Use Splunk realm for endpoint if defined

CHANGELOG.md

@@ -22,6 +22,8 @@ This project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.htm
 - Add the `WithLogger` option to `github.com/signalfx/splunk-otel-go/distro`
   along with parsing of the `OTEL_LOG_LEVEL` environment variable to set the
   logging level of the default logger used. (#336)
+- The `SPLUNK_REALM` environment variable is now supported. If set, the
+  exporter will use the corresponding Splunk ingest endpoint. (#725)
 
 ### Changed
 

distro/config.go

@@ -41,14 +41,19 @@ const (
 	otelTracesExporterKey = "OTEL_TRACES_EXPORTER"
 
 	// OpenTelemetry exporter endpoints.
-	otelExporterJaegerEndpointKey = "OTEL_EXPORTER_JAEGER_ENDPOINT"
+	otelExporterJaegerEndpointKey     = "OTEL_EXPORTER_JAEGER_ENDPOINT"
+	otelExporterOTLPEndpointKey       = "OTEL_EXPORTER_OTLP_ENDPOINT"
+	otelExporterOTLPTracesEndpointKey = "OTEL_EXPORTER_OTLP_TRACES_ENDPOINT"
 
 	// Logging level to set when using the default logger.
 	otelLogLevelKey = "OTEL_LOG_LEVEL"
 
 	// splunkMetricsEndpointKey defines the endpoint Splunk specific metrics
 	// are sent. This is not currently supported.
 	splunkMetricsEndpointKey = "SPLUNK_METRICS_ENDPOINT"
+
+	// splunkRealmKey defines the Splunk realm to build an endpoint from.
+	splunkRealmKey = "SPLUNK_REALM"
 )
 
 // Default configuration values.
@@ -59,6 +64,9 @@ const (
 	defaultLogLevel      = "info"
 
 	defaultJaegerEndpoint = "http://127.0.0.1:9080/v1/trace"
+
+	realmEndpointFormat     = "https://ingest.%s.signalfx.com/v2/trace"
+	otlpRealmEndpointFormat = realmEndpointFormat + "/otlp"
 )
 
 type exporterConfig struct {
@@ -209,8 +217,28 @@ func (fn optionFunc) apply(c *config) {
 	fn(c)
 }
 
-// WithEndpoint configures the endpoint telemetry is sent to. Passing an empty
-// string results in the default value being used.
+// WithEndpoint configures the endpoint telemetry is sent to.
+//
+// If the SPLUNK_REALM environment variable is defined and this option is not
+// provided the splunk remote endpoint for that realm will be used. The value
+// depends on what exporter is used. For the otlp exporter it will be
+// https://ingest.${SPLUNK_REALM}.signalfx.com/v2/trace/otlp and for the
+// Jaeger thrift exporter it will be
+// https://ingest.${SPLUNK_REALM}.signalfx.com/v2/trace.
+//
+// If the OpenTelemetry endpoint environment variables are defined and this
+// option is not provided, those values will be used (for the appropriate
+// exporter). These environment variables will take precedence over the
+// SPLUNK_REALM environment variable. See the OpenTelemetry documentation for
+// more information on these environment variables:
+// https://github.com/open-telemetry/opentelemetry-specification/blob/v1.9.0/specification/sdk-environment-variables.md
+// and
+// https://github.com/open-telemetry/opentelemetry-specification/blob/v1.9.0/specification/protocol/exporter.md
+//
+// Passing an empty string or not providing this option at all will result in
+// the default value being used. That value depends on what exporter is used.
+// For the otlp exporter it will be http://localhost:4317, and for the Jaeger
+// thrift exporter it will be http://127.0.0.1:9080/v1/trace.
 func WithEndpoint(endpoint string) Option {
 	return optionFunc(func(c *config) {
 		c.ExportConfig.Endpoint = endpoint

distro/exporter.go

@@ -16,6 +16,7 @@ package distro
 
 import (
 	"context"
+	"fmt"
 	"net/http"
 	"os"
 
@@ -41,8 +42,8 @@ var exporters = map[string]traceExporterFunc{
 func newOTLPExporter(c *exporterConfig) (trace.SpanExporter, error) {
 	var opts []otlptracegrpc.Option
 
-	if c.Endpoint != "" {
-		opts = append(opts, otlptracegrpc.WithEndpoint(c.Endpoint))
+	if e := otlpEndpoint(c.Endpoint); e != "" {
+		opts = append(opts, otlptracegrpc.WithEndpoint(e))
 	}
 
 	if c.TLSConfig != nil {
@@ -61,21 +62,33 @@ func newOTLPExporter(c *exporterConfig) (trace.SpanExporter, error) {
 	return otlptracegrpc.New(context.Background(), opts...)
 }
 
+func otlpEndpoint(configured string) string {
+	if configured != "" {
+		return configured
+	}
+
+	// Allow the exporter to interpret these environment variables directly.
+	envs := []string{otelExporterOTLPEndpointKey, otelExporterOTLPTracesEndpointKey}
+	for _, env := range envs {
+		if _, ok := os.LookupEnv(env); ok {
+			return ""
+		}
+	}
+
+	// Use the realm only if OTEL_EXPORTER_OTLP*_ENDPOINT are not defined.
+	if realm, ok := os.LookupEnv(splunkRealmKey); ok {
+		return fmt.Sprintf(otlpRealmEndpointFormat, realm)
+	}
+
+	// The OTel default is the same as Splunk's.
+	return ""
+}
+
 func newJaegerThriftExporter(c *exporterConfig) (trace.SpanExporter, error) {
 	var opts []jaeger.CollectorEndpointOption
 
-	if c.Endpoint == "" {
-		if endpoint := func() string {
-			// Allow the exporter to use environment variables.
-			if _, ok := os.LookupEnv(otelExporterJaegerEndpointKey); ok {
-				return ""
-			}
-			return defaultJaegerEndpoint
-		}(); endpoint != "" {
-			opts = append(opts, jaeger.WithEndpoint(endpoint))
-		}
-	} else {
-		opts = append(opts, jaeger.WithEndpoint(c.Endpoint))
+	if e := jaegerEndpoint(c.Endpoint); e != "" {
+		opts = append(opts, jaeger.WithEndpoint(e))
 	}
 
 	if c.AccessToken != "" {
@@ -97,3 +110,22 @@ func newJaegerThriftExporter(c *exporterConfig) (trace.SpanExporter, error) {
 		jaeger.WithCollectorEndpoint(opts...),
 	)
 }
+
+func jaegerEndpoint(configured string) string {
+	if configured != "" {
+		return configured
+	}
+
+	// Allow the exporter to interpret this environment variable directly.
+	if _, ok := os.LookupEnv(otelExporterJaegerEndpointKey); ok {
+		return ""
+	}
+
+	// Use the realm only if OTEL_EXPORTER_JAGER_ENDPOINT is not defined.
+	if realm, ok := os.LookupEnv(splunkRealmKey); ok {
+		return fmt.Sprintf(realmEndpointFormat, realm)
+	}
+
+	// Use Splunk specific default (locally running collector).
+	return defaultJaegerEndpoint
+}

distro/exporter_test.go

@@ -0,0 +1,77 @@
+// Copyright Splunk Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package distro
+
+import (
+	"fmt"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+const (
+	invalidRealm = "not-a-valid-realm"
+	fakeEndpoint = "some non-zero value"
+)
+
+func TestOTLPEndpoint(t *testing.T) {
+	t.Run("configured", func(t *testing.T) {
+		assert.Equal(t, fakeEndpoint, otlpEndpoint(fakeEndpoint))
+	})
+
+	t.Run("default", func(t *testing.T) {
+		assert.Equal(t, "", otlpEndpoint(""))
+	})
+
+	t.Cleanup(Setenv(splunkRealmKey, invalidRealm))
+	t.Run("realm", func(t *testing.T) {
+		want := fmt.Sprintf(otlpRealmEndpointFormat, invalidRealm)
+		assert.Equal(t, want, otlpEndpoint(""))
+	})
+
+	t.Run(otelExporterOTLPEndpointKey, func(t *testing.T) {
+		t.Cleanup(Setenv(otelExporterOTLPEndpointKey, fakeEndpoint))
+		// SPLUNK_REALM is still set, make sure it does not take precedence.
+		assert.Equal(t, "", otlpEndpoint(""))
+	})
+
+	t.Run(otelExporterOTLPTracesEndpointKey, func(t *testing.T) {
+		t.Cleanup(Setenv(otelExporterOTLPTracesEndpointKey, "some non-zero value"))
+		// SPLUNK_REALM is still set, make sure it does not take precedence.
+		assert.Equal(t, "", otlpEndpoint(""))
+	})
+}
+
+func TestJaegerEndpoint(t *testing.T) {
+	t.Run("configured", func(t *testing.T) {
+		assert.Equal(t, fakeEndpoint, jaegerEndpoint(fakeEndpoint))
+	})
+
+	t.Run("default", func(t *testing.T) {
+		assert.Equal(t, defaultJaegerEndpoint, jaegerEndpoint(""))
+	})
+
+	t.Cleanup(Setenv(splunkRealmKey, invalidRealm))
+	t.Run("realm", func(t *testing.T) {
+		want := fmt.Sprintf(realmEndpointFormat, invalidRealm)
+		assert.Equal(t, want, jaegerEndpoint(""))
+	})
+
+	t.Run(otelExporterJaegerEndpointKey, func(t *testing.T) {
+		t.Cleanup(Setenv(otelExporterJaegerEndpointKey, fakeEndpoint))
+		// SPLUNK_REALM is still set, make sure it does not take precedence.
+		assert.Equal(t, "", jaegerEndpoint(""))
+	})
+}