POC for how to avoid duplicating WithStart and WithShutdown

Signed-off-by: Bogdan Drutu <[email protected]>

component/component.go

@@ -77,6 +77,41 @@ func (f ShutdownFunc) Shutdown(ctx context.Context) error {
 	return f(ctx)
 }
 
+type baseComponent struct {
+	StartFunc
+	ShutdownFunc
+}
+
+type Option interface {
+	apply(bc *baseComponent)
+}
+
+type optionFunc func(*baseComponent)
+
+func (of optionFunc) apply(bc *baseComponent) {
+	of(bc)
+}
+
+func WithStartFunc(start StartFunc) Option {
+	return optionFunc(func(o *baseComponent) {
+		o.StartFunc = start
+	})
+}
+
+func WithShutdownFunc(shutdown ShutdownFunc) Option {
+	return optionFunc(func(o *baseComponent) {
+		o.ShutdownFunc = shutdown
+	})
+}
+
+func NewComponent(opts ...Option) Component {
+	bc := baseComponent{}
+	for _, opt := range opts {
+		opt.apply(&bc)
+	}
+	return bc
+}
+
 // Kind represents component kinds.
 type Kind struct {
 	name string

extension/auth/client.go

@@ -27,12 +27,12 @@ type Client interface {
 
 // ClientOption represents the possible options for NewClient.
 type ClientOption interface {
-	apply(*defaultClient)
+	apply(*clientOptions)
 }
 
-type clientOptionFunc func(*defaultClient)
+type clientOptionFunc func(*clientOptions)
 
-func (of clientOptionFunc) apply(e *defaultClient) {
+func (of clientOptionFunc) apply(e *clientOptions) {
 	of(e)
 }
 
@@ -56,52 +56,63 @@ func (f ClientPerRPCCredentialsFunc) PerRPCCredentials() (credentials.PerRPCCred
 	return f()
 }
 
-type defaultClient struct {
-	component.StartFunc
-	component.ShutdownFunc
-	ClientRoundTripperFunc
-	ClientPerRPCCredentialsFunc
+type clientOptions struct {
+	componentOptions  []component.Option
+	roundTripper      ClientRoundTripperFunc
+	perRPCCredentials ClientPerRPCCredentialsFunc
 }
 
-// WithClientStart overrides the default `Start` function for a component.Component.
-// The default always returns nil.
-func WithClientStart(startFunc component.StartFunc) ClientOption {
-	return clientOptionFunc(func(o *defaultClient) {
-		o.StartFunc = startFunc
+// WithClientComponentOptions overrides the default component.Component (start/shutdown) functions for a Client.
+// The default functions do nothing and always returns nil.
+func WithClientComponentOptions(option ...component.Option) ClientOption {
+	return clientOptionFunc(func(e *clientOptions) {
+		e.componentOptions = append(e.componentOptions, option...)
 	})
 }
 
-// WithClientShutdown overrides the default `Shutdown` function for a component.Component.
-// The default always returns nil.
-func WithClientShutdown(shutdownFunc component.ShutdownFunc) ClientOption {
-	return clientOptionFunc(func(o *defaultClient) {
-		o.ShutdownFunc = shutdownFunc
-	})
+// Deprecated: [v0.121.0] use WithClientComponentOptions.
+func WithClientStart(start component.StartFunc) ClientOption {
+	return WithClientComponentOptions(component.WithStartFunc(start))
+}
+
+// Deprecated: [v0.121.0] use WithClientComponentOptions.
+func WithClientShutdown(shutdown component.ShutdownFunc) ClientOption {
+	return WithClientComponentOptions(component.WithShutdownFunc(shutdown))
 }
 
 // WithClientRoundTripper provides a `RoundTripper` function for this client authenticator.
 // The default round tripper is no-op.
 func WithClientRoundTripper(roundTripperFunc ClientRoundTripperFunc) ClientOption {
-	return clientOptionFunc(func(o *defaultClient) {
-		o.ClientRoundTripperFunc = roundTripperFunc
+	return clientOptionFunc(func(o *clientOptions) {
+		o.roundTripper = roundTripperFunc
 	})
 }
 
 // WithClientPerRPCCredentials provides a `PerRPCCredentials` function for this client authenticator.
 // There's no default.
 func WithClientPerRPCCredentials(perRPCCredentialsFunc ClientPerRPCCredentialsFunc) ClientOption {
-	return clientOptionFunc(func(o *defaultClient) {
-		o.ClientPerRPCCredentialsFunc = perRPCCredentialsFunc
+	return clientOptionFunc(func(o *clientOptions) {
+		o.perRPCCredentials = perRPCCredentialsFunc
 	})
 }
 
+type baseClient struct {
+	component.Component
+	ClientRoundTripperFunc
+	ClientPerRPCCredentialsFunc
+}
+
 // NewClient returns a Client configured with the provided options.
 func NewClient(options ...ClientOption) Client {
-	bc := &defaultClient{}
+	bc := &clientOptions{}
 
 	for _, op := range options {
 		op.apply(bc)
 	}
 
-	return bc
+	return baseClient{
+		Component:                   component.NewComponent(bc.componentOptions...),
+		ClientRoundTripperFunc:      bc.roundTripper,
+		ClientPerRPCCredentialsFunc: bc.perRPCCredentials,
+	}
 }

extension/auth/server.go

@@ -29,20 +29,19 @@ type Server interface {
 	Authenticate(ctx context.Context, sources map[string][]string) (context.Context, error)
 }
 
-type defaultServer struct {
-	ServerAuthenticateFunc
-	component.StartFunc
-	component.ShutdownFunc
+type serverOptions struct {
+	componentOptions []component.Option
+	serverAuth       ServerAuthenticateFunc
 }
 
 // ServerOption represents the possible options for NewServer.
 type ServerOption interface {
-	apply(*defaultServer)
+	apply(*serverOptions)
 }
 
-type serverOptionFunc func(*defaultServer)
+type serverOptionFunc func(*serverOptions)
 
-func (of serverOptionFunc) apply(e *defaultServer) {
+func (of serverOptionFunc) apply(e *serverOptions) {
 	of(e)
 }
 
@@ -59,34 +58,44 @@ func (f ServerAuthenticateFunc) Authenticate(ctx context.Context, sources map[st
 
 // WithServerAuthenticate specifies which function to use to perform the authentication.
 func WithServerAuthenticate(authFunc ServerAuthenticateFunc) ServerOption {
-	return serverOptionFunc(func(o *defaultServer) {
-		o.ServerAuthenticateFunc = authFunc
+	return serverOptionFunc(func(o *serverOptions) {
+		o.serverAuth = authFunc
 	})
 }
 
-// WithServerStart overrides the default `Start` function for a component.Component.
-// The default always returns nil.
-func WithServerStart(startFunc component.StartFunc) ServerOption {
-	return serverOptionFunc(func(o *defaultServer) {
-		o.StartFunc = startFunc
+// WithServerComponentOptions overrides the default component.Component (start/shutdown) functions for a Server.
+// The default functions do nothing and always returns nil.
+func WithServerComponentOptions(option ...component.Option) ServerOption {
+	return serverOptionFunc(func(e *serverOptions) {
+		e.componentOptions = append(e.componentOptions, option...)
 	})
 }
 
-// WithServerShutdown overrides the default `Shutdown` function for a component.Component.
-// The default always returns nil.
-func WithServerShutdown(shutdownFunc component.ShutdownFunc) ServerOption {
-	return serverOptionFunc(func(o *defaultServer) {
-		o.ShutdownFunc = shutdownFunc
-	})
+// Deprecated: [v0.121.0] use WithServerComponentOptions.
+func WithServerStart(start component.StartFunc) ServerOption {
+	return WithServerComponentOptions(component.WithStartFunc(start))
+}
+
+// Deprecated: [v0.121.0] use WithServerComponentOptions.
+func WithServerShutdown(shutdown component.ShutdownFunc) ServerOption {
+	return WithServerComponentOptions(component.WithShutdownFunc(shutdown))
+}
+
+type baseServer struct {
+	component.Component
+	ServerAuthenticateFunc
 }
 
 // NewServer returns a Server configured with the provided options.
 func NewServer(options ...ServerOption) Server {
-	bc := &defaultServer{}
+	so := &serverOptions{}
 
 	for _, op := range options {
-		op.apply(bc)
+		op.apply(so)
 	}
 
-	return bc
+	return baseServer{
+		Component:              component.NewComponent(so.componentOptions...),
+		ServerAuthenticateFunc: so.serverAuth,
+	}
 }

processor/processorhelper/logs.go

@@ -21,8 +21,7 @@ import (
 type ProcessLogsFunc func(context.Context, plog.Logs) (plog.Logs, error)
 
 type logs struct {
-	component.StartFunc
-	component.ShutdownFunc
+	component.Component
 	consumer.Logs
 }
 
@@ -70,8 +69,7 @@ func NewLogs(
 	}
 
 	return &logs{
-		StartFunc:    bs.StartFunc,
-		ShutdownFunc: bs.ShutdownFunc,
-		Logs:         logsConsumer,
+		Component: component.NewComponent(bs.componentOptions...),
+		Logs:      logsConsumer,
 	}, nil
 }

processor/processorhelper/metrics.go

@@ -21,8 +21,7 @@ import (
 type ProcessMetricsFunc func(context.Context, pmetric.Metrics) (pmetric.Metrics, error)
 
 type metrics struct {
-	component.StartFunc
-	component.ShutdownFunc
+	component.Component
 	consumer.Metrics
 }
 
@@ -70,8 +69,7 @@ func NewMetrics(
 	}
 
 	return &metrics{
-		StartFunc:    bs.StartFunc,
-		ShutdownFunc: bs.ShutdownFunc,
-		Metrics:      metricsConsumer,
+		Component: component.NewComponent(bs.componentOptions...),
+		Metrics:   metricsConsumer,
 	}, nil
 }

processor/processorhelper/processor.go

@@ -32,20 +32,22 @@ func (of optionFunc) apply(e *baseSettings) {
 	of(e)
 }
 
-// WithStart overrides the default Start function for an processor.
-// The default shutdown function does nothing and always returns nil.
-func WithStart(start component.StartFunc) Option {
-	return optionFunc(func(o *baseSettings) {
-		o.StartFunc = start
+// WithComponentOptions overrides the default component (start/shutdown) functions for a processor.
+// The default functions do nothing and always returns nil.
+func WithComponentOptions(option ...component.Option) Option {
+	return optionFunc(func(e *baseSettings) {
+		e.componentOptions = append(e.componentOptions, option...)
 	})
 }
 
-// WithShutdown overrides the default Shutdown function for an processor.
-// The default shutdown function does nothing and always returns nil.
+// Deprecated: [v0.121.0] use WithComponentOptions.
+func WithStart(start component.StartFunc) Option {
+	return WithComponentOptions(component.WithStartFunc(start))
+}
+
+// Deprecated: [v0.121.0] use WithComponentOptions.
 func WithShutdown(shutdown component.ShutdownFunc) Option {
-	return optionFunc(func(o *baseSettings) {
-		o.ShutdownFunc = shutdown
-	})
+	return WithComponentOptions(component.WithShutdownFunc(shutdown))
 }
 
 // WithCapabilities overrides the default GetCapabilities function for an processor.
@@ -57,9 +59,8 @@ func WithCapabilities(capabilities consumer.Capabilities) Option {
 }
 
 type baseSettings struct {
-	component.StartFunc
-	component.ShutdownFunc
-	consumerOptions []consumer.Option
+	componentOptions []component.Option
+	consumerOptions  []consumer.Option
 }
 
 // fromOptions returns the internal settings starting from the default and applying all options.

processor/processorhelper/traces.go

@@ -21,8 +21,7 @@ import (
 type ProcessTracesFunc func(context.Context, ptrace.Traces) (ptrace.Traces, error)
 
 type traces struct {
-	component.StartFunc
-	component.ShutdownFunc
+	component.Component
 	consumer.Traces
 }
 
@@ -70,8 +69,7 @@ func NewTraces(
 	}
 
 	return &traces{
-		StartFunc:    bs.StartFunc,
-		ShutdownFunc: bs.ShutdownFunc,
-		Traces:       traceConsumer,
+		Component: component.NewComponent(bs.componentOptions...),
+		Traces:    traceConsumer,
 	}, nil
 }