Error if the store gateway is run on an invalid engine (#3287)

This pull request returns an explicit error if the user asks to start
the store gateway but omits to set the storage type to `blocks`.

The previous behaviour was to silently ignore the -target=store-gateway
argument.

Note that this does not apply when target is `all`.

Signed-off-by: Julien Pivotto <[email protected]>

Co-authored-by: Marco Pracucci <[email protected]>

Author: Julien Pivotto

CHANGELOG.md

@@ -65,6 +65,7 @@
 * [ENHANCEMENT] Experimental Ruler API: Fetch rule groups from object storage in parallel. #3218
 * [ENHANCEMENT] Chunks GCS object storage client uses the `fields` selector to limit the payload size when listing objects in the bucket. #3218 #3292
 * [ENHANCEMENT] Added shuffle sharding support to ruler. Added new metric `cortex_ruler_sync_rules_total`. #3235
+* [ENHANCEMENT] Return an explicit error when the store-gateway is explicitly requested without a blocks storage engine. #3287
 * [ENHANCEMENT] Ruler: only load rules that belong to the ruler. Improves rules synching performances when ruler sharding is enabled. #3269
 * [BUGFIX] No-longer-needed ingester operations for queries triggered by queriers and rulers are now canceled. #3178
 * [BUGFIX] Ruler: directories in the configured `rules-path` will be removed on startup and shutdown in order to ensure they don't persist between runs. #3195

pkg/cortex/modules.go

@@ -593,6 +593,9 @@ func (t *Cortex) initCompactor() (serv services.Service, err error) {
 
 func (t *Cortex) initStoreGateway() (serv services.Service, err error) {
 	if t.Cfg.Storage.Engine != storage.StorageEngineBlocks {
+		if t.Cfg.Target != All {
+			return nil, fmt.Errorf("storage engine must be set to blocks to enable the store-gateway")
+		}
 		return nil, nil
 	}