Comments.

Signed-off-by: Peter Štibraný <[email protected]>

Author: pstibrany

CHANGELOG.md

@@ -3,7 +3,7 @@
 ## master / unreleased
 
 * [CHANGE] Alertmanager now removes local files after Alertmanager is no longer running for removed or resharded user. #3910
-* [CHANGE] Alertmanager now stores local files in per-tenant folders. Files stored by Alertmanager previously are migrated to new hierarchy. #3910
+* [CHANGE] Alertmanager now stores local files in per-tenant folders. Files stored by Alertmanager previously are migrated to new hierarchy. Support for this migration will be removed in Cortex 1.10. #3910
 * [ENHANCEMENT] Ruler: optimized `<prefix>/api/v1/rules` and `<prefix>/api/v1/alerts` when ruler sharding is enabled. #3916
 * [ENHANCEMENT] Ruler: added the following metrics when ruler sharding is enabled: #3916
   * `cortex_ruler_clients`

pkg/alertmanager/multitenant.go

@@ -507,7 +507,8 @@ func (am *MultitenantAlertmanager) starting(ctx context.Context) (err error) {
 	return nil
 }
 
-// migrateStateFilesToPerTenantDirectories migrate any existing configuration from old place to new hierarchy.
+// migrateStateFilesToPerTenantDirectories migrates any existing configuration from old place to new hierarchy.
+// TODO: Remove in Cortex 1.10.
 func (am *MultitenantAlertmanager) migrateStateFilesToPerTenantDirectories() error {
 	migrate := func(from, to string) error {
 		level.Info(am.logger).Log("msg", "migrating AM state", "from", from, "to", to)
@@ -1106,6 +1107,8 @@ func (am *MultitenantAlertmanager) deleteUnusedLocalUserState() {
 	}
 }
 
+// getPerUserDirectories returns map of users to their directories (full path). Only users with local
+// directory are returned.
 func (am *MultitenantAlertmanager) getPerUserDirectories() map[string]string {
 	files, err := ioutil.ReadDir(am.cfg.DataDir)
 	if err != nil {