Avoid double for loops in notification init (#8691)

cmd/iam.go

@@ -20,6 +20,7 @@ import (
 	"bytes"
 	"context"
 	"encoding/json"
+	"fmt"
 	"strings"
 	"sync"
 
@@ -365,46 +366,41 @@ func (sys *IAMSys) Init(objAPI ObjectLayer) error {
 	doneCh := make(chan struct{})
 	defer close(doneCh)
 
-	// Migrating IAM needs a retry mechanism for
+	// Migrating IAM amd Loading IAM needs a retry mechanism for
 	// the following reasons:
 	//  - Read quorum is lost just after the initialization
 	//    of the object layer.
-	for range newRetryTimerSimple(doneCh) {
-		// Migrate IAM configuration
-		if err := sys.doIAMConfigMigration(objAPI); err != nil {
-			if err == errDiskNotFound ||
-				strings.Contains(err.Error(), InsufficientReadQuorum{}.Error()) ||
-				strings.Contains(err.Error(), InsufficientWriteQuorum{}.Error()) {
-				logger.Info("Waiting for IAM subsystem to be initialized..")
-				continue
+	retryCh := newRetryTimerSimple(doneCh)
+	for {
+		select {
+		case <-retryCh:
+			// Migrate IAM configuration
+			if err := sys.doIAMConfigMigration(objAPI); err != nil {
+				if err == errDiskNotFound ||
+					strings.Contains(err.Error(), InsufficientReadQuorum{}.Error()) ||
+					strings.Contains(err.Error(), InsufficientWriteQuorum{}.Error()) {
+					logger.Info("Waiting for IAM subsystem to be initialized..")
+					continue
+				}
+				return err
 			}
-			return err
-		}
-		break
-	}
 
-	sys.store.watch(sys)
+			sys.store.watch(sys)
 
-	// Initializing IAM needs a retry mechanism for
-	// the following reasons:
-	//  - Read quorum is lost just after the initialization
-	//    of the object layer.
-	for range newRetryTimerSimple(doneCh) {
-		// Load IAMSys once during boot. Need to pass in
-		// objAPI as server has not yet initialized.
-		if err := sys.store.loadAll(sys, objAPI); err != nil {
-			if err == errDiskNotFound ||
-				strings.Contains(err.Error(), InsufficientReadQuorum{}.Error()) ||
-				strings.Contains(err.Error(), InsufficientWriteQuorum{}.Error()) {
-				logger.Info("Waiting for IAM subsystem to be initialized..")
-				continue
+			if err := sys.store.loadAll(sys, objAPI); err != nil {
+				if err == errDiskNotFound ||
+					strings.Contains(err.Error(), InsufficientReadQuorum{}.Error()) ||
+					strings.Contains(err.Error(), InsufficientWriteQuorum{}.Error()) {
+					logger.Info("Waiting for IAM subsystem to be initialized..")
+					continue
+				}
+				return err
 			}
-			return err
+			return nil
+		case <-globalOSSignalCh:
+			return fmt.Errorf("Initializing IAM sub-system gracefully stopped")
 		}
-		break
 	}
-
-	return nil
 }
 
 // DeletePolicy - deletes a canned policy from backend or etcd.