Connect("test-cluster", "client-123")
+
+// client re-subscribes to "foo" with same durable name "my-durable"
+sc.Subscribe("foo", func(m *stan.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+}, stan.DurableName("my-durable"))
+...
+// client receives messages 41-current
+```
+
+### Queue Groups
+
+All subscriptions with the same queue name (regardless of the connection
+they originate from) will form a queue group.
+Each message will be delivered to only one subscriber per queue group,
+using queuing semantics. You can have as many queue groups as you wish.
+
+Normal subscribers will continue to work as expected.
+
+#### Creating a Queue Group
+
+A queue group is automatically created when the first queue subscriber is
+created. If the group already exists, the member is added to the group.
+
+```go
+sc, _ := stan.Connect("test-cluster", "clientid")
+
+// Create a queue subscriber on "foo" for group "bar"
+qsub1, _ := sc.QueueSubscribe("foo", "bar", qcb)
+
+// Add a second member
+qsub2, _ := sc.QueueSubscribe("foo", "bar", qcb)
+
+// Notice that you can have a regular subscriber on that subject
+sub, _ := sc.Subscribe("foo", cb)
+
+// A message on "foo" will be received by sub and qsub1 or qsub2.
+```
+
+#### Start Position
+
+Note that once a queue group is formed, a member's start position is ignored
+when added to the group. It will start receive messages from the last
+position in the group.
+
+Suppose the channel `foo` exists and there are `500` messages stored, the group
+`bar` is already created, there are two members and the last
+message sequence sent is `100`. A new member is added. Note its start position:
+
+```go
+sc.QueueSubscribe("foo", "bar", qcb, stan.StartAtSequence(200))
+```
+
+This will not produce an error, but the start position will be ignored. Assuming
+this member would be the one receiving the next message, it would receive message
+sequence `101`.
+
+#### Leaving the Group
+
+There are two ways of leaving the group: closing the subscriber's connection or
+calling `Unsubscribe`:
+
+```go
+// Have qsub leave the queue group
+qsub.Unsubscribe()
+```
+
+If the leaving member had un-acknowledged messages, those messages are reassigned
+to the remaining members.
+
+#### Closing a Queue Group
+
+There is no special API for that. Once all members have left (either calling `Unsubscribe`,
+or their connections are closed), the group is removed from the server.
+
+The next call to `QueueSubscribe` with the same group name will create a brand new group,
+that is, the start position will take effect and delivery will start from there.
+
+### Durable Queue Groups
+
+As described above, for non durable queue subscribers, when the last member leaves the group,
+that group is removed. A durable queue group allows you to have all members leave but still
+maintain state. When a member re-joins, it starts at the last position in that group.
+
+#### Creating a Durable Queue Group
+
+A durable queue group is created in a similar manner as that of a standard queue group,
+except the `DurableName` option must be used to specify durability.
+
+```go
+sc.QueueSubscribe("foo", "bar", qcb, stan.DurableName("dur"))
+```
+A group called `dur:bar` (the concatenation of durable name and group name) is created in
+the server. This means two things:
+
+- The character `:` is not allowed for a queue subscriber's durable name.
+- Durable and non-durable queue groups with the same name can coexist.
+
+```go
+// Non durable queue subscriber on group "bar"
+qsub, _ := sc.QueueSubscribe("foo", "bar", qcb)
+
+// Durable queue subscriber on group "bar"
+durQsub, _ := sc.QueueSubscribe("foo", "bar", qcb, stan.DurableName("mydurablegroup"))
+
+// The same message produced on "foo" would be received by both queue subscribers.
+```
+
+#### Start Position
+
+The rules for non-durable queue subscribers apply to durable subscribers.
+
+#### Leaving the Group
+
+As for non-durable queue subscribers, if a member's connection is closed, or if
+`Unsubscribe` its called, the member leaves the group. Any unacknowledged message
+is transferred to remaining members. See *Closing the Group* for important difference
+with non-durable queue subscribers.
+
+#### Closing the Group
+
+The *last* member calling `Unsubscribe` will close (that is destroy) the
+group. So if you want to maintain durability of the group, you should not be
+calling `Unsubscribe`.
+
+So unlike for non-durable queue subscribers, it is possible to maintain a queue group
+with no member in the server. When a new member re-joins the durable queue group,
+it will resume from where the group left of, actually first receiving all unacknowledged
+messages that may have been left when the last member previously left.
+
+
+### Wildcard Subscriptions
+
+NATS Streaming subscriptions **do not** support wildcards.
+
+
+## Advanced Usage
+
+### Asynchronous Publishing
+
+The basic publish API (`Publish(subject, payload)`) is synchronous; it does not return control to the caller until the NATS Streaming server has acknowledged receipt of the message. To accomplish this, a [NUID](https://github.com/nats-io/nuid) is generated for the message on creation, and the client library waits for a publish acknowledgement from the server with a matching NUID before it returns control to the caller, possibly with an error indicating that the operation was not successful due to some server problem or authorization error.
+
+Advanced users may wish to process these publish acknowledgements manually to achieve higher publish throughput by not waiting on individual acknowledgements during the publish operation. An asynchronous publish API is provided for this purpose:
+
+```go
+    ackHandler := func(ackedNuid string, err error) {
+        if err != nil {
+            log.Printf("Warning: error publishing msg id %s: %v\n", ackedNuid, err.Error())
+        } else {
+            log.Printf("Received ack for msg id %s\n", ackedNuid)
+        }
+    }
+
+    // can also use PublishAsyncWithReply(subj, replysubj, payload, ah)
+    nuid, err := sc.PublishAsync("foo", []byte("Hello World"), ackHandler) // returns immediately
+    if err != nil {
+        log.Printf("Error publishing msg %s: %v\n", nuid, err.Error())
+    }
+```
+
+### Message Acknowledgements and Redelivery
+
+NATS Streaming offers At-Least-Once delivery semantics, meaning that once a message has been delivered to an eligible subscriber, if an acknowledgement is not received within the configured timeout interval, NATS Streaming will attempt redelivery of the message.
+This timeout interval is specified by the subscription option `AckWait`, which defaults to 30 seconds.
+
+By default, messages are automatically acknowledged by the NATS Streaming client library after the subscriber's message handler is invoked. However, there may be cases in which the subscribing client wishes to accelerate or defer acknowledgement of the message.
+To do this, the client must set manual acknowledgement mode on the subscription, and invoke `Ack()` on the `Msg`. ex:
+
+```go
+// Subscribe with manual ack mode, and set AckWait to 60 seconds
+aw, _ := time.ParseDuration("60s")
+sub, err := sc.Subscribe("foo", func(m *stan.Msg) {
+  m.Ack() // ack message before performing I/O intensive operation
+  ///...
+  fmt.Printf("Received a message: %s\n", string(m.Data))
+}, stan.SetManualAckMode(), stan.AckWait(aw))
+```
+
+## Rate limiting/matching
+
+A classic problem of publish-subscribe messaging is matching the rate of message producers with the rate of message consumers.
+Message producers can often outpace the speed of the subscribers that are consuming their messages.
+This mismatch is commonly called a "fast producer/slow consumer" problem, and may result in dramatic resource utilization spikes in the underlying messaging system as it tries to buffer messages until the slow consumer(s) can catch up.
+
+### Publisher rate limiting
+
+NATS Streaming provides a connection option called `MaxPubAcksInflight` that effectively limits the number of unacknowledged messages that a publisher may have in-flight at any given time. When this maximum is reached, further `PublishAsync()` calls will block until the number of unacknowledged messages falls below the specified limit. ex:
+
+```go
+sc, _ := stan.Connect(clusterID, clientID, MaxPubAcksInflight(25))
+
+ah := func(nuid string, err error) {
+    // process the ack
+    ...
+}
+
+for i := 1; i < 1000; i++ {
+    // If the server is unable to keep up with the publisher, the number of outstanding acks will eventually
+    // reach the max and this call will block
+    guid, _ := sc.PublishAsync("foo", []byte("Hello World"), ah)
+}
+```
+
+### Subscriber rate limiting
+
+Rate limiting may also be accomplished on the subscriber side, on a per-subscription basis, using a subscription option called `MaxInflight`.
+This option specifies the maximum number of outstanding acknowledgements (messages that have been delivered but not acknowledged) that NATS Streaming will allow for a given subscription.
+When this limit is reached, NATS Streaming will suspend delivery of messages to this subscription until the number of unacknowledged messages falls below the specified limit. ex:
+
+```go
+// Subscribe with manual ack mode and a max in-flight limit of 25
+sc.Subscribe("foo", func(m *stan.Msg) {
+  fmt.Printf("Received message #: %s\n", string(m.Data))
+  ...
+  // Does not ack, or takes a very long time to ack
+  ...
+  // Message delivery will suspend when the number of unacknowledged messages reaches 25
+}, stan.SetManualAckMode(), stan.MaxInflight(25))
+
+```
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2012-2016 Apcera Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.

gateway/vendor/github.com/nats-io/go-nats-streaming/pb/protocol.proto

@@ -0,0 +1,115 @@
+// Copyright 2016 Apcera Inc. All rights reserved.
+//
+// Uses https://github.com/gogo/protobuf
+// compiled via `protoc -I=. -I=$GOPATH/src  --gogofaster_out=. protocol.proto`
+
+syntax = "proto3";
+package pb;
+
+import "github.com/gogo/protobuf/gogoproto/gogo.proto";
+
+option (gogoproto.marshaler_all) = true;
+option (gogoproto.sizer_all) = true;
+option (gogoproto.unmarshaler_all) = true;
+option (gogoproto.goproto_getters_all) = false;
+
+// How messages are delivered to the STAN cluster
+message PubMsg {
+  string clientID = 1;  // ClientID
+  string guid     = 2;  // guid
+  string subject  = 3;  // subject
+  string reply    = 4;  // optional reply
+  bytes  data     = 5;  // payload
+
+  bytes  sha256  = 10; // optional sha256 of data
+}
+
+// Used to ACK to publishers
+message PubAck {
+  string guid  = 1; // guid
+  string error = 2; // err string, empty/omitted if no error
+}
+
+// Msg struct. Sequence is assigned for global ordering by
+// the cluster after the publisher has been acknowledged.
+message MsgProto {
+  uint64 sequence    = 1;  // globally ordered sequence number for the subject's channel
+  string subject     = 2;  // subject
+  string reply       = 3;  // optional reply
+  bytes  data        = 4;  // payload
+  int64  timestamp   = 5;  // received timestamp
+  bool   redelivered = 6;  // Flag specifying if the message is being redelivered
+
+  uint32 CRC32       = 10; // optional IEEE CRC32
+}
+
+// Ack will deliver an ack for a delivered msg.
+message Ack {
+  string subject  = 1; // Subject
+  uint64 sequence = 2; // Sequence to acknowledge
+}
+
+// Connection Request
+message ConnectRequest {
+  string clientID       = 1;  // Client name/identifier.
+  string heartbeatInbox = 2;  // Inbox for server initiated heartbeats.
+}
+
+// Response to a client connect
+message ConnectResponse {
+  string pubPrefix        = 1;   // Prefix to use when publishing to this STAN cluster
+  string subRequests      = 2;   // Subject to use for subscription requests
+  string unsubRequests    = 3;   // Subject to use for unsubscribe requests
+  string closeRequests    = 4;   // Subject for closing the stan connection
+  string error            = 5;   // err string, empty/omitted if no error
+  string subCloseRequests = 6;   // Subject to use for subscription close requests
+
+  string publicKey     = 100; // Possibly used to sign acks, etc.
+}
+
+// Enum for start position type.
+enum StartPosition {
+    NewOnly        = 0;
+    LastReceived   = 1;
+    TimeDeltaStart = 2;
+    SequenceStart  = 3;
+    First          = 4;
+  }
+
+// Protocol for a client to subscribe
+message SubscriptionRequest {
+  string        clientID       = 1;  // ClientID
+  string        subject        = 2;  // Formal subject to subscribe to, e.g. foo.bar
+  string        qGroup         = 3;  // Optional queue group
+  string        inbox          = 4;  // Inbox subject to deliver messages on
+  int32         maxInFlight    = 5;  // Maximum inflight messages without an ack allowed
+  int32         ackWaitInSecs  = 6;  // Timeout for receiving an ack from the client
+  string        durableName    = 7;  // Optional durable name which survives client restarts
+  StartPosition startPosition  = 10; // Start position
+  uint64        startSequence  = 11; // Optional start sequence number
+  int64         startTimeDelta = 12; // Optional start time
+}
+
+// Response for SubscriptionRequest and UnsubscribeRequests
+message SubscriptionResponse {
+  string ackInbox = 2; // ackInbox for sending acks
+  string error    = 3; // err string, empty/omitted if no error
+}
+
+// Protocol for a clients to unsubscribe. Will return a SubscriptionResponse
+message UnsubscribeRequest {
+  string clientID    = 1; // ClientID
+  string subject     = 2; // subject for the subscription
+  string inbox       = 3; // Inbox subject to identify subscription
+  string durableName = 4; // Optional durable name which survives client restarts
+}
+
+// Protocol for a client to close a connection
+message CloseRequest {
+  string clientID = 1;  // Client name provided to Connect() requests
+}
+
+// Response for CloseRequest
+message CloseResponse {
+  string error = 1; // err string, empty/omitted if no error
+}

gateway/vendor/github.com/nats-io/go-nats-streaming/stan.go

@@ -0,0 +1,474 @@
+// Copyright 2016 Apcera Inc. All rights reserved.
+
+// Package stan is a Go client for the NATS Streaming messaging system (https://nats.io).
+package stan
+
+import (
+	"errors"
+	"fmt"
+	"runtime"
+	"sync"
+	"time"
+
+	"github.com/nats-io/go-nats"
+	"github.com/nats-io/go-nats-streaming/pb"
+	"github.com/nats-io/nuid"
+)
+
+// Version is the NATS Streaming Go Client version
+const Version = "0.3.4"
+
+const (
+	// DefaultNatsURL is the default URL the client connects to
+	DefaultNatsURL = "nats://localhost:4222"
+	// DefaultConnectWait is the default timeout used for the connect operation
+	DefaultConnectWait = 2 * time.Second
+	// DefaultDiscoverPrefix is the prefix subject used to connect to the NATS Streaming server
+	DefaultDiscoverPrefix = "_STAN.discover"
+	// DefaultACKPrefix is the prefix subject used to send ACKs to the NATS Streaming server
+	DefaultACKPrefix = "_STAN.acks"
+	// DefaultMaxPubAcksInflight is the default maximum number of published messages
+	// without outstanding ACKs from the server
+	DefaultMaxPubAcksInflight = 16384
+)
+
+// Conn represents a connection to the NATS Streaming subsystem. It can Publish and
+// Subscribe to messages within the NATS Streaming cluster.
+type Conn interface {
+	// Publish
+	Publish(subject string, data []byte) error
+	PublishAsync(subject string, data []byte, ah AckHandler) (string, error)
+
+	// Subscribe
+	Subscribe(subject string, cb MsgHandler, opts ...SubscriptionOption) (Subscription, error)
+
+	// QueueSubscribe
+	QueueSubscribe(subject, qgroup string, cb MsgHandler, opts ...SubscriptionOption) (Subscription, error)
+
+	// Close
+	Close() error
+
+	// NatsConn returns the underlying NATS conn. Use this with care. For
+	// example, closing the wrapped NATS conn will put the NATS Streaming Conn
+	// in an invalid state.
+	NatsConn() *nats.Conn
+}
+
+// Errors
+var (
+	ErrConnectReqTimeout = errors.New("stan: connect request timeout")
+	ErrCloseReqTimeout   = errors.New("stan: close request timeout")
+	ErrSubReqTimeout     = errors.New("stan: subscribe request timeout")
+	ErrUnsubReqTimeout   = errors.New("stan: unsubscribe request timeout")
+	ErrConnectionClosed  = errors.New("stan: connection closed")
+	ErrTimeout           = errors.New("stan: publish ack timeout")
+	ErrBadAck            = errors.New("stan: malformed ack")
+	ErrBadSubscription   = errors.New("stan: invalid subscription")
+	ErrBadConnection     = errors.New("stan: invalid connection")
+	ErrManualAck         = errors.New("stan: cannot manually ack in auto-ack mode")
+	ErrNilMsg            = errors.New("stan: nil message")
+	ErrNoServerSupport   = errors.New("stan: not supported by server")
+)
+
+// AckHandler is used for Async Publishing to provide status of the ack.
+// The func will be passed the GUID and any error state. No error means the
+// message was successfully received by NATS Streaming.
+type AckHandler func(string, error)
+
+// Options can be used to a create a customized connection.
+type Options struct {
+	NatsURL            string
+	NatsConn           *nats.Conn
+	ConnectTimeout     time.Duration
+	AckTimeout         time.Duration
+	DiscoverPrefix     string
+	MaxPubAcksInflight int
+}
+
+// DefaultOptions are the NATS Streaming client's default options
+var DefaultOptions = Options{
+	NatsURL:            DefaultNatsURL,
+	ConnectTimeout:     DefaultConnectWait,
+	AckTimeout:         DefaultAckWait,
+	DiscoverPrefix:     DefaultDiscoverPrefix,
+	MaxPubAcksInflight: DefaultMaxPubAcksInflight,
+}
+
+// Option is a function on the options for a connection.
+type Option func(*Options) error
+
+// NatsURL is an Option to set the URL the client should connect to.
+func NatsURL(u string) Option {
+	return func(o *Options) error {
+		o.NatsURL = u
+		return nil
+	}
+}
+
+// ConnectWait is an Option to set the timeout for establishing a connection.
+func ConnectWait(t time.Duration) Option {
+	return func(o *Options) error {
+		o.ConnectTimeout = t
+		return nil
+	}
+}
+
+// PubAckWait is an Option to set the timeout for waiting for an ACK for a
+// published message.
+func PubAckWait(t time.Duration) Option {
+	return func(o *Options) error {
+		o.AckTimeout = t
+		return nil
+	}
+}
+
+// MaxPubAcksInflight is an Option to set the maximum number of published
+// messages without outstanding ACKs from the server.
+func MaxPubAcksInflight(max int) Option {
+	return func(o *Options) error {
+		o.MaxPubAcksInflight = max
+		return nil
+	}
+}
+
+// NatsConn is an Option to set the underlying NATS connection to be used
+// by a NATS Streaming Conn object.
+func NatsConn(nc *nats.Conn) Option {
+	return func(o *Options) error {
+		o.NatsConn = nc
+		return nil
+	}
+}
+
+// A conn represents a bare connection to a stan cluster.
+type conn struct {
+	sync.RWMutex
+	clientID         string
+	pubPrefix        string // Publish prefix set by stan, append our subject.
+	subRequests      string // Subject to send subscription requests.
+	unsubRequests    string // Subject to send unsubscribe requests.
+	subCloseRequests string // Subject to send subscription close requests.
+	closeRequests    string // Subject to send close requests.
+	ackSubject       string // publish acks
+	ackSubscription  *nats.Subscription
+	hbSubscription   *nats.Subscription
+	subMap           map[string]*subscription
+	pubAckMap        map[string]*ack
+	pubAckChan       chan (struct{})
+	opts             Options
+	nc               *nats.Conn
+	ncOwned          bool // NATS Streaming created the connection, so needs to close it.
+}
+
+// Closure for ack contexts.
+type ack struct {
+	t  *time.Timer
+	ah AckHandler
+	ch chan error
+}
+
+// Connect will form a connection to the NATS Streaming subsystem.
+// Note that clientID can contain only alphanumeric and `-` or `_` characters.
+func Connect(stanClusterID, clientID string, options ...Option) (Conn, error) {
+	// Process Options
+	c := conn{clientID: clientID, opts: DefaultOptions}
+	for _, opt := range options {
+		if err := opt(&c.opts); err != nil {
+			return nil, err
+		}
+	}
+	// Check if the user has provided a connection as an option
+	c.nc = c.opts.NatsConn
+	// Create a NATS connection if it doesn't exist.
+	if c.nc == nil {
+		nc, err := nats.Connect(c.opts.NatsURL, nats.Name(clientID))
+		if err != nil {
+			return nil, err
+		}
+		c.nc = nc
+		c.ncOwned = true
+	} else if !c.nc.IsConnected() {
+		// Bail if the custom NATS connection is disconnected
+		return nil, ErrBadConnection
+	}
+
+	// Create a heartbeat inbox
+	hbInbox := nats.NewInbox()
+	var err error
+	if c.hbSubscription, err = c.nc.Subscribe(hbInbox, c.processHeartBeat); err != nil {
+		c.Close()
+		return nil, err
+	}
+
+	// Send Request to discover the cluster
+	discoverSubject := c.opts.DiscoverPrefix + "." + stanClusterID
+	req := &pb.ConnectRequest{ClientID: clientID, HeartbeatInbox: hbInbox}
+	b, _ := req.Marshal()
+	reply, err := c.nc.Request(discoverSubject, b, c.opts.ConnectTimeout)
+	if err != nil {
+		c.Close()
+		if err == nats.ErrTimeout {
+			return nil, ErrConnectReqTimeout
+		}
+		return nil, err
+	}
+	// Process the response, grab server pubPrefix
+	cr := &pb.ConnectResponse{}
+	err = cr.Unmarshal(reply.Data)
+	if err != nil {
+		c.Close()
+		return nil, err
+	}
+	if cr.Error != "" {
+		c.Close()
+		return nil, errors.New(cr.Error)
+	}
+
+	// Capture cluster configuration endpoints to publish and subscribe/unsubscribe.
+	c.pubPrefix = cr.PubPrefix
+	c.subRequests = cr.SubRequests
+	c.unsubRequests = cr.UnsubRequests
+	c.subCloseRequests = cr.SubCloseRequests
+	c.closeRequests = cr.CloseRequests
+
+	// Setup the ACK subscription
+	c.ackSubject = DefaultACKPrefix + "." + nuid.Next()
+	if c.ackSubscription, err = c.nc.Subscribe(c.ackSubject, c.processAck); err != nil {
+		c.Close()
+		return nil, err
+	}
+	c.ackSubscription.SetPendingLimits(1024*1024, 32*1024*1024)
+	c.pubAckMap = make(map[string]*ack)
+
+	// Create Subscription map
+	c.subMap = make(map[string]*subscription)
+
+	c.pubAckChan = make(chan struct{}, c.opts.MaxPubAcksInflight)
+
+	// Attach a finalizer
+	runtime.SetFinalizer(&c, func(sc *conn) { sc.Close() })
+
+	return &c, nil
+}
+
+// Close a connection to the stan system.
+func (sc *conn) Close() error {
+	sc.Lock()
+	defer sc.Unlock()
+
+	if sc.nc == nil {
+		// We are already closed.
+		return nil
+	}
+
+	// Capture for NATS calls below.
+	nc := sc.nc
+	if sc.ncOwned {
+		defer nc.Close()
+	}
+
+	// Signals we are closed.
+	sc.nc = nil
+
+	// Now close ourselves.
+	if sc.ackSubscription != nil {
+		sc.ackSubscription.Unsubscribe()
+	}
+
+	req := &pb.CloseRequest{ClientID: sc.clientID}
+	b, _ := req.Marshal()
+	reply, err := nc.Request(sc.closeRequests, b, sc.opts.ConnectTimeout)
+	if err != nil {
+		if err == nats.ErrTimeout {
+			return ErrCloseReqTimeout
+		}
+		return err
+	}
+	cr := &pb.CloseResponse{}
+	err = cr.Unmarshal(reply.Data)
+	if err != nil {
+		return err
+	}
+	if cr.Error != "" {
+		return errors.New(cr.Error)
+	}
+	return nil
+}
+
+// NatsConn returns the underlying NATS conn. Use this with care. For example,
+// closing the wrapped NATS conn will put the NATS Streaming Conn in an invalid
+// state.
+func (sc *conn) NatsConn() *nats.Conn {
+	return sc.nc
+}
+
+// Process a heartbeat from the NATS Streaming cluster
+func (sc *conn) processHeartBeat(m *nats.Msg) {
+	// No payload assumed, just reply.
+	sc.RLock()
+	nc := sc.nc
+	sc.RUnlock()
+	if nc != nil {
+		nc.Publish(m.Reply, nil)
+	}
+}
+
+// Process an ack from the NATS Streaming cluster
+func (sc *conn) processAck(m *nats.Msg) {
+	pa := &pb.PubAck{}
+	err := pa.Unmarshal(m.Data)
+	if err != nil {
+		panic(fmt.Errorf("Error during ack unmarshal: %v", err))
+	}
+
+	// Remove
+	a := sc.removeAck(pa.Guid)
+	if a != nil {
+		// Capture error if it exists.
+		if pa.Error != "" {
+			err = errors.New(pa.Error)
+		}
+		if a.ah != nil {
+			// Perform the ackHandler callback
+			a.ah(pa.Guid, err)
+		} else if a.ch != nil {
+			// Send to channel directly
+			a.ch <- err
+		}
+	}
+}
+
+// Publish will publish to the cluster and wait for an ACK.
+func (sc *conn) Publish(subject string, data []byte) error {
+	ch := make(chan error)
+	_, err := sc.publishAsync(subject, data, nil, ch)
+	if err == nil {
+		err = <-ch
+	}
+	return err
+}
+
+// PublishAsync will publish to the cluster on pubPrefix+subject and asynchronously
+// process the ACK or error state. It will return the GUID for the message being sent.
+func (sc *conn) PublishAsync(subject string, data []byte, ah AckHandler) (string, error) {
+	return sc.publishAsync(subject, data, ah, nil)
+}
+
+func (sc *conn) publishAsync(subject string, data []byte, ah AckHandler, ch chan error) (string, error) {
+	a := &ack{ah: ah, ch: ch}
+	sc.Lock()
+	if sc.nc == nil {
+		sc.Unlock()
+		return "", ErrConnectionClosed
+	}
+
+	subj := sc.pubPrefix + "." + subject
+	// This is only what we need from PubMsg in the timer below,
+	// so do this so that pe doesn't escape (and we same on new object)
+	peGUID := nuid.Next()
+	pe := &pb.PubMsg{ClientID: sc.clientID, Guid: peGUID, Subject: subject, Data: data}
+	b, _ := pe.Marshal()
+
+	// Map ack to guid.
+	sc.pubAckMap[peGUID] = a
+	// snapshot
+	ackSubject := sc.ackSubject
+	ackTimeout := sc.opts.AckTimeout
+	pac := sc.pubAckChan
+	sc.Unlock()
+
+	// Use the buffered channel to control the number of outstanding acks.
+	pac <- struct{}{}
+
+	err := sc.nc.PublishRequest(subj, ackSubject, b)
+	if err != nil {
+		sc.removeAck(peGUID)
+		return "", err
+	}
+
+	// Setup the timer for expiration.
+	sc.Lock()
+	a.t = time.AfterFunc(ackTimeout, func() {
+		pubAck := sc.removeAck(peGUID)
+		// processAck could get here before and handle the ack.
+		// If that's the case, we would get nil here and simply return.
+		if pubAck == nil {
+			return
+		}
+		if pubAck.ah != nil {
+			pubAck.ah(peGUID, ErrTimeout)
+		} else if a.ch != nil {
+			pubAck.ch <- ErrTimeout
+		}
+	})
+	sc.Unlock()
+
+	return peGUID, nil
+}
+
+// removeAck removes the ack from the pubAckMap and cancels any state, e.g. timers
+func (sc *conn) removeAck(guid string) *ack {
+	var t *time.Timer
+	sc.Lock()
+	a := sc.pubAckMap[guid]
+	if a != nil {
+		t = a.t
+		delete(sc.pubAckMap, guid)
+	}
+	pac := sc.pubAckChan
+	sc.Unlock()
+
+	// Cancel timer if needed.
+	if t != nil {
+		t.Stop()
+	}
+
+	// Remove from channel to unblock PublishAsync
+	if a != nil && len(pac) > 0 {
+		<-pac
+	}
+	return a
+}
+
+// Process an msg from the NATS Streaming cluster
+func (sc *conn) processMsg(raw *nats.Msg) {
+	msg := &Msg{}
+	err := msg.Unmarshal(raw.Data)
+	if err != nil {
+		panic(fmt.Errorf("Error processing unmarshal for msg: %v", err))
+	}
+	// Lookup the subscription
+	sc.RLock()
+	nc := sc.nc
+	isClosed := nc == nil
+	sub := sc.subMap[raw.Subject]
+	sc.RUnlock()
+
+	// Check if sub is no longer valid or connection has been closed.
+	if sub == nil || isClosed {
+		return
+	}
+
+	// Store in msg for backlink
+	msg.Sub = sub
+
+	sub.RLock()
+	cb := sub.cb
+	ackSubject := sub.ackInbox
+	isManualAck := sub.opts.ManualAcks
+	subsc := sub.sc // Can be nil if sub has been unsubscribed.
+	sub.RUnlock()
+
+	// Perform the callback
+	if cb != nil && subsc != nil {
+		cb(msg)
+	}
+
+	// Process auto-ack
+	if !isManualAck && nc != nil {
+		ack := &pb.Ack{Subject: msg.Subject, Sequence: msg.Sequence}
+		b, _ := ack.Marshal()
+		// FIXME(dlc) - Async error handler? Retry?
+		nc.Publish(ackSubject, b)
+	}
+}

gateway/vendor/github.com/nats-io/go-nats-streaming/sub.go

@@ -0,0 +1,461 @@
+// Copyright 2016 Apcera Inc. All rights reserved.
+
+// Package stan is a Go client for the NATS Streaming messaging system (https://nats.io).
+package stan
+
+import (
+	"errors"
+	"sync"
+	"time"
+
+	"github.com/nats-io/go-nats"
+	"github.com/nats-io/go-nats-streaming/pb"
+)
+
+const (
+	// DefaultAckWait indicates how long the server should wait for an ACK before resending a message
+	DefaultAckWait = 30 * time.Second
+	// DefaultMaxInflight indicates how many messages with outstanding ACKs the server can send
+	DefaultMaxInflight = 1024
+)
+
+// Msg is the client defined message, which includes proto, then back link to subscription.
+type Msg struct {
+	pb.MsgProto // MsgProto: Seq, Subject, Reply[opt], Data, Timestamp, CRC32[opt]
+	Sub         Subscription
+}
+
+// Subscriptions and Options
+
+// Subscription represents a subscription within the NATS Streaming cluster. Subscriptions
+// will be rate matched and follow at-least delivery semantics.
+type Subscription interface {
+	ClearMaxPending() error
+	Delivered() (int64, error)
+	Dropped() (int, error)
+	IsValid() bool
+	MaxPending() (int, int, error)
+	Pending() (int, int, error)
+	PendingLimits() (int, int, error)
+	SetPendingLimits(msgLimit, bytesLimit int) error
+	// Unsubscribe removes interest in the subscription.
+	// For durables, it means that the durable interest is also removed from
+	// the server. Restarting a durable with the same name will not resume
+	// the subscription, it will be considered a new one.
+	Unsubscribe() error
+
+	// Close removes this subscriber from the server, but unlike Unsubscribe(),
+	// the durable interest is not removed. If the client has connected to a server
+	// for which this feature is not available, Close() will return a ErrNoServerSupport
+	// error.
+	Close() error
+}
+
+// A subscription represents a subscription to a stan cluster.
+type subscription struct {
+	sync.RWMutex
+	sc       *conn
+	subject  string
+	qgroup   string
+	inbox    string
+	ackInbox string
+	inboxSub *nats.Subscription
+	opts     SubscriptionOptions
+	cb       MsgHandler
+}
+
+// SubscriptionOption is a function on the options for a subscription.
+type SubscriptionOption func(*SubscriptionOptions) error
+
+// MsgHandler is a callback function that processes messages delivered to
+// asynchronous subscribers.
+type MsgHandler func(msg *Msg)
+
+// SubscriptionOptions are used to control the Subscription's behavior.
+type SubscriptionOptions struct {
+	// DurableName, if set will survive client restarts.
+	DurableName string
+	// Controls the number of messages the cluster will have inflight without an ACK.
+	MaxInflight int
+	// Controls the time the cluster will wait for an ACK for a given message.
+	AckWait time.Duration
+	// StartPosition enum from proto.
+	StartAt pb.StartPosition
+	// Optional start sequence number.
+	StartSequence uint64
+	// Optional start time.
+	StartTime time.Time
+	// Option to do Manual Acks
+	ManualAcks bool
+}
+
+// DefaultSubscriptionOptions are the default subscriptions' options
+var DefaultSubscriptionOptions = SubscriptionOptions{
+	MaxInflight: DefaultMaxInflight,
+	AckWait:     DefaultAckWait,
+}
+
+// MaxInflight is an Option to set the maximum number of messages the cluster will send
+// without an ACK.
+func MaxInflight(m int) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.MaxInflight = m
+		return nil
+	}
+}
+
+// AckWait is an Option to set the timeout for waiting for an ACK from the cluster's
+// point of view for delivered messages.
+func AckWait(t time.Duration) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.AckWait = t
+		return nil
+	}
+}
+
+// StartAt sets the desired start position for the message stream.
+func StartAt(sp pb.StartPosition) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.StartAt = sp
+		return nil
+	}
+}
+
+// StartAtSequence sets the desired start sequence position and state.
+func StartAtSequence(seq uint64) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.StartAt = pb.StartPosition_SequenceStart
+		o.StartSequence = seq
+		return nil
+	}
+}
+
+// StartAtTime sets the desired start time position and state.
+func StartAtTime(start time.Time) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.StartAt = pb.StartPosition_TimeDeltaStart
+		o.StartTime = start
+		return nil
+	}
+}
+
+// StartAtTimeDelta sets the desired start time position and state using the delta.
+func StartAtTimeDelta(ago time.Duration) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.StartAt = pb.StartPosition_TimeDeltaStart
+		o.StartTime = time.Now().Add(-ago)
+		return nil
+	}
+}
+
+// StartWithLastReceived is a helper function to set start position to last received.
+func StartWithLastReceived() SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.StartAt = pb.StartPosition_LastReceived
+		return nil
+	}
+}
+
+// DeliverAllAvailable will deliver all messages available.
+func DeliverAllAvailable() SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.StartAt = pb.StartPosition_First
+		return nil
+	}
+}
+
+// SetManualAckMode will allow clients to control their own acks to delivered messages.
+func SetManualAckMode() SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.ManualAcks = true
+		return nil
+	}
+}
+
+// DurableName sets the DurableName for the subcriber.
+func DurableName(name string) SubscriptionOption {
+	return func(o *SubscriptionOptions) error {
+		o.DurableName = name
+		return nil
+	}
+}
+
+// Subscribe will perform a subscription with the given options to the NATS Streaming cluster.
+func (sc *conn) Subscribe(subject string, cb MsgHandler, options ...SubscriptionOption) (Subscription, error) {
+	return sc.subscribe(subject, "", cb, options...)
+}
+
+// QueueSubscribe will perform a queue subscription with the given options to the NATS Streaming cluster.
+func (sc *conn) QueueSubscribe(subject, qgroup string, cb MsgHandler, options ...SubscriptionOption) (Subscription, error) {
+	return sc.subscribe(subject, qgroup, cb, options...)
+}
+
+// subscribe will perform a subscription with the given options to the NATS Streaming cluster.
+func (sc *conn) subscribe(subject, qgroup string, cb MsgHandler, options ...SubscriptionOption) (Subscription, error) {
+	sub := &subscription{subject: subject, qgroup: qgroup, inbox: nats.NewInbox(), cb: cb, sc: sc, opts: DefaultSubscriptionOptions}
+	for _, opt := range options {
+		if err := opt(&sub.opts); err != nil {
+			return nil, err
+		}
+	}
+	sc.Lock()
+	if sc.nc == nil {
+		sc.Unlock()
+		return nil, ErrConnectionClosed
+	}
+
+	// Register subscription.
+	sc.subMap[sub.inbox] = sub
+	nc := sc.nc
+	sc.Unlock()
+
+	// Hold lock throughout.
+	sub.Lock()
+	defer sub.Unlock()
+
+	// Listen for actual messages.
+	nsub, err := nc.Subscribe(sub.inbox, sc.processMsg)
+	if err != nil {
+		return nil, err
+	}
+	sub.inboxSub = nsub
+
+	// Create a subscription request
+	// FIXME(dlc) add others.
+	sr := &pb.SubscriptionRequest{
+		ClientID:      sc.clientID,
+		Subject:       subject,
+		QGroup:        qgroup,
+		Inbox:         sub.inbox,
+		MaxInFlight:   int32(sub.opts.MaxInflight),
+		AckWaitInSecs: int32(sub.opts.AckWait / time.Second),
+		StartPosition: sub.opts.StartAt,
+		DurableName:   sub.opts.DurableName,
+	}
+
+	// Conditionals
+	switch sr.StartPosition {
+	case pb.StartPosition_TimeDeltaStart:
+		sr.StartTimeDelta = time.Now().UnixNano() - sub.opts.StartTime.UnixNano()
+	case pb.StartPosition_SequenceStart:
+		sr.StartSequence = sub.opts.StartSequence
+	}
+
+	b, _ := sr.Marshal()
+	reply, err := sc.nc.Request(sc.subRequests, b, sc.opts.ConnectTimeout)
+	if err != nil {
+		sub.inboxSub.Unsubscribe()
+		if err == nats.ErrTimeout {
+			err = ErrSubReqTimeout
+		}
+		return nil, err
+	}
+	r := &pb.SubscriptionResponse{}
+	if err := r.Unmarshal(reply.Data); err != nil {
+		sub.inboxSub.Unsubscribe()
+		return nil, err
+	}
+	if r.Error != "" {
+		sub.inboxSub.Unsubscribe()
+		return nil, errors.New(r.Error)
+	}
+	sub.ackInbox = r.AckInbox
+
+	return sub, nil
+}
+
+// ClearMaxPending resets the maximums seen so far.
+func (sub *subscription) ClearMaxPending() error {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return ErrBadSubscription
+	}
+	return sub.inboxSub.ClearMaxPending()
+}
+
+// Delivered returns the number of delivered messages for this subscription.
+func (sub *subscription) Delivered() (int64, error) {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return -1, ErrBadSubscription
+	}
+	return sub.inboxSub.Delivered()
+}
+
+// Dropped returns the number of known dropped messages for this subscription.
+// This will correspond to messages dropped by violations of PendingLimits. If
+// the server declares the connection a SlowConsumer, this number may not be
+// valid.
+func (sub *subscription) Dropped() (int, error) {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return -1, ErrBadSubscription
+	}
+	return sub.inboxSub.Dropped()
+}
+
+// IsValid returns a boolean indicating whether the subscription
+// is still active. This will return false if the subscription has
+// already been closed.
+func (sub *subscription) IsValid() bool {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return false
+	}
+	return sub.inboxSub.IsValid()
+}
+
+// MaxPending returns the maximum number of queued messages and queued bytes seen so far.
+func (sub *subscription) MaxPending() (int, int, error) {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return -1, -1, ErrBadSubscription
+	}
+	return sub.inboxSub.MaxPending()
+}
+
+// Pending returns the number of queued messages and queued bytes in the client for this subscription.
+func (sub *subscription) Pending() (int, int, error) {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return -1, -1, ErrBadSubscription
+	}
+	return sub.inboxSub.Pending()
+}
+
+// PendingLimits returns the current limits for this subscription.
+// If no error is returned, a negative value indicates that the
+// given metric is not limited.
+func (sub *subscription) PendingLimits() (int, int, error) {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return -1, -1, ErrBadSubscription
+	}
+	return sub.inboxSub.PendingLimits()
+}
+
+// SetPendingLimits sets the limits for pending msgs and bytes for this subscription.
+// Zero is not allowed. Any negative value means that the given metric is not limited.
+func (sub *subscription) SetPendingLimits(msgLimit, bytesLimit int) error {
+	sub.Lock()
+	defer sub.Unlock()
+	if sub.inboxSub == nil {
+		return ErrBadSubscription
+	}
+	return sub.inboxSub.SetPendingLimits(msgLimit, bytesLimit)
+}
+
+// closeOrUnsubscribe performs either close or unsubsribe based on
+// given boolean.
+func (sub *subscription) closeOrUnsubscribe(doClose bool) error {
+	sub.Lock()
+	sc := sub.sc
+	if sc == nil {
+		// Already closed.
+		sub.Unlock()
+		return ErrBadSubscription
+	}
+	sub.sc = nil
+	sub.inboxSub.Unsubscribe()
+	sub.inboxSub = nil
+	sub.Unlock()
+
+	sc.Lock()
+	if sc.nc == nil {
+		sc.Unlock()
+		return ErrConnectionClosed
+	}
+
+	delete(sc.subMap, sub.inbox)
+	reqSubject := sc.unsubRequests
+	if doClose {
+		reqSubject = sc.subCloseRequests
+		if reqSubject == "" {
+			sc.Unlock()
+			return ErrNoServerSupport
+		}
+	}
+
+	// Snapshot connection to avoid data race, since the connection may be
+	// closing while we try to send the request
+	nc := sc.nc
+	sc.Unlock()
+
+	usr := &pb.UnsubscribeRequest{
+		ClientID: sc.clientID,
+		Subject:  sub.subject,
+		Inbox:    sub.ackInbox,
+	}
+	b, _ := usr.Marshal()
+	reply, err := nc.Request(reqSubject, b, sc.opts.ConnectTimeout)
+	if err != nil {
+		if err == nats.ErrTimeout {
+			if doClose {
+				return ErrCloseReqTimeout
+			}
+			return ErrUnsubReqTimeout
+		}
+		return err
+	}
+	r := &pb.SubscriptionResponse{}
+	if err := r.Unmarshal(reply.Data); err != nil {
+		return err
+	}
+	if r.Error != "" {
+		return errors.New(r.Error)
+	}
+
+	return nil
+}
+
+// Unsubscribe implements the Subscription interface
+func (sub *subscription) Unsubscribe() error {
+	return sub.closeOrUnsubscribe(false)
+}
+
+// Close implements the Subscription interface
+func (sub *subscription) Close() error {
+	return sub.closeOrUnsubscribe(true)
+}
+
+// Ack manually acknowledges a message.
+// The subscriber had to be created with SetManualAckMode() option.
+func (msg *Msg) Ack() error {
+	if msg == nil {
+		return ErrNilMsg
+	}
+	// Look up subscription (cannot be nil)
+	sub := msg.Sub.(*subscription)
+	sub.RLock()
+	ackSubject := sub.ackInbox
+	isManualAck := sub.opts.ManualAcks
+	sc := sub.sc
+	sub.RUnlock()
+
+	// Check for error conditions.
+	if !isManualAck {
+		return ErrManualAck
+	}
+	if sc == nil {
+		return ErrBadSubscription
+	}
+	// Get nc from the connection (needs locking to avoid race)
+	sc.RLock()
+	nc := sc.nc
+	sc.RUnlock()
+	if nc == nil {
+		return ErrBadConnection
+	}
+
+	// Ack here.
+	ack := &pb.Ack{Subject: msg.Subject, Sequence: msg.Sequence}
+	b, _ := ack.Marshal()
+	return nc.Publish(ackSubject, b)
+}

gateway/vendor/github.com/nats-io/go-nats/LICENSE

@@ -0,0 +1,20 @@
+The MIT License (MIT)
+
+Copyright (c) 2012-2016 Apcera Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy of
+this software and associated documentation files (the "Software"), to deal in
+the Software without restriction, including without limitation the rights to
+use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of
+the Software, and to permit persons to whom the Software is furnished to do so,
+subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS
+FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR
+COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER
+IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

gateway/vendor/github.com/nats-io/go-nats/README.md

@@ -0,0 +1,350 @@
+# NATS - Go Client
+A [Go](http://golang.org) client for the [NATS messaging system](https://nats.io).
+
+[![License MIT](https://img.shields.io/badge/License-MIT-blue.svg)](http://opensource.org/licenses/MIT)
+[![Go Report Card](https://goreportcard.com/badge/github.com/nats-io/go-nats)](https://goreportcard.com/report/github.com/nats-io/go-nats) [![Build Status](https://travis-ci.org/nats-io/go-nats.svg?branch=master)](http://travis-ci.org/nats-io/go-nats) [![GoDoc](https://godoc.org/github.com/nats-io/go-nats?status.svg)](http://godoc.org/github.com/nats-io/go-nats) [![Coverage Status](https://coveralls.io/repos/nats-io/go-nats/badge.svg?branch=master)](https://coveralls.io/r/nats-io/go-nats?branch=master)
+
+## Installation
+
+```bash
+# Go client
+go get github.com/nats-io/go-nats
+
+# Server
+go get github.com/nats-io/gnatsd
+```
+
+## Basic Usage
+
+```go
+
+nc, _ := nats.Connect(nats.DefaultURL)
+
+// Simple Publisher
+nc.Publish("foo", []byte("Hello World"))
+
+// Simple Async Subscriber
+nc.Subscribe("foo", func(m *nats.Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+})
+
+// Simple Sync Subscriber
+sub, err := nc.SubscribeSync("foo")
+m, err := sub.NextMsg(timeout)
+
+// Channel Subscriber
+ch := make(chan *nats.Msg, 64)
+sub, err := nc.ChanSubscribe("foo", ch)
+msg := <- ch
+
+// Unsubscribe
+sub.Unsubscribe()
+
+// Requests
+msg, err := nc.Request("help", []byte("help me"), 10*time.Millisecond)
+
+// Replies
+nc.Subscribe("help", func(m *Msg) {
+    nc.Publish(m.Reply, []byte("I can help!"))
+})
+
+// Close connection
+nc, _ := nats.Connect("nats://localhost:4222")
+nc.Close();
+```
+
+## Encoded Connections
+
+```go
+
+nc, _ := nats.Connect(nats.DefaultURL)
+c, _ := nats.NewEncodedConn(nc, nats.JSON_ENCODER)
+defer c.Close()
+
+// Simple Publisher
+c.Publish("foo", "Hello World")
+
+// Simple Async Subscriber
+c.Subscribe("foo", func(s string) {
+    fmt.Printf("Received a message: %s\n", s)
+})
+
+// EncodedConn can Publish any raw Go type using the registered Encoder
+type person struct {
+     Name     string
+     Address  string
+     Age      int
+}
+
+// Go type Subscriber
+c.Subscribe("hello", func(p *person) {
+    fmt.Printf("Received a person: %+v\n", p)
+})
+
+me := &person{Name: "derek", Age: 22, Address: "140 New Montgomery Street, San Francisco, CA"}
+
+// Go type Publisher
+c.Publish("hello", me)
+
+// Unsubscribe
+sub, err := c.Subscribe("foo", nil)
+...
+sub.Unsubscribe()
+
+// Requests
+var response string
+err := c.Request("help", "help me", &response, 10*time.Millisecond)
+if err != nil {
+    fmt.Printf("Request failed: %v\n", err)
+}
+
+// Replying
+c.Subscribe("help", func(subj, reply string, msg string) {
+    c.Publish(reply, "I can help!")
+})
+
+// Close connection
+c.Close();
+```
+
+## TLS
+
+```go
+// tls as a scheme will enable secure connections by default. This will also verify the server name.
+nc, err := nats.Connect("tls://nats.demo.io:4443")
+
+// If you are using a self-signed certificate, you need to have a tls.Config with RootCAs setup.
+// We provide a helper method to make this case easier.
+nc, err = nats.Connect("tls://localhost:4443", nats.RootCAs("./configs/certs/ca.pem"))
+
+// If the server requires client certificate, there is an helper function for that too:
+cert := nats.ClientCert("./configs/certs/client-cert.pem", "./configs/certs/client-key.pem")
+nc, err = nats.Connect("tls://localhost:4443", cert)
+
+// You can also supply a complete tls.Config
+
+certFile := "./configs/certs/client-cert.pem"
+keyFile := "./configs/certs/client-key.pem"
+cert, err := tls.LoadX509KeyPair(certFile, keyFile)
+if err != nil {
+    t.Fatalf("error parsing X509 certificate/key pair: %v", err)
+}
+
+config := &tls.Config{
+    ServerName: 	opts.Host,
+    Certificates: 	[]tls.Certificate{cert},
+    RootCAs:    	pool,
+    MinVersion: 	tls.VersionTLS12,
+}
+
+nc, err = nats.Connect("nats://localhost:4443", nats.Secure(config))
+if err != nil {
+	t.Fatalf("Got an error on Connect with Secure Options: %+v\n", err)
+}
+
+```
+
+## Using Go Channels (netchan)
+
+```go
+nc, _ := nats.Connect(nats.DefaultURL)
+ec, _ := nats.NewEncodedConn(nc, nats.JSON_ENCODER)
+defer ec.Close()
+
+type person struct {
+     Name     string
+     Address  string
+     Age      int
+}
+
+recvCh := make(chan *person)
+ec.BindRecvChan("hello", recvCh)
+
+sendCh := make(chan *person)
+ec.BindSendChan("hello", sendCh)
+
+me := &person{Name: "derek", Age: 22, Address: "140 New Montgomery Street"}
+
+// Send via Go channels
+sendCh <- me
+
+// Receive via Go channels
+who := <- recvCh
+```
+
+## Wildcard Subscriptions
+
+```go
+
+// "*" matches any token, at any level of the subject.
+nc.Subscribe("foo.*.baz", func(m *Msg) {
+    fmt.Printf("Msg received on [%s] : %s\n", m.Subject, string(m.Data));
+})
+
+nc.Subscribe("foo.bar.*", func(m *Msg) {
+    fmt.Printf("Msg received on [%s] : %s\n", m.Subject, string(m.Data));
+})
+
+// ">" matches any length of the tail of a subject, and can only be the last token
+// E.g. 'foo.>' will match 'foo.bar', 'foo.bar.baz', 'foo.foo.bar.bax.22'
+nc.Subscribe("foo.>", func(m *Msg) {
+    fmt.Printf("Msg received on [%s] : %s\n", m.Subject, string(m.Data));
+})
+
+// Matches all of the above
+nc.Publish("foo.bar.baz", []byte("Hello World"))
+
+```
+
+## Queue Groups
+
+```go
+// All subscriptions with the same queue name will form a queue group.
+// Each message will be delivered to only one subscriber per queue group,
+// using queuing semantics. You can have as many queue groups as you wish.
+// Normal subscribers will continue to work as expected.
+
+nc.QueueSubscribe("foo", "job_workers", func(_ *Msg) {
+  received += 1;
+})
+
+```
+
+## Advanced Usage
+
+```go
+
+// Flush connection to server, returns when all messages have been processed.
+nc.Flush()
+fmt.Println("All clear!")
+
+// FlushTimeout specifies a timeout value as well.
+err := nc.FlushTimeout(1*time.Second)
+if err != nil {
+    fmt.Println("All clear!")
+} else {
+    fmt.Println("Flushed timed out!")
+}
+
+// Auto-unsubscribe after MAX_WANTED messages received
+const MAX_WANTED = 10
+sub, err := nc.Subscribe("foo")
+sub.AutoUnsubscribe(MAX_WANTED)
+
+// Multiple connections
+nc1 := nats.Connect("nats://host1:4222")
+nc2 := nats.Connect("nats://host2:4222")
+
+nc1.Subscribe("foo", func(m *Msg) {
+    fmt.Printf("Received a message: %s\n", string(m.Data))
+})
+
+nc2.Publish("foo", []byte("Hello World!"));
+
+```
+
+## Clustered Usage
+
+```go
+
+var servers = "nats://localhost:1222, nats://localhost:1223, nats://localhost:1224"
+
+nc, err := nats.Connect(servers)
+
+// Optionally set ReconnectWait and MaxReconnect attempts.
+// This example means 10 seconds total per backend.
+nc, err = nats.Connect(servers, nats.MaxReconnects(5), nats.ReconnectWait(2 * time.Second))
+
+// Optionally disable randomization of the server pool
+nc, err = nats.Connect(servers, nats.DontRandomize())
+
+// Setup callbacks to be notified on disconnects, reconnects and connection closed.
+nc, err = nats.Connect(servers,
+	nats.DisconnectHandler(func(nc *nats.Conn) {
+		fmt.Printf("Got disconnected!\n")
+	}),
+	nats.ReconnectHandler(func(_ *nats.Conn) {
+		fmt.Printf("Got reconnected to %v!\n", nc.ConnectedUrl())
+	}),
+	nats.ClosedHandler(func(nc *nats.Conn) {
+		fmt.Printf("Connection closed. Reason: %q\n", nc.LastError())
+	})
+)
+
+// When connecting to a mesh of servers with auto-discovery capabilities,
+// you may need to provide a username/password or token in order to connect
+// to any server in that mesh when authentication is required.
+// Instead of providing the credentials in the initial URL, you will use
+// new option setters:
+nc, err = nats.Connect("nats://localhost:4222", nats.UserInfo("foo", "bar"))
+
+// For token based authentication:
+nc, err = nats.Connect("nats://localhost:4222", nats.Token("S3cretT0ken"))
+
+// You can even pass the two at the same time in case one of the server
+// in the mesh requires token instead of user name and password.
+nc, err = nats.Connect("nats://localhost:4222",
+    nats.UserInfo("foo", "bar"),
+    nats.Token("S3cretT0ken"))
+
+// Note that if credentials are specified in the initial URLs, they take
+// precedence on the credentials specfied through the options.
+// For instance, in the connect call below, the client library will use
+// the user "my" and password "pwd" to connect to locahost:4222, however,
+// it will use username "foo" and password "bar" when (re)connecting to
+// a different server URL that it got as part of the auto-discovery.
+nc, err = nats.Connect("nats://my:pwd@localhost:4222", nats.UserInfo("foo", "bar"))
+
+```
+
+## Context support (+Go 1.7)
+
+```go
+ctx, cancel := context.WithTimeout(context.Background(), 2*time.Second)
+defer cancel()
+
+nc, err := nats.Connect(nats.DefaultURL)
+
+// Request with context
+msg, err := nc.RequestWithContext(ctx, "foo", []byte("bar"))
+
+// Synchronous subscriber with context
+sub, err := nc.SubscribeSync("foo")
+msg, err := sub.NextMsgWithContext(ctx)
+
+// Encoded Request with context
+c, err := nats.NewEncodedConn(nc, nats.JSON_ENCODER)
+type request struct {
+	Message string `json:"message"`
+}
+type response struct {
+	Code int `json:"code"`
+}
+req := &request{Message: "Hello"}
+resp := &response{}
+err := c.RequestWithContext(ctx, "foo", req, resp)
+```
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2012-2017 Apcera Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.

gateway/vendor/github.com/nats-io/go-nats/context.go

@@ -0,0 +1,166 @@
+// Copyright 2012-2017 Apcera Inc. All rights reserved.
+
+// +build go1.7
+
+// A Go client for the NATS messaging system (https://nats.io).
+package nats
+
+import (
+	"context"
+	"fmt"
+	"reflect"
+)
+
+// RequestWithContext takes a context, a subject and payload
+// in bytes and request expecting a single response.
+func (nc *Conn) RequestWithContext(ctx context.Context, subj string, data []byte) (*Msg, error) {
+	if ctx == nil {
+		return nil, ErrInvalidContext
+	}
+	if nc == nil {
+		return nil, ErrInvalidConnection
+	}
+
+	nc.mu.Lock()
+	// If user wants the old style.
+	if nc.Opts.UseOldRequestStyle {
+		nc.mu.Unlock()
+		return nc.oldRequestWithContext(ctx, subj, data)
+	}
+
+	// Do setup for the new style.
+	if nc.respMap == nil {
+		// _INBOX wildcard
+		nc.respSub = fmt.Sprintf("%s.*", NewInbox())
+		nc.respMap = make(map[string]chan *Msg)
+	}
+	// Create literal Inbox and map to a chan msg.
+	mch := make(chan *Msg, RequestChanLen)
+	respInbox := nc.newRespInbox()
+	token := respToken(respInbox)
+	nc.respMap[token] = mch
+	createSub := nc.respMux == nil
+	ginbox := nc.respSub
+	nc.mu.Unlock()
+
+	if createSub {
+		// Make sure scoped subscription is setup only once.
+		var err error
+		nc.respSetup.Do(func() { err = nc.createRespMux(ginbox) })
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	err := nc.PublishRequest(subj, respInbox, data)
+	if err != nil {
+		return nil, err
+	}
+
+	var ok bool
+	var msg *Msg
+
+	select {
+	case msg, ok = <-mch:
+		if !ok {
+			return nil, ErrConnectionClosed
+		}
+	case <-ctx.Done():
+		nc.mu.Lock()
+		delete(nc.respMap, token)
+		nc.mu.Unlock()
+		return nil, ctx.Err()
+	}
+
+	return msg, nil
+}
+
+// oldRequestWithContext utilizes inbox and subscription per request.
+func (nc *Conn) oldRequestWithContext(ctx context.Context, subj string, data []byte) (*Msg, error) {
+	inbox := NewInbox()
+	ch := make(chan *Msg, RequestChanLen)
+
+	s, err := nc.subscribe(inbox, _EMPTY_, nil, ch)
+	if err != nil {
+		return nil, err
+	}
+	s.AutoUnsubscribe(1)
+	defer s.Unsubscribe()
+
+	err = nc.PublishRequest(subj, inbox, data)
+	if err != nil {
+		return nil, err
+	}
+
+	return s.NextMsgWithContext(ctx)
+}
+
+// NextMsgWithContext takes a context and returns the next message
+// available to a synchronous subscriber, blocking until it is delivered
+// or context gets canceled.
+func (s *Subscription) NextMsgWithContext(ctx context.Context) (*Msg, error) {
+	if ctx == nil {
+		return nil, ErrInvalidContext
+	}
+	if s == nil {
+		return nil, ErrBadSubscription
+	}
+
+	s.mu.Lock()
+	err := s.validateNextMsgState()
+	if err != nil {
+		s.mu.Unlock()
+		return nil, err
+	}
+
+	// snapshot
+	mch := s.mch
+	s.mu.Unlock()
+
+	var ok bool
+	var msg *Msg
+
+	select {
+	case msg, ok = <-mch:
+		if !ok {
+			return nil, ErrConnectionClosed
+		}
+		err := s.processNextMsgDelivered(msg)
+		if err != nil {
+			return nil, err
+		}
+	case <-ctx.Done():
+		return nil, ctx.Err()
+	}
+
+	return msg, nil
+}
+
+// RequestWithContext will create an Inbox and perform a Request
+// using the provided cancellation context with the Inbox reply
+// for the data v. A response will be decoded into the vPtrResponse.
+func (c *EncodedConn) RequestWithContext(ctx context.Context, subject string, v interface{}, vPtr interface{}) error {
+	if ctx == nil {
+		return ErrInvalidContext
+	}
+
+	b, err := c.Enc.Encode(subject, v)
+	if err != nil {
+		return err
+	}
+	m, err := c.Conn.RequestWithContext(ctx, subject, b)
+	if err != nil {
+		return err
+	}
+	if reflect.TypeOf(vPtr) == emptyMsgType {
+		mPtr := vPtr.(*Msg)
+		*mPtr = *m
+	} else {
+		err := c.Enc.Decode(m.Subject, m.Data, vPtr)
+		if err != nil {
+			return err
+		}
+	}
+
+	return nil
+}

gateway/vendor/github.com/nats-io/go-nats/enc.go

@@ -0,0 +1,249 @@
+// Copyright 2012-2015 Apcera Inc. All rights reserved.
+
+package nats
+
+import (
+	"errors"
+	"fmt"
+	"reflect"
+	"sync"
+	"time"
+
+	// Default Encoders
+	. "github.com/nats-io/go-nats/encoders/builtin"
+)
+
+// Encoder interface is for all register encoders
+type Encoder interface {
+	Encode(subject string, v interface{}) ([]byte, error)
+	Decode(subject string, data []byte, vPtr interface{}) error
+}
+
+var encMap map[string]Encoder
+var encLock sync.Mutex
+
+// Indexe names into the Registered Encoders.
+const (
+	JSON_ENCODER    = "json"
+	GOB_ENCODER     = "gob"
+	DEFAULT_ENCODER = "default"
+)
+
+func init() {
+	encMap = make(map[string]Encoder)
+	// Register json, gob and default encoder
+	RegisterEncoder(JSON_ENCODER, &JsonEncoder{})
+	RegisterEncoder(GOB_ENCODER, &GobEncoder{})
+	RegisterEncoder(DEFAULT_ENCODER, &DefaultEncoder{})
+}
+
+// EncodedConn are the preferred way to interface with NATS. They wrap a bare connection to
+// a nats server and have an extendable encoder system that will encode and decode messages
+// from raw Go types.
+type EncodedConn struct {
+	Conn *Conn
+	Enc  Encoder
+}
+
+// NewEncodedConn will wrap an existing Connection and utilize the appropriate registered
+// encoder.
+func NewEncodedConn(c *Conn, encType string) (*EncodedConn, error) {
+	if c == nil {
+		return nil, errors.New("nats: Nil Connection")
+	}
+	if c.IsClosed() {
+		return nil, ErrConnectionClosed
+	}
+	ec := &EncodedConn{Conn: c, Enc: EncoderForType(encType)}
+	if ec.Enc == nil {
+		return nil, fmt.Errorf("No encoder registered for '%s'", encType)
+	}
+	return ec, nil
+}
+
+// RegisterEncoder will register the encType with the given Encoder. Useful for customization.
+func RegisterEncoder(encType string, enc Encoder) {
+	encLock.Lock()
+	defer encLock.Unlock()
+	encMap[encType] = enc
+}
+
+// EncoderForType will return the registered Encoder for the encType.
+func EncoderForType(encType string) Encoder {
+	encLock.Lock()
+	defer encLock.Unlock()
+	return encMap[encType]
+}
+
+// Publish publishes the data argument to the given subject. The data argument
+// will be encoded using the associated encoder.
+func (c *EncodedConn) Publish(subject string, v interface{}) error {
+	b, err := c.Enc.Encode(subject, v)
+	if err != nil {
+		return err
+	}
+	return c.Conn.publish(subject, _EMPTY_, b)
+}
+
+// PublishRequest will perform a Publish() expecting a response on the
+// reply subject. Use Request() for automatically waiting for a response
+// inline.
+func (c *EncodedConn) PublishRequest(subject, reply string, v interface{}) error {
+	b, err := c.Enc.Encode(subject, v)
+	if err != nil {
+		return err
+	}
+	return c.Conn.publish(subject, reply, b)
+}
+
+// Request will create an Inbox and perform a Request() call
+// with the Inbox reply for the data v. A response will be
+// decoded into the vPtrResponse.
+func (c *EncodedConn) Request(subject string, v interface{}, vPtr interface{}, timeout time.Duration) error {
+	b, err := c.Enc.Encode(subject, v)
+	if err != nil {
+		return err
+	}
+	m, err := c.Conn.Request(subject, b, timeout)
+	if err != nil {
+		return err
+	}
+	if reflect.TypeOf(vPtr) == emptyMsgType {
+		mPtr := vPtr.(*Msg)
+		*mPtr = *m
+	} else {
+		err = c.Enc.Decode(m.Subject, m.Data, vPtr)
+	}
+	return err
+}
+
+// Handler is a specific callback used for Subscribe. It is generalized to
+// an interface{}, but we will discover its format and arguments at runtime
+// and perform the correct callback, including de-marshaling JSON strings
+// back into the appropriate struct based on the signature of the Handler.
+//
+// Handlers are expected to have one of four signatures.
+//
+//	type person struct {
+//		Name string `json:"name,omitempty"`
+//		Age  uint   `json:"age,omitempty"`
+//	}
+//
+//	handler := func(m *Msg)
+//	handler := func(p *person)
+//	handler := func(subject string, o *obj)
+//	handler := func(subject, reply string, o *obj)
+//
+// These forms allow a callback to request a raw Msg ptr, where the processing
+// of the message from the wire is untouched. Process a JSON representation
+// and demarshal it into the given struct, e.g. person.
+// There are also variants where the callback wants either the subject, or the
+// subject and the reply subject.
+type Handler interface{}
+
+// Dissect the cb Handler's signature
+func argInfo(cb Handler) (reflect.Type, int) {
+	cbType := reflect.TypeOf(cb)
+	if cbType.Kind() != reflect.Func {
+		panic("nats: Handler needs to be a func")
+	}
+	numArgs := cbType.NumIn()
+	if numArgs == 0 {
+		return nil, numArgs
+	}
+	return cbType.In(numArgs - 1), numArgs
+}
+
+var emptyMsgType = reflect.TypeOf(&Msg{})
+
+// Subscribe will create a subscription on the given subject and process incoming
+// messages using the specified Handler. The Handler should be a func that matches
+// a signature from the description of Handler from above.
+func (c *EncodedConn) Subscribe(subject string, cb Handler) (*Subscription, error) {
+	return c.subscribe(subject, _EMPTY_, cb)
+}
+
+// QueueSubscribe will create a queue subscription on the given subject and process
+// incoming messages using the specified Handler. The Handler should be a func that
+// matches a signature from the description of Handler from above.
+func (c *EncodedConn) QueueSubscribe(subject, queue string, cb Handler) (*Subscription, error) {
+	return c.subscribe(subject, queue, cb)
+}
+
+// Internal implementation that all public functions will use.
+func (c *EncodedConn) subscribe(subject, queue string, cb Handler) (*Subscription, error) {
+	if cb == nil {
+		return nil, errors.New("nats: Handler required for EncodedConn Subscription")
+	}
+	argType, numArgs := argInfo(cb)
+	if argType == nil {
+		return nil, errors.New("nats: Handler requires at least one argument")
+	}
+
+	cbValue := reflect.ValueOf(cb)
+	wantsRaw := (argType == emptyMsgType)
+
+	natsCB := func(m *Msg) {
+		var oV []reflect.Value
+		if wantsRaw {
+			oV = []reflect.Value{reflect.ValueOf(m)}
+		} else {
+			var oPtr reflect.Value
+			if argType.Kind() != reflect.Ptr {
+				oPtr = reflect.New(argType)
+			} else {
+				oPtr = reflect.New(argType.Elem())
+			}
+			if err := c.Enc.Decode(m.Subject, m.Data, oPtr.Interface()); err != nil {
+				if c.Conn.Opts.AsyncErrorCB != nil {
+					c.Conn.ach <- func() {
+						c.Conn.Opts.AsyncErrorCB(c.Conn, m.Sub, errors.New("nats: Got an error trying to unmarshal: "+err.Error()))
+					}
+				}
+				return
+			}
+			if argType.Kind() != reflect.Ptr {
+				oPtr = reflect.Indirect(oPtr)
+			}
+
+			// Callback Arity
+			switch numArgs {
+			case 1:
+				oV = []reflect.Value{oPtr}
+			case 2:
+				subV := reflect.ValueOf(m.Subject)
+				oV = []reflect.Value{subV, oPtr}
+			case 3:
+				subV := reflect.ValueOf(m.Subject)
+				replyV := reflect.ValueOf(m.Reply)
+				oV = []reflect.Value{subV, replyV, oPtr}
+			}
+
+		}
+		cbValue.Call(oV)
+	}
+
+	return c.Conn.subscribe(subject, queue, natsCB, nil)
+}
+
+// FlushTimeout allows a Flush operation to have an associated timeout.
+func (c *EncodedConn) FlushTimeout(timeout time.Duration) (err error) {
+	return c.Conn.FlushTimeout(timeout)
+}
+
+// Flush will perform a round trip to the server and return when it
+// receives the internal reply.
+func (c *EncodedConn) Flush() error {
+	return c.Conn.Flush()
+}
+
+// Close will close the connection to the server. This call will release
+// all blocking calls, such as Flush(), etc.
+func (c *EncodedConn) Close() {
+	c.Conn.Close()
+}
+
+// LastError reports the last error encountered via the Connection.
+func (c *EncodedConn) LastError() error {
+	return c.Conn.err
+}

gateway/vendor/github.com/nats-io/go-nats/encoders/builtin/default_enc.go

@@ -0,0 +1,106 @@
+// Copyright 2012-2015 Apcera Inc. All rights reserved.
+
+package builtin
+
+import (
+	"bytes"
+	"fmt"
+	"reflect"
+	"strconv"
+	"unsafe"
+)
+
+// DefaultEncoder implementation for EncodedConn.
+// This encoder will leave []byte and string untouched, but will attempt to
+// turn numbers into appropriate strings that can be decoded. It will also
+// propely encoded and decode bools. If will encode a struct, but if you want
+// to properly handle structures you should use JsonEncoder.
+type DefaultEncoder struct {
+	// Empty
+}
+
+var trueB = []byte("true")
+var falseB = []byte("false")
+var nilB = []byte("")
+
+// Encode
+func (je *DefaultEncoder) Encode(subject string, v interface{}) ([]byte, error) {
+	switch arg := v.(type) {
+	case string:
+		bytes := *(*[]byte)(unsafe.Pointer(&arg))
+		return bytes, nil
+	case []byte:
+		return arg, nil
+	case bool:
+		if arg {
+			return trueB, nil
+		} else {
+			return falseB, nil
+		}
+	case nil:
+		return nilB, nil
+	default:
+		var buf bytes.Buffer
+		fmt.Fprintf(&buf, "%+v", arg)
+		return buf.Bytes(), nil
+	}
+}
+
+// Decode
+func (je *DefaultEncoder) Decode(subject string, data []byte, vPtr interface{}) error {
+	// Figure out what it's pointing to...
+	sData := *(*string)(unsafe.Pointer(&data))
+	switch arg := vPtr.(type) {
+	case *string:
+		*arg = sData
+		return nil
+	case *[]byte:
+		*arg = data
+		return nil
+	case *int:
+		n, err := strconv.ParseInt(sData, 10, 64)
+		if err != nil {
+			return err
+		}
+		*arg = int(n)
+		return nil
+	case *int32:
+		n, err := strconv.ParseInt(sData, 10, 64)
+		if err != nil {
+			return err
+		}
+		*arg = int32(n)
+		return nil
+	case *int64:
+		n, err := strconv.ParseInt(sData, 10, 64)
+		if err != nil {
+			return err
+		}
+		*arg = int64(n)
+		return nil
+	case *float32:
+		n, err := strconv.ParseFloat(sData, 32)
+		if err != nil {
+			return err
+		}
+		*arg = float32(n)
+		return nil
+	case *float64:
+		n, err := strconv.ParseFloat(sData, 64)
+		if err != nil {
+			return err
+		}
+		*arg = float64(n)
+		return nil
+	case *bool:
+		b, err := strconv.ParseBool(sData)
+		if err != nil {
+			return err
+		}
+		*arg = b
+		return nil
+	default:
+		vt := reflect.TypeOf(arg).Elem()
+		return fmt.Errorf("nats: Default Encoder can't decode to type %s", vt)
+	}
+}

gateway/vendor/github.com/nats-io/go-nats/encoders/builtin/gob_enc.go

@@ -0,0 +1,34 @@
+// Copyright 2013-2015 Apcera Inc. All rights reserved.
+
+package builtin
+
+import (
+	"bytes"
+	"encoding/gob"
+)
+
+// GobEncoder is a Go specific GOB Encoder implementation for EncodedConn.
+// This encoder will use the builtin encoding/gob to Marshal
+// and Unmarshal most types, including structs.
+type GobEncoder struct {
+	// Empty
+}
+
+// FIXME(dlc) - This could probably be more efficient.
+
+// Encode
+func (ge *GobEncoder) Encode(subject string, v interface{}) ([]byte, error) {
+	b := new(bytes.Buffer)
+	enc := gob.NewEncoder(b)
+	if err := enc.Encode(v); err != nil {
+		return nil, err
+	}
+	return b.Bytes(), nil
+}
+
+// Decode
+func (ge *GobEncoder) Decode(subject string, data []byte, vPtr interface{}) (err error) {
+	dec := gob.NewDecoder(bytes.NewBuffer(data))
+	err = dec.Decode(vPtr)
+	return
+}

gateway/vendor/github.com/nats-io/go-nats/encoders/builtin/json_enc.go

@@ -0,0 +1,45 @@
+// Copyright 2012-2015 Apcera Inc. All rights reserved.
+
+package builtin
+
+import (
+	"encoding/json"
+	"strings"
+)
+
+// JsonEncoder is a JSON Encoder implementation for EncodedConn.
+// This encoder will use the builtin encoding/json to Marshal
+// and Unmarshal most types, including structs.
+type JsonEncoder struct {
+	// Empty
+}
+
+// Encode
+func (je *JsonEncoder) Encode(subject string, v interface{}) ([]byte, error) {
+	b, err := json.Marshal(v)
+	if err != nil {
+		return nil, err
+	}
+	return b, nil
+}
+
+// Decode
+func (je *JsonEncoder) Decode(subject string, data []byte, vPtr interface{}) (err error) {
+	switch arg := vPtr.(type) {
+	case *string:
+		// If they want a string and it is a JSON string, strip quotes
+		// This allows someone to send a struct but receive as a plain string
+		// This cast should be efficient for Go 1.3 and beyond.
+		str := string(data)
+		if strings.HasPrefix(str, `"`) && strings.HasSuffix(str, `"`) {
+			*arg = str[1 : len(str)-1]
+		} else {
+			*arg = str
+		}
+	case *[]byte:
+		*arg = data
+	default:
+		err = json.Unmarshal(data, arg)
+	}
+	return
+}

gateway/vendor/github.com/nats-io/go-nats/netchan.go

@@ -0,0 +1,100 @@
+// Copyright 2013-2017 Apcera Inc. All rights reserved.
+
+package nats
+
+import (
+	"errors"
+	"reflect"
+)
+
+// This allows the functionality for network channels by binding send and receive Go chans
+// to subjects and optionally queue groups.
+// Data will be encoded and decoded via the EncodedConn and its associated encoders.
+
+// BindSendChan binds a channel for send operations to NATS.
+func (c *EncodedConn) BindSendChan(subject string, channel interface{}) error {
+	chVal := reflect.ValueOf(channel)
+	if chVal.Kind() != reflect.Chan {
+		return ErrChanArg
+	}
+	go chPublish(c, chVal, subject)
+	return nil
+}
+
+// Publish all values that arrive on the channel until it is closed or we
+// encounter an error.
+func chPublish(c *EncodedConn, chVal reflect.Value, subject string) {
+	for {
+		val, ok := chVal.Recv()
+		if !ok {
+			// Channel has most likely been closed.
+			return
+		}
+		if e := c.Publish(subject, val.Interface()); e != nil {
+			// Do this under lock.
+			c.Conn.mu.Lock()
+			defer c.Conn.mu.Unlock()
+
+			if c.Conn.Opts.AsyncErrorCB != nil {
+				// FIXME(dlc) - Not sure this is the right thing to do.
+				// FIXME(ivan) - If the connection is not yet closed, try to schedule the callback
+				if c.Conn.isClosed() {
+					go c.Conn.Opts.AsyncErrorCB(c.Conn, nil, e)
+				} else {
+					c.Conn.ach <- func() { c.Conn.Opts.AsyncErrorCB(c.Conn, nil, e) }
+				}
+			}
+			return
+		}
+	}
+}
+
+// BindRecvChan binds a channel for receive operations from NATS.
+func (c *EncodedConn) BindRecvChan(subject string, channel interface{}) (*Subscription, error) {
+	return c.bindRecvChan(subject, _EMPTY_, channel)
+}
+
+// BindRecvQueueChan binds a channel for queue-based receive operations from NATS.
+func (c *EncodedConn) BindRecvQueueChan(subject, queue string, channel interface{}) (*Subscription, error) {
+	return c.bindRecvChan(subject, queue, channel)
+}
+
+// Internal function to bind receive operations for a channel.
+func (c *EncodedConn) bindRecvChan(subject, queue string, channel interface{}) (*Subscription, error) {
+	chVal := reflect.ValueOf(channel)
+	if chVal.Kind() != reflect.Chan {
+		return nil, ErrChanArg
+	}
+	argType := chVal.Type().Elem()
+
+	cb := func(m *Msg) {
+		var oPtr reflect.Value
+		if argType.Kind() != reflect.Ptr {
+			oPtr = reflect.New(argType)
+		} else {
+			oPtr = reflect.New(argType.Elem())
+		}
+		if err := c.Enc.Decode(m.Subject, m.Data, oPtr.Interface()); err != nil {
+			c.Conn.err = errors.New("nats: Got an error trying to unmarshal: " + err.Error())
+			if c.Conn.Opts.AsyncErrorCB != nil {
+				c.Conn.ach <- func() { c.Conn.Opts.AsyncErrorCB(c.Conn, m.Sub, c.Conn.err) }
+			}
+			return
+		}
+		if argType.Kind() != reflect.Ptr {
+			oPtr = reflect.Indirect(oPtr)
+		}
+		// This is a bit hacky, but in this instance we may be trying to send to a closed channel.
+		// and the user does not know when it is safe to close the channel.
+		defer func() {
+			// If we have panicked, recover and close the subscription.
+			if r := recover(); r != nil {
+				m.Sub.Unsubscribe()
+			}
+		}()
+		// Actually do the send to the channel.
+		chVal.Send(oPtr)
+	}
+
+	return c.Conn.subscribe(subject, queue, cb, nil)
+}

gateway/vendor/github.com/nats-io/go-nats/parser.go

@@ -0,0 +1,470 @@
+// Copyright 2012-2017 Apcera Inc. All rights reserved.
+
+package nats
+
+import (
+	"fmt"
+)
+
+type msgArg struct {
+	subject []byte
+	reply   []byte
+	sid     int64
+	size    int
+}
+
+const MAX_CONTROL_LINE_SIZE = 1024
+
+type parseState struct {
+	state   int
+	as      int
+	drop    int
+	ma      msgArg
+	argBuf  []byte
+	msgBuf  []byte
+	scratch [MAX_CONTROL_LINE_SIZE]byte
+}
+
+const (
+	OP_START = iota
+	OP_PLUS
+	OP_PLUS_O
+	OP_PLUS_OK
+	OP_MINUS
+	OP_MINUS_E
+	OP_MINUS_ER
+	OP_MINUS_ERR
+	OP_MINUS_ERR_SPC
+	MINUS_ERR_ARG
+	OP_M
+	OP_MS
+	OP_MSG
+	OP_MSG_SPC
+	MSG_ARG
+	MSG_PAYLOAD
+	MSG_END
+	OP_P
+	OP_PI
+	OP_PIN
+	OP_PING
+	OP_PO
+	OP_PON
+	OP_PONG
+	OP_I
+	OP_IN
+	OP_INF
+	OP_INFO
+	OP_INFO_SPC
+	INFO_ARG
+)
+
+// parse is the fast protocol parser engine.
+func (nc *Conn) parse(buf []byte) error {
+	var i int
+	var b byte
+
+	// Move to loop instead of range syntax to allow jumping of i
+	for i = 0; i < len(buf); i++ {
+		b = buf[i]
+
+		switch nc.ps.state {
+		case OP_START:
+			switch b {
+			case 'M', 'm':
+				nc.ps.state = OP_M
+			case 'P', 'p':
+				nc.ps.state = OP_P
+			case '+':
+				nc.ps.state = OP_PLUS
+			case '-':
+				nc.ps.state = OP_MINUS
+			case 'I', 'i':
+				nc.ps.state = OP_I
+			default:
+				goto parseErr
+			}
+		case OP_M:
+			switch b {
+			case 'S', 's':
+				nc.ps.state = OP_MS
+			default:
+				goto parseErr
+			}
+		case OP_MS:
+			switch b {
+			case 'G', 'g':
+				nc.ps.state = OP_MSG
+			default:
+				goto parseErr
+			}
+		case OP_MSG:
+			switch b {
+			case ' ', '\t':
+				nc.ps.state = OP_MSG_SPC
+			default:
+				goto parseErr
+			}
+		case OP_MSG_SPC:
+			switch b {
+			case ' ', '\t':
+				continue
+			default:
+				nc.ps.state = MSG_ARG
+				nc.ps.as = i
+			}
+		case MSG_ARG:
+			switch b {
+			case '\r':
+				nc.ps.drop = 1
+			case '\n':
+				var arg []byte
+				if nc.ps.argBuf != nil {
+					arg = nc.ps.argBuf
+				} else {
+					arg = buf[nc.ps.as : i-nc.ps.drop]
+				}
+				if err := nc.processMsgArgs(arg); err != nil {
+					return err
+				}
+				nc.ps.drop, nc.ps.as, nc.ps.state = 0, i+1, MSG_PAYLOAD
+
+				// jump ahead with the index. If this overruns
+				// what is left we fall out and process split
+				// buffer.
+				i = nc.ps.as + nc.ps.ma.size - 1
+			default:
+				if nc.ps.argBuf != nil {
+					nc.ps.argBuf = append(nc.ps.argBuf, b)
+				}
+			}
+		case MSG_PAYLOAD:
+			if nc.ps.msgBuf != nil {
+				if len(nc.ps.msgBuf) >= nc.ps.ma.size {
+					nc.processMsg(nc.ps.msgBuf)
+					nc.ps.argBuf, nc.ps.msgBuf, nc.ps.state = nil, nil, MSG_END
+				} else {
+					// copy as much as we can to the buffer and skip ahead.
+					toCopy := nc.ps.ma.size - len(nc.ps.msgBuf)
+					avail := len(buf) - i
+
+					if avail < toCopy {
+						toCopy = avail
+					}
+
+					if toCopy > 0 {
+						start := len(nc.ps.msgBuf)
+						// This is needed for copy to work.
+						nc.ps.msgBuf = nc.ps.msgBuf[:start+toCopy]
+						copy(nc.ps.msgBuf[start:], buf[i:i+toCopy])
+						// Update our index
+						i = (i + toCopy) - 1
+					} else {
+						nc.ps.msgBuf = append(nc.ps.msgBuf, b)
+					}
+				}
+			} else if i-nc.ps.as >= nc.ps.ma.size {
+				nc.processMsg(buf[nc.ps.as:i])
+				nc.ps.argBuf, nc.ps.msgBuf, nc.ps.state = nil, nil, MSG_END
+			}
+		case MSG_END:
+			switch b {
+			case '\n':
+				nc.ps.drop, nc.ps.as, nc.ps.state = 0, i+1, OP_START
+			default:
+				continue
+			}
+		case OP_PLUS:
+			switch b {
+			case 'O', 'o':
+				nc.ps.state = OP_PLUS_O
+			default:
+				goto parseErr
+			}
+		case OP_PLUS_O:
+			switch b {
+			case 'K', 'k':
+				nc.ps.state = OP_PLUS_OK
+			default:
+				goto parseErr
+			}
+		case OP_PLUS_OK:
+			switch b {
+			case '\n':
+				nc.processOK()
+				nc.ps.drop, nc.ps.state = 0, OP_START
+			}
+		case OP_MINUS:
+			switch b {
+			case 'E', 'e':
+				nc.ps.state = OP_MINUS_E
+			default:
+				goto parseErr
+			}
+		case OP_MINUS_E:
+			switch b {
+			case 'R', 'r':
+				nc.ps.state = OP_MINUS_ER
+			default:
+				goto parseErr
+			}
+		case OP_MINUS_ER:
+			switch b {
+			case 'R', 'r':
+				nc.ps.state = OP_MINUS_ERR
+			default:
+				goto parseErr
+			}
+		case OP_MINUS_ERR:
+			switch b {
+			case ' ', '\t':
+				nc.ps.state = OP_MINUS_ERR_SPC
+			default:
+				goto parseErr
+			}
+		case OP_MINUS_ERR_SPC:
+			switch b {
+			case ' ', '\t':
+				continue
+			default:
+				nc.ps.state = MINUS_ERR_ARG
+				nc.ps.as = i
+			}
+		case MINUS_ERR_ARG:
+			switch b {
+			case '\r':
+				nc.ps.drop = 1
+			case '\n':
+				var arg []byte
+				if nc.ps.argBuf != nil {
+					arg = nc.ps.argBuf
+					nc.ps.argBuf = nil
+				} else {
+					arg = buf[nc.ps.as : i-nc.ps.drop]
+				}
+				nc.processErr(string(arg))
+				nc.ps.drop, nc.ps.as, nc.ps.state = 0, i+1, OP_START
+			default:
+				if nc.ps.argBuf != nil {
+					nc.ps.argBuf = append(nc.ps.argBuf, b)
+				}
+			}
+		case OP_P:
+			switch b {
+			case 'I', 'i':
+				nc.ps.state = OP_PI
+			case 'O', 'o':
+				nc.ps.state = OP_PO
+			default:
+				goto parseErr
+			}
+		case OP_PO:
+			switch b {
+			case 'N', 'n':
+				nc.ps.state = OP_PON
+			default:
+				goto parseErr
+			}
+		case OP_PON:
+			switch b {
+			case 'G', 'g':
+				nc.ps.state = OP_PONG
+			default:
+				goto parseErr
+			}
+		case OP_PONG:
+			switch b {
+			case '\n':
+				nc.processPong()
+				nc.ps.drop, nc.ps.state = 0, OP_START
+			}
+		case OP_PI:
+			switch b {
+			case 'N', 'n':
+				nc.ps.state = OP_PIN
+			default:
+				goto parseErr
+			}
+		case OP_PIN:
+			switch b {
+			case 'G', 'g':
+				nc.ps.state = OP_PING
+			default:
+				goto parseErr
+			}
+		case OP_PING:
+			switch b {
+			case '\n':
+				nc.processPing()
+				nc.ps.drop, nc.ps.state = 0, OP_START
+			}
+		case OP_I:
+			switch b {
+			case 'N', 'n':
+				nc.ps.state = OP_IN
+			default:
+				goto parseErr
+			}
+		case OP_IN:
+			switch b {
+			case 'F', 'f':
+				nc.ps.state = OP_INF
+			default:
+				goto parseErr
+			}
+		case OP_INF:
+			switch b {
+			case 'O', 'o':
+				nc.ps.state = OP_INFO
+			default:
+				goto parseErr
+			}
+		case OP_INFO:
+			switch b {
+			case ' ', '\t':
+				nc.ps.state = OP_INFO_SPC
+			default:
+				goto parseErr
+			}
+		case OP_INFO_SPC:
+			switch b {
+			case ' ', '\t':
+				continue
+			default:
+				nc.ps.state = INFO_ARG
+				nc.ps.as = i
+			}
+		case INFO_ARG:
+			switch b {
+			case '\r':
+				nc.ps.drop = 1
+			case '\n':
+				var arg []byte
+				if nc.ps.argBuf != nil {
+					arg = nc.ps.argBuf
+					nc.ps.argBuf = nil
+				} else {
+					arg = buf[nc.ps.as : i-nc.ps.drop]
+				}
+				nc.processAsyncInfo(arg)
+				nc.ps.drop, nc.ps.as, nc.ps.state = 0, i+1, OP_START
+			default:
+				if nc.ps.argBuf != nil {
+					nc.ps.argBuf = append(nc.ps.argBuf, b)
+				}
+			}
+		default:
+			goto parseErr
+		}
+	}
+	// Check for split buffer scenarios
+	if (nc.ps.state == MSG_ARG || nc.ps.state == MINUS_ERR_ARG || nc.ps.state == INFO_ARG) && nc.ps.argBuf == nil {
+		nc.ps.argBuf = nc.ps.scratch[:0]
+		nc.ps.argBuf = append(nc.ps.argBuf, buf[nc.ps.as:i-nc.ps.drop]...)
+		// FIXME, check max len
+	}
+	// Check for split msg
+	if nc.ps.state == MSG_PAYLOAD && nc.ps.msgBuf == nil {
+		// We need to clone the msgArg if it is still referencing the
+		// read buffer and we are not able to process the msg.
+		if nc.ps.argBuf == nil {
+			nc.cloneMsgArg()
+		}
+
+		// If we will overflow the scratch buffer, just create a
+		// new buffer to hold the split message.
+		if nc.ps.ma.size > cap(nc.ps.scratch)-len(nc.ps.argBuf) {
+			lrem := len(buf[nc.ps.as:])
+
+			nc.ps.msgBuf = make([]byte, lrem, nc.ps.ma.size)
+			copy(nc.ps.msgBuf, buf[nc.ps.as:])
+		} else {
+			nc.ps.msgBuf = nc.ps.scratch[len(nc.ps.argBuf):len(nc.ps.argBuf)]
+			nc.ps.msgBuf = append(nc.ps.msgBuf, (buf[nc.ps.as:])...)
+		}
+	}
+
+	return nil
+
+parseErr:
+	return fmt.Errorf("nats: Parse Error [%d]: '%s'", nc.ps.state, buf[i:])
+}
+
+// cloneMsgArg is used when the split buffer scenario has the pubArg in the existing read buffer, but
+// we need to hold onto it into the next read.
+func (nc *Conn) cloneMsgArg() {
+	nc.ps.argBuf = nc.ps.scratch[:0]
+	nc.ps.argBuf = append(nc.ps.argBuf, nc.ps.ma.subject...)
+	nc.ps.argBuf = append(nc.ps.argBuf, nc.ps.ma.reply...)
+	nc.ps.ma.subject = nc.ps.argBuf[:len(nc.ps.ma.subject)]
+	if nc.ps.ma.reply != nil {
+		nc.ps.ma.reply = nc.ps.argBuf[len(nc.ps.ma.subject):]
+	}
+}
+
+const argsLenMax = 4
+
+func (nc *Conn) processMsgArgs(arg []byte) error {
+	// Unroll splitArgs to avoid runtime/heap issues
+	a := [argsLenMax][]byte{}
+	args := a[:0]
+	start := -1
+	for i, b := range arg {
+		switch b {
+		case ' ', '\t', '\r', '\n':
+			if start >= 0 {
+				args = append(args, arg[start:i])
+				start = -1
+			}
+		default:
+			if start < 0 {
+				start = i
+			}
+		}
+	}
+	if start >= 0 {
+		args = append(args, arg[start:])
+	}
+
+	switch len(args) {
+	case 3:
+		nc.ps.ma.subject = args[0]
+		nc.ps.ma.sid = parseInt64(args[1])
+		nc.ps.ma.reply = nil
+		nc.ps.ma.size = int(parseInt64(args[2]))
+	case 4:
+		nc.ps.ma.subject = args[0]
+		nc.ps.ma.sid = parseInt64(args[1])
+		nc.ps.ma.reply = args[2]
+		nc.ps.ma.size = int(parseInt64(args[3]))
+	default:
+		return fmt.Errorf("nats: processMsgArgs Parse Error: '%s'", arg)
+	}
+	if nc.ps.ma.sid < 0 {
+		return fmt.Errorf("nats: processMsgArgs Bad or Missing Sid: '%s'", arg)
+	}
+	if nc.ps.ma.size < 0 {
+		return fmt.Errorf("nats: processMsgArgs Bad or Missing Size: '%s'", arg)
+	}
+	return nil
+}
+
+// Ascii numbers 0-9
+const (
+	ascii_0 = 48
+	ascii_9 = 57
+)
+
+// parseInt64 expects decimal positive numbers. We
+// return -1 to signal error
+func parseInt64(d []byte) (n int64) {
+	if len(d) == 0 {
+		return -1
+	}
+	for _, dec := range d {
+		if dec < ascii_0 || dec > ascii_9 {
+			return -1
+		}
+		n = n*10 + (int64(dec) - ascii_0)
+	}
+	return n
+}

gateway/vendor/github.com/nats-io/go-nats/timer.go

@@ -0,0 +1,43 @@
+package nats
+
+import (
+	"sync"
+	"time"
+)
+
+// global pool of *time.Timer's. can be used by multiple goroutines concurrently.
+var globalTimerPool timerPool
+
+// timerPool provides GC-able pooling of *time.Timer's.
+// can be used by multiple goroutines concurrently.
+type timerPool struct {
+	p sync.Pool
+}
+
+// Get returns a timer that completes after the given duration.
+func (tp *timerPool) Get(d time.Duration) *time.Timer {
+	if t, _ := tp.p.Get().(*time.Timer); t != nil {
+		t.Reset(d)
+		return t
+	}
+
+	return time.NewTimer(d)
+}
+
+// Put pools the given timer.
+//
+// There is no need to call t.Stop() before calling Put.
+//
+// Put will try to stop the timer before pooling. If the
+// given timer already expired, Put will read the unreceived
+// value if there is one.
+func (tp *timerPool) Put(t *time.Timer) {
+	if !t.Stop() {
+		select {
+		case <-t.C:
+		default:
+		}
+	}
+
+	tp.p.Put(t)
+}

gateway/vendor/github.com/nats-io/go-nats/util/tls.go

@@ -0,0 +1,37 @@
+// Copyright 2016 Apcera Inc. All rights reserved.
+// +build go1.7
+
+package util
+
+import (
+	"crypto/tls"
+)
+
+// CloneTLSConfig returns a copy of c. Only the exported fields are copied.
+// This is temporary, until this is provided by the language.
+// https://go-review.googlesource.com/#/c/28075/
+func CloneTLSConfig(c *tls.Config) *tls.Config {
+	return &tls.Config{
+		Rand:                        c.Rand,
+		Time:                        c.Time,
+		Certificates:                c.Certificates,
+		NameToCertificate:           c.NameToCertificate,
+		GetCertificate:              c.GetCertificate,
+		RootCAs:                     c.RootCAs,
+		NextProtos:                  c.NextProtos,
+		ServerName:                  c.ServerName,
+		ClientAuth:                  c.ClientAuth,
+		ClientCAs:                   c.ClientCAs,
+		InsecureSkipVerify:          c.InsecureSkipVerify,
+		CipherSuites:                c.CipherSuites,
+		PreferServerCipherSuites:    c.PreferServerCipherSuites,
+		SessionTicketsDisabled:      c.SessionTicketsDisabled,
+		SessionTicketKey:            c.SessionTicketKey,
+		ClientSessionCache:          c.ClientSessionCache,
+		MinVersion:                  c.MinVersion,
+		MaxVersion:                  c.MaxVersion,
+		CurvePreferences:            c.CurvePreferences,
+		DynamicRecordSizingDisabled: c.DynamicRecordSizingDisabled,
+		Renegotiation:               c.Renegotiation,
+	}
+}

gateway/vendor/github.com/nats-io/go-nats/util/tls_pre17.go

@@ -0,0 +1,35 @@
+// Copyright 2016 Apcera Inc. All rights reserved.
+// +build go1.5,!go1.7
+
+package util
+
+import (
+	"crypto/tls"
+)
+
+// CloneTLSConfig returns a copy of c. Only the exported fields are copied.
+// This is temporary, until this is provided by the language.
+// https://go-review.googlesource.com/#/c/28075/
+func CloneTLSConfig(c *tls.Config) *tls.Config {
+	return &tls.Config{
+		Rand:                     c.Rand,
+		Time:                     c.Time,
+		Certificates:             c.Certificates,
+		NameToCertificate:        c.NameToCertificate,
+		GetCertificate:           c.GetCertificate,
+		RootCAs:                  c.RootCAs,
+		NextProtos:               c.NextProtos,
+		ServerName:               c.ServerName,
+		ClientAuth:               c.ClientAuth,
+		ClientCAs:                c.ClientCAs,
+		InsecureSkipVerify:       c.InsecureSkipVerify,
+		CipherSuites:             c.CipherSuites,
+		PreferServerCipherSuites: c.PreferServerCipherSuites,
+		SessionTicketsDisabled:   c.SessionTicketsDisabled,
+		SessionTicketKey:         c.SessionTicketKey,
+		ClientSessionCache:       c.ClientSessionCache,
+		MinVersion:               c.MinVersion,
+		MaxVersion:               c.MaxVersion,
+		CurvePreferences:         c.CurvePreferences,
+	}
+}

gateway/vendor/github.com/nats-io/nuid/LICENSE

@@ -0,0 +1,21 @@
+The MIT License (MIT)
+
+Copyright (c) 2012-2016 Apcera Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

gateway/vendor/github.com/nats-io/nuid/README.md

@@ -0,0 +1,66 @@
+# NUID
+
+[![License MIT](https://img.shields.io/npm/l/express.svg)](http://opensource.org/licenses/MIT)
+[![ReportCard](http://goreportcard.com/badge/nats-io/nuid)](http://goreportcard.com/report/nats-io/nuid)
+[![Build Status](https://travis-ci.org/nats-io/nuid.svg?branch=master)](http://travis-ci.org/nats-io/nuid)
+[![Release](https://img.shields.io/badge/release-v1.0.0-1eb0fc.svg)](https://github.com/nats-io/nuid/releases/tag/v1.0.0)
+[![GoDoc](http://godoc.org/github.com/nats-io/nuid?status.png)](http://godoc.org/github.com/nats-io/nuid)
+[![Coverage Status](https://coveralls.io/repos/github/nats-io/nuid/badge.svg?branch=master)](https://coveralls.io/github/nats-io/nuid?branch=master)
+
+A highly performant unique identifier generator.
+
+## Installation
+
+Use the `go` command:
+
+	$ go get github.com/nats-io/nuid
+
+## Basic Usage
+```go
+
+// Utilize the global locked instance
+nuid := nuid.Next()
+
+// Create an instance, these are not locked.
+n := nuid.New()
+nuid = n.Next()
+
+// Generate a new crypto/rand seeded prefix.
+// Generally not needed, happens automatically.
+n.RandomizePrefix()
+```
+
+## Performance
+NUID needs to be very fast to generate and be truly unique, all while being entropy pool friendly.
+NUID uses 12 bytes of crypto generated data (entropy draining), and 10 bytes of pseudo-random
+sequential data that increments with a pseudo-random increment.
+
+Total length of a NUID string is 22 bytes of base 62 ascii text, so 62^22 or
+2707803647802660400290261537185326956544 possibilities.
+
+NUID can generate identifiers as fast as 60ns, or ~16 million per second. There is an associated
+benchmark you can use to test performance on your own hardware.
+
+## License
+
+(The MIT License)
+
+Copyright (c) 2016 Apcera Inc.
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to
+deal in the Software without restriction, including without limitation the
+rights to use, copy, modify, merge, publish, distribute, sublicense, and/or
+sell copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+IN THE SOFTWARE.

gateway/vendor/github.com/nats-io/nuid/nuid.go

@@ -0,0 +1,124 @@
+// Copyright 2016 Apcera Inc. All rights reserved.
+
+// A unique identifier generator that is high performance, very fast, and tries to be entropy pool friendly.
+package nuid
+
+import (
+	"crypto/rand"
+	"fmt"
+	"math"
+	"math/big"
+	"sync"
+	"time"
+
+	prand "math/rand"
+)
+
+// NUID needs to be very fast to generate and truly unique, all while being entropy pool friendly.
+// We will use 12 bytes of crypto generated data (entropy draining), and 10 bytes of sequential data
+// that is started at a pseudo random number and increments with a pseudo-random increment.
+// Total is 22 bytes of base 62 ascii text :)
+
+// Version of the library
+const Version = "1.0.0"
+
+const (
+	digits   = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz"
+	base     = 62
+	preLen   = 12
+	seqLen   = 10
+	maxSeq   = int64(839299365868340224) // base^seqLen == 62^10
+	minInc   = int64(33)
+	maxInc   = int64(333)
+	totalLen = preLen + seqLen
+)
+
+type NUID struct {
+	pre []byte
+	seq int64
+	inc int64
+}
+
+type lockedNUID struct {
+	sync.Mutex
+	*NUID
+}
+
+// Global NUID
+var globalNUID *lockedNUID
+
+// Seed sequential random with crypto or math/random and current time
+// and generate crypto prefix.
+func init() {
+	r, err := rand.Int(rand.Reader, big.NewInt(math.MaxInt64))
+	if err != nil {
+		prand.Seed(time.Now().UnixNano())
+	} else {
+		prand.Seed(r.Int64())
+	}
+	globalNUID = &lockedNUID{NUID: New()}
+	globalNUID.RandomizePrefix()
+}
+
+// New will generate a new NUID and properly initialize the prefix, sequential start, and sequential increment.
+func New() *NUID {
+	n := &NUID{
+		seq: prand.Int63n(maxSeq),
+		inc: minInc + prand.Int63n(maxInc-minInc),
+		pre: make([]byte, preLen),
+	}
+	n.RandomizePrefix()
+	return n
+}
+
+// Generate the next NUID string from the global locked NUID instance.
+func Next() string {
+	globalNUID.Lock()
+	nuid := globalNUID.Next()
+	globalNUID.Unlock()
+	return nuid
+}
+
+// Generate the next NUID string.
+func (n *NUID) Next() string {
+	// Increment and capture.
+	n.seq += n.inc
+	if n.seq >= maxSeq {
+		n.RandomizePrefix()
+		n.resetSequential()
+	}
+	seq := n.seq
+
+	// Copy prefix
+	var b [totalLen]byte
+	bs := b[:preLen]
+	copy(bs, n.pre)
+
+	// copy in the seq in base36.
+	for i, l := len(b), seq; i > preLen; l /= base {
+		i -= 1
+		b[i] = digits[l%base]
+	}
+	return string(b[:])
+}
+
+// Resets the sequential portion of the NUID.
+func (n *NUID) resetSequential() {
+	n.seq = prand.Int63n(maxSeq)
+	n.inc = minInc + prand.Int63n(maxInc-minInc)
+}
+
+// Generate a new prefix from crypto/rand.
+// This call *can* drain entropy and will be called automatically when we exhaust the sequential range.
+// Will panic if it gets an error from rand.Int()
+func (n *NUID) RandomizePrefix() {
+	var cb [preLen]byte
+	cbs := cb[:]
+	if nb, err := rand.Read(cbs); nb != preLen || err != nil {
+		panic(fmt.Sprintf("nuid: failed generating crypto random number: %v\n", err))
+	}
+
+	for i := 0; i < preLen; i++ {
+		n.pre[i] = digits[int(cbs[i])%base]
+	}
+}