agent: run alias checks

agent/agent.go

@@ -151,6 +151,9 @@ type Agent struct {
 	// checkDockers maps the check ID to an associated Docker Exec based check
 	checkDockers map[types.CheckID]*checks.CheckDocker
 
+	// checkAliases maps the check ID to an associated Alias checks
+	checkAliases map[types.CheckID]*checks.CheckAlias
+
 	// checkLock protects updates to the check* maps
 	checkLock sync.Mutex
 
@@ -232,6 +235,7 @@ func New(c *config.RuntimeConfig) (*Agent, error) {
 		checkTCPs:       make(map[types.CheckID]*checks.CheckTCP),
 		checkGRPCs:      make(map[types.CheckID]*checks.CheckGRPC),
 		checkDockers:    make(map[types.CheckID]*checks.CheckDocker),
+		checkAliases:    make(map[types.CheckID]*checks.CheckAlias),
 		eventCh:         make(chan serf.UserEvent, 1024),
 		eventBuf:        make([]*UserEvent, 256),
 		joinLANNotifier: &systemd.Notifier{},
@@ -1329,6 +1333,9 @@ func (a *Agent) ShutdownAgent() error {
 	for _, chk := range a.checkDockers {
 		chk.Stop()
 	}
+	for _, chk := range a.checkAliases {
+		chk.Stop()
+	}
 
 	// Stop the proxy manager
 	if a.proxyManager != nil {
@@ -2017,6 +2024,32 @@ func (a *Agent) AddCheck(check *structs.HealthCheck, chkType *structs.CheckType,
 			monitor.Start()
 			a.checkMonitors[check.CheckID] = monitor
 
+		case chkType.IsAlias():
+			if existing, ok := a.checkAliases[check.CheckID]; ok {
+				existing.Stop()
+				delete(a.checkAliases, check.CheckID)
+			}
+			if chkType.Interval < checks.MinInterval {
+				a.logger.Printf("[WARN] agent: check '%s' has interval below minimum of %v",
+					check.CheckID, checks.MinInterval)
+				chkType.Interval = checks.MinInterval
+			}
+
+			var rpcReq structs.NodeSpecificRequest
+			rpcReq.Datacenter = a.config.Datacenter
+			rpcReq.Token = a.tokens.AgentToken()
+
+			chkImpl := &checks.CheckAlias{
+				Notify:    a.State,
+				RPC:       a.delegate,
+				RPCReq:    rpcReq,
+				CheckID:   check.CheckID,
+				Node:      chkType.AliasNode,
+				ServiceID: chkType.AliasService,
+			}
+			chkImpl.Start()
+			a.checkAliases[check.CheckID] = chkImpl
+
 		default:
 			return fmt.Errorf("Check type is not valid")
 		}

agent/agent_test.go

@@ -935,6 +935,42 @@ func TestAgent_AddCheck_GRPC(t *testing.T) {
 	}
 }
 
+func TestAgent_AddCheck_Alias(t *testing.T) {
+	t.Parallel()
+	a := NewTestAgent(t.Name(), "")
+	defer a.Shutdown()
+
+	health := &structs.HealthCheck{
+		Node:    "foo",
+		CheckID: "aliashealth",
+		Name:    "Alias health check",
+		Status:  api.HealthCritical,
+	}
+	chk := &structs.CheckType{
+		AliasService: "foo",
+	}
+	err := a.AddCheck(health, chk, false, "")
+	if err != nil {
+		t.Fatalf("err: %v", err)
+	}
+
+	// Ensure we have a check mapping
+	sChk, ok := a.State.Checks()["aliashealth"]
+	if !ok {
+		t.Fatalf("missing aliashealth check")
+	}
+
+	// Ensure our check is in the right state
+	if sChk.Status != api.HealthCritical {
+		t.Fatalf("check not critical")
+	}
+
+	// Ensure a check is setup
+	if _, ok := a.checkAliases["aliashealth"]; !ok {
+		t.Fatalf("missing aliashealth check")
+	}
+}
+
 func TestAgent_RemoveCheck(t *testing.T) {
 	t.Parallel()
 	a := NewTestAgent(t.Name(), `