fix(exporter-collector): set content-encoding header only when compressing

Author: alisabzevari

packages/opentelemetry-exporter-collector/src/platform/node/util.ts

@@ -51,7 +51,6 @@ export function sendWithHttp<ExportItem, ServiceRequest>(
     headers: {
       'Content-Length': Buffer.byteLength(data),
       'Content-Type': contentType,
-      'Content-Encoding': 'gzip',
       ...collector.headers,
     },
     agent: collector.agent,
@@ -84,6 +83,7 @@ export function sendWithHttp<ExportItem, ServiceRequest>(
 
   switch (collector.compression) {
     case CompressionAlgorithm.GZIP: {
+      req.setHeader('Content-Encoding', 'gzip');
       const dataStream = readableFromBuffer(data);
       dataStream.on('error', onError)
         .pipe(gzip).on('error', onError)

packages/opentelemetry-exporter-collector/test/node/CollectorTraceExporter.test.ts

@@ -44,6 +44,7 @@ describe('CollectorTraceExporter - node with json over http', () => {
   let collectorExporter: CollectorTraceExporter;
   let collectorExporterConfig: CollectorExporterNodeConfigBase;
   let stubRequest: sinon.SinonStub;
+  let spySetHeader: sinon.SinonSpy;
   let spans: ReadableSpan[];
 
   afterEach(() => {
@@ -148,6 +149,17 @@ describe('CollectorTraceExporter - node with json over http', () => {
       });
     });
 
+    it('should not have Content-Encoding header', done => {
+      collectorExporter.export(spans, () => { });
+
+      setTimeout(() => {
+        const args = stubRequest.args[0];
+        const options = args[0];
+        assert.strictEqual(options.headers['Content-Encoding'], undefined);
+        done();
+      });
+    });
+
     it('should have keep alive and keepAliveMsecs option set', done => {
       collectorExporter.export(spans, () => { });
 
@@ -251,6 +263,8 @@ describe('CollectorTraceExporter - node with json over http', () => {
   describe('export - with compression', () => {
     beforeEach(() => {
       stubRequest = sinon.stub(http, 'request').returns(fakeRequest as any);
+      spySetHeader = sinon.spy();
+      (fakeRequest as any).setHeader = spySetHeader;
       collectorExporterConfig = {
         headers: {
           foo: 'bar',
@@ -285,6 +299,7 @@ describe('CollectorTraceExporter - node with json over http', () => {
         }
 
         ensureExportTraceServiceRequestIsSet(json);
+        assert.ok(spySetHeader.calledWith('Content-Encoding', 'gzip'));
 
         done();
       });