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
 		}

cmd/config/scanner/scanner.go

@@ -14,7 +14,7 @@
  * limitations under the License.
  */
 
-package crawler
+package scanner
 
 import (
 	"strconv"
@@ -29,8 +29,10 @@ const (
 	Delay   = "delay"
 	MaxWait = "max_wait"
 
-	EnvDelay   = "MINIO_CRAWLER_DELAY"
-	EnvMaxWait = "MINIO_CRAWLER_MAX_WAIT"
+	EnvDelay         = "MINIO_SCANNER_DELAY"
+	EnvDelayLegacy   = "MINIO_CRAWLER_DELAY"
+	EnvMaxWait       = "MINIO_SCANNER_MAX_WAIT"
+	EnvMaxWaitLegacy = "MINIO_CRAWLER_MAX_WAIT"
 )
 
 // Config represents the heal settings.
@@ -58,7 +60,7 @@ var (
 	Help = config.HelpKVS{
 		config.HelpKV{
 			Key:         Delay,
-			Description: `crawler delay multiplier, defaults to '10.0'`,
+			Description: `scanner delay multiplier, defaults to '10.0'`,
 			Optional:    true,
 			Type:        "float",
 		},
@@ -73,14 +75,22 @@ var (
 
 // LookupConfig - lookup config and override with valid environment settings if any.
 func LookupConfig(kvs config.KVS) (cfg Config, err error) {
-	if err = config.CheckValidKeys(config.CrawlerSubSys, kvs, DefaultKVS); err != nil {
+	if err = config.CheckValidKeys(config.ScannerSubSys, kvs, DefaultKVS); err != nil {
 		return cfg, err
 	}
-	cfg.Delay, err = strconv.ParseFloat(env.Get(EnvDelay, kvs.Get(Delay)), 64)
+	delay := env.Get(EnvDelayLegacy, "")
+	if delay == "" {
+		delay = env.Get(EnvDelay, kvs.Get(Delay))
+	}
+	cfg.Delay, err = strconv.ParseFloat(delay, 64)
 	if err != nil {
 		return cfg, err
 	}
-	cfg.MaxWait, err = time.ParseDuration(env.Get(EnvMaxWait, kvs.Get(MaxWait)))
+	maxWait := env.Get(EnvMaxWaitLegacy, "")
+	if maxWait == "" {
+		maxWait = env.Get(EnvMaxWait, kvs.Get(MaxWait))
+	}
+	cfg.MaxWait, err = time.ParseDuration(maxWait)
 	if err != nil {
 		return cfg, err
 	}