Add shim for collecting logs

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>

Gopkg.lock

@@ -55,7 +55,7 @@
   version = "0.7.1"
 
 [[projects]]
-  digest = "1:386ca0ac781cc1b630b3ed21725759770174140164b3faf3810e6ed6366a970b"
+  digest = "1:cf83a14c8042951b0dcd74758fc32258111ecc7838cbdf5007717172cab9ca9b"
   name = "github.com/containerd/containerd"
   packages = [
     ".",
@@ -103,6 +103,7 @@
     "remotes/docker/schema1",
     "rootfs",
     "runtime/linux/runctypes",
+    "runtime/v2/logging",
     "runtime/v2/runc/options",
     "snapshots",
     "snapshots/proxy",
@@ -169,6 +170,14 @@
   revision = "4cfb7b568922a3c79a23e438dc52fe537fc9687e"
   version = "v0.7.1"
 
+[[projects]]
+  digest = "1:bcf36df8d43860bfde913d008301aef27c6e9a303582118a837c4a34c0d18167"
+  name = "github.com/coreos/go-systemd"
+  packages = ["journal"]
+  pruneopts = "UT"
+  revision = "2d78030078ef61b3cae27f42ad6d0e46db51b339"
+  version = "v22.0.0"
+
 [[projects]]
   digest = "1:92ebc9c068ab8e3fff03a58694ee33830964f6febd0130069aadce328802de14"
   name = "github.com/docker/cli"
@@ -574,7 +583,9 @@
     "github.com/containerd/containerd/oci",
     "github.com/containerd/containerd/remotes",
     "github.com/containerd/containerd/remotes/docker",
+    "github.com/containerd/containerd/runtime/v2/logging",
     "github.com/containerd/go-cni",
+    "github.com/coreos/go-systemd/journal",
     "github.com/docker/cli/cli/config",
     "github.com/docker/cli/cli/config/configfile",
     "github.com/docker/distribution/reference",

cmd/collect.go

@@ -0,0 +1,56 @@
+package cmd
+
+import (
+	"bufio"
+	"context"
+	"fmt"
+	"io"
+	"sync"
+
+	"github.com/containerd/containerd/runtime/v2/logging"
+	"github.com/coreos/go-systemd/journal"
+	"github.com/spf13/cobra"
+)
+
+var collectCmd = &cobra.Command{
+	Use:   "collect",
+	Short: "Collect logs to the journal",
+	RunE:  runCollect,
+}
+
+func runCollect(_ *cobra.Command, _ []string) error {
+	logging.Run(logStdio)
+	return nil
+}
+
+// logStdio copied from
+// https://github.com/containerd/containerd/pull/3085
+// https://github.com/stellarproject/orbit
+func logStdio(ctx context.Context, config *logging.Config, ready func() error) error {
+	// construct any log metadata for the container
+	vars := map[string]string{
+		"SYSLOG_IDENTIFIER": fmt.Sprintf("%s:%s", config.Namespace, config.ID),
+	}
+	var wg sync.WaitGroup
+	wg.Add(2)
+	// forward both stdout and stderr to the journal
+	go copy(&wg, config.Stdout, journal.PriInfo, vars)
+	go copy(&wg, config.Stderr, journal.PriErr, vars)
+	// signal that we are ready and setup for the container to be started
+	if err := ready(); err != nil {
+		return err
+	}
+	wg.Wait()
+	return nil
+}
+
+func copy(wg *sync.WaitGroup, r io.Reader, pri journal.Priority, vars map[string]string) {
+	defer wg.Done()
+	s := bufio.NewScanner(r)
+	for s.Scan() {
+		if s.Err() != nil {
+			return
+		}
+		journal.Send(s.Text(), pri, vars)
+	}
+}

cmd/root.go

@@ -15,6 +15,7 @@ func init() {
 	rootCommand.AddCommand(upCmd)
 	rootCommand.AddCommand(installCmd)
 	rootCommand.AddCommand(providerCmd)
+	rootCommand.AddCommand(collectCmd)
 }
 
 var (

vendor/github.com/containerd/containerd/runtime/v2/logging/logging.go

@@ -0,0 +1,77 @@
+// +build !windows
+
+/*
+   Copyright The containerd Authors.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.
+*/
+
+package logging
+
+import (
+	"context"
+	"fmt"
+	"io"
+	"os"
+	"os/signal"
+
+	"golang.org/x/sys/unix"
+)
+
+// Config of the container logs
+type Config struct {
+	ID        string
+	Namespace string
+	Stdout    io.Reader
+	Stderr    io.Reader
+}
+
+// LoggerFunc is implemented by custom v2 logging binaries
+type LoggerFunc func(context.Context, *Config, func() error) error
+
+// Run the logging driver
+func Run(fn LoggerFunc) {
+	ctx, cancel := context.WithCancel(context.Background())
+	config := &Config{
+		ID:        os.Getenv("CONTAINER_ID"),
+		Namespace: os.Getenv("CONTAINER_NAMESPACE"),
+		Stdout:    os.NewFile(3, "CONTAINER_STDOUT"),
+		Stderr:    os.NewFile(4, "CONTAINER_STDERR"),
+	}
+	var (
+		s     = make(chan os.Signal, 32)
+		errCh = make(chan error, 1)
+		wait  = os.NewFile(5, "CONTAINER_WAIT")
+	)
+	signal.Notify(s, unix.SIGTERM)
+
+	go func() {
+		if err := fn(ctx, config, wait.Close); err != nil {
+			errCh <- err
+		}
+		errCh <- nil
+	}()
+
+	for {
+		select {
+		case <-s:
+			cancel()
+		case err := <-errCh:
+			if err != nil {
+				fmt.Fprintln(os.Stderr, err)
+				os.Exit(1)
+			}
+			os.Exit(0)
+		}
+	}
+}

vendor/github.com/coreos/go-systemd/LICENSE

@@ -0,0 +1,191 @@
+Apache License
+Version 2.0, January 2004
+http://www.apache.org/licenses/
+
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+for inclusion in the Work by You to the Licensor shall be under the terms and
+conditions of this License, without any additional terms or conditions.
+Notwithstanding the above, nothing herein shall supersede or modify the terms of
+any separate license agreement you may have executed with Licensor regarding
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+6. Trademarks.
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+This License does not grant permission to use the trade names, trademarks,
+service marks, or product names of the Licensor, except as required for
+reasonable and customary use in describing the origin of the Work and
+reproducing the content of the NOTICE file.
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+7. Disclaimer of Warranty.
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+
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+contract, or otherwise, unless required by applicable law (such as deliberate
+and grossly negligent acts) or agreed to in writing, shall any Contributor be
+liable to You for damages, including any direct, indirect, special, incidental,
+or consequential damages of any character arising as a result of this License or
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+   Unless required by applicable law or agreed to in writing, software
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+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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vendor/github.com/coreos/go-systemd/NOTICE

@@ -0,0 +1,5 @@
+CoreOS Project
+Copyright 2018 CoreOS, Inc
+
+This product includes software developed at CoreOS, Inc.
+(http://www.coreos.com/).

vendor/github.com/coreos/go-systemd/journal/journal.go

@@ -0,0 +1,225 @@
+// Copyright 2015 CoreOS, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Package journal provides write bindings to the local systemd journal.
+// It is implemented in pure Go and connects to the journal directly over its
+// unix socket.
+//
+// To read from the journal, see the "sdjournal" package, which wraps the
+// sd-journal a C API.
+//
+// http://www.freedesktop.org/software/systemd/man/systemd-journald.service.html
+package journal
+
+import (
+	"bytes"
+	"encoding/binary"
+	"errors"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net"
+	"os"
+	"strconv"
+	"strings"
+	"sync"
+	"sync/atomic"
+	"syscall"
+	"unsafe"
+)
+
+// Priority of a journal message
+type Priority int
+
+const (
+	PriEmerg Priority = iota
+	PriAlert
+	PriCrit
+	PriErr
+	PriWarning
+	PriNotice
+	PriInfo
+	PriDebug
+)
+
+var (
+	// This can be overridden at build-time:
+	// https://github.com/golang/go/wiki/GcToolchainTricks#including-build-information-in-the-executable
+	journalSocket = "/run/systemd/journal/socket"
+
+	// unixConnPtr atomically holds the local unconnected Unix-domain socket.
+	// Concrete safe pointer type: *net.UnixConn
+	unixConnPtr unsafe.Pointer
+	// onceConn ensures that unixConnPtr is initialized exactly once.
+	onceConn sync.Once
+)
+
+func init() {
+	onceConn.Do(initConn)
+}
+
+// Enabled checks whether the local systemd journal is available for logging.
+func Enabled() bool {
+	onceConn.Do(initConn)
+
+	if (*net.UnixConn)(atomic.LoadPointer(&unixConnPtr)) == nil {
+		return false
+	}
+
+	if _, err := net.Dial("unixgram", journalSocket); err != nil {
+		return false
+	}
+
+	return true
+}
+
+// Send a message to the local systemd journal. vars is a map of journald
+// fields to values.  Fields must be composed of uppercase letters, numbers,
+// and underscores, but must not start with an underscore. Within these
+// restrictions, any arbitrary field name may be used.  Some names have special
+// significance: see the journalctl documentation
+// (http://www.freedesktop.org/software/systemd/man/systemd.journal-fields.html)
+// for more details.  vars may be nil.
+func Send(message string, priority Priority, vars map[string]string) error {
+	conn := (*net.UnixConn)(atomic.LoadPointer(&unixConnPtr))
+	if conn == nil {
+		return errors.New("could not initialize socket to journald")
+	}
+
+	socketAddr := &net.UnixAddr{
+		Name: journalSocket,
+		Net:  "unixgram",
+	}
+
+	data := new(bytes.Buffer)
+	appendVariable(data, "PRIORITY", strconv.Itoa(int(priority)))
+	appendVariable(data, "MESSAGE", message)
+	for k, v := range vars {
+		appendVariable(data, k, v)
+	}
+
+	_, _, err := conn.WriteMsgUnix(data.Bytes(), nil, socketAddr)
+	if err == nil {
+		return nil
+	}
+	if !isSocketSpaceError(err) {
+		return err
+	}
+
+	// Large log entry, send it via tempfile and ancillary-fd.
+	file, err := tempFd()
+	if err != nil {
+		return err
+	}
+	defer file.Close()
+	_, err = io.Copy(file, data)
+	if err != nil {
+		return err
+	}
+	rights := syscall.UnixRights(int(file.Fd()))
+	_, _, err = conn.WriteMsgUnix([]byte{}, rights, socketAddr)
+	if err != nil {
+		return err
+	}
+
+	return nil
+}
+
+// Print prints a message to the local systemd journal using Send().
+func Print(priority Priority, format string, a ...interface{}) error {
+	return Send(fmt.Sprintf(format, a...), priority, nil)
+}
+
+func appendVariable(w io.Writer, name, value string) {
+	if err := validVarName(name); err != nil {
+		fmt.Fprintf(os.Stderr, "variable name %s contains invalid character, ignoring\n", name)
+	}
+	if strings.ContainsRune(value, '\n') {
+		/* When the value contains a newline, we write:
+		 * - the variable name, followed by a newline
+		 * - the size (in 64bit little endian format)
+		 * - the data, followed by a newline
+		 */
+		fmt.Fprintln(w, name)
+		binary.Write(w, binary.LittleEndian, uint64(len(value)))
+		fmt.Fprintln(w, value)
+	} else {
+		/* just write the variable and value all on one line */
+		fmt.Fprintf(w, "%s=%s\n", name, value)
+	}
+}
+
+// validVarName validates a variable name to make sure journald will accept it.
+// The variable name must be in uppercase and consist only of characters,
+// numbers and underscores, and may not begin with an underscore:
+// https://www.freedesktop.org/software/systemd/man/sd_journal_print.html
+func validVarName(name string) error {
+	if name == "" {
+		return errors.New("Empty variable name")
+	} else if name[0] == '_' {
+		return errors.New("Variable name begins with an underscore")
+	}
+
+	for _, c := range name {
+		if !(('A' <= c && c <= 'Z') || ('0' <= c && c <= '9') || c == '_') {
+			return errors.New("Variable name contains invalid characters")
+		}
+	}
+	return nil
+}
+
+// isSocketSpaceError checks whether the error is signaling
+// an "overlarge message" condition.
+func isSocketSpaceError(err error) bool {
+	opErr, ok := err.(*net.OpError)
+	if !ok || opErr == nil {
+		return false
+	}
+
+	sysErr, ok := opErr.Err.(*os.SyscallError)
+	if !ok || sysErr == nil {
+		return false
+	}
+
+	return sysErr.Err == syscall.EMSGSIZE || sysErr.Err == syscall.ENOBUFS
+}
+
+// tempFd creates a temporary, unlinked file under `/dev/shm`.
+func tempFd() (*os.File, error) {
+	file, err := ioutil.TempFile("/dev/shm/", "journal.XXXXX")
+	if err != nil {
+		return nil, err
+	}
+	err = syscall.Unlink(file.Name())
+	if err != nil {
+		return nil, err
+	}
+	return file, nil
+}
+
+// initConn initializes the global `unixConnPtr` socket.
+// It is meant to be called exactly once, at program startup.
+func initConn() {
+	autobind, err := net.ResolveUnixAddr("unixgram", "")
+	if err != nil {
+		return
+	}
+
+	sock, err := net.ListenUnixgram("unixgram", autobind)
+	if err != nil {
+		return
+	}
+
+	atomic.StorePointer(&unixConnPtr, unsafe.Pointer(sock))
+}