etcdctl, e2e: add --check-key option to endpoint health

This commit adds a new option --check-key to endpoint health command
for health checking with a custom key. It is mainly for avoiding
permission problem.

e2e/ctl_v3_endpoint_test.go

@@ -40,6 +40,15 @@ func ctlV3EndpointHealth(cx ctlCtx) error {
 	return spawnWithExpects(cmdArgs, lines...)
 }
 
+func ctlV3EndpointHealthWithKey(cx ctlCtx, key string) error {
+	cmdArgs := append(cx.PrefixArgs(), "endpoint", "health", "--health-check-key", key)
+	lines := make([]string, cx.epc.cfg.clusterSize)
+	for i := range lines {
+		lines[i] = "is healthy"
+	}
+	return spawnWithExpects(cmdArgs, lines...)
+}
+
 func endpointStatusTest(cx ctlCtx) {
 	if err := ctlV3EndpointStatus(cx); err != nil {
 		cx.t.Fatalf("endpointStatusTest ctlV3EndpointStatus error (%v)", err)
@@ -82,4 +91,14 @@ func endpointHealthTestWithAuth(cx ctlCtx) {
 	if err := ctlV3EndpointHealthFailPermissionDenied(cx); err != nil {
 		cx.t.Fatalf("endpointStatusTest ctlV3EndpointHealth error (%v)", err)
 	}
+
+	cx.user, cx.pass = "root", "root"
+	if err := ctlV3RoleGrantPermission(cx, "test-role", grantingPerm{true, true, "custom-key", "", false}); err != nil {
+		cx.t.Fatal(err)
+	}
+
+	cx.user, cx.pass = "test-user", "pass"
+	if err := ctlV3EndpointHealthWithKey(cx, "custom-key"); err != nil {
+		cx.t.Fatalf("endpointStatusTest ctlV3EndpointHealth error (%v)", err)
+	}
 }

etcdctl/ctlv3/command/ep_command.go

@@ -25,6 +25,10 @@ import (
 	"github.com/spf13/cobra"
 )
 
+var (
+	healthCheckKey string
+)
+
 // NewEndpointCommand returns the cobra command for "endpoint".
 func NewEndpointCommand() *cobra.Command {
 	ec := &cobra.Command{
@@ -44,6 +48,9 @@ func newEpHealthCommand() *cobra.Command {
 		Short: "Checks the healthiness of endpoints specified in `--endpoints` flag",
 		Run:   epHealthCommandFunc,
 	}
+
+	cmd.Flags().StringVar(&healthCheckKey, "health-check-key", "health", "The key used to perform the health check. Makes sure the user can access the key.")
+
 	return cmd
 }
 
@@ -94,7 +101,7 @@ func epHealthCommandFunc(cmd *cobra.Command, args []string) {
 			// get a random key. As long as we can get the response without an error, the
 			// endpoint is health.
 			ctx, cancel := commandCtx(cmd)
-			_, err = cli.Get(ctx, "health")
+			_, err = cli.Get(ctx, healthCheckKey)
 			cancel()
 			if err != nil {
 				fmt.Printf("%s is unhealthy: failed to commit proposal: %v\n", ep, err)