Updates for text streaming functions

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

vendor/github.com/openfaas/faas-provider/proxy/proxy.go

@@ -26,11 +26,12 @@ import (
 	"log"
 	"net"
 	"net/http"
+	"net/http/httputil"
 	"net/url"
 	"time"
 
 	"github.com/gorilla/mux"
-	"github.com/openfaas/faas-provider/httputil"
+	fhttputil "github.com/openfaas/faas-provider/httputil"
 	"github.com/openfaas/faas-provider/types"
 )
 
@@ -68,6 +69,17 @@ func NewHandlerFunc(config types.FaaSConfig, resolver BaseURLResolver, verbose b
 
 	proxyClient := NewProxyClientFromConfig(config)
 
+	reverseProxy := httputil.ReverseProxy{}
+	reverseProxy.Director = func(req *http.Request) {
+		// At least an empty director is required to prevent runtime errors.
+		req.URL.Scheme = "http"
+	}
+	reverseProxy.ErrorHandler = func(w http.ResponseWriter, r *http.Request, err error) {
+	}
+
+	// Errors are common during disconnect of client, no need to log them.
+	reverseProxy.ErrorLog = log.New(io.Discard, "", 0)
+
 	return func(w http.ResponseWriter, r *http.Request) {
 		if r.Body != nil {
 			defer r.Body.Close()
@@ -81,7 +93,7 @@ func NewHandlerFunc(config types.FaaSConfig, resolver BaseURLResolver, verbose b
 			http.MethodGet,
 			http.MethodOptions,
 			http.MethodHead:
-			proxyRequest(w, r, proxyClient, resolver, verbose)
+			proxyRequest(w, r, proxyClient, resolver, &reverseProxy, verbose)
 
 		default:
 			w.WriteHeader(http.StatusMethodNotAllowed)
@@ -134,7 +146,7 @@ func NewProxyClient(timeout time.Duration, maxIdleConns int, maxIdleConnsPerHost
 }
 
 // proxyRequest handles the actual resolution of and then request to the function service.
-func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient *http.Client, resolver BaseURLResolver, verbose bool) {
+func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient *http.Client, resolver BaseURLResolver, reverseProxy *httputil.ReverseProxy, verbose bool) {
 	ctx := originalReq.Context()
 
 	pathVars := mux.Vars(originalReq)
@@ -142,7 +154,7 @@ func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient
 	if functionName == "" {
 		w.Header().Add(openFaaSInternalHeader, "proxy")
 
-		httputil.Errorf(w, http.StatusBadRequest, "Provide function name in the request path")
+		fhttputil.Errorf(w, http.StatusBadRequest, "Provide function name in the request path")
 		return
 	}
 
@@ -152,7 +164,7 @@ func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient
 
 		// TODO: Should record the 404/not found error in Prometheus.
 		log.Printf("resolver error: no endpoints for %s: %s\n", functionName, err.Error())
-		httputil.Errorf(w, http.StatusServiceUnavailable, "No endpoints available for: %s.", functionName)
+		fhttputil.Errorf(w, http.StatusServiceUnavailable, "No endpoints available for: %s.", functionName)
 		return
 	}
 
@@ -161,7 +173,7 @@ func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient
 
 		w.Header().Add(openFaaSInternalHeader, "proxy")
 
-		httputil.Errorf(w, http.StatusInternalServerError, "Failed to resolve service: %s.", functionName)
+		fhttputil.Errorf(w, http.StatusInternalServerError, "Failed to resolve service: %s.", functionName)
 		return
 	}
 
@@ -169,16 +181,29 @@ func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient
 		defer proxyReq.Body.Close()
 	}
 
-	start := time.Now()
+	if verbose {
+		start := time.Now()
+		defer func() {
+			seconds := time.Since(start)
+			log.Printf("%s took %f seconds\n", functionName, seconds.Seconds())
+		}()
+	}
+
+	if v := originalReq.Header.Get("Accept"); v == "text/event-stream" {
+		originalReq.URL = proxyReq.URL
+
+		reverseProxy.ServeHTTP(w, originalReq)
+		return
+	}
+
 	response, err := proxyClient.Do(proxyReq.WithContext(ctx))
-	seconds := time.Since(start)
 
 	if err != nil {
 		log.Printf("error with proxy request to: %s, %s\n", proxyReq.URL.String(), err.Error())
 
 		w.Header().Add(openFaaSInternalHeader, "proxy")
 
-		httputil.Errorf(w, http.StatusInternalServerError, "Can't reach service for: %s.", functionName)
+		fhttputil.Errorf(w, http.StatusInternalServerError, "Can't reach service for: %s.", functionName)
 		return
 	}
 
@@ -186,10 +211,6 @@ func proxyRequest(w http.ResponseWriter, originalReq *http.Request, proxyClient
 		defer response.Body.Close()
 	}
 
-	if verbose {
-		log.Printf("%s took %f seconds\n", functionName, seconds.Seconds())
-	}
-
 	clientHeader := w.Header()
 	copyHeaders(clientHeader, &response.Header)
 	w.Header().Set("Content-Type", getContentType(originalReq.Header, response.Header))