Fix ilm config at startup (#19189)

Remove api.expiration_workers config setting which was inadvertently left behind. Per review comment 

https://github.com/minio/minio/pull/18926, expiration_workers can be configured via ilm.expiration_workers.

internal/config/api/api.go

@@ -41,7 +41,6 @@ const (
 	apiReplicationMaxWorkers   = "replication_max_workers"
 
 	apiTransitionWorkers           = "transition_workers"
-	apiExpiryWorkers               = "expiry_workers"
 	apiStaleUploadsCleanupInterval = "stale_uploads_cleanup_interval"
 	apiStaleUploadsExpiry          = "stale_uploads_expiry"
 	apiDeleteCleanupInterval       = "delete_cleanup_interval"
@@ -57,7 +56,6 @@ const (
 	EnvAPICorsAllowOrigin             = "MINIO_API_CORS_ALLOW_ORIGIN"
 	EnvAPIRemoteTransportDeadline     = "MINIO_API_REMOTE_TRANSPORT_DEADLINE"
 	EnvAPITransitionWorkers           = "MINIO_API_TRANSITION_WORKERS"
-	EnvAPIExpiryWorkers               = "MINIO_API_EXPIRY_WORKERS"
 	EnvAPIListQuorum                  = "MINIO_API_LIST_QUORUM"
 	EnvAPISecureCiphers               = "MINIO_API_SECURE_CIPHERS" // default config.EnableOn
 	EnvAPIReplicationPriority         = "MINIO_API_REPLICATION_PRIORITY"
@@ -119,10 +117,6 @@ var (
 			Key:   apiTransitionWorkers,
 			Value: "100",
 		},
-		config.KV{
-			Key:   apiExpiryWorkers,
-			Value: "100",
-		},
 		config.KV{
 			Key:   apiStaleUploadsCleanupInterval,
 			Value: "6h",
@@ -288,15 +282,6 @@ func LookupConfig(kvs config.KVS) (cfg Config, err error) {
 	}
 	cfg.TransitionWorkers = transitionWorkers
 
-	expiryWorkers, err := strconv.Atoi(env.Get(EnvAPIExpiryWorkers, kvs.GetWithDefault(apiExpiryWorkers, DefaultKVS)))
-	if err != nil {
-		return cfg, err
-	}
-	if expiryWorkers <= 0 || expiryWorkers > 500 {
-		return cfg, config.ErrInvalidExpiryWorkersValue(nil).Msg("Number of expiry workers should be between 1 and 500")
-	}
-	cfg.ExpiryWorkers = expiryWorkers
-
 	v := env.Get(EnvAPIDeleteCleanupInterval, kvs.Get(apiDeleteCleanupInterval))
 	if v == "" {
 		v = env.Get(EnvDeleteCleanupInterval, kvs.GetWithDefault(apiDeleteCleanupInterval, DefaultKVS))

internal/config/api/help.go

@@ -80,12 +80,6 @@ var (
 			Optional:    true,
 			Type:        "number",
 		},
-		config.HelpKV{
-			Key:         apiExpiryWorkers,
-			Description: `set the number of expiry workers` + defaultHelpPostfix(apiExpiryWorkers),
-			Optional:    true,
-			Type:        "number",
-		},
 		config.HelpKV{
 			Key:         apiStaleUploadsExpiry,
 			Description: `set to expire stale multipart uploads older than this values` + defaultHelpPostfix(apiStaleUploadsExpiry),