faas/gateway/handlers/forwarding_proxy.go
Alex Ellis (OpenFaaS Ltd) 2bfca6d848 Publish to multiple topics
Enables publishing to various topics according to annotations
on the functions. The function cache is moved up one level so
that it can be shared between the scale from zero code and the
queue proxy.

Unit tests added for new internal methods.

Tested e2e with arkade and the newest queue-worker and RC
gateway image with two queues and an annotation on one of the
functions of com.openfaas.queue. It worked as expected including
with multiple namespace support.

Signed-off-by: Alex Ellis (OpenFaaS Ltd) <alexellis2@gmail.com>
2020-04-22 15:26:42 +01:00

259 lines
7.1 KiB
Go

// Copyright (c) OpenFaaS Author(s). All rights reserved.
// Licensed under the MIT license. See LICENSE file in the project root for full license information.
package handlers
import (
"context"
"fmt"
"io"
"log"
"net/http"
"os"
"regexp"
"strings"
"time"
"github.com/openfaas/faas/gateway/pkg/middleware"
"github.com/openfaas/faas/gateway/types"
)
// functionMatcher parses out the service name (group 1) and rest of path (group 2).
var functionMatcher = regexp.MustCompile("^/?(?:async-)?function/([^/?]+)([^?]*)")
// Indices and meta-data for functionMatcher regex parts
const (
hasPathCount = 3
routeIndex = 0 // routeIndex corresponds to /function/ or /async-function/
nameIndex = 1 // nameIndex is the function name
pathIndex = 2 // pathIndex is the path i.e. /employee/:id/
)
// BaseURLResolver URL resolver for upstream requests
type BaseURLResolver interface {
Resolve(r *http.Request) string
}
// URLPathTransformer Transform the incoming URL path for upstream requests
type URLPathTransformer interface {
Transform(r *http.Request) string
}
// MakeForwardingProxyHandler create a handler which forwards HTTP requests
func MakeForwardingProxyHandler(proxy *types.HTTPClientReverseProxy,
notifiers []HTTPNotifier,
baseURLResolver BaseURLResolver,
urlPathTransformer URLPathTransformer,
serviceAuthInjector middleware.AuthInjector) http.HandlerFunc {
writeRequestURI := false
if _, exists := os.LookupEnv("write_request_uri"); exists {
writeRequestURI = exists
}
return func(w http.ResponseWriter, r *http.Request) {
baseURL := baseURLResolver.Resolve(r)
originalURL := r.URL.String()
requestURL := urlPathTransformer.Transform(r)
for _, notifier := range notifiers {
notifier.Notify(r.Method, requestURL, originalURL, http.StatusProcessing, "started", time.Second*0)
}
start := time.Now()
statusCode, err := forwardRequest(w, r, proxy.Client, baseURL, requestURL, proxy.Timeout, writeRequestURI, serviceAuthInjector)
seconds := time.Since(start)
if err != nil {
log.Printf("error with upstream request to: %s, %s\n", requestURL, err.Error())
}
for _, notifier := range notifiers {
notifier.Notify(r.Method, requestURL, originalURL, statusCode, "completed", seconds)
}
}
}
func buildUpstreamRequest(r *http.Request, baseURL string, requestURL string) *http.Request {
url := baseURL + requestURL
if len(r.URL.RawQuery) > 0 {
url = fmt.Sprintf("%s?%s", url, r.URL.RawQuery)
}
upstreamReq, _ := http.NewRequest(r.Method, url, nil)
copyHeaders(upstreamReq.Header, &r.Header)
deleteHeaders(&upstreamReq.Header, &hopHeaders)
if len(r.Host) > 0 && upstreamReq.Header.Get("X-Forwarded-Host") == "" {
upstreamReq.Header["X-Forwarded-Host"] = []string{r.Host}
}
if upstreamReq.Header.Get("X-Forwarded-For") == "" {
upstreamReq.Header["X-Forwarded-For"] = []string{r.RemoteAddr}
}
if r.Body != nil {
upstreamReq.Body = r.Body
}
return upstreamReq
}
func forwardRequest(w http.ResponseWriter,
r *http.Request,
proxyClient *http.Client,
baseURL string,
requestURL string,
timeout time.Duration,
writeRequestURI bool,
serviceAuthInjector middleware.AuthInjector) (int, error) {
upstreamReq := buildUpstreamRequest(r, baseURL, requestURL)
if upstreamReq.Body != nil {
defer upstreamReq.Body.Close()
}
if serviceAuthInjector != nil {
serviceAuthInjector.Inject(upstreamReq)
}
if writeRequestURI {
log.Printf("forwardRequest: %s %s\n", upstreamReq.Host, upstreamReq.URL.String())
}
ctx, cancel := context.WithTimeout(r.Context(), timeout)
defer cancel()
res, resErr := proxyClient.Do(upstreamReq.WithContext(ctx))
if resErr != nil {
badStatus := http.StatusBadGateway
w.WriteHeader(badStatus)
return badStatus, resErr
}
if res.Body != nil {
defer res.Body.Close()
}
copyHeaders(w.Header(), &res.Header)
// Write status code
w.WriteHeader(res.StatusCode)
if res.Body != nil {
// Copy the body over
io.CopyBuffer(w, res.Body, nil)
}
return res.StatusCode, nil
}
func copyHeaders(destination http.Header, source *http.Header) {
for k, v := range *source {
vClone := make([]string, len(v))
copy(vClone, v)
(destination)[k] = vClone
}
}
func deleteHeaders(target *http.Header, exclude *[]string) {
for _, h := range *exclude {
target.Del(h)
}
}
// SingleHostBaseURLResolver resolves URLs against a single BaseURL
type SingleHostBaseURLResolver struct {
BaseURL string
}
// Resolve the base URL for a request
func (s SingleHostBaseURLResolver) Resolve(r *http.Request) string {
baseURL := s.BaseURL
if strings.HasSuffix(baseURL, "/") {
baseURL = baseURL[0 : len(baseURL)-1]
}
return baseURL
}
// FunctionAsHostBaseURLResolver resolves URLs using a function from the URL as a host
type FunctionAsHostBaseURLResolver struct {
FunctionSuffix string
FunctionNamespace string
}
// Resolve the base URL for a request
func (f FunctionAsHostBaseURLResolver) Resolve(r *http.Request) string {
svcName := getServiceName(r.URL.Path)
const watchdogPort = 8080
var suffix string
if len(f.FunctionSuffix) > 0 {
if index := strings.LastIndex(svcName, "."); index > -1 && len(svcName) > index+1 {
suffix = strings.Replace(f.FunctionSuffix, f.FunctionNamespace, "", -1)
} else {
suffix = "." + f.FunctionSuffix
}
}
return fmt.Sprintf("http://%s%s:%d", svcName, suffix, watchdogPort)
}
// TransparentURLPathTransformer passes the requested URL path through untouched.
type TransparentURLPathTransformer struct {
}
// Transform returns the URL path unchanged.
func (f TransparentURLPathTransformer) Transform(r *http.Request) string {
return r.URL.Path
}
// FunctionPrefixTrimmingURLPathTransformer removes the "/function/servicename/" prefix from the URL path.
type FunctionPrefixTrimmingURLPathTransformer struct {
}
// Transform removes the "/function/servicename/" prefix from the URL path.
func (f FunctionPrefixTrimmingURLPathTransformer) Transform(r *http.Request) string {
ret := r.URL.Path
if ret != "" {
// When forwarding to a function, since the `/function/xyz` portion
// of a path like `/function/xyz/rest/of/path` is only used or needed
// by the Gateway, we want to trim it down to `/rest/of/path` for the
// upstream request. In the following regex, in the case of a match
// the r.URL.Path will be at `0`, the function name at `1` and the
// rest of the path (the part we are interested in) at `2`.
matcher := functionMatcher.Copy()
parts := matcher.FindStringSubmatch(ret)
if len(parts) == hasPathCount {
ret = parts[pathIndex]
}
}
return ret
}
// Hop-by-hop headers. These are removed when sent to the backend.
// As of RFC 7230, hop-by-hop headers are required to appear in the
// Connection header field. These are the headers defined by the
// obsoleted RFC 2616 (section 13.5.1) and are used for backward
// compatibility.
// Copied from: https://golang.org/src/net/http/httputil/reverseproxy.go
var hopHeaders = []string{
"Connection",
"Proxy-Connection", // non-standard but still sent by libcurl and rejected by e.g. google
"Keep-Alive",
"Proxy-Authenticate",
"Proxy-Authorization",
"Te", // canonicalized version of "TE"
"Trailer", // not Trailers per URL above; https://www.rfc-editor.org/errata_search.php?eid=4522
"Transfer-Encoding",
"Upgrade",
}