allow leader election to accept namespace

* remove isRunLocal()
* change errNoNamespace value, it now returns
  "Namespace is required when running outside the cluster"
* update tests

Author: jmrodri

leader/leader.go

@@ -44,11 +44,10 @@ var forceRunModeEnv = "OSDK_FORCE_RUN_MODE"
 
 // errNoNamespace indicates that a namespace could not be found for the current
 // environment
-var errNoNamespace = fmt.Errorf("namespace not found for current environment")
+var errNoNamespace = fmt.Errorf("Namespace is required when running outside the cluster")
 
-// errRunLocal indicates that the operator is set to run in local mode (this error
-// is returned by functions that only work on operators running in cluster mode)
-var errRunLocal = fmt.Errorf("operator run mode forced to local")
+// namespaceDir is the default location where namespace information is stored
+var namespaceDir = "/var/run/secrets/kubernetes.io/serviceaccount/namespace"
 
 // podNameEnvVar is the constant for env variable POD_NAME
 // which is the name of the current pod.
@@ -60,23 +59,22 @@ var log = logf.Log.WithName("leader")
 // attempts to become the leader.
 const maxBackoffInterval = time.Second * 16
 
-// Become ensures that the current pod is the leader within its namespace. If
-// run outside a cluster, it will skip leader election and return nil. It
+// Become ensures that the current pod is the leader within the given
+// namespace. If run outside a cluster, it will return an error. It
 // continuously tries to create a ConfigMap with the provided name and the
 // current pod set as the owner reference. Only one can exist at a time with
 // the same name, so the pod that successfully creates the ConfigMap is the
-// leader. Upon termination of that pod, the garbage collector will delete the
-// ConfigMap, enabling a different pod to become the leader.
-func Become(ctx context.Context, lockName string) error {
+// leader. Upon termination of that pod, the garbage collector will delete
+// the ConfigMap, enabling a different pod to become the leader.
+func Become(ctx context.Context, lockName string, ns string) error {
 	log.Info("Trying to become the leader.")
 
-	ns, err := getOperatorNamespace()
-	if err != nil {
-		if err == errNoNamespace || err == errRunLocal {
-			log.Info("Skipping leader election; not running in a cluster.")
-			return nil
+	if ns == "" {
+		namespace, err := getOperatorNamespace()
+		if err != nil {
+			return err
 		}
-		return err
+		ns = namespace
 	}
 
 	config, err := config.GetConfig()
@@ -211,10 +209,7 @@ func isPodEvicted(pod corev1.Pod) bool {
 
 // getOperatorNamespace returns the namespace the operator should be running in.
 func getOperatorNamespace() (string, error) {
-	if isRunModeLocal() {
-		return "", errRunLocal
-	}
-	nsBytes, err := ioutil.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace")
+	nsBytes, err := ioutil.ReadFile(namespaceDir)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return "", errNoNamespace
@@ -226,17 +221,10 @@ func getOperatorNamespace() (string, error) {
 	return ns, nil
 }
 
-func isRunModeLocal() bool {
-	return os.Getenv(forceRunModeEnv) == string(localRunMode)
-}
-
 // getPod returns a Pod object that corresponds to the pod in which the code
 // is currently running.
 // It expects the environment variable POD_NAME to be set by the downwards API.
 func getPod(ctx context.Context, client crclient.Client, ns string) (*corev1.Pod, error) {
-	if isRunModeLocal() {
-		return nil, errRunLocal
-	}
 	podName := os.Getenv(podNameEnvVar)
 	if podName == "" {
 		return nil, fmt.Errorf("required env %s not set, please configure downward API", podNameEnvVar)

leader/leader_test.go

@@ -0,0 +1,104 @@
+package leader
+
+import (
+	"context"
+	"testing"
+
+	corev1 "k8s.io/api/core/v1"
+)
+
+func TestBecome(t *testing.T) {
+	err := Become(context.TODO(), "testOperator", "foobar")
+	if err == nil {
+		t.Fatal("expected it to fail")
+	}
+}
+
+func TestGetOperatorNamespace(t *testing.T) {
+	namespaceDir = "/tmp/namespace"
+
+	testCases := []struct {
+		name        string
+		expected    string
+		expectedErr bool
+	}{
+		{
+			name:        "no namespace available",
+			expectedErr: true,
+		},
+	}
+
+	// test
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual, err := getOperatorNamespace()
+			if tc.expectedErr {
+				if err == nil {
+					t.Fatal("expected error but got none")
+				}
+			}
+			if actual != tc.expected {
+				t.Fatalf("expected %v received %v", tc.expected, actual)
+			}
+		})
+	}
+}
+
+func TestIsPodEvicted(t *testing.T) {
+	testCases := []struct {
+		name     string
+		pod      corev1.Pod
+		expected bool
+	}{
+		{
+			name:     "Evicted pod returns true",
+			expected: true,
+			pod: corev1.Pod{
+				Status: corev1.PodStatus{
+					Phase:  corev1.PodFailed,
+					Reason: "Evicted",
+				},
+			},
+		},
+		{
+			name:     "Failed pod but not evicted returns false",
+			expected: false,
+			pod: corev1.Pod{
+				Status: corev1.PodStatus{
+					Phase:  corev1.PodFailed,
+					Reason: "Don't know",
+				},
+			},
+		},
+		{
+			name:     "Succeded pod returns false",
+			expected: false,
+			pod: corev1.Pod{
+				Status: corev1.PodStatus{
+					Phase: corev1.PodSucceeded,
+				},
+			},
+		},
+		{
+			name:     "Invalid reason for pod returns false",
+			expected: false,
+			pod: corev1.Pod{
+				Status: corev1.PodStatus{
+					Phase:  corev1.PodSucceeded,
+					Reason: "Evicted",
+				},
+			},
+		},
+	}
+
+	// test
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			actual := isPodEvicted(tc.pod)
+			if actual != tc.expected {
+				t.Fatalf("expected %v received %v", tc.expected, actual)
+			}
+		})
+	}
+
+}