fix: rename crawler as scanner in config (#11549)

cmd/config/config.go

@@ -77,6 +77,7 @@ const (
 	LoggerWebhookSubSys  = "logger_webhook"
 	AuditWebhookSubSys   = "audit_webhook"
 	HealSubSys           = "heal"
+	ScannerSubSys        = "scanner"
 	CrawlerSubSys        = "crawler"
 
 	// Add new constants here if you add new fields to config.
@@ -114,7 +115,7 @@ var SubSystems = set.CreateStringSet(
 	PolicyOPASubSys,
 	IdentityLDAPSubSys,
 	IdentityOpenIDSubSys,
-	CrawlerSubSys,
+	ScannerSubSys,
 	HealSubSys,
 	NotifyAMQPSubSys,
 	NotifyESSubSys,
@@ -132,7 +133,7 @@ var SubSystems = set.CreateStringSet(
 var SubSystemsDynamic = set.CreateStringSet(
 	APISubSys,
 	CompressionSubSys,
-	CrawlerSubSys,
+	ScannerSubSys,
 	HealSubSys,
 )
 
@@ -151,7 +152,7 @@ var SubSystemsSingleTargets = set.CreateStringSet([]string{
 	IdentityLDAPSubSys,
 	IdentityOpenIDSubSys,
 	HealSubSys,
-	CrawlerSubSys,
+	ScannerSubSys,
 }...)
 
 // Constant separators
@@ -462,6 +463,13 @@ func LookupWorm() (bool, error) {
 	return ParseBool(env.Get(EnvWorm, EnableOff))
 }
 
+// Carries all the renamed sub-systems from their
+// previously known names
+var renamedSubsys = map[string]string{
+	CrawlerSubSys: ScannerSubSys,
+	// Add future sub-system renames
+}
+
 // Merge - merges a new config with all the
 // missing values for default configs,
 // returns a config.
@@ -477,9 +485,21 @@ func (c Config) Merge() Config {
 				}
 			}
 			if _, ok := cp[subSys]; !ok {
-				// A config subsystem was removed or server was downgraded.
-				Logger.Info("config: ignoring unknown subsystem config %q\n", subSys)
-				continue
+				rnSubSys, ok := renamedSubsys[subSys]
+				if !ok {
+					// A config subsystem was removed or server was downgraded.
+					Logger.Info("config: ignoring unknown subsystem config %q\n", subSys)
+					continue
+				}
+				// Copy over settings from previous sub-system
+				// to newly renamed sub-system
+				for _, kv := range cp[rnSubSys][Default] {
+					_, ok := c[subSys][tgt].Lookup(kv.Key)
+					if !ok {
+						ckvs.Set(kv.Key, kv.Value)
+					}
+				}
+				subSys = rnSubSys
 			}
 			cp[subSys][tgt] = ckvs
 		}