fix: wait for file and internal before applying configurations

Co-authored-by: Ludovic Fernandez <ldez@users.noreply.github.com>

cmd/traefik/traefik.go

@@ -256,6 +256,7 @@ func setupServer(staticConfiguration *static.Configuration) (*server.Server, err
 		providerAggregator,
 		time.Duration(staticConfiguration.Providers.ProvidersThrottleDuration),
 		getDefaultsEntrypoints(staticConfiguration),
+		"internal",
 	)
 
 	// TLS

pkg/provider/aggregator/aggregator.go

@@ -119,10 +119,6 @@ func (p ProviderAggregator) Init() error {
 
 // Provide calls the provide method of every providers.
 func (p ProviderAggregator) Provide(configurationChan chan<- dynamic.Message, pool *safe.Pool) error {
-	if p.internalProvider != nil {
-		launchProvider(configurationChan, pool, p.internalProvider)
-	}
-
 	if p.fileProvider != nil {
 		launchProvider(configurationChan, pool, p.fileProvider)
 	}
@@ -134,6 +130,12 @@ func (p ProviderAggregator) Provide(configurationChan chan<- dynamic.Message, po
 		})
 	}
 
+	// internal provider must be the last because we use it to know if all the providers are loaded.
+	// ConfigurationWatcher will wait for this requiredProvider before applying configurations.
+	if p.internalProvider != nil {
+		launchProvider(configurationChan, pool, p.internalProvider)
+	}
+
 	return nil
 }
 

pkg/provider/aggregator/aggregator_test.go

@@ -32,12 +32,11 @@ func TestProviderAggregator_Provide(t *testing.T) {
 		errCh <- aggregator.Provide(cfgCh, pool)
 	}()
 
-	// Make sure the internal provider is always called first, followed by the file provider.
-	requireReceivedMessageFromProviders(t, cfgCh, []string{"internal"})
+	// Make sure the file provider is always called first.
 	requireReceivedMessageFromProviders(t, cfgCh, []string{"file"})
 
 	// Check if all providers have been called, the order doesn't matter.
-	requireReceivedMessageFromProviders(t, cfgCh, []string{"salad", "tomato", "onion"})
+	requireReceivedMessageFromProviders(t, cfgCh, []string{"salad", "tomato", "onion", "internal"})
 
 	require.NoError(t, <-errCh)
 }

pkg/server/configurationwatcher.go

@@ -28,6 +28,7 @@ type ConfigurationWatcher struct {
 	configurationValidatedChan chan dynamic.Message
 	providerConfigUpdateMap    map[string]chan dynamic.Message
 
+	requiredProvider       string
 	configurationListeners []func(dynamic.Configuration)
 
 	routinesPool *safe.Pool
@@ -39,6 +40,7 @@ func NewConfigurationWatcher(
 	pvd provider.Provider,
 	providersThrottleDuration time.Duration,
 	defaultEntryPoints []string,
+	requiredProvider string,
 ) *ConfigurationWatcher {
 	watcher := &ConfigurationWatcher{
 		provider:                   pvd,
@@ -48,6 +50,7 @@ func NewConfigurationWatcher(
 		providersThrottleDuration:  providersThrottleDuration,
 		routinesPool:               routinesPool,
 		defaultEntryPoints:         defaultEntryPoints,
+		requiredProvider:           requiredProvider,
 	}
 
 	currentConfigurations := make(dynamic.Configurations)
@@ -146,8 +149,11 @@ func (c *ConfigurationWatcher) loadMessage(configMsg dynamic.Message) {
 	conf := mergeConfiguration(newConfigurations, c.defaultEntryPoints)
 	conf = applyModel(conf)
 
-	for _, listener := range c.configurationListeners {
-		listener(conf)
+	// We wait for first configuration of the require provider before applying configurations.
+	if _, ok := newConfigurations[c.requiredProvider]; c.requiredProvider == "" || ok {
+		for _, listener := range c.configurationListeners {
+			listener(conf)
+		}
 	}
 }
 

pkg/server/configurationwatcher_test.go

@@ -55,7 +55,7 @@ func TestNewConfigurationWatcher(t *testing.T) {
 		}},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, time.Second, []string{})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, time.Second, []string{}, "")
 
 	run := make(chan struct{})
 
@@ -112,7 +112,7 @@ func TestListenProvidersThrottleProviderConfigReload(t *testing.T) {
 		})
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, 30*time.Millisecond, []string{})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, 30*time.Millisecond, []string{}, "")
 
 	publishedConfigCount := 0
 	watcher.AddListener(func(_ dynamic.Configuration) {
@@ -136,7 +136,7 @@ func TestListenProvidersSkipsEmptyConfigs(t *testing.T) {
 		messages: []dynamic.Message{{ProviderName: "mock"}},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, time.Second, []string{})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, time.Second, []string{}, "")
 	watcher.AddListener(func(_ dynamic.Configuration) {
 		t.Error("An empty configuration was published but it should not")
 	})
@@ -162,7 +162,7 @@ func TestListenProvidersSkipsSameConfigurationForProvider(t *testing.T) {
 		messages: []dynamic.Message{message, message},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, 0, []string{})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, 0, []string{}, "")
 
 	alreadyCalled := false
 	watcher.AddListener(func(_ dynamic.Configuration) {
@@ -205,7 +205,7 @@ func TestListenProvidersDoesNotSkipFlappingConfiguration(t *testing.T) {
 		},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, 15*time.Millisecond, []string{"defaultEP"})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, 15*time.Millisecond, []string{"defaultEP"}, "")
 
 	var lastConfig dynamic.Configuration
 	watcher.AddListener(func(conf dynamic.Configuration) {
@@ -260,7 +260,7 @@ func TestListenProvidersPublishesConfigForEachProvider(t *testing.T) {
 		},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, 0, []string{"defaultEP"})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, 0, []string{"defaultEP"}, "")
 
 	var publishedProviderConfig dynamic.Configuration
 
@@ -327,7 +327,7 @@ func TestPublishConfigUpdatedByProvider(t *testing.T) {
 		},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, 30*time.Millisecond, []string{})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, 30*time.Millisecond, []string{}, "")
 
 	publishedConfigCount := 0
 	watcher.AddListener(func(configuration dynamic.Configuration) {
@@ -375,7 +375,7 @@ func TestPublishConfigUpdatedByConfigWatcherListener(t *testing.T) {
 		},
 	}
 
-	watcher := NewConfigurationWatcher(routinesPool, pvd, 30*time.Millisecond, []string{})
+	watcher := NewConfigurationWatcher(routinesPool, pvd, 30*time.Millisecond, []string{}, "")
 
 	publishedConfigCount := 0
 	watcher.AddListener(func(configuration dynamic.Configuration) {