Extend /flush to support flushing a single tenant

CHANGELOG.md

@@ -22,6 +22,7 @@
 * [ENHANCEMENT] Add support for arbitrary arithemtic to TraceQL queries [#2146](https://github.com/grafana/tempo/pull/2146) (@joe-elliott)
 * [ENHANCEMENT] tempo-cli: add command to migrate a tenant [#2130](https://github.com/grafana/tempo/pull/2130) (@kvrhdn)
 * [ENHANCEMENT] Added the ability to multiple span metrics by an attribute such as `X-SampleRatio` [#2172](https://github.com/grafana/tempo/pull/2172) (@altanozlu)
+* [ENHANCEMENT] Extend `/flush` to support flushing a single tenant [#2260](https://github.com/grafana/tempo/pull/2260) (@kvrhdn)
 * [BUGFIX] Apply `rate()` to bytes/s panel in tenant's dashboard. [#2081](https://github.com/grafana/tempo/pull/2081) (@mapno)
 * [CHANGE] Update Go to 1.20 [#2079](https://github.com/grafana/tempo/pull/2079) (@scalalang2)
 * [BUGFIX] Retry copy operations during compaction in GCS backend [#2111](https://github.com/grafana/tempo/pull/2111) (@mapno)

docs/sources/tempo/api_docs/_index.md

@@ -373,6 +373,12 @@ GET,POST /flush
 
 Triggers a flush of all in-memory traces to the WAL. Useful at the time of rollout restarts and unexpected crashes.
 
+Specify the `instance` parameter to flush data of a single tenant only.
+
+```
+GET,POST /flush?instance=dev
+```
+
 ### Shutdown
 
 ```

modules/ingester/flush.go

@@ -115,9 +115,23 @@ func (i *Ingester) ShutdownHandler(w http.ResponseWriter, _ *http.Request) {
 }
 
 // FlushHandler calls sweepAllInstances(true) which will force push all traces into the WAL and force
-// mark all head blocks as ready to flush.
-func (i *Ingester) FlushHandler(w http.ResponseWriter, _ *http.Request) {
-	i.sweepAllInstances(true)
+// mark all head blocks as ready to flush. It will either flush all instances or if an instance is specified,
+// just that one.
+func (i *Ingester) FlushHandler(w http.ResponseWriter, r *http.Request) {
+	queryParamInstance := "instance"
+
+	if r.URL.Query().Has(queryParamInstance) {
+		instance, ok := i.getInstanceByID(r.URL.Query().Get(queryParamInstance))
+		if !ok {
+			w.WriteHeader(http.StatusNotFound)
+			return
+		}
+		level.Info(log.Logger).Log("msg", "flushing instance", "instance", instance.instanceID)
+		i.sweepInstance(instance, true)
+	} else {
+		i.sweepAllInstances(true)
+	}
+
 	w.WriteHeader(http.StatusNoContent)
 }