support not follow redirect for HTTP client

codegen/templates/http_client.tmpl

@@ -90,6 +90,10 @@ func {{$exportName}}(deps *module.Dependencies) Client {
 	if deps.Default.Config.ContainsKey("http.clients.requestUUIDHeaderKey") {
 		requestUUIDHeaderKey = deps.Default.Config.MustGetString("http.clients.requestUUIDHeaderKey")
 	}
+	followRedirect := true
+	if deps.Default.Config.ContainsKey("clients.{{$clientID}}.followRedirect") {
+		followRedirect = deps.Default.Config.MustGetBoolean("clients.{{$clientID}}.followRedirect")
+	}
 
 
 	circuitBreakerDisabled := configureCicruitBreaker(deps, timeoutVal)
@@ -113,6 +117,7 @@ func {{$exportName}}(deps *module.Dependencies) Client {
 			baseURL,
 			defaultHeaders,
 			timeout,
+			followRedirect,
 		),
 		circuitBreakerDisabled: circuitBreakerDisabled,
 		requestUUIDHeaderKey: requestUUIDHeaderKey,

codegen/test_data/clients/bar.gogen

@@ -248,6 +248,7 @@ func NewClient(deps *module.Dependencies) Client {
 			baseURL,
 			defaultHeaders,
 			timeout,
+			true,
 		),
 	}
 }

package.json

@@ -1,5 +1,6 @@
 {
   "dependencies": {
+    "eclint": "^1.1.5",
     "uber-licence": "^3.1.1"
   }
 }

runtime/client_http_request_test.go

@@ -75,6 +75,7 @@ func TestMakingClientWriteJSONWithBadJSON(t *testing.T) {
 		"/",
 		map[string]string{},
 		time.Second,
+		true,
 	)
 	ctx := context.Background()
 	req := zanzibar.NewClientHTTPRequest(ctx, "clientID", "DoStuff", "clientID::DoStuff", client)

runtime/client_http_response_test.go

@@ -78,6 +78,7 @@ func TestReadAndUnmarshalNonStructBody(t *testing.T) {
 		baseURL,
 		map[string]string{},
 		time.Second,
+		true,
 	)
 	ctx := context.Background()
 
@@ -139,6 +140,7 @@ func TestReadAndUnmarshalNonStructBodyUnmarshalError(t *testing.T) {
 		baseURL,
 		map[string]string{},
 		time.Second,
+		true,
 	)
 	ctx := context.Background()
 
@@ -177,16 +179,25 @@ func TestUnknownStatusCode(t *testing.T) {
 
 	bgateway := gateway.(*benchGateway.BenchGateway)
 
+	addr := bgateway.HTTPBackends()["bar"].RealAddr
+	baseURL := "http://" + addr
+
+	// test UnknownStatusCode along with follow redirect by default
 	fakeEcho := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Location", baseURL+"/bar-path")
+		w.WriteHeader(303)
+		_, err := w.Write([]byte(`false`))
+		assert.NoError(t, err)
+	}
+
+	fakeNormal := func(w http.ResponseWriter, r *http.Request) {
 		w.WriteHeader(999)
 		_, err := w.Write([]byte(`false`))
 		assert.NoError(t, err)
 	}
 
 	bgateway.HTTPBackends()["bar"].HandleFunc("POST", "/bar/echo", fakeEcho)
-
-	addr := bgateway.HTTPBackends()["bar"].RealAddr
-	baseURL := "http://" + addr
+	bgateway.HTTPBackends()["bar"].HandleFunc("GET", "/bar-path", fakeNormal)
 
 	client := zanzibar.NewHTTPClientContext(
 		bgateway.ActualGateway.Logger,
@@ -199,6 +210,7 @@ func TestUnknownStatusCode(t *testing.T) {
 		baseURL,
 		map[string]string{},
 		time.Second,
+		true,
 	)
 
 	ctx := context.Background()
@@ -230,6 +242,79 @@ func TestUnknownStatusCode(t *testing.T) {
 	assert.Len(t, logs["Finished an outgoing client HTTP request"], 1)
 }
 
+func TestNotFollowRedirect(t *testing.T) {
+	gateway, err := benchGateway.CreateGateway(
+		defaultTestConfig,
+		&testGateway.Options{
+			LogWhitelist: map[string]bool{
+				"Could not emit statusCode metric": true,
+			},
+			KnownHTTPBackends: []string{"bar"},
+			ConfigFiles:       util.DefaultConfigFiles("example-gateway"),
+		},
+		exampleGateway.CreateGateway,
+	)
+	if !assert.NoError(t, err) {
+		return
+	}
+	defer gateway.Close()
+
+	bgateway := gateway.(*benchGateway.BenchGateway)
+
+	addr := bgateway.HTTPBackends()["bar"].RealAddr
+	baseURL := "http://" + addr
+
+	redirectURI := baseURL + "/bar-path"
+	fakeEcho := func(w http.ResponseWriter, r *http.Request) {
+		w.Header().Add("Location", redirectURI)
+		w.WriteHeader(303)
+		_, err := w.Write([]byte(`false`))
+		assert.NoError(t, err)
+	}
+
+	fakeNormal := func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(999)
+		_, err := w.Write([]byte(`false`))
+		assert.NoError(t, err)
+	}
+
+	bgateway.HTTPBackends()["bar"].HandleFunc("POST", "/bar/echo", fakeEcho)
+	bgateway.HTTPBackends()["bar"].HandleFunc("GET", "/bar-path", fakeNormal)
+
+	client := zanzibar.NewHTTPClientContext(
+		bgateway.ActualGateway.Logger,
+		bgateway.ActualGateway.ContextMetrics,
+		jsonwrapper.NewDefaultJSONWrapper(),
+		"bar",
+		map[string]string{
+			"echo": "bar::echo",
+		},
+		baseURL,
+		map[string]string{},
+		time.Second,
+		false,
+	)
+
+	ctx := context.Background()
+
+	req := zanzibar.NewClientHTTPRequest(ctx, "bar", "echo", "bar::echo", client)
+
+	err = req.WriteJSON("POST", baseURL+"/bar/echo", nil, myJson{})
+	assert.NoError(t, err)
+
+	res, err := req.Do()
+	assert.NoError(t, err)
+
+	var resp string
+	assert.Error(t, res.ReadAndUnmarshalBody(&resp))
+	assert.Equal(t, "", resp)
+	assert.Equal(t, 303, res.StatusCode)
+	assert.Equal(t, redirectURI, res.Header["Location"][0])
+
+	logs := bgateway.AllLogs()
+	assert.Len(t, logs["Finished an outgoing client HTTP request"], 1)
+}
+
 type myJson struct{}
 
 func (sj myJson) MarshalJSON() ([]byte, error) {

runtime/http_client.go

@@ -72,6 +72,7 @@ func NewHTTPClient(
 		baseURL,
 		defaultHeaders,
 		timeout,
+		true,
 	)
 }
 
@@ -85,6 +86,7 @@ func NewHTTPClientContext(
 	baseURL string,
 	defaultHeaders map[string]string,
 	timeout time.Duration,
+	followRedirect bool,
 ) *HTTPClient {
 	loggers := make(map[string]*zap.Logger, len(methodToTargetEndpoint))
 
@@ -95,14 +97,23 @@ func NewHTTPClientContext(
 			zap.String(logFieldClientThriftMethod, targetEndpointName),
 		)
 	}
+
+	var checkRedirect func(req *http.Request, via []*http.Request) error
+	if !followRedirect {
+		checkRedirect = func(req *http.Request, via []*http.Request) error {
+			return http.ErrUseLastResponse
+		}
+	}
+
 	return &HTTPClient{
 		Client: &http.Client{
 			Transport: &http.Transport{
 				DisableKeepAlives:   false,
 				MaxIdleConns:        500,
 				MaxIdleConnsPerHost: 500,
 			},
-			Timeout: timeout,
+			Timeout:       timeout,
+			CheckRedirect: checkRedirect,
 		},
 		BaseURL:        baseURL,
 		DefaultHeaders: defaultHeaders,