feature(OcAgentExpoter): Allow to setup the service name from a window variable. (#157)

Author: Blightwidow

packages/opencensus-web-core/package-lock.json

@@ -53,4 +53,7 @@ export declare interface WindowWithOcwGlobals extends Window {
    * That way the header is not added to all xhrs.
    */
   ocTraceHeaderHostRegex?: string | RegExp;
+
+  /** Custom name for the service */
+  ocServiceName?: string;
 }

packages/opencensus-web-core/src/trace/model/types.ts

@@ -38,7 +38,8 @@ const TRACE_ENDPOINT = '/v1/trace';
 /**
  * Waits until after the document `load` event fires, and then uses the
  * `window.ocAgent` setting to configure an OpenCensus agent exporter and
- * export the spans for the initial page load.
+ * export the spans for the initial page load. You can customize the name
+ * of the service by specifying `window.ocServiceName`
  */
 export function exportRootSpanAfterLoadEvent() {
   if (!windowWithOcwGlobals.ocAgent) {
@@ -49,6 +50,7 @@ export function exportRootSpanAfterLoadEvent() {
   tracing.registerExporter(
     new OCAgentExporter({
       agentEndpoint: `${windowWithOcwGlobals.ocAgent}${TRACE_ENDPOINT}`,
+      serviceName: windowWithOcwGlobals.ocServiceName,
     })
   );
 

packages/opencensus-web-exporter-ocagent/package-lock.json

@@ -67,7 +67,26 @@ describe('exportRootSpanAfterLoadEvent', () => {
     // Check that trace and span ID from `window.traceparent` are in body sent.
     const sendBody = sendSpy.calls.argsFor(0)[0];
     expect(sendBody).toContain(hexToBase64(traceId));
-    expect(sendBody).toContain(hexToBase64(traceId));
+    expect(sendBody).toContain(hexToBase64(spanId));
+  });
+
+  it('uses service name from window.ocServiceName if specified', () => {
+    windowWithOcwGlobals.ocAgent = 'http://agent';
+    windowWithOcwGlobals.ocServiceName = 'serviceName';
+    windowWithOcwGlobals.traceparent =
+      '00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-01';
+
+    exportRootSpanAfterLoadEvent();
+
+    jasmine.clock().tick(300000);
+    expect(XMLHttpRequest.prototype.open).toHaveBeenCalledWith(
+      'POST',
+      'http://agent/v1/trace'
+    );
+    expect(XMLHttpRequest.prototype.send).toHaveBeenCalledTimes(1);
+    // Check that serviceName from `window.ocServiceName` is in body sent.
+    const sendBody = sendSpy.calls.argsFor(0)[0];
+    expect(sendBody).toContain(windowWithOcwGlobals.ocServiceName);
   });
 
   it('does not export spans if traceparent sampling hint set to zero', () => {