fix: dont trace ourselves

closes open-telemetry#332

Signed-off-by: Olivier Albertini <[email protected]>

Author: OlivierAlbertini

packages/opentelemetry-exporter-zipkin/src/zipkin.ts

@@ -56,6 +56,7 @@ export class ZipkinExporter implements SpanExporter {
         method: 'POST',
         headers: {
           'Content-Type': 'application/json',
+          'x-ot-request': 1,
         },
       },
       urlOpts

packages/opentelemetry-plugin-http/src/http.ts

@@ -346,9 +346,11 @@ export class HttpPlugin extends BasePlugin<Http> {
           ? (args.shift() as RequestOptions)
           : undefined
       );
+
       options = optionsParsed;
 
       if (
+        Utils.isOpenTelemetryRequest(options) ||
         Utils.isIgnored(origin + pathname, plugin._config.ignoreOutgoingUrls)
       ) {
         return original.apply(this, [options, ...args]);

packages/opentelemetry-plugin-http/src/utils.ts

@@ -242,4 +242,15 @@ export class Utils {
     const type = typeof options;
     return type === 'string' || (type === 'object' && !Array.isArray(options));
   }
+
+  /**
+   * Check whether the given request should be ignored
+   * Use case: Typically, exporter `SpanExporter` can use http module to send spans.
+   * This will also generate spans (from the http-plugin) that will be sended through the exporter
+   * and here we have loop.
+   * @param {RequestOptions} options
+   */
+  static isOpenTelemetryRequest(options: RequestOptions) {
+    return options && options.headers && !!options.headers['x-ot-request'];
+  }
 }

packages/opentelemetry-plugin-http/test/functionals/http-enable.test.ts

@@ -125,6 +125,22 @@ describe('HttpPlugin', () => {
       assertSpan(outgoingSpan, SpanKind.CLIENT, validations);
     });
 
+    it("should not trace requests with 'x-ot-request' header", async () => {
+      const testPath = '/outgoing/do-not-trace';
+      doNock(hostname, testPath, 200, 'Ok');
+
+      const options = {
+        host: hostname,
+        path: testPath,
+        headers: { 'x-ot-request': 1 },
+      };
+
+      const result = await httpRequest.get(options);
+      const spans = memoryExporter.getFinishedSpans();
+      assert.strictEqual(result.data, 'Ok');
+      assert.strictEqual(spans.length, 0);
+    });
+
     const httpErrorCodes = [400, 401, 403, 404, 429, 501, 503, 504, 500];
 
     for (let i = 0; i < httpErrorCodes.length; i++) {