[addon-operator] refactoring (#574)

Signed-off-by: Evsyukov Denis <denis.evsyukov@flant.com>
Signed-off-by: Pavel Okhlopkov <pavel.okhlopkov@flant.com>
Co-authored-by: Evsyukov Denis <denis.evsyukov@flant.com>
Co-authored-by: Pavel Okhlopkov <pavel.okhlopkov@flant.com>

Author: ldmonster

cmd/addon-operator/main.go

@@ -90,19 +90,25 @@ func start(logger *log.Logger) func(_ *kingpin.ParseContext) error {
 	}
 }
 
+// run initializes and starts the addon operator, blocking until it receives an OS signal to shutdown.
 func run(ctx context.Context, operator *addon_operator.AddonOperator) error {
+	// Create a ConfigMap-based backend for storing configuration
 	bk := configmap.New(operator.KubeClient(), operator.DefaultNamespace, app.ConfigMapName, operator.Logger.Named("kube-config-manager"))
+	// Configure the operator to use this backend for configuration management
 	operator.SetupKubeConfigManager(bk)
 
+	// Setup the operator (initialize controllers, register hooks, etc.)
 	if err := operator.Setup(); err != nil {
 		operator.Logger.Fatal("setup failed", log.Err(err))
 	}
 
+	// Start the operator (begin watching for events and executing hooks)
 	if err := operator.Start(ctx); err != nil {
 		operator.Logger.Fatal("start failed", log.Err(err))
 	}
 
-	// Block action by waiting signals from OS.
+	// Block the main goroutine until the process receives a termination signal
+	// When a signal is received, stop the operator gracefully before exiting
 	utils_signal.WaitForProcessInterruption(func() {
 		operator.Stop()
 		os.Exit(0)

go.mod

@@ -16,7 +16,7 @@ require (
 	github.com/go-openapi/strfmt v0.19.5
 	github.com/go-openapi/swag v0.22.5
 	github.com/go-openapi/validate v0.19.12
-	github.com/goccy/go-graphviz v0.1.3
+	github.com/goccy/go-graphviz v0.2.9
 	github.com/gofrs/uuid/v5 v5.3.2
 	github.com/hashicorp/go-multierror v1.1.1
 	github.com/kennygrant/sanitize v1.2.4
@@ -60,6 +60,7 @@ require (
 	github.com/containerd/log v0.1.0 // indirect
 	github.com/containerd/platforms v0.2.1 // indirect
 	github.com/cyphar/filepath-securejoin v0.2.4 // indirect
+	github.com/disintegration/imaging v1.6.2 // indirect
 	github.com/distribution/reference v0.6.0 // indirect
 	github.com/docker/cli v27.1.1+incompatible // indirect
 	github.com/docker/distribution v2.8.3+incompatible // indirect
@@ -74,6 +75,7 @@ require (
 	github.com/fatih/camelcase v1.0.0 // indirect
 	github.com/fatih/color v1.13.0 // indirect
 	github.com/felixge/httpsnoop v1.0.4 // indirect
+	github.com/flopp/go-findfont v0.1.0 // indirect
 	github.com/fogleman/gg v1.3.0 // indirect
 	github.com/fvbommel/sortorder v1.1.0 // indirect
 	github.com/go-errors/errors v1.4.2 // indirect
@@ -152,6 +154,7 @@ require (
 	github.com/spf13/cast v1.5.0 // indirect
 	github.com/spf13/cobra v1.8.1 // indirect
 	github.com/spf13/pflag v1.0.5 // indirect
+	github.com/tetratelabs/wazero v1.8.1 // indirect
 	github.com/tidwall/match v1.1.1 // indirect
 	github.com/tidwall/pretty v1.2.0 // indirect
 	github.com/xeipuuv/gojsonpointer v0.0.0-20190905194746-02993c407bfb // indirect
@@ -166,7 +169,7 @@ require (
 	go.starlark.net v0.0.0-20230525235612-a134d8f9ddca // indirect
 	golang.org/x/crypto v0.36.0 // indirect
 	golang.org/x/exp v0.0.0-20240719175910-8a7402abbf56 // indirect
-	golang.org/x/image v0.18.0 // indirect
+	golang.org/x/image v0.21.0 // indirect
 	golang.org/x/net v0.38.0 // indirect
 	golang.org/x/oauth2 v0.21.0 // indirect
 	golang.org/x/sync v0.12.0 // indirect

go.sum

@@ -16,16 +16,20 @@ import (
 )
 
 // Bootstrap inits all dependencies for a full-fledged AddonOperator instance.
+// It initializes the debug server and assembles all components needed for operation.
 func (op *AddonOperator) bootstrap() error {
+	// Log application startup message
 	log.Info(shapp.AppStartMessage)
 
+	// Log the path where modules will be searched
 	log.Info("Search modules",
 		slog.String("path", app.ModulesDir))
 
+	// Log the namespace in which the operator will work
 	log.Info("Addon-operator namespace",
 		slog.String("namespace", op.DefaultNamespace))
 
-	// Debug server.
+	// Initialize the debug server for troubleshooting and monitoring
 	// TODO: rewrite shapp global variables to the addon-operator ones
 	var err error
 	op.DebugServer, err = shell_operator.RunDefaultDebugServer(shapp.DebugUnixSocket, shapp.DebugHttpServerAddr, op.Logger.Named("debug-server"))
@@ -34,6 +38,7 @@ func (op *AddonOperator) bootstrap() error {
 		return fmt.Errorf("start Debug server: %w", err)
 	}
 
+	// Assemble all operator components including routes, admission server, metrics updaters, and module management
 	err = op.Assemble(op.DebugServer)
 	if err != nil {
 		log.Error("Fatal", log.Err(err))
@@ -43,25 +48,34 @@ func (op *AddonOperator) bootstrap() error {
 	return nil
 }
 
+// Assemble initializes and connects components of the AddonOperator.
+// It sets up debugging http endpoints, starts netrics services, and initializes the module manager.
 func (op *AddonOperator) Assemble(debugServer *debug.Server) error {
+	// Register default HTTP routes for the operator
 	op.registerDefaultRoutes()
+
+	// Start the admission server if enabled in application configuration
 	if app.AdmissionServerEnabled {
 		op.AdmissionServer.start(op.ctx)
 	}
+
+	// Start background updaters for metrics
 	StartLiveTicksUpdater(op.engine.MetricStorage)
 	StartTasksQueueLengthUpdater(op.engine.MetricStorage, op.engine.TaskQueues)
 
-	// Register routes in debug server.
+	// Register debug HTTP endpoints to inspect internal state
 	op.engine.RegisterDebugQueueRoutes(debugServer)
 	op.engine.RegisterDebugConfigRoutes(debugServer, op.runtimeConfig)
 	op.RegisterDebugGlobalRoutes(debugServer)
 	op.RegisterDebugModuleRoutes(debugServer)
 	op.RegisterDiscoveryRoute(debugServer)
 
+	// Initialize the module manager which handles modules lifecycle
 	if err := op.InitModuleManager(); err != nil {
 		return err
 	}
 
+	// Register graph visualization routes after module manager is initialized
 	op.RegisterDebugGraphRoutes(debugServer)
 
 	return nil
@@ -86,6 +100,7 @@ func (op *AddonOperator) SetupModuleManager(modulesDir string, globalHooksDir st
 		TempDir:        tempDir,
 		ChrootDir:      app.ShellChrootDir,
 	}
+
 	deps := module_manager.ModuleManagerDependencies{
 		KubeObjectPatcher:    op.engine.ObjectPatcher,
 		KubeEventsManager:    op.engine.KubeEventsManager,