Remove legacy ingester shutdown handler (#10655)

The handler was deprecated for a while and is removed in favour or `/ingester/shutdown?flush=true`.

Signed-off-by: Christian Haudum <christian.haudum@gmail.com>
Co-authored-by: J Stickler <julie.stickler@grafana.com>

CHANGELOG.md

@@ -17,6 +17,7 @@
 * [10395](https://github.com/grafana/loki/pull/10395/) **shantanualshi** Remove deprecated `split_queries_by_interval` and `forward_headers_list` configuration options in the `query_range` section
 * [10456](https://github.com/grafana/loki/pull/10456) **dannykopping** Add `loki_distributor_ingester_append_timeouts_total` metric, remove `loki_distributor_ingester_append_failures_total` metric
 * [10534](https://github.com/grafana/loki/pull/10534) **chaudum** Remove configuration `use_boltdb_shipper_as_backup`
+* [10655](https://github.com/grafana/loki/pull/10655) **chaudum** Remove legacy ingester shutdown handler `/ingester/flush_shutdown`.
 
 ##### Fixes
 

docs/sources/reference/api.md

@@ -55,7 +55,6 @@ These endpoints are exposed by the ingester:
 
 - [`POST /flush`](#flush-in-memory-chunks-to-backing-store)
 - [`POST /ingester/shutdown`](#flush-in-memory-chunks-and-shut-down)
-- **Deprecated** [`POST /ingester/flush_shutdown`](#post-ingesterflush_shutdown)
 
 The API endpoints starting with `/loki/` are [Prometheus API-compatible](https://prometheus.io/docs/prometheus/latest/querying/api/) and the result formats can be used interchangeably.
 
@@ -1470,14 +1469,3 @@ In microservices mode, `/api/prom/push` is exposed by the distributor.
 $ curl -H "Content-Type: application/json" -XPOST -s "https://localhost:3100/api/prom/push" --data-raw \
   '{"streams": [{ "labels": "{foo=\"bar\"}", "entries": [{ "ts": "2018-12-18T08:28:06.801064-04:00", "line": "fizzbuzz" }] }]}'
 ```
-
-### `POST /ingester/flush_shutdown`
-
-> **WARNING**: `/ingester/flush_shutdown` is DEPRECATED; use `/ingester/shutdown?flush=true`
-> instead.
-
-`/ingester/flush_shutdown` triggers a shutdown of the ingester and notably will _always_ flush any in memory chunks it holds.
-This is helpful for scaling down WAL-enabled ingesters where we want to ensure old WAL directories are not orphaned,
-but instead flushed to our chunk backend.
-
-In microservices mode, the `/ingester/flush_shutdown` endpoint is exposed by the ingester.

docs/sources/setup/upgrade/_index.md

@@ -55,6 +55,10 @@ The previous default value `false` is applied.
 6. `split_queries_by_interval` is removed from `query_range` YAML section. You can instead configure it in [Limits Config](/docs/loki/latest/configuration/#limits_config).
 7. `frontend.forward-headers-list` CLI flag and its corresponding YAML setting are removed.
 
+#### Legacy ingester shutdown handler is removed
+
+The already deprecated handler `/ingester/flush_shutdown` is removed in favor of `/ingester/shutdown?flush=true`.
+
 #### Distributor metric changes
 
 The `loki_distributor_ingester_append_failures_total` metric has been removed in favour of `loki_distributor_ingester_append_timeouts_total`.

pkg/ingester/ingester.go

@@ -188,8 +188,6 @@ type Interface interface {
 	CheckReady(ctx context.Context) error
 	FlushHandler(w http.ResponseWriter, _ *http.Request)
 	GetOrCreateInstance(instanceID string) (*instance, error)
-	// deprecated
-	LegacyShutdownHandler(w http.ResponseWriter, r *http.Request)
 	ShutdownHandler(w http.ResponseWriter, r *http.Request)
 	PrepareShutdown(w http.ResponseWriter, r *http.Request)
 }
@@ -612,25 +610,6 @@ func (i *Ingester) loop() {
 	}
 }
 
-// LegacyShutdownHandler triggers the following set of operations in order:
-//   - Change the state of ring to stop accepting writes.
-//   - Flush all the chunks.
-//
-// Note: This handler does not trigger a termination of the Loki process,
-// despite its name. Instead, the ingester service is stopped, so an external
-// source can trigger a safe termination through a signal to the process.
-// The handler is deprecated and usage is discouraged. Use ShutdownHandler
-// instead.
-func (i *Ingester) LegacyShutdownHandler(w http.ResponseWriter, _ *http.Request) {
-	level.Warn(util_log.Logger).Log("msg", "The handler /ingester/flush_shutdown is deprecated and usage is discouraged. Please use /ingester/shutdown?flush=true instead.")
-	originalState := i.lifecycler.FlushOnShutdown()
-	// We want to flush the chunks if transfer fails irrespective of original flag.
-	i.lifecycler.SetFlushOnShutdown(true)
-	_ = services.StopAndAwaitTerminated(context.Background(), i)
-	i.lifecycler.SetFlushOnShutdown(originalState)
-	w.WriteHeader(http.StatusNoContent)
-}
-
 // PrepareShutdown will handle the /ingester/prepare_shutdown endpoint.
 //
 // Internally, when triggered, this handler will configure the ingester service to release their resources whenever a SIGTERM is received.

pkg/loki/modules.go

@@ -506,9 +506,6 @@ func (t *Loki) initIngester() (_ services.Service, err error) {
 	t.Server.HTTP.Methods("GET", "POST").Path("/flush").Handler(
 		httpMiddleware.Wrap(http.HandlerFunc(t.Ingester.FlushHandler)),
 	)
-	t.Server.HTTP.Methods("POST").Path("/ingester/flush_shutdown").Handler(
-		httpMiddleware.Wrap(http.HandlerFunc(t.Ingester.LegacyShutdownHandler)),
-	)
 	t.Server.HTTP.Methods("POST", "GET", "DELETE").Path("/ingester/prepare_shutdown").Handler(
 		httpMiddleware.Wrap(http.HandlerFunc(t.Ingester.PrepareShutdown)),
 	)