Merge pull request #206 from stripe/cory-flush-ls-tracer

Flush the LS tracer, since Close() doesn't seem to.

CHANGELOG.md

@@ -1,4 +1,7 @@
-# 1.5.1, PENDING
+# 1.5.1, 2017-07-18
+
+## Bugfixes
+* Flush the lightstep tracer before closing it. Thanks [gphat](https://github.com/gphat) with assist from [stangles](https://github.com/joshu-stripe)!
 
 ## Improvements
 * Better document how to configure Veneur as a DogStatsD replacement. Thanks [gphat](https://github.com/gphat) with assist from [stangles](https://github.com/stangles)!

flusher.go

@@ -512,11 +512,13 @@ func (s *Server) flushTraces(ctx context.Context) {
 	})
 
 	for _, sink := range s.tracerSinks {
+		sinkFlushStart := time.Now()
 		sink.flush(span.Attach(ctx), s, sink.tracerThunk, ssfSpans)
 		tags := []string{
 			fmt.Sprintf("sink:%s", sink.name),
 			fmt.Sprintf("service:%s", trace.Service),
 		}
+		s.Statsd.TimeInMilliseconds("worker.trace.sink.flush_duration_ns", float64(time.Since(sinkFlushStart).Nanoseconds()), []string{fmt.Sprintf("sink:%s", sink.name)}, 1.0)
 
 		s.Statsd.Count("worker.trace.sink.flushed_total", int64(len(ssfSpans)), tags, 1)
 	}
@@ -784,6 +786,7 @@ func flushSpansLightstep(ctx context.Context, s *Server, tracerThunk func() open
 	for _, ssfSpan := range ssfSpans {
 		flushSpanLightstep(lightstepTracer, ssfSpan)
 	}
+	lightstep.FlushLightStepTracer(lightstepTracer)
 
 	// Confusingly, this will still get called even if the Opentracing client fails to reach the collector
 	// because we don't get access to the error if that happens.