agent: when enable_central_service_config is enabled ensure agent reload doesn't revert check state to critical (#8747)

Likely introduced when #7345 landed.

.changelog/8747.txt

@@ -0,0 +1,3 @@
+```release-note:bug
+agent: when enable_central_service_config is enabled ensure agent reload doesn't revert check state to critical
+```

agent/agent.go

@@ -1840,7 +1840,8 @@ func (a *Agent) AddServiceAndReplaceChecks(service *structs.NodeService, chkType
 		token:                 token,
 		replaceExistingChecks: true,
 		source:                source,
-	}, a.snapshotCheckState())
+		snap:                  a.snapshotCheckState(),
+	})
 }
 
 // AddService is used to add a service entry.
@@ -1859,12 +1860,13 @@ func (a *Agent) AddService(service *structs.NodeService, chkTypes []*structs.Che
 		token:                 token,
 		replaceExistingChecks: false,
 		source:                source,
-	}, a.snapshotCheckState())
+		snap:                  a.snapshotCheckState(),
+	})
 }
 
 // addServiceLocked adds a service entry to the service manager if enabled, or directly
 // to the local state if it is not. This function assumes the state lock is already held.
-func (a *Agent) addServiceLocked(req *addServiceRequest, snap map[structs.CheckID]*structs.HealthCheck) error {
+func (a *Agent) addServiceLocked(req *addServiceRequest) error {
 	req.fixupForAddServiceLocked()
 
 	req.service.EnterpriseMeta.Normalize()
@@ -1882,7 +1884,7 @@ func (a *Agent) addServiceLocked(req *addServiceRequest, snap map[structs.CheckI
 	req.persistDefaults = nil
 	req.persistServiceConfig = false
 
-	return a.addServiceInternal(req, snap)
+	return a.addServiceInternal(req)
 }
 
 // addServiceRequest is the union of arguments for calling both
@@ -1907,6 +1909,7 @@ type addServiceRequest struct {
 	token                 string
 	replaceExistingChecks bool
 	source                configSource
+	snap                  map[structs.CheckID]*structs.HealthCheck
 }
 
 func (r *addServiceRequest) fixupForAddServiceLocked() {
@@ -1920,7 +1923,7 @@ func (r *addServiceRequest) fixupForAddServiceInternal() {
 }
 
 // addServiceInternal adds the given service and checks to the local state.
-func (a *Agent) addServiceInternal(req *addServiceRequest, snap map[structs.CheckID]*structs.HealthCheck) error {
+func (a *Agent) addServiceInternal(req *addServiceRequest) error {
 	req.fixupForAddServiceInternal()
 	var (
 		service               = req.service
@@ -1932,6 +1935,7 @@ func (a *Agent) addServiceInternal(req *addServiceRequest, snap map[structs.Chec
 		token                 = req.token
 		replaceExistingChecks = req.replaceExistingChecks
 		source                = req.source
+		snap                  = req.snap
 	)
 
 	// Pause the service syncs during modification
@@ -3066,7 +3070,8 @@ func (a *Agent) loadServices(conf *config.RuntimeConfig, snap map[structs.CheckI
 			token:                 service.Token,
 			replaceExistingChecks: false, // do default behavior
 			source:                ConfigSourceLocal,
-		}, snap)
+			snap:                  snap,
+		})
 		if err != nil {
 			return fmt.Errorf("Failed to register service %q: %v", service.Name, err)
 		}
@@ -3084,7 +3089,8 @@ func (a *Agent) loadServices(conf *config.RuntimeConfig, snap map[structs.CheckI
 				token:                 sidecarToken,
 				replaceExistingChecks: false, // do default behavior
 				source:                ConfigSourceLocal,
-			}, snap)
+				snap:                  snap,
+			})
 			if err != nil {
 				return fmt.Errorf("Failed to register sidecar for service %q: %v", service.Name, err)
 			}
@@ -3176,7 +3182,8 @@ func (a *Agent) loadServices(conf *config.RuntimeConfig, snap map[structs.CheckI
 				token:                 p.Token,
 				replaceExistingChecks: false, // do default behavior
 				source:                source,
-			}, snap)
+				snap:                  snap,
+			})
 			if err != nil {
 				return fmt.Errorf("failed adding service %q: %s", serviceID, err)
 			}

agent/agent_test.go

@@ -3397,14 +3397,24 @@ func TestAgent_ReloadConfigOutgoingRPCConfig(t *testing.T) {
 }
 
 func TestAgent_ReloadConfigAndKeepChecksStatus(t *testing.T) {
-	t.Parallel()
+	t.Run("normal", func(t *testing.T) {
+		t.Parallel()
+		testAgent_ReloadConfigAndKeepChecksStatus(t, "")
+	})
+	t.Run("service manager", func(t *testing.T) {
+		t.Parallel()
+		testAgent_ReloadConfigAndKeepChecksStatus(t, "enable_central_service_config = true")
+	})
+}
+
+func testAgent_ReloadConfigAndKeepChecksStatus(t *testing.T, extraHCL string) {
 	dataDir := testutil.TempDir(t, "agent") // we manage the data dir
 	hcl := `data_dir = "` + dataDir + `"
 		enable_local_script_checks=true
 		services=[{
 		  name="webserver1",
 		  check{id="check1", ttl="30s"}
-		}]`
+		}] ` + extraHCL
 	a := NewTestAgent(t, hcl)
 	defer a.Shutdown()
 
@@ -3419,6 +3429,7 @@ func TestAgent_ReloadConfigAndKeepChecksStatus(t *testing.T) {
 
 	c := TestConfig(testutil.Logger(t), config.FileSource{Name: t.Name(), Format: "hcl", Data: hcl})
 	require.NoError(t, a.reloadConfigInternal(c))
+
 	// After reload, should be passing directly (no critical state)
 	for id, check := range a.State.Checks(nil) {
 		require.Equal(t, "passing", check.Status, "check %q is wrong", id)

agent/service_manager.go

@@ -87,7 +87,11 @@ func (s *ServiceManager) registerOnce(args *addServiceRequest) error {
 	s.agent.stateLock.Lock()
 	defer s.agent.stateLock.Unlock()
 
-	err := s.agent.addServiceInternal(args, s.agent.snapshotCheckState())
+	if args.snap == nil {
+		args.snap = s.agent.snapshotCheckState()
+	}
+
+	err := s.agent.addServiceInternal(args)
 	if err != nil {
 		return fmt.Errorf("error updating service registration: %v", err)
 	}
@@ -128,7 +132,7 @@ func (s *ServiceManager) AddService(req *addServiceRequest) error {
 		req.persistService = nil
 		req.persistDefaults = nil
 		req.persistServiceConfig = false
-		return s.agent.addServiceInternal(req, s.agent.snapshotCheckState())
+		return s.agent.addServiceInternal(req)
 	}
 
 	var (
@@ -273,7 +277,8 @@ func (w *serviceConfigWatch) RegisterAndStart(
 		token:                 w.registration.token,
 		replaceExistingChecks: w.registration.replaceExistingChecks,
 		source:                w.registration.source,
-	}, w.agent.snapshotCheckState())
+		snap:                  w.agent.snapshotCheckState(),
+	})
 	if err != nil {
 		return fmt.Errorf("error updating service registration: %v", err)
 	}