remove sleep (#3687)

Co-authored-by: Joe Elliott <[email protected]>

Author: chodges15

CHANGELOG.md

@@ -1,4 +1,6 @@
 ## main / unreleased
+
+* [ENHANCEMENT] Remove hardcoded delay in distributor shutdown [#3687](https://github.com/grafana/tempo/pull/3687) (@chodges15)
 * [ENHANCEMENT] Tempo CLI - add percentage support for query blocks #3697 [#3697](https://github.com/grafana/tempo/pull/3697) (@edgarkz)
 * [ENHANCEMENT] Update OTLP and add attributes to instrumentation scope in vParquet4 [#3649](https://github.com/grafana/tempo/pull/3649) (@stoewer)
   **Breaking Change** The update to OTLP 1.3.0 removes the deprecated `InstrumentationLibrary`

modules/distributor/receiver/shim.go

@@ -305,12 +305,6 @@ func (r *receiversShim) starting(ctx context.Context) error {
 
 // Called after distributor is asked to stop via StopAsync.
 func (r *receiversShim) stopping(_ error) error {
-	// when shutdown is called on the receiver it immediately shuts down its connection
-	// which drops requests on the floor. at this point in the shutdown process
-	// the readiness handler is already down so we are not receiving any more requests.
-	// sleep for 30 seconds to here to all pending requests to finish.
-	time.Sleep(30 * time.Second)
-
 	ctx, cancelFn := context.WithTimeout(context.Background(), 30*time.Second)
 	defer cancelFn()