Support streaming responses from functions

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

gateway/Dockerfile

@@ -1,6 +1,6 @@
 FROM --platform=${BUILDPLATFORM:-linux/amd64} ghcr.io/openfaas/license-check:0.4.1 as license-check
 
-FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.20 as build
+FROM --platform=${BUILDPLATFORM:-linux/amd64} golang:1.21 as build
 
 ENV GO111MODULE=on
 ENV CGO_ENABLED=0
@@ -42,9 +42,9 @@ RUN CGO_ENABLED=${CGO_ENABLED} GOOS=${TARGETOS} GOARCH=${TARGETARCH} go build --
     -X \"github.com/openfaas/faas/gateway/version.GitCommitSHA=${GIT_COMMIT}\" \
     -X \"github.com/openfaas/faas/gateway/version.Version=${VERSION}\" \
     -X github.com/openfaas/faas/gateway/types.Arch=${TARGETARCH}" \
-    -a -installsuffix cgo -o gateway .
+    -o gateway .
 
-FROM --platform=${TARGETPLATFORM:-linux/amd64} alpine:3.18.3 as ship
+FROM --platform=${TARGETPLATFORM:-linux/amd64} alpine:3.19.0 as ship
 
 LABEL org.label-schema.license="MIT" \
     org.label-schema.vcs-url="https://github.com/openfaas/faas" \

gateway/Makefile

@@ -1,6 +1,6 @@
 export DOCKER_CLI_EXPERIMENTAL=enabled
 
-PLATFORM := "linux/amd64,linux/arm/v7,linux/arm64"
+PLATFORM?="linux/amd64,linux/arm/v7,linux/arm64"
 
 TAG?=dev
 SERVER?=ttl.sh
@@ -19,6 +19,16 @@ buildx-local:
 
 .PHONY: buildx-push
 buildx-push:
+	@echo $(SERVER)/$(OWNER)/$(NAME):$(TAG) \
+	&& docker buildx create --use --name=multiarch --node multiarch \
+	&& docker buildx build \
+		--progress=plain \
+		--platform linux/amd64 \
+		--output "type=image,push=true" \
+		--tag $(SERVER)/$(OWNER)/$(NAME):$(TAG) .
+
+.PHONY: buildx-push-all
+buildx-push-all:
 	@echo $(SERVER)/$(OWNER)/$(NAME):$(TAG) \
 	&& docker buildx create --use --name=multiarch --node multiarch \
 	&& docker buildx build \

gateway/go.mod

@@ -1,11 +1,11 @@
 module github.com/openfaas/faas/gateway
 
-go 1.20
+go 1.21
 
 require (
 	github.com/docker/distribution v2.8.3+incompatible
 	github.com/gorilla/mux v1.8.0
-	github.com/openfaas/faas-provider v0.24.4
+	github.com/openfaas/faas-provider v0.25.2
 	github.com/openfaas/nats-queue-worker v0.0.0-20231023101743-fa54e89c9db2
 	github.com/prometheus/client_golang v1.17.0
 	github.com/prometheus/client_model v0.5.0

gateway/go.sum

@@ -192,6 +192,8 @@ github.com/openfaas/faas-provider v0.19.1 h1:xH8lTWabfDZwzIvC0u1AO48ghD3BNw6Vo23
 github.com/openfaas/faas-provider v0.19.1/go.mod h1:Farrp+9Med8LeK3aoYpqplMP8f5ebTILbCSLg2LPLZk=
 github.com/openfaas/faas-provider v0.24.4 h1:Zzbkabgd0PoQmnRjy53NbMXjhLaIyoIiwP3qaLkm9rE=
 github.com/openfaas/faas-provider v0.24.4/go.mod h1:NsETIfEndZn4mn/w/XnBTcDTwKqULCziphLp7KgeRcA=
+github.com/openfaas/faas-provider v0.25.2 h1:sAyL96CzAk/YnuXQZiRJcHo7UrcYMaf7RDvKxsQb/2o=
+github.com/openfaas/faas-provider v0.25.2/go.mod h1:NsETIfEndZn4mn/w/XnBTcDTwKqULCziphLp7KgeRcA=
 github.com/openfaas/nats-queue-worker v0.0.0-20230303171817-9dfe6fa61387 h1:D4xbdy309Wdyhlm6PgJqUV/aR77VQQG8UTF+q0ay71c=
 github.com/openfaas/nats-queue-worker v0.0.0-20230303171817-9dfe6fa61387/go.mod h1:s86POyW6C8S4CALFRhO8ax5sR2uaQUJQ0HaQGvbTpTc=
 github.com/openfaas/nats-queue-worker v0.0.0-20231023101743-fa54e89c9db2 h1:I8U2kq2h7Wl6pkd4hjRK6P0/o3AcCNdfmNJS5gdgxKU=

gateway/handlers/forwarding_proxy.go

@@ -9,9 +9,12 @@ import (
 	"io"
 	"log"
 	"net/http"
+	"net/http/httputil"
 	"os"
+	"strings"
 	"time"
 
+	fhttputil "github.com/openfaas/faas-provider/httputil"
 	"github.com/openfaas/faas/gateway/pkg/middleware"
 	"github.com/openfaas/faas/gateway/types"
 )
@@ -28,7 +31,10 @@ func MakeForwardingProxyHandler(proxy *types.HTTPClientReverseProxy,
 		writeRequestURI = exists
 	}
 
+	reverseProxy := makeRewriteProxy(baseURLResolver, urlPathTransformer)
+
 	return func(w http.ResponseWriter, r *http.Request) {
+
 		baseURL := baseURLResolver.Resolve(r)
 		originalURL := r.URL.String()
 		requestURL := urlPathTransformer.Transform(r)
@@ -39,13 +45,13 @@ func MakeForwardingProxyHandler(proxy *types.HTTPClientReverseProxy,
 
 		start := time.Now()
 
-		statusCode, err := forwardRequest(w, r, proxy.Client, baseURL, requestURL, proxy.Timeout, writeRequestURI, serviceAuthInjector)
-
-		seconds := time.Since(start)
+		statusCode, err := forwardRequest(w, r, proxy.Client, baseURL, requestURL, proxy.Timeout, writeRequestURI, serviceAuthInjector, reverseProxy)
 		if err != nil {
 			log.Printf("error with upstream request to: %s, %s\n", requestURL, err.Error())
 		}
 
+		seconds := time.Since(start)
+
 		for _, notifier := range notifiers {
 			notifier.Notify(r.Method, requestURL, originalURL, statusCode, "completed", seconds)
 		}
@@ -86,7 +92,12 @@ func forwardRequest(w http.ResponseWriter,
 	requestURL string,
 	timeout time.Duration,
 	writeRequestURI bool,
-	serviceAuthInjector middleware.AuthInjector) (int, error) {
+	serviceAuthInjector middleware.AuthInjector,
+	reverseProxy *httputil.ReverseProxy) (int, error) {
+
+	if r.Body != nil {
+		defer r.Body.Close()
+	}
 
 	upstreamReq := buildUpstreamRequest(r, baseURL, requestURL)
 	if upstreamReq.Body != nil {
@@ -101,14 +112,20 @@ func forwardRequest(w http.ResponseWriter,
 		log.Printf("forwardRequest: %s %s\n", upstreamReq.Host, upstreamReq.URL.String())
 	}
 
+	if strings.HasPrefix(r.Header.Get("Accept"), "text/event-stream") {
+		ww := fhttputil.NewHttpWriteInterceptor(w)
+		reverseProxy.ServeHTTP(ww, upstreamReq)
+		return ww.Status(), nil
+	}
+
 	ctx, cancel := context.WithTimeout(r.Context(), timeout)
 	defer cancel()
 
-	res, resErr := proxyClient.Do(upstreamReq.WithContext(ctx))
-	if resErr != nil {
+	res, err := proxyClient.Do(upstreamReq.WithContext(ctx))
+	if err != nil {
 		badStatus := http.StatusBadGateway
 		w.WriteHeader(badStatus)
-		return badStatus, resErr
+		return badStatus, err
 	}
 
 	if res.Body != nil {
@@ -117,12 +134,10 @@ func forwardRequest(w http.ResponseWriter,
 
 	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)
+		io.Copy(w, res.Body)
 	}
 
 	return res.StatusCode, nil
@@ -159,3 +174,14 @@ var hopHeaders = []string{
 	"Transfer-Encoding",
 	"Upgrade",
 }
+
+func makeRewriteProxy(baseURLResolver middleware.BaseURLResolver, urlPathTransformer middleware.URLPathTransformer) *httputil.ReverseProxy {
+	return &httputil.ReverseProxy{
+		ErrorLog:  log.New(io.Discard, "proxy:", 0),
+		Transport: http.DefaultClient.Transport,
+		ErrorHandler: func(w http.ResponseWriter, r *http.Request, err error) {
+		},
+		Director: func(r *http.Request) {
+		},
+	}
+}

gateway/vendor/modules.txt

@@ -40,7 +40,7 @@ github.com/nats-io/nuid
 ## explicit; go 1.14
 github.com/nats-io/stan.go
 github.com/nats-io/stan.go/pb
-# github.com/openfaas/faas-provider v0.24.4
+# github.com/openfaas/faas-provider v0.25.2
 ## explicit; go 1.20
 github.com/openfaas/faas-provider/auth
 github.com/openfaas/faas-provider/httputil