add integration test for graceful shutdowns which release leader leases

test/integration/main_test.go

@@ -1,4 +1,4 @@
-// Copyright 2020-2021 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2023 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package integration
@@ -65,7 +65,7 @@ func splitIntegrationTestsIntoBuckets(m *testing.M) {
 	serialTest := testing.InternalTest{
 		Name: "TestIntegrationSerial",
 		F: func(t *testing.T) {
-			_ = testlib.IntegrationEnv(t) // make sure these tests do not run during unit tests
+			testlib.SkipUnlessIntegration(t) // make sure these tests do not run during unit tests
 			t.Parallel()                     // outer test always runs in parallel for this bucket
 
 			for _, test := range serialTests {
@@ -80,7 +80,7 @@ func splitIntegrationTestsIntoBuckets(m *testing.M) {
 	parallelTest := testing.InternalTest{
 		Name: "TestIntegrationParallel",
 		F: func(t *testing.T) {
-			_ = testlib.IntegrationEnv(t) // make sure these tests do not run during unit tests
+			testlib.SkipUnlessIntegration(t) // make sure these tests do not run during unit tests
 			t.Parallel()                     // outer test always runs in parallel for this bucket
 
 			for _, test := range parallelTests {
@@ -97,7 +97,7 @@ func splitIntegrationTestsIntoBuckets(m *testing.M) {
 	disruptiveTest := testing.InternalTest{
 		Name: "TestIntegrationDisruptive",
 		F: func(t *testing.T) {
-			_ = testlib.IntegrationEnv(t) // make sure these tests do not run during unit tests
+			testlib.SkipUnlessIntegration(t) // make sure these tests do not run during unit tests
 			// outer test never runs in parallel for this bucket
 
 			for _, test := range disruptiveTests {

test/integration/pod_shutdown_test.go

@@ -0,0 +1,232 @@
+// Copyright 2023 the Pinniped contributors. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package integration
+
+import (
+	"bytes"
+	"context"
+	"io"
+	"strings"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/utils/strings/slices"
+
+	"go.pinniped.dev/test/testlib"
+)
+
+// TestPodShutdown_Disruptive is intended to test that the Supervisor and Concierge pods can
+// perform a graceful shutdown. Most importantly, the leader pods should give up their leases
+// before they die.
+// Never run this test in parallel since deleting the pods is disruptive, see main_test.go.
+func TestPodShutdown_Disruptive(t *testing.T) {
+	// Only run this test in CI on Kind clusters, because something about restarting the pods
+	// in this test breaks the "kubectl port-forward" commands that we are using in CI for
+	// AKS, EKS, and GKE clusters. The Go code that we wrote for graceful pod shutdown should
+	// not be sensitive to which distribution it runs on, so running this test only on Kind
+	// should give us sufficient coverage for what we are trying to test here.
+	env := testlib.IntegrationEnv(t, testlib.SkipPodRestartAssertions()).
+		WithKubeDistribution(testlib.KindDistro)
+
+	testShutdownAllPodsOfApp(t, env, env.ConciergeNamespace, env.ConciergeAppName, "-kube-cert-agent-")
+	testShutdownAllPodsOfApp(t, env, env.SupervisorNamespace, env.SupervisorAppName, "")
+}
+
+func testShutdownAllPodsOfApp(t *testing.T, env *testlib.TestEnv, namespace string, appName string, ignorePodsWithNameSubstring string) {
+	// Precondition: the app should have some pods running initially.
+	initialPods := getRunningPodsByNamePrefix(t, namespace, appName+"-", ignorePodsWithNameSubstring)
+	require.Greater(t, len(initialPods), 0)
+
+	// Precondition: the leader election lease should contain the name of one of the initial pods as the lease's holder.
+	waitForLeaderElectionLeaseToHaveHolderIdentity(t, namespace, appName,
+		func(holder string) bool { return holder != "" && slices.Contains(namesOfPods(initialPods), holder) }, 2*time.Minute)
+
+	// Start tailing the logs of all the pods in background goroutines. This struct will keep track
+	// of each background log tail.
+	type podLog struct {
+		pod        corev1.Pod    // which pod's logs are being tailed
+		tailDoneCh chan struct{} // this channel will be closed when it is safe to read from logsBuf
+		logsBuf    *bytes.Buffer // the text of the logs will be put in this buffer
+	}
+	podLogs := make([]*podLog, 0)
+	// Skip tailing pod logs for test runs that are using alternate group suffixes. There seems to be a bug in our
+	// kubeclient package which causes an "unable to find resp serialier" (sic) error for pod log API responses when
+	// the middleware is active. Since we do not tail pod logs in production code (or anywhere else at this time),
+	// we don't need to fix that bug right now just for this test.
+	if env.APIGroupSuffix == "pinniped.dev" {
+		// For each pod, start tailing its logs.
+		for _, pod := range initialPods {
+			tailDoneCh, logTailBuf := tailFollowPodLogs(t, pod)
+			podLogs = append(podLogs, &podLog{
+				pod:        pod,
+				tailDoneCh: tailDoneCh,
+				logsBuf:    logTailBuf,
+			})
+		}
+	}
+
+	// Scale down the deployment's number of replicas to 0, which will shut down all the pods.
+	originalScale := updateDeploymentScale(t, namespace, appName, 0)
+
+	// When the test is over, restore the deployment to the original scale.
+	t.Cleanup(func() {
+		updateDeploymentScale(t, namespace, appName, originalScale)
+
+		// Wait for all the new pods to be running.
+		var newPods []corev1.Pod
+		testlib.RequireEventually(t, func(requireEventually *require.Assertions) {
+			newPods = getRunningPodsByNamePrefix(t, namespace, appName+"-", ignorePodsWithNameSubstring)
+			requireEventually.Len(newPods, originalScale, "wanted pods to return to original scale")
+		}, 2*time.Minute, 200*time.Millisecond)
+
+		// After a short time, leader election should have finished and the lease should contain the name of
+		// one of the new pods as the lease's holder.
+		waitForLeaderElectionLeaseToHaveHolderIdentity(t, namespace, appName,
+			func(holder string) bool { return holder != "" && slices.Contains(namesOfPods(newPods), holder) }, 1*time.Minute)
+
+		t.Logf("new pod of Deployment %s/%s has acquired the leader election lease", namespace, appName)
+	})
+
+	// Double check: the deployment's previous scale should have equaled the actual number of running pods from
+	// the start of the test (before we scaled down).
+	require.Equal(t, len(initialPods), originalScale)
+
+	// Now that we have adjusted the scale to 0, the pods should go away.
+	// Our pods are intended to gracefully shut down within a few seconds, so fail unless it happens fairly quickly.
+	testlib.RequireEventually(t, func(requireEventually *require.Assertions) {
+		pods := getRunningPodsByNamePrefix(t, namespace, appName+"-", ignorePodsWithNameSubstring)
+		requireEventually.Len(pods, 0, "wanted no pods but found some")
+	}, 20*time.Second, 200*time.Millisecond)
+
+	// Look for some interesting log messages in each of the now-dead pod's logs, if we started tailing them above.
+	for _, pl := range podLogs {
+		// Wait for the logs of the now-dead pod to be finished collecting.
+		t.Logf("waiting for tail of pod logs for pod %q", pl.pod.Name)
+		<-pl.tailDoneCh
+		// Assert that the Kubernetes generic apiserver library has started and finished a graceful
+		// shutdown according to its log messages. This is to make sure that the whole graceful shutdown
+		// process was performed successfully and without being blocked.
+		require.Containsf(t, pl.logsBuf.String(), `"[graceful-termination] shutdown event","name":"ShutdownInitiated"`,
+			"did not find expected message in pod log for pod %q", pl.pod.Name)
+		require.Containsf(t, pl.logsBuf.String(), `"[graceful-termination] apiserver is exiting\n"`,
+			"did not find expected message in pod log for pod %q", pl.pod.Name)
+		t.Logf("found expected graceful-termination messages in the logs of pod %q", pl.pod.Name)
+	}
+
+	// The leader election lease should already contain the empty string as the holder, because the old leader
+	// pod should have given up the lease during its graceful shutdown.
+	waitForLeaderElectionLeaseToHaveHolderIdentity(t, namespace, appName,
+		func(holder string) bool { return holder == "" }, 200*time.Millisecond)
+}
+
+// Given a list of pods, return a list of their names.
+func namesOfPods(pods []corev1.Pod) []string {
+	names := make([]string, len(pods))
+	for i, pod := range pods {
+		names[i] = pod.Name
+	}
+	return names
+}
+
+func getRunningPodsByNamePrefix(
+	t *testing.T,
+	namespace string,
+	podNamePrefix string,
+	podNameExcludeSubstring string,
+) (foundPods []corev1.Pod) {
+	t.Helper()
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
+	defer cancel()
+	client := testlib.NewKubernetesClientset(t)
+
+	pods, err := client.CoreV1().Pods(namespace).List(ctx, metav1.ListOptions{})
+	require.NoError(t, err)
+
+	for _, pod := range pods.Items {
+		if !strings.HasPrefix(pod.Name, podNamePrefix) {
+			continue
+		}
+		if podNameExcludeSubstring != "" && strings.Contains(pod.Name, podNameExcludeSubstring) {
+			continue
+		}
+		if pod.Status.Phase != corev1.PodRunning {
+			continue
+		}
+		foundPods = append(foundPods, pod)
+	}
+
+	return foundPods
+}
+
+func updateDeploymentScale(t *testing.T, namespace string, deploymentName string, newScale int) int {
+	t.Helper()
+	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
+	defer cancel()
+	client := testlib.NewKubernetesClientset(t)
+
+	initialScale, err := client.AppsV1().Deployments(namespace).GetScale(ctx, deploymentName, metav1.GetOptions{})
+	require.NoError(t, err)
+
+	desiredScale := initialScale.DeepCopy()
+	desiredScale.Spec.Replicas = int32(newScale)
+	updatedScale, err := client.AppsV1().Deployments(namespace).UpdateScale(ctx, deploymentName, desiredScale, metav1.UpdateOptions{})
+	require.NoError(t, err)
+	t.Logf("updated scale of Deployment %s/%s from %d to %d",
+		namespace, deploymentName, initialScale.Spec.Replicas, updatedScale.Spec.Replicas)
+
+	return int(initialScale.Spec.Replicas)
+}
+
+func tailFollowPodLogs(t *testing.T, pod corev1.Pod) (chan struct{}, *bytes.Buffer) {
+	t.Helper()
+	done := make(chan struct{})
+	var buf bytes.Buffer
+	client := testlib.NewKubernetesClientset(t)
+
+	go func() {
+		// At the end of this block, signal that we are done writing to the returned buf,
+		// so it is now safe to read the logs from the returned buf.
+		defer close(done)
+
+		ctx, cancel := context.WithTimeout(context.Background(), 2*time.Minute)
+		defer cancel()
+
+		req := client.CoreV1().Pods(pod.Namespace).GetLogs(pod.Name, &corev1.PodLogOptions{
+			Follow: true, // keep streaming until completion
+		})
+
+		// This line should block until the pod dies or the context expires.
+		body, err := req.Stream(ctx)
+		require.NoError(t, err)
+
+		_, err = io.Copy(&buf, body)
+		require.NoError(t, err)
+
+		require.NoError(t, body.Close())
+	}()
+
+	return done, &buf
+}
+
+func waitForLeaderElectionLeaseToHaveHolderIdentity(
+	t *testing.T,
+	namespace string,
+	leaseName string,
+	holderIdentityPredicate func(string) bool,
+	waitDuration time.Duration,
+) {
+	t.Helper()
+	ctx, cancel := context.WithTimeout(context.Background(), 3*time.Minute)
+	defer cancel()
+	client := testlib.NewKubernetesClientset(t)
+
+	testlib.RequireEventually(t, func(requireEventually *require.Assertions) {
+		lease, err := client.CoordinationV1().Leases(namespace).Get(ctx, leaseName, metav1.GetOptions{})
+		requireEventually.NoError(err)
+		requireEventually.True(holderIdentityPredicate(*lease.Spec.HolderIdentity))
+	}, waitDuration, 200*time.Millisecond)
+}

test/testlib/env.go

@@ -37,6 +37,8 @@ const (
 type TestEnv struct {
 	t *testing.T
 
+	skipPodRestartAssertions bool
+
 	ToolsNamespace                 string                               `json:"toolsNamespace"`
 	ConciergeNamespace             string                               `json:"conciergeNamespace"`
 	SupervisorNamespace            string                               `json:"supervisorNamespace"`
@@ -120,15 +122,28 @@ func (e *TestEnv) ProxyEnv() []string {
 // environment parsing N times per test and so that any implicit assertions happen only once.
 var memoizedTestEnvsByTest sync.Map //nolint:gochecknoglobals
 
+type TestEnvOption func(env *TestEnv)
+
+// SkipPodRestartAssertions is a functional option that can be passed to IntegrationEnv()
+// to skip using the implicit assertions which check that no pods get restarted during tests.
+// Please using this sparingly, since most pod restarts are caused by unintentional crashes
+// and should therefore cause tests to fail.
+func SkipPodRestartAssertions() TestEnvOption {
+	return func(t *TestEnv) {
+		t.skipPodRestartAssertions = true
+		t.t.Log("skipping pod restart assertions for test", t.t.Name())
+	}
+}
+
 // IntegrationEnv gets the integration test environment from OS environment variables. This
 // method also implies SkipUnlessIntegration().
-func IntegrationEnv(t *testing.T) *TestEnv {
+func IntegrationEnv(t *testing.T, opts ...TestEnvOption) *TestEnv {
 	if existing, exists := memoizedTestEnvsByTest.Load(t); exists {
 		return existing.(*TestEnv)
 	}
 
 	t.Helper()
-	skipUnlessIntegration(t)
+	SkipUnlessIntegration(t)
 
 	capabilitiesDescriptionYAML := os.Getenv("PINNIPED_TEST_CLUSTER_CAPABILITY_YAML")
 	capabilitiesDescriptionFile := os.Getenv("PINNIPED_TEST_CLUSTER_CAPABILITY_FILE")
@@ -142,18 +157,26 @@ func IntegrationEnv(t *testing.T) *TestEnv {
 		require.NoError(t, err)
 	}
 
-	var result TestEnv
-	err := yaml.Unmarshal([]byte(capabilitiesDescriptionYAML), &result)
+	var testEnv TestEnv
+	err := yaml.Unmarshal([]byte(capabilitiesDescriptionYAML), &testEnv)
 	require.NoErrorf(t, err, "capabilities specification was invalid YAML")
 
-	loadEnvVars(t, &result)
-	result.t = t
-	memoizedTestEnvsByTest.Store(t, &result)
+	loadEnvVars(t, &testEnv)
+	testEnv.t = t
 
-	// In every integration test, assert that no pods in our namespaces restart during the test.
-	assertNoRestartsDuringTest(t, result.ConciergeNamespace, "!pinniped.dev/test")
-	assertNoRestartsDuringTest(t, result.SupervisorNamespace, "!pinniped.dev/test")
-	return &result
+	for _, opt := range opts {
+		opt(&testEnv)
+	}
+
+	memoizedTestEnvsByTest.Store(t, &testEnv)
+
+	// By default, in every integration test, assert that no pods in our namespaces restart during the test.
+	if !testEnv.skipPodRestartAssertions {
+		assertNoRestartsDuringTest(t, testEnv.ConciergeNamespace, "!pinniped.dev/test")
+		assertNoRestartsDuringTest(t, testEnv.SupervisorNamespace, "!pinniped.dev/test")
+	}
+
+	return &testEnv
 }
 
 func needEnv(t *testing.T, key string) string {

test/testlib/skip.go

@@ -1,12 +1,12 @@
-// Copyright 2020-2022 the Pinniped contributors. All Rights Reserved.
+// Copyright 2020-2023 the Pinniped contributors. All Rights Reserved.
 // SPDX-License-Identifier: Apache-2.0
 
 package testlib
 
 import "testing"
 
-// skipUnlessIntegration skips the current test if `-short` has been passed to `go test`.
-func skipUnlessIntegration(t *testing.T) {
+// SkipUnlessIntegration skips the current test if `-short` has been passed to `go test`.
+func SkipUnlessIntegration(t *testing.T) {
 	t.Helper()
 
 	if testing.Short() {