support none value for OTEL_TRACES_EXPORTER and OTEL_METRICS_EXPORTER

docs/advanced-config.md

@@ -64,7 +64,7 @@ This distribution supports all the configuration options supported by the compon
 | `OTEL_SPAN_ATTRIBUTE_VALUE_LENGTH_LIMIT`                        |                         | Stable  | Maximum allowed attribute value size. Empty value is treated as infinity
 | `OTEL_SPAN_EVENT_COUNT_LIMIT`                                   | `128`                   | Stable  |
 | `OTEL_SPAN_LINK_COUNT_LIMIT`                                    | `1000`\*                | Stable  |
-| `OTEL_TRACES_EXPORTER`<br>`tracing.spanExporterFactory`         | `otlp`                  | Stable  | Chooses the trace exporters. Shortcut for setting `spanExporterFactory`. Comma-delimited list of exporters. Currently supported values: `otlp`, `console`.
+| `OTEL_TRACES_EXPORTER`<br>`tracing.spanExporterFactory`         | `otlp`                  | Stable  | Chooses the trace exporters. Shortcut for setting `spanExporterFactory`. Comma-delimited list of exporters. Currently supported values: `otlp`, `console`, `none`.
 | `OTEL_TRACES_SAMPLER`                                           | `parentbased_always_on` | Stable  | Sampler to be used for traces. See [Sampling](https://github.com/open-telemetry/opentelemetry-specification/blob/main/specification/trace/sdk.md#sampling)
 | `OTEL_TRACES_SAMPLER_ARG`                                       |                         | Stable  | String value to be used as the sampler argument. Only be used if OTEL_TRACES_SAMPLER is set.
 | `SPLUNK_ACCESS_TOKEN`<br>`accessToken`                          |                         | Stable  | The optional access token for exporting signal data directly to SignalFx API.
@@ -99,7 +99,7 @@ The following config options can be set by passing them as tracing arguments to
 | `OTEL_SERVICE_NAME`<br>`serviceName`                            | `unnamed-node-service`  | Stable  | The service name of this Node service.
 | `OTEL_EXPORTER_OTLP_METRICS_ENDPOINT`<br>`endpoint`             | `http://localhost:4317` | Stable | The OTLP endpoint to export to.
 | `OTEL_METRIC_EXPORT_INTERVAL`<br>`metrics.exportIntervalMillis` | `30000`                 | Stable | The interval, in milliseconds, of metrics collection and exporting.
-| `OTEL_METRICS_EXPORTER`<br>`metrics.metricReaderFactory`        | `otlp`                  | Stable  | Chooses the metric exporters. Comma-delimited list of exporters. Currently supported values: `otlp`, `console`.
+| `OTEL_METRICS_EXPORTER`<br>`metrics.metricReaderFactory`        | `otlp`                  | Stable  | Chooses the metric exporters. Comma-delimited list of exporters. Currently supported values: `otlp`, `console`, `none`.
 | `OTEL_EXPORTER_OTLP_METRICS_PROTOCOL`<br>`metrics.metricReaderFactory` | `grpc`           | Stable  | Chooses the metric exporter protocol. Currently supported values: `grpc`, `http/protobuf`.
 | `OTEL_RESOURCE_ATTRIBUTES`                                      |                         | Stable  | The resource attributes to metric data. <details><summary>Environment variable example</summary>`key1=val1,key2=val2`</details>
 | `SPLUNK_METRICS_ENABLED`<br>n/a (enabled by calling `start`) | `false`             | Experimental | Sets up the metrics pipeline (global meter provider, exporters).

src/logging/index.ts

@@ -116,13 +116,13 @@ export function _setDefaultOptions(
   };
 }
 
-const SUPPORTED_EXPORTER_TYPES = ['console', 'otlp'];
+const SUPPORTED_EXPORTER_TYPES = ['console', 'otlp', 'none'];
 
 function areValidExporterTypes(types: string[]): boolean {
   return types.every((t) => SUPPORTED_EXPORTER_TYPES.includes(t));
 }
 
-function createExporters(options: LoggingOptions) {
+export function createExporters(options: LoggingOptions) {
   const logExporters: string[] = getEnvArray('OTEL_LOGS_EXPORTER', ['otlp']);
 
   if (!areValidExporterTypes(logExporters)) {

src/metrics/index.ts

@@ -134,7 +134,7 @@ function areValidExporterTypes(types: string[]): boolean {
   return types.every((t) => SUPPORTED_EXPORTER_TYPES.includes(t));
 }
 
-function createOtlpExporter(options: MetricsOptions) {
+export function createOtlpExporter(options: MetricsOptions) {
   let protocol = getEnvValueByPrecedence([
     'OTEL_EXPORTER_OTLP_METRICS_PROTOCOL',
     'OTEL_EXPORTER_OTLP_PROTOCOL',

src/tracing/options.ts

@@ -147,19 +147,16 @@ export function _setDefaultOptions(options: Partial<Options> = {}): Options {
     ...extraTracerConfig,
   };
 
-  const exporterTypes = getExporterTypes(options);
-
-  // factories
   if (options.spanExporterFactory === undefined) {
-    options.spanExporterFactory = resolveTraceExporters(exporterTypes);
+    options.spanExporterFactory = defaultSpanExporterFactory(options);
   }
+
   options.spanProcessorFactory =
     options.spanProcessorFactory || defaultSpanProcessorFactory;
 
   options.propagatorFactory =
     options.propagatorFactory || defaultPropagatorFactory;
 
-  // instrumentations
   if (options.instrumentations === undefined) {
     options.instrumentations = getInstrumentations();
   }
@@ -190,13 +187,14 @@ export function _setDefaultOptions(options: Partial<Options> = {}): Options {
   };
 }
 
-const SUPPORTED_EXPORTER_TYPES = ['console', 'otlp'];
+const SUPPORTED_EXPORTER_TYPES = ['console', 'otlp', 'none'];
 
-type ExporterType = (typeof SUPPORTED_EXPORTER_TYPES)[number];
+export type ExporterType = (typeof SUPPORTED_EXPORTER_TYPES)[number];
 
 const SpanExporterMap: Record<ExporterType, SpanExporterFactory> = {
   console: consoleSpanExporterFactory,
   otlp: otlpSpanExporterFactory,
+  none: () => [],
 };
 
 function containsSupportedRealmExporter(exporterTypes: string[]) {
@@ -239,11 +237,14 @@ function getExporterTypes(options: Partial<Options>): ExporterType[] {
   return traceExporters;
 }
 
-function resolveTraceExporters(
-  exporterTypes: ExporterType[]
+export function defaultSpanExporterFactory(
+  options: Partial<Options>
 ): SpanExporterFactory {
-  const factories = exporterTypes.map((t) => SpanExporterMap[t]);
-  return (options) => factories.flatMap((factory) => factory(options));
+  const exporterTypes = getExporterTypes(options);
+  return (options) => {
+    const factories = exporterTypes.map((t) => SpanExporterMap[t]);
+    return factories.flatMap((factory) => factory(options));
+  };
 }
 
 export function otlpSpanExporterFactory(options: Options): SpanExporter {

test/options.test.ts

@@ -280,6 +280,8 @@ describe('options', () => {
   });
 
   describe('OTEL_TRACES_EXPORTER', () => {
+    beforeEach(utils.cleanEnvironment);
+
     it('accepts a single key', () => {
       process.env.OTEL_TRACES_EXPORTER = 'console';
       const options = _setDefaultOptions();
@@ -290,6 +292,15 @@ describe('options', () => {
       assert(exporters[0] instanceof ConsoleSpanExporter);
     });
 
+    it('can be set to none', () => {
+      process.env.OTEL_TRACES_EXPORTER = 'none';
+      const options = _setDefaultOptions();
+      const exporters = options.spanExporterFactory(options);
+
+      assert(Array.isArray(exporters));
+      assert.deepStrictEqual(exporters.length, 0);
+    });
+
     it('accepts multiple keys', () => {
       process.env.OTEL_TRACES_EXPORTER = 'otlp,console';
       const options = _setDefaultOptions();
@@ -404,9 +415,7 @@ describe('options', () => {
   });
 
   describe('OTLP span exporter factory', () => {
-    beforeEach(() => {
-      beforeEach(utils.cleanEnvironment);
-    });
+    beforeEach(utils.cleanEnvironment);
 
     it('throws when called with an unsupported OTLP protocol', () => {
       process.env.OTEL_EXPORTER_OTLP_TRACES_PROTOCOL = 'http/json';