restructuring the discovery package

cmd/main.go

@@ -42,7 +42,7 @@ import (
 	"github.com/gnmic/operator/internal/apiserver"
 	"github.com/gnmic/operator/internal/controller"
 	"github.com/gnmic/operator/internal/controller/discovery/core"
-	"github.com/gnmic/operator/internal/controller/discovery/registry"
+	"github.com/gnmic/operator/internal/controller/discovery"
 	webhookv1alpha1 "github.com/gnmic/operator/internal/webhook/v1alpha1"
 	//+kubebuilder:scaffold:imports
 )
@@ -86,7 +86,7 @@ func main() {
 
 	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
 
-	discoveryRegistry := registry.NewRegistry[types.NamespacedName, []core.DiscoveryMessage]()
+	discoveryRegistry := discovery.NewRegistry[types.NamespacedName, core.DiscoveryRegistryValue]()
 
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
 		Scheme:                 scheme,

internal/apiserver/apiserver.go

@@ -6,15 +6,15 @@ import (
 
 	"github.com/gnmic/operator/internal/controller"
 	"github.com/gnmic/operator/internal/controller/discovery/core"
-	"github.com/gnmic/operator/internal/controller/discovery/registry"
+	"github.com/gnmic/operator/internal/controller/discovery"
 	"k8s.io/apimachinery/pkg/types"
 )
 
 type APIServer struct {
 	Server            *http.Server
 	clusterReconciler *controller.ClusterReconciler
 
-	DiscoveryRegistry *registry.Registry[types.NamespacedName, []core.DiscoveryMessage]
+	DiscoveryRegistry *discovery.Registry[types.NamespacedName, core.DiscoveryRegistryValue]
 }
 
 func New(addr string, clusterReconciler *controller.ClusterReconciler) *APIServer {

internal/controller/discovery/client.go

@@ -1,23 +1,27 @@
 package discovery
 
-// File may become obsolete, depends on how the logic to compare desired vs. existing state will get implemented
-
 import (
 	"context"
 
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
 	gnmicv1alpha1 "github.com/gnmic/operator/api/v1alpha1"
-	"github.com/gnmic/operator/internal/controller/discovery/core"
 )
 
-func FetchExistingTargets(ctx context.Context, c client.Client, ts gnmicv1alpha1.TargetSource) ([]gnmicv1alpha1.Target, error) {
+func fetchExistingTargets(
+	ctx context.Context,
+	c client.Client,
+	ts *gnmicv1alpha1.TargetSource,
+) ([]gnmicv1alpha1.Target, error) {
+
 	var targetList gnmicv1alpha1.TargetList
 
-	err := c.List(ctx, &targetList,
+	err := c.List(
+		ctx,
+		&targetList,
 		client.InNamespace(ts.Namespace),
 		client.MatchingLabels{
-			core.LabelTargetSourceName: ts.Name,
+			LabelTargetSourceName: ts.Name,
 		},
 	)
 	if err != nil {

internal/controller/discovery/core/const.go → internal/controller/discovery/const.go

@@ -1,4 +1,4 @@
-package core
+package discovery
 
 const (
 	// Labels

internal/controller/discovery/core/loader_interface.go

@@ -14,7 +14,7 @@ type Loader interface {
 	Name() string
 
 	// Start begins discovery and pushes target snapshots or events into the out channel
-	// The loader must stop cleanly when ctx is cancelled
+	// The loader must stop cleanly when ctx is canceled
 	Start(
 		ctx context.Context,
 		targetsourceName types.NamespacedName,

internal/controller/discovery/core/types.go

@@ -1,9 +1,24 @@
 package core
 
+type DiscoveryRegistryValue struct {
+	Channel        chan<- []DiscoveryMessage
+	WebhookEnabled bool
+}
+
 type LoaderConfig struct {
 	ChunkSize int
 }
 
+// EventAction represents the type of a discovery event
+type EventAction int
+
+const (
+	// EventDelete indicates that a target should be removed
+	EventDelete EventAction = iota
+	// EventApply indicates that a target should be applied (created or updated)
+	EventApply
+)
+
 // DiscoveredTarget represents a target discovered from an external source
 // before it is materialized as a Kubernetes Target CR
 type DiscoveredTarget struct {
@@ -12,14 +27,6 @@ type DiscoveredTarget struct {
 	Labels  map[string]string
 }
 
-const (
-	DELETE EventAction = 0
-	CREATE EventAction = 1
-	UPDATE EventAction = 2
-)
-
-type EventAction int
-
 type DiscoveryEvent struct {
 	Target DiscoveredTarget
 	Event  EventAction

internal/controller/discovery/discovery.go

@@ -0,0 +1,17 @@
+package discovery
+
+// Package discovery implements the discovery runtime subsystem.
+//
+// The discovery subsystem is responsible for:
+// - Receiving discovery data from external providers (loaders, webhooks).
+// - Supervising discovery pipelines and restart semantics.
+// - Applying discovered state to Kubernetes Targets.
+//
+// The package is structured into the following subpackages:
+// - core: message contracts, snapshot/event types, and transport helpers.
+// - pipeline: supervision, restart policies, and lifecycle control.
+// - reconciler: snapshot + event target state application logic.
+// - loaders: target discovery providers (HTTP, webhook, etc.).
+// - registry: key -> channel registry.
+//
+// At the moment, the targetsource controller imports specific subpackages explicitly.

internal/controller/discovery/loaders/http/loader.go

@@ -10,6 +10,7 @@ import (
 
 	gnmicv1alpha1 "github.com/gnmic/operator/api/v1alpha1"
 	"github.com/gnmic/operator/internal/controller/discovery/core"
+	loaderUtils "github.com/gnmic/operator/internal/controller/discovery/loaders/utils"
 	"github.com/google/uuid"
 )
 
@@ -66,7 +67,7 @@ func (l *Loader) Start(
 				},
 			}
 
-			if err := core.SendSnapshot(ctx, out, targets, snapshotID, l.cfg.ChunkSize); err != nil {
+			if err := loaderUtils.SendSnapshot(ctx, out, targets, snapshotID, l.cfg.ChunkSize); err != nil {
 				return err
 			}
 		}

internal/controller/discovery/core/helpers.go → internal/controller/discovery/loaders/utils/send.go

@@ -1,12 +1,14 @@
-package core
+package utils
 
 import (
 	"context"
 	"fmt"
+
+	"github.com/gnmic/operator/internal/controller/discovery/core"
 )
 
 // sendMessages sends discovery messages over a channel in a context-aware manner
-func sendMessages(ctx context.Context, out chan<- []DiscoveryMessage, messages []DiscoveryMessage) error {
+func sendMessages(ctx context.Context, out chan<- []core.DiscoveryMessage, messages []core.DiscoveryMessage) error {
 	select {
 	case <-ctx.Done():
 		return ctx.Err()
@@ -30,14 +32,14 @@ func forEachChunk(total, chunkSize int, fn func(start, end int) error) error {
 }
 
 // createDiscoverySnapshots takes a list of discovered targets and returns chunked DiscoverySnapshots
-func createDiscoverySnapshots(targets []DiscoveredTarget, snapshotID string, chunkSize int) []DiscoverySnapshot {
-	var snapshots []DiscoverySnapshot
+func createDiscoverySnapshots(targets []core.DiscoveredTarget, snapshotID string, chunkSize int) []core.DiscoverySnapshot {
+	var snapshots []core.DiscoverySnapshot
 	totalTargets := len(targets)
 	totalChunks := (totalTargets + chunkSize - 1) / chunkSize
 
 	_ = forEachChunk(totalTargets, chunkSize, func(i, end int) error {
 		chunk := targets[i:end]
-		snapshots = append(snapshots, DiscoverySnapshot{
+		snapshots = append(snapshots, core.DiscoverySnapshot{
 			Targets:     chunk,
 			SnapshotID:  snapshotID,
 			ChunkIndex:  i / chunkSize,
@@ -50,15 +52,15 @@ func createDiscoverySnapshots(targets []DiscoveredTarget, snapshotID string, chu
 }
 
 // SendSnapshot sends discovered targets as a snapshot over a channel in chunks
-func SendSnapshot(ctx context.Context, out chan<- []DiscoveryMessage, targets []DiscoveredTarget, snapshotID string, chunkSize int) error {
+func SendSnapshot(ctx context.Context, out chan<- []core.DiscoveryMessage, targets []core.DiscoveredTarget, snapshotID string, chunkSize int) error {
 	if len(targets) == 0 {
 		return fmt.Errorf("no targets in Snapshot")
 	}
 
 	snapshots := createDiscoverySnapshots(targets, snapshotID, chunkSize)
 	for _, snapshot := range snapshots {
 		// Convert DiscoverySnapshot to DiscoveryMessage
-		messages := make([]DiscoveryMessage, 1)
+		messages := make([]core.DiscoveryMessage, 1)
 		messages[0] = snapshot
 
 		if err := sendMessages(ctx, out, messages); err != nil {
@@ -69,16 +71,16 @@ func SendSnapshot(ctx context.Context, out chan<- []DiscoveryMessage, targets []
 	return nil
 }
 
-func eventsToMessages(events []DiscoveryEvent) []DiscoveryMessage {
-	message := make([]DiscoveryMessage, len(events))
+func eventsToMessages(events []core.DiscoveryEvent) []core.DiscoveryMessage {
+	message := make([]core.DiscoveryMessage, len(events))
 	for i, event := range events {
 		message[i] = event
 	}
 	return message
 }
 
 // SendEvents sends discovery messages over channel in a context-aware manner
-func SendEvents(ctx context.Context, out chan<- []DiscoveryMessage, events []DiscoveryEvent, chunkSize int) error {
+func SendEvents(ctx context.Context, out chan<- []core.DiscoveryMessage, events []core.DiscoveryEvent, chunkSize int) error {
 	if len(events) == 0 {
 		return fmt.Errorf("no events to process")
 	}

internal/controller/discovery/registry/registry.go → internal/controller/discovery/registry.go

@@ -1,4 +1,4 @@
-package registry
+package discovery
 
 import (
 	"fmt"
@@ -10,20 +10,20 @@ import (
 // DO NOT USE a pointer type as K
 type Registry[K comparable, V any] struct {
 	mu sync.RWMutex
-	m  map[K]chan<- V
+	m  map[K]V
 }
 
 func NewRegistry[K comparable, V any]() *Registry[K, V] {
-	return &Registry[K, V]{m: make(map[K]chan<- V)}
+	return &Registry[K, V]{m: make(map[K]V)}
 }
 
-func (r *Registry[K, V]) Register(key K, ch chan<- V) error {
+func (r *Registry[K, V]) Register(key K, value V) error {
 	r.mu.Lock()
 	defer r.mu.Unlock()
 	if _, exists := r.m[key]; exists {
 		return fmt.Errorf("already registered: %v", key)
 	}
-	r.m[key] = ch
+	r.m[key] = value
 	return nil
 }
 
@@ -33,9 +33,9 @@ func (r *Registry[K, V]) Unregister(key K) {
 	r.mu.Unlock()
 }
 
-func (r *Registry[K, V]) Get(key K) (chan<- V, bool) {
+func (r *Registry[K, V]) Get(key K) (V, bool) {
 	r.mu.RLock()
-	ch, ok := r.m[key]
+	value, ok := r.m[key]
 	r.mu.RUnlock()
-	return ch, ok
+	return value, ok
 }

internal/controller/discovery/supervisor.go

@@ -25,12 +25,13 @@ type Supervisor struct {
 	stopped bool
 }
 
-// RestartPolicy defines the restart behavior for a component
+// RestartPolicy defines restart behavior of a component
 type RestartPolicy struct {
 	MaxRestarts int
 	Backoff     time.Duration
 }
 
+// ComponentSpec defines a supervised component
 type ComponentSpec struct {
 	Name   string
 	Run    func(ctx context.Context) error