Refactor to use Interceptor options & introduce default Client/Server metrics

Author: easyCZ

interceptor.go

@@ -8,12 +8,15 @@ import (
 	"github.com/bufbuild/connect-go"
 )
 
-var ()
+func NewInterceptor(opts ...InterecptorOption) *Interceptor {
+	options := evaluteInterceptorOptions(&interceptorOptions{
+		client: DefaultClientMetrics,
+		server: DefaultServerMetrics,
+	}, opts...)
 
-func NewInterceptor(client *Metrics, server *Metrics) *Interceptor {
 	return &Interceptor{
-		client: client,
-		server: server,
+		client: options.client,
+		server: options.server,
 	}
 }
 
@@ -95,3 +98,29 @@ func codeOf(err error) string {
 	}
 	return connect.CodeOf(err).String()
 }
+
+type interceptorOptions struct {
+	client *Metrics
+	server *Metrics
+}
+
+type InterecptorOption func(*interceptorOptions)
+
+func WithClientMetrics(m *Metrics) InterecptorOption {
+	return func(io *interceptorOptions) {
+		io.client = m
+	}
+}
+
+func WithServerMetrics(m *Metrics) InterecptorOption {
+	return func(io *interceptorOptions) {
+		io.server = m
+	}
+}
+
+func evaluteInterceptorOptions(defaults *interceptorOptions, opts ...InterecptorOption) *interceptorOptions {
+	for _, opt := range opts {
+		opt(defaults)
+	}
+	return defaults
+}

interceptor_test.go

@@ -14,21 +14,25 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func TestInterceptor_WithHistogram(t *testing.T) {
-	reg := prom.NewRegistry()
-	opts := []MetricsOption{
+var (
+	testMetricOptions = []MetricsOption{
 		WithHistogram(true),
 		WithNamespace("namespace"),
 		WithSubsystem("subsystem"),
 		WithConstLabels(prom.Labels{"component": "foo"}),
 		WithHistogramBuckets([]float64{1, 5}),
 	}
-	clientMetrics := NewClientMetrics(opts...)
-	serverMetrics := NewServerMetrics(opts...)
+)
+
+func TestInterceptor_WithClient_WithServer_Histogram(t *testing.T) {
+	reg := prom.NewRegistry()
+
+	clientMetrics := NewClientMetrics(testMetricOptions...)
+	serverMetrics := NewServerMetrics(testMetricOptions...)
 
 	reg.MustRegister(clientMetrics, serverMetrics)
 
-	intereceptor := NewInterceptor(clientMetrics, serverMetrics)
+	intereceptor := NewInterceptor(WithClientMetrics(clientMetrics), WithServerMetrics(serverMetrics))
 
 	_, handler := greetconnect.NewGreetServiceHandler(greetconnect.UnimplementedGreetServiceHandler{}, connect.WithInterceptors(intereceptor))
 	srv := httptest.NewServer(handler)
@@ -54,19 +58,37 @@ func TestInterceptor_WithHistogram(t *testing.T) {
 	require.Equal(t, len(expectedMetrics), count)
 }
 
-func TestInterceptor_WithoutHistogram(t *testing.T) {
-	reg := prom.NewRegistry()
-	opts := []MetricsOption{
-		WithNamespace("namespace"),
-		WithSubsystem("subsystem"),
-		WithConstLabels(prom.Labels{"component": "foo"}),
+func TestInterceptor_Default(t *testing.T) {
+	intereceptor := NewInterceptor()
+
+	_, handler := greetconnect.NewGreetServiceHandler(greetconnect.UnimplementedGreetServiceHandler{}, connect.WithInterceptors(intereceptor))
+	srv := httptest.NewServer(handler)
+
+	client := greetconnect.NewGreetServiceClient(http.DefaultClient, srv.URL, connect.WithInterceptors(intereceptor))
+	_, err := client.Greet(context.Background(), connect.NewRequest(&greet.GreetRequest{
+		Name: "elza",
+	}))
+	require.Error(t, err)
+	require.Equal(t, connect.CodeOf(err), connect.CodeUnimplemented)
+
+	expectedMetrics := []string{
+		"connect_client_handled_total",
+		"connect_client_started_total",
+
+		"connect_server_handled_total",
+		"connect_server_started_total",
 	}
-	clientMetrics := NewClientMetrics(opts...)
-	serverMetrics := NewServerMetrics(opts...)
+	count, err := testutil.GatherAndCount(prom.DefaultGatherer, expectedMetrics...)
+	require.NoError(t, err)
+	require.Equal(t, len(expectedMetrics), count)
+}
 
-	reg.MustRegister(clientMetrics, serverMetrics)
+func TestInterceptor_WithClientMetrics(t *testing.T) {
+	reg := prom.NewRegistry()
+	clientMetrics := NewClientMetrics(testMetricOptions...)
+	require.NoError(t, reg.Register(clientMetrics))
 
-	intereceptor := NewInterceptor(clientMetrics, serverMetrics)
+	intereceptor := NewInterceptor(WithClientMetrics(clientMetrics))
 
 	_, handler := greetconnect.NewGreetServiceHandler(greetconnect.UnimplementedGreetServiceHandler{}, connect.WithInterceptors(intereceptor))
 	srv := httptest.NewServer(handler)
@@ -81,7 +103,30 @@ func TestInterceptor_WithoutHistogram(t *testing.T) {
 	expectedMetrics := []string{
 		"namespace_subsystem_connect_client_handled_total",
 		"namespace_subsystem_connect_client_started_total",
+	}
+	count, err := testutil.GatherAndCount(reg, expectedMetrics...)
+	require.NoError(t, err)
+	require.Equal(t, len(expectedMetrics), count)
+}
+
+func TestInterceptor_WithServerMetrics(t *testing.T) {
+	reg := prom.NewRegistry()
+	serverMetrics := NewServerMetrics(testMetricOptions...)
+	require.NoError(t, reg.Register(serverMetrics))
+
+	intereceptor := NewInterceptor(WithServerMetrics(serverMetrics))
 
+	_, handler := greetconnect.NewGreetServiceHandler(greetconnect.UnimplementedGreetServiceHandler{}, connect.WithInterceptors(intereceptor))
+	srv := httptest.NewServer(handler)
+
+	client := greetconnect.NewGreetServiceClient(http.DefaultClient, srv.URL, connect.WithInterceptors(intereceptor))
+	_, err := client.Greet(context.Background(), connect.NewRequest(&greet.GreetRequest{
+		Name: "elza",
+	}))
+	require.Error(t, err)
+	require.Equal(t, connect.CodeOf(err), connect.CodeUnimplemented)
+
+	expectedMetrics := []string{
 		"namespace_subsystem_connect_server_handled_total",
 		"namespace_subsystem_connect_server_started_total",
 	}

metrics.go

@@ -4,6 +4,17 @@ import (
 	prom "github.com/prometheus/client_golang/prometheus"
 )
 
+var (
+	DefaultClientMetrics = NewClientMetrics()
+	DefaultServerMetrics = NewServerMetrics()
+)
+
+func init() {
+	// Register default metrics against default prometheus metrics registry.
+	prom.MustRegister(DefaultServerMetrics)
+	prom.MustRegister(DefaultClientMetrics)
+}
+
 // NewServerMetrics creates new Connect metrics for server-side handling.
 func NewServerMetrics(opts ...MetricsOption) *Metrics {
 	config := evaluateMetricsOptions(&metricsOptions{
@@ -163,24 +174,6 @@ func WithSubsystem(subsystem string) MetricsOption {
 	}
 }
 
-func withRequestStartedName(name string) MetricsOption {
-	return func(opts *metricsOptions) {
-		opts.requestStartedName = name
-	}
-}
-
-func withrequestHandledName(name string) MetricsOption {
-	return func(opts *metricsOptions) {
-		opts.requestHandledName = name
-	}
-}
-
-func withRequestedHandledSecondsName(name string) MetricsOption {
-	return func(opts *metricsOptions) {
-		opts.requestHandledSecondsName = name
-	}
-}
-
 func WithConstLabels(labels prom.Labels) MetricsOption {
 	return func(opts *metricsOptions) {
 		opts.constLabels = labels