kube-apiserver: add e2e graceful shutdown integration test

staging/src/k8s.io/apiserver/pkg/server/genericapiserver_test.go

@@ -529,7 +529,6 @@ func TestGracefulShutdown(t *testing.T) {
 		graceShutdown = true
 	})
 	okHandler := http.HandlerFunc(func(w http.ResponseWriter, req *http.Request) {
-		wg.Done()
 		w.WriteHeader(http.StatusOK)
 	})
 

test/integration/master/BUILD

@@ -12,6 +12,7 @@ go_test(
     srcs = [
         "audit_test.go",
         "crd_test.go",
+        "graceful_shutdown_test.go",
         "kms_transformation_test.go",
         "kube_apiserver_test.go",
         "main_test.go",

test/integration/master/graceful_shutdown_test.go

+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package master
+
+import (
+	"io"
+	"io/ioutil"
+	"net/http"
+	"sync"
+	"testing"
+	"time"
+
+	"k8s.io/apimachinery/pkg/util/wait"
+	"k8s.io/client-go/rest"
+	kubeapiservertesting "k8s.io/kubernetes/cmd/kube-apiserver/app/testing"
+	"k8s.io/kubernetes/test/integration/framework"
+)
+
+func TestGracefulShutdown(t *testing.T) {
+	server := kubeapiservertesting.StartTestServerOrDie(t, nil, nil, framework.SharedEtcd())
+
+	tearDownOnce := sync.Once{}
+	defer tearDownOnce.Do(server.TearDownFn)
+
+	transport, err := rest.TransportFor(server.ClientConfig)
+	if err != nil {
+		t.Fatalf("unexpected error: %v", err)
+	}
+	client := http.Client{Transport: transport}
+
+	req, body, err := newBlockingRequest("POST", server.ClientConfig.Host+"/api/v1/namespaces")
+	if err != nil {
+		t.Fatal(err)
+	}
+	respErrCh := backgroundRoundtrip(transport, req)
+
+	t.Logf("server should be blocking request for data in body")
+	time.Sleep(time.Millisecond * 500)
+	select {
+	case respErr := <-respErrCh:
+		if respErr.err != nil {
+			t.Fatalf("unexpected error: %v", err)
+		}
+		bs, err := ioutil.ReadAll(respErr.resp.Body)
+		if err != nil {
+			t.Fatal(err)
+		}
+		t.Fatalf("unexpected server answer: %d, body: %s", respErr.resp.StatusCode, string(bs))
+	default:
+	}
+
+	t.Logf("server should answer")
+	resp, err := client.Get(server.ClientConfig.Host + "/")
+	if err != nil {
+		t.Fatal(err)
+	}
+	resp.Body.Close()
+
+	t.Logf("shutting down server")
+	tearDownOnce.Do(server.TearDownFn)
+
+	t.Logf("server should fail new requests")
+	if err := wait.Poll(time.Millisecond*100, wait.ForeverTestTimeout, func() (done bool, err error) {
+		resp, err := client.Get(server.ClientConfig.Host + "/")
+		if err != nil {
+			return true, nil
+		}
+		resp.Body.Close()
+		return false, nil
+	}); err != nil {
+		t.Fatalf("server did not shutdown")
+	}
+
+	t.Logf("server should answer pending request")
+	time.Sleep(time.Millisecond * 500)
+	if _, err := body.Write([]byte("garbage")); err != nil {
+		t.Fatal(err)
+	}
+	body.Close()
+	respErr := <-respErrCh
+	if err != nil {
+		t.Fatal(err)
+	}
+	defer respErr.resp.Body.Close()
+	bs, err := ioutil.ReadAll(respErr.resp.Body)
+	if err != nil {
+		t.Fatal(err)
+	}
+	t.Logf("response: code %d, body: %s", respErr.resp.StatusCode, string(bs))
+}
+
+type responseErrorPair struct {
+	resp *http.Response
+	err  error
+}
+
+func backgroundRoundtrip(transport http.RoundTripper, req *http.Request) <-chan responseErrorPair {
+	ch := make(chan responseErrorPair)
+	go func() {
+		resp, err := transport.RoundTrip(req)
+		ch <- responseErrorPair{resp, err}
+	}()
+	return ch
+}
+
+func newBlockingRequest(method, url string) (*http.Request, io.WriteCloser, error) {
+	bodyReader, bodyWriter := io.Pipe()
+	req, err := http.NewRequest(method, url, bodyReader)
+	return req, bodyWriter, err
+}