Revert "Add support for deferred sampling (#107)" (#113)

This reverts commit caac859.

src/constants.js

@@ -24,11 +24,6 @@ export const SAMPLED_MASK = 0x1;
 // DEBUG_MASK is the bit mask indicationg that a span has been marked for debug.
 export const DEBUG_MASK = 0x2;
 
-// DEFERRED_SAMPLING_MASK is the bit mask indicating that the upstream service that generated the
-// span did not make a definitive sampling decision, but deferred it to be made by some
-// downstream service.
-export const DEFERRED_SAMPLING_MASK = 0x4;
-
 // JAEGER_CLIENT_VERSION_TAG_KEY is the name of the tag used to report client version.
 export const JAEGER_CLIENT_VERSION_TAG_KEY = 'jaeger.version';
 

src/span_context.js

@@ -161,14 +161,6 @@ export default class SpanContext {
         return !!((this._traceId || this._traceIdStr) && (this._spanId || this._spanIdStr));
     }
 
-    get isDeferredSampling(): boolean {
-        return (this._flags & constants.DEFERRED_SAMPLING_MASK) === constants.DEFERRED_SAMPLING_MASK;
-    }
-
-    unsetDeferredSampling(): void {
-        this._flags &= ~constants.DEFERRED_SAMPLING_MASK;
-    }
-
     finalizeSampling(): void {
         this._samplingFinalized = true;
     }

src/tracer.js

@@ -237,7 +237,6 @@ export default class Tracer {
             ctx.baggage = parent.baggage;
 
             parent.finalizeSampling();
-            this.processDeferredSampling(ctx, operationName, internalTags);
             ctx.finalizeSampling();
         }
 
@@ -253,27 +252,6 @@ export default class Tracer {
         );
     }
 
-    /**
-     *  Makes a concrete sampling decision for the ctx span context based on information
-     *  available to it's child span.
-     *
-     *  The ctx context's deferred mask is unset after this decision is made
-     *
-     * @param ctx the span context
-     * @param operationName the operation name for the child
-     * @param tags tags to be applied by the sampler
-     */
-    processDeferredSampling(ctx: SpanContext, operationName: string, tags: any) {
-        if (ctx.isDeferredSampling) {
-            if (this._sampler.isSampled(operationName, tags)) {
-                ctx._flags |= constants.SAMPLED_MASK;
-            } else {
-                ctx._flags &= ~constants.SAMPLED_MASK;
-            }
-            ctx.unsetDeferredSampling();
-        }
-    }
-
     /**
      * Saves the span context into the carrier object for various formats, and encoders.
      *

test/span.js

@@ -185,34 +185,6 @@ describe('span should', () => {
         assert.isOk(unnormalizedKey in Span._getBaggageHeaderCache());
     });
 
-    describe('with deferred sampling', () => {
-        beforeEach(function () {
-            spanContext._flags = constants.DEFERRED_SAMPLING_MASK;
-        });
-        it('should not pass deferred sampling flag to child spans', () => {
-            let child = tracer.startSpan('child', {childOf: span.context()});
-            assert.notEqual(child.context.flags & constants.DEFERRED_SAMPLING_MASK,
-                            constants.DEFERRED_SAMPLING_MASK);
-            assert.isOk(child._spanContext.samplingFinalized);
-        });
-
-        it('should make a call to the underlying sampler and use the sampling decision when true', () => {
-            let mockSampler = sinon.mock(tracer._sampler);
-            mockSampler.expects('isSampled').withExactArgs('goodOperation', {}).returns(true);
-            let child = tracer.startSpan('goodOperation', {childOf: span.context()});
-            mockSampler.verify();
-            assert.isOk(child.context().isSampled());
-        });
-
-        it('should make a call to the underlying sampler and use the sampling decision when false', () => {
-            let mockSampler = sinon.mock(tracer._sampler);
-            mockSampler.expects('isSampled').withExactArgs('horridOperation', {}).returns(false);
-            let child = tracer.startSpan('horridOperation', {childOf: span.context()});
-            mockSampler.verify();
-            assert.isNotOk(child.context().isSampled());
-        });
-    });
-
     describe('adaptive sampling tests for span', () => {
         let options = [
             { desc: 'sampled: ', sampling: true, reportedSpans: 1 },
@@ -341,7 +313,7 @@ describe('span should', () => {
             tracer._sampler = new ProbabilisticSampler(1.0);
 
             // The second cal lshould rename the operation name, but
-            // not re-sample the span.  This is because finalize was set
+            // not re-sample the span.  This is because finalize was set 
             // in the first 'setOperationName' call.
             span.setOperationName('new-span-two');