X-Git-Url: https://git.arvados.org/arvados.git/blobdiff_plain/95e5ccacf6c1193b313fa90a6d39baafa2ba67d8..a7cdd1faaf1de132fa556944bc86831ebdfe8886:/lib/controller/proxy.go

diff --git a/lib/controller/proxy.go b/lib/controller/proxy.go
index 712071bef9..c0b94c2b5f 100644
--- a/lib/controller/proxy.go
+++ b/lib/controller/proxy.go
@@ -5,18 +5,24 @@
 package controller
 
 import (
-	"context"
 	"io"
 	"net/http"
 	"net/url"
-	"time"
 
 	"git.curoverse.com/arvados.git/sdk/go/httpserver"
 )
 
 type proxy struct {
-	Name           string // to use in Via header
-	RequestTimeout time.Duration
+	Name string // to use in Via header
+}
+
+type HTTPError struct {
+	Message string
+	Code    int
+}
+
+func (h HTTPError) Error() string {
+	return h.Message
 }
 
 // headers that shouldn't be forwarded when proxying. See
@@ -26,13 +32,23 @@ var dropHeaders = map[string]bool{
 	"Keep-Alive":          true,
 	"Proxy-Authenticate":  true,
 	"Proxy-Authorization": true,
+	// this line makes gofmt 1.10 and 1.11 agree
 	"TE":                true,
 	"Trailer":           true,
-	"Transfer-Encoding": true,
+	"Transfer-Encoding": true, // *-Encoding headers interfer with Go's automatic compression/decompression
+	"Content-Encoding":  true,
+	"Accept-Encoding":   true,
 	"Upgrade":           true,
 }
 
-func (p *proxy) Do(w http.ResponseWriter, reqIn *http.Request, urlOut *url.URL, client *http.Client) {
+type ResponseFilter func(*http.Response, error) (*http.Response, error)
+
+// Forward a request to upstream service, and return response or error.
+func (p *proxy) Do(
+	reqIn *http.Request,
+	urlOut *url.URL,
+	client *http.Client) (*http.Response, error) {
+
 	// Copy headers from incoming request, then add/replace proxy
 	// headers like Via and X-Forwarded-For.
 	hdrOut := http.Header{}
@@ -51,33 +67,35 @@ func (p *proxy) Do(w http.ResponseWriter, reqIn *http.Request, urlOut *url.URL,
 	}
 	hdrOut.Add("Via", reqIn.Proto+" arvados-controller")
 
-	ctx := reqIn.Context()
-	if p.RequestTimeout > 0 {
-		var cancel context.CancelFunc
-		ctx, cancel = context.WithDeadline(ctx, time.Now().Add(time.Duration(p.RequestTimeout)))
-		defer cancel()
-	}
-
 	reqOut := (&http.Request{
 		Method: reqIn.Method,
 		URL:    urlOut,
 		Host:   reqIn.Host,
 		Header: hdrOut,
 		Body:   reqIn.Body,
-	}).WithContext(ctx)
+	}).WithContext(reqIn.Context())
+
 	resp, err := client.Do(reqOut)
+	return resp, err
+}
+
+// Copy a response (or error) to the downstream client
+func (p *proxy) ForwardResponse(w http.ResponseWriter, resp *http.Response, err error) (int64, error) {
 	if err != nil {
-		httpserver.Error(w, err.Error(), http.StatusBadGateway)
-		return
+		if he, ok := err.(HTTPError); ok {
+			httpserver.Error(w, he.Message, he.Code)
+		} else {
+			httpserver.Error(w, err.Error(), http.StatusBadGateway)
+		}
+		return 0, nil
 	}
+
+	defer resp.Body.Close()
 	for k, v := range resp.Header {
 		for _, v := range v {
 			w.Header().Add(k, v)
 		}
 	}
 	w.WriteHeader(resp.StatusCode)
-	n, err := io.Copy(w, resp.Body)
-	if err != nil {
-		httpserver.Logger(reqIn).WithError(err).WithField("bytesCopied", n).Error("error copying response body")
-	}
+	return io.Copy(w, resp.Body)
 }