give feedback to CLI user on forceleave command if node does not exist (#6841)

agent/agent.go

@@ -1782,6 +1782,9 @@ func (a *Agent) JoinWAN(addrs []string) (n int, err error) {
 // ForceLeave is used to remove a failed node from the cluster
 func (a *Agent) ForceLeave(node string, prune bool) (err error) {
 	a.logger.Printf("[INFO] agent: Force leaving node: %v", node)
+	if ok := a.IsMember(node); !ok {
+		return fmt.Errorf("agent: No node found with name '%s'", node)
+	}
 	err = a.delegate.RemoveFailedNode(node, prune)
 	if err != nil {
 		a.logger.Printf("[WARN] agent: Failed to remove node: %v", err)
@@ -1807,6 +1810,18 @@ func (a *Agent) WANMembers() []serf.Member {
 	return nil
 }
 
+// IsMember is used to check if a node with the given nodeName
+// is a member
+func (a *Agent) IsMember(nodeName string) bool {
+	for _, m := range a.LANMembers() {
+		if m.Name == nodeName {
+			return true
+		}
+	}
+
+	return false
+}
+
 // StartSync is called once Services and Checks are registered.
 // This is called to prevent a race between clients and the anti-entropy routines
 func (a *Agent) StartSync() {

agent/agent_endpoint_test.go

@@ -1632,15 +1632,17 @@ func TestAgent_ForceLeave_ACLDeny(t *testing.T) {
 	defer a.Shutdown()
 	testrpc.WaitForLeader(t, a.RPC, "dc1")
 
+	uri := fmt.Sprintf("/v1/agent/force-leave/%s", a.Config.NodeName)
+
 	t.Run("no token", func(t *testing.T) {
-		req, _ := http.NewRequest("PUT", "/v1/agent/force-leave/nope", nil)
+		req, _ := http.NewRequest("PUT", uri, nil)
 		if _, err := a.srv.AgentForceLeave(nil, req); !acl.IsErrPermissionDenied(err) {
 			t.Fatalf("err: %v", err)
 		}
 	})
 
 	t.Run("agent master token", func(t *testing.T) {
-		req, _ := http.NewRequest("PUT", "/v1/agent/force-leave/nope?token=towel", nil)
+		req, _ := http.NewRequest("PUT", uri+"?token=towel", nil)
 		if _, err := a.srv.AgentForceLeave(nil, req); err != nil {
 			t.Fatalf("err: %v", err)
 		}
@@ -1648,7 +1650,7 @@ func TestAgent_ForceLeave_ACLDeny(t *testing.T) {
 
 	t.Run("read-only token", func(t *testing.T) {
 		ro := makeReadOnlyAgentACL(t, a.srv)
-		req, _ := http.NewRequest("PUT", fmt.Sprintf("/v1/agent/force-leave/nope?token=%s", ro), nil)
+		req, _ := http.NewRequest("PUT", fmt.Sprintf(uri+"?token=%s", ro), nil)
 		if _, err := a.srv.AgentForceLeave(nil, req); !acl.IsErrPermissionDenied(err) {
 			t.Fatalf("err: %v", err)
 		}

api/agent_test.go

@@ -1073,7 +1073,7 @@ func TestAPI_AgentForceLeave(t *testing.T) {
 	agent := c.Agent()
 
 	// Eject somebody
-	err := agent.ForceLeave("foo")
+	err := agent.ForceLeave(s.Config.NodeName)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}
@@ -1087,7 +1087,7 @@ func TestAPI_AgentForceLeavePrune(t *testing.T) {
 	agent := c.Agent()
 
 	// Eject somebody
-	err := agent.ForceLeavePrune("foo")
+	err := agent.ForceLeavePrune(s.Config.NodeName)
 	if err != nil {
 		t.Fatalf("err: %v", err)
 	}

command/forceleave/forceleave_test.go

@@ -56,6 +56,24 @@ func TestForceLeaveCommand(t *testing.T) {
 	})
 }
 
+func TestForceLeaveCommand_NoNodeWithName(t *testing.T) {
+	t.Parallel()
+	a1 := agent.NewTestAgent(t, t.Name(), ``)
+	defer a1.Shutdown()
+
+	ui := cli.NewMockUi()
+	c := New(ui)
+	args := []string{
+		"-http-addr=" + a1.HTTPAddr(),
+		"garbage-name",
+	}
+
+	code := c.Run(args)
+	if code != 1 {
+		t.Fatalf("bad: %d. %#v", code, ui.ErrorWriter.String())
+	}
+}
+
 func TestForceLeaveCommand_prune(t *testing.T) {
 	t.Parallel()
 	a1 := agent.NewTestAgent(t, t.Name()+"-a1", ``)