Gateway trigger support (#1225)

* initial gateway trigger support

* Pass Content-Type down to wrapped writer

* Move req header setting

* Adding call id to responses

* add dupe Fn-Call-Id headers

api/server/runner_httptrigger.go

@@ -7,6 +7,8 @@ import (
 	"strconv"
 	"time"
 
+	"strings"
+
 	"github.com/fnproject/fn/api"
 	"github.com/fnproject/fn/api/agent"
 	"github.com/fnproject/fn/api/common"
@@ -62,28 +64,89 @@ func (s *Server) handleTriggerHTTPFunctionCall2(c *gin.Context) error {
 	return s.ServeHTTPTrigger(c, app, fn, trigger)
 }
 
-//ServeHTTPTrigger serves an HTTP trigger for a given app/fn/trigger  based on the current request
+type triggerResponseWriter struct {
+	w         http.ResponseWriter
+	headers   http.Header
+	committed bool
+}
+
+var _ http.ResponseWriter = new(triggerResponseWriter)
+
+func (trw *triggerResponseWriter) Header() http.Header {
+	return trw.headers
+}
+
+func (trw *triggerResponseWriter) Write(b []byte) (int, error) {
+	if !trw.committed {
+		trw.WriteHeader(http.StatusOK)
+	}
+	return trw.w.Write(b)
+}
+
+func (trw *triggerResponseWriter) WriteHeader(statusCode int) {
+	if trw.committed {
+		return
+	}
+	trw.committed = true
+	gatewayStatus := 200
+
+	if statusCode >= 400 {
+		gatewayStatus = 502
+	}
+
+	status := trw.headers.Get("Fn-Http-Status")
+	if status != "" {
+		statusInt, err := strconv.Atoi(status)
+		if err == nil {
+			gatewayStatus = statusInt
+		}
+	}
+
+	for k, vs := range trw.headers {
+		if strings.HasPrefix(k, "Fn-Http-H-") {
+			// TODO strip out content-length and stuff here.
+			realHeader := strings.TrimPrefix(k, "Fn-Http-H-")
+			if realHeader != "" { // case where header is exactly the prefix
+				for _, v := range vs {
+					trw.w.Header().Add(realHeader, v)
+				}
+			}
+		}
+	}
+
+	contentType := trw.headers.Get("Content-Type")
+	if contentType != "" {
+		trw.w.Header().Add("Content-Type", contentType)
+	}
+	trw.w.WriteHeader(gatewayStatus)
+}
+
+//ServeHTTPTr	igger serves an HTTP trigger for a given app/fn/trigger  based on the current request
 // This is exported to allow extensions to handle their own trigger naming and publishing
 func (s *Server) ServeHTTPTrigger(c *gin.Context, app *models.App, fn *models.Fn, trigger *models.Trigger) error {
 	buf := bufPool.Get().(*bytes.Buffer)
 	buf.Reset()
-	writer := syncResponseWriter{
+	writer := &syncResponseWriter{
 		Buffer:  buf,
 		headers: c.Writer.Header(), // copy ref
 	}
 	defer bufPool.Put(buf) // TODO need to ensure this is safe with Dispatch?
 
+	triggerWriter := &triggerResponseWriter{
+		w:       writer,
+		headers: make(http.Header),
+	}
 	// GetCall can mod headers, assign an id, look up the route/app (cached),
 	// strip params, etc.
 	// this should happen ASAP to turn app name to app ID
 
 	// GetCall can mod headers, assign an id, look up the route/app (cached),
 	// strip params, etc.
-
 	call, err := s.agent.GetCall(
-		agent.WithWriter(&writer), // XXX (reed): order matters [for now]
+		agent.WithWriter(triggerWriter), // XXX (reed): order matters [for now]
 		agent.FromHTTPTriggerRequest(app, fn, trigger, c.Request),
 	)
+
 	if err != nil {
 		return err
 	}
@@ -92,6 +155,7 @@ func (s *Server) ServeHTTPTrigger(c *gin.Context, app *models.App, fn *models.Fn
 		ctx, _ := common.LoggerWithFields(c.Request.Context(), logrus.Fields{"id": model.ID})
 		c.Request = c.Request.WithContext(ctx)
 	}
+	writer.Header().Add("Fn_call_id", model.ID)
 
 	// TODO TRIGGERWIP  not clear this makes sense here - but it works  so...
 	if model.Type == "async" {
@@ -146,7 +210,7 @@ func (s *Server) ServeHTTPTrigger(c *gin.Context, app *models.App, fn *models.Fn
 	if writer.status > 0 {
 		c.Writer.WriteHeader(writer.status)
 	}
-	io.Copy(c.Writer, &writer)
+	io.Copy(c.Writer, writer)
 
 	return nil
 }

api/server/runner_httptrigger_test.go

@@ -56,16 +56,16 @@ func testRunner(_ *testing.T, args ...interface{}) (agent.Agent, context.CancelF
 
 func checkLogs(t *testing.T, tnum int, ds models.LogStore, callID string, expected []string) bool {
 
-	logReader, err := ds.GetLog(context.Background(), "myapp", callID)
+	logReader, err := ds.GetLog(context.Background(), "fnid_not_needed_by_mock", callID)
 	if err != nil {
-		t.Errorf("Test %d: GetLog for call_id:%s returned err %s",
+		t.Errorf("Test %d: GetLog for call_id:'%s' returned err %s",
 			tnum, callID, err.Error())
 		return false
 	}
 
 	logBytes, err := ioutil.ReadAll(logReader)
 	if err != nil {
-		t.Errorf("Test %d: GetLog read IO call_id:%s returned err %s",
+		t.Errorf("Test %d: GetLog read IO call_id:'%s' returned err %s",
 			tnum, callID, err.Error())
 		return false
 	}
@@ -398,7 +398,7 @@ func TestTriggerRunnerExecution(t *testing.T) {
 				for name, header := range test.expectedHeaders {
 					if header[0] != rec.Header().Get(name) {
 						isFailure = true
-						t.Errorf("Test %d: Expected header `%s` to be %s but was %s. body: %s",
+						t.Errorf("Test %d: Expected header `%s` to be `%s` but was `%s`. body: `%s`",
 							i, name, header[0], rec.Header().Get(name), respBody)
 					}
 				}