update interface and changelog

Signed-off-by: Ben Ye <ben.ye@bytedance.com>

CHANGELOG.md

@@ -8,6 +8,10 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 
 ## [Unreleased]
 
+### Added
+
+- Support `OTEL_EXPORTER_ZIPKIN_ENDPOINT` env to specify zipkin collector endpoint.
+
 ### Deprecated
 
 - Deprecate module `"go.opentelemetry.io/otel/sdk/export/metric"`, new functionality available in "go.opentelemetry.io/otel/sdk/metric" module:

example/zipkin/main.go

@@ -41,7 +41,7 @@ func initTracer(url string) func() {
 	// configure the sampler to a trace.ParentBased(trace.TraceIDRatioBased) set at the desired
 	// ratio.
 	exporter, err := zipkin.New(
-		zipkin.WithEndpoint(url),
+		url,
 		zipkin.WithLogger(logger),
 	)
 	if err != nil {

exporters/zipkin/zipkin.go

@@ -51,7 +51,6 @@ var (
 type config struct {
 	client *http.Client
 	logger *log.Logger
-	url    string
 }
 
 // Option defines a function that configures the exporter.
@@ -65,13 +64,6 @@ func (fn optionFunc) apply(cfg *config) {
 	fn(cfg)
 }
 
-// WithEndpoint configures the exporter to use the passed collector endpoint.
-func WithEndpoint(endpoint string) Option {
-	return optionFunc(func(cfg *config) {
-		cfg.url = endpoint
-	})
-}
-
 // WithLogger configures the exporter to use the passed logger.
 func WithLogger(logger *log.Logger) Option {
 	return optionFunc(func(cfg *config) {
@@ -87,34 +79,29 @@ func WithClient(client *http.Client) Option {
 }
 
 // New creates a new Zipkin exporter.
-func New(opts ...Option) (*Exporter, error) {
-	var (
-		err error
-		u   *url.URL
-	)
-
-	cfg := config{}
-	for _, opt := range opts {
-		opt.apply(&cfg)
-	}
-
-	if cfg.url == "" {
+func New(collectorURL string, opts ...Option) (*Exporter, error) {
+	if collectorURL == "" {
 		// Use endpoint from env var or default collector URL.
-		cfg.url = envOr(envEndpoint, defaultCollectorURL)
+		collectorURL = envOr(envEndpoint, defaultCollectorURL)
 	}
-	u, err = url.Parse(cfg.url)
+	u, err := url.Parse(collectorURL)
 	if err != nil {
-		return nil, fmt.Errorf("invalid collector URL %q: %v", cfg.url, err)
+		return nil, fmt.Errorf("invalid collector URL %q: %v", collectorURL, err)
 	}
 	if u.Scheme == "" || u.Host == "" {
-		return nil, fmt.Errorf("invalid collector URL %q: no scheme or host", cfg.url)
+		return nil, fmt.Errorf("invalid collector URL %q: no scheme or host", collectorURL)
+	}
+
+	cfg := config{}
+	for _, opt := range opts {
+		opt.apply(&cfg)
 	}
 
 	if cfg.client == nil {
 		cfg.client = http.DefaultClient
 	}
 	return &Exporter{
-		url:    cfg.url,
+		url:    collectorURL,
 		client: cfg.client,
 		logger: cfg.logger,
 	}, nil

exporters/zipkin/zipkin_test.go

@@ -41,7 +41,7 @@ import (
 
 func TestNewRawExporter(t *testing.T) {
 	_, err := New(
-		WithEndpoint(defaultCollectorURL),
+		defaultCollectorURL,
 	)
 
 	assert.NoError(t, err)
@@ -55,7 +55,7 @@ func TestNewRawExporterShouldFailInvalidCollectorURL(t *testing.T) {
 
 	// invalid URL
 	exp, err = New(
-		WithEndpoint("localhost"),
+		"localhost",
 	)
 
 	assert.Error(t, err)
@@ -70,7 +70,7 @@ func TestNewRawExporterEmptyDefaultCollectorURL(t *testing.T) {
 	)
 
 	// use default collector URL if not specified
-	exp, err = New()
+	exp, err = New("")
 
 	assert.NoError(t, err)
 	assert.Equal(t, defaultCollectorURL, exp.url)
@@ -91,7 +91,7 @@ func TestNewRawExporterCollectorURLFromEnv(t *testing.T) {
 		require.NoError(t, envStore.Restore())
 	}()
 
-	exp, err = New()
+	exp, err = New("")
 
 	assert.NoError(t, err)
 	assert.Equal(t, expectedEndpoint, exp.url)
@@ -306,7 +306,7 @@ func TestExportSpans(t *testing.T) {
 	defer collector.Close()
 	ls := &logStore{T: t}
 	logger := logStoreLogger(ls)
-	exporter, err := New(WithEndpoint(collector.url), WithLogger(logger))
+	exporter, err := New(collector.url, WithLogger(logger))
 	require.NoError(t, err)
 	ctx := context.Background()
 	require.Len(t, ls.Messages, 0)
@@ -331,7 +331,7 @@ func TestExporterShutdownHonorsTimeout(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
 	defer cancel()
 
-	exp, err := New()
+	exp, err := New("")
 	require.NoError(t, err)
 
 	innerCtx, innerCancel := context.WithTimeout(ctx, time.Nanosecond)
@@ -344,7 +344,7 @@ func TestExporterShutdownHonorsCancel(t *testing.T) {
 	ctx, cancel := context.WithTimeout(context.Background(), 1*time.Minute)
 	defer cancel()
 
-	exp, err := New()
+	exp, err := New("")
 	require.NoError(t, err)
 
 	innerCtx, innerCancel := context.WithCancel(ctx)
@@ -353,7 +353,7 @@ func TestExporterShutdownHonorsCancel(t *testing.T) {
 }
 
 func TestErrorOnExportShutdownExporter(t *testing.T) {
-	exp, err := New()
+	exp, err := New("")
 	require.NoError(t, err)
 	assert.NoError(t, exp.Shutdown(context.Background()))
 	assert.NoError(t, exp.ExportSpans(context.Background(), nil))