[AGTHEAL-112] refactor(snmptraps): migrate forwarder component to v2 (#49774)

### What does this PR do?

Migrates `comp/snmptraps/forwarder` to V2 component architecture.

- `component.go` → `def/component.go`
- `forwarderimpl/forwarder.go` → `impl/forwarder.go`
- New `fx/fx.go` with `FxLifecycleAdapter()`
- `fx.In`/`fx.Lifecycle`/`fx.Hook` → `compdef.In`/`compdef.Lifecycle`/`compdef.Hook`
- `lc fx.Lifecycle` direct parameter moved into `Requires` struct as `Lc compdef.Lifecycle`
- `Module()` removed from impl, lives in `fx/fx.go`
- `newTrapForwarder` renamed to `NewComponent` with `Requires`/`Provides` pattern

### Motivation

Part of the ongoing V1→V2 component migration effort across the codebase.

### Describe how you validated your changes

Pre-commit hooks (go-fmt, copyright) pass. Callers updated accordingly.

### Additional Notes

The only external caller (`comp/snmptraps/server/serverimpl/server.go`) has been updated to import `forwarder/def` and `forwarder/fx` instead of the old `forwarder` and `forwarder/forwarderimpl` paths.

Co-authored-by: louis.coquerelle <louis.coquerelle@datadoghq.com>

Author: louis-cqrl

comp/snmptraps/forwarder/BUILD.bazel

@@ -0,0 +1,19 @@
+// Unless explicitly stated otherwise all files in this repository are licensed
+// under the Apache License Version 2.0.
+// This product includes software developed at Datadog (https://www.datadoghq.com/).
+// Copyright 2023-present Datadog, Inc.
+
+// Package fx provides the fx module for the snmptraps forwarder component.
+package fx
+
+import (
+	forwarderimpl "github.com/DataDog/datadog-agent/comp/snmptraps/forwarder/impl"
+	"github.com/DataDog/datadog-agent/pkg/util/fxutil"
+)
+
+// Module defines the fx options for this component.
+func Module() fxutil.Module {
+	return fxutil.Component(
+		fxutil.ProvideComponentConstructor(forwarderimpl.NewComponent),
+	)
+}

comp/snmptraps/forwarder/component.go comp/snmptraps/forwarder/def/component.gocomp/snmptraps/forwarder/component.go renamed to comp/snmptraps/forwarder/def/component.go

@@ -10,27 +10,18 @@ import (
 	"context"
 	"time"
 
-	"go.uber.org/fx"
-
 	"github.com/DataDog/datadog-agent/comp/aggregator/demultiplexer"
 	log "github.com/DataDog/datadog-agent/comp/core/log/def"
+	compdef "github.com/DataDog/datadog-agent/comp/def"
 	"github.com/DataDog/datadog-agent/comp/forwarder/eventplatform"
 	config "github.com/DataDog/datadog-agent/comp/snmptraps/config/def"
 	formatter "github.com/DataDog/datadog-agent/comp/snmptraps/formatter/def"
-	"github.com/DataDog/datadog-agent/comp/snmptraps/forwarder"
+	forwarder "github.com/DataDog/datadog-agent/comp/snmptraps/forwarder/def"
 	listener "github.com/DataDog/datadog-agent/comp/snmptraps/listener/def"
 	"github.com/DataDog/datadog-agent/comp/snmptraps/packet"
 	"github.com/DataDog/datadog-agent/pkg/aggregator/sender"
-	"github.com/DataDog/datadog-agent/pkg/util/fxutil"
 )
 
-// Module defines the fx options for this component.
-func Module() fxutil.Module {
-	return fxutil.Component(
-		fx.Provide(newTrapForwarder),
-	)
-}
-
 // trapForwarder consumes SNMP packets, formats traps and send them as EventPlatformEvents
 // The trapForwarder is an intermediate step between the listener and the epforwarder in order to limit the processing of the listener
 // to the minimum. The forwarder process payloads received by the listener via the trapsIn channel, formats them and finally
@@ -43,20 +34,28 @@ type trapForwarder struct {
 	logger    log.Component
 }
 
-type dependencies struct {
-	fx.In
+// Requires defines the dependencies for the forwarder component.
+type Requires struct {
+	compdef.In
+	Lc        compdef.Lifecycle
 	Config    config.Component
 	Formatter formatter.Component
 	Demux     demultiplexer.Component
 	Listener  listener.Component
 	Logger    log.Component
 }
 
-// newTrapForwarder creates a simple TrapForwarder instance
-func newTrapForwarder(lc fx.Lifecycle, dep dependencies) (forwarder.Component, error) {
+// Provides defines the output of the forwarder component.
+type Provides struct {
+	compdef.Out
+	Comp forwarder.Component
+}
+
+// NewComponent creates a simple TrapForwarder instance
+func NewComponent(dep Requires) (Provides, error) {
 	sender, err := dep.Demux.GetDefaultSender()
 	if err != nil {
-		return nil, err
+		return Provides{}, err
 	}
 	tf := &trapForwarder{
 		trapsIn:   dep.Listener.Packets(),
@@ -67,7 +66,7 @@ func newTrapForwarder(lc fx.Lifecycle, dep dependencies) (forwarder.Component, e
 	}
 	conf := dep.Config.Get()
 	if conf.Enabled {
-		lc.Append(fx.Hook{
+		dep.Lc.Append(compdef.Hook{
 			OnStart: func(_ context.Context) error {
 				tf.Start()
 				return nil
@@ -79,7 +78,7 @@ func newTrapForwarder(lc fx.Lifecycle, dep dependencies) (forwarder.Component, e
 		})
 	}
 
-	return tf, nil
+	return Provides{Comp: tf}, nil
 }
 
 // Start the TrapForwarder instance. Need to Stop it manually.

comp/snmptraps/forwarder/fx/fx.go

@@ -18,7 +18,7 @@ import (
 	configfx "github.com/DataDog/datadog-agent/comp/snmptraps/config/fx"
 	formatter "github.com/DataDog/datadog-agent/comp/snmptraps/formatter/def"
 	formatterfx "github.com/DataDog/datadog-agent/comp/snmptraps/formatter/fx"
-	"github.com/DataDog/datadog-agent/comp/snmptraps/forwarder"
+	forwarder "github.com/DataDog/datadog-agent/comp/snmptraps/forwarder/def"
 	listener "github.com/DataDog/datadog-agent/comp/snmptraps/listener/def"
 	listenerfx "github.com/DataDog/datadog-agent/comp/snmptraps/listener/fx"
 	"github.com/DataDog/datadog-agent/comp/snmptraps/packet"
@@ -44,7 +44,7 @@ func setUp(t *testing.T) *services {
 		senderhelper.Opts,
 		formatterfx.MockModule(),
 		listenerfx.MockModule(),
-		Module(),
+		fxutil.ProvideComponentConstructor(NewComponent),
 	)
 	return &s
 }

…aps/forwarder/forwarderimpl/forwarder.go …mp/snmptraps/forwarder/impl/forwarder.gocomp/snmptraps/forwarder/forwarderimpl/forwarder.go renamed to comp/snmptraps/forwarder/impl/forwarder.go comp/snmptraps/forwarder/forwarderimpl/forwarder.go renamed to comp/snmptraps/forwarder/impl/forwarder.go

@@ -23,8 +23,8 @@ import (
 	configfx "github.com/DataDog/datadog-agent/comp/snmptraps/config/fx"
 	formatter "github.com/DataDog/datadog-agent/comp/snmptraps/formatter/def"
 	formatterimpl "github.com/DataDog/datadog-agent/comp/snmptraps/formatter/impl"
-	"github.com/DataDog/datadog-agent/comp/snmptraps/forwarder"
-	"github.com/DataDog/datadog-agent/comp/snmptraps/forwarder/forwarderimpl"
+	forwarder "github.com/DataDog/datadog-agent/comp/snmptraps/forwarder/def"
+	forwarderimpl "github.com/DataDog/datadog-agent/comp/snmptraps/forwarder/fx"
 	listener "github.com/DataDog/datadog-agent/comp/snmptraps/listener/def"
 	listenerfx "github.com/DataDog/datadog-agent/comp/snmptraps/listener/fx"
 	oidresolverfx "github.com/DataDog/datadog-agent/comp/snmptraps/oidresolver/fx"