add retry logic upto 3 times for policy map and policy (#19173)

cmd/iam-object-store.go

@@ -25,6 +25,7 @@ import (
 	"path"
 	"strings"
 	"sync"
+	"time"
 	"unicode/utf8"
 
 	jsoniter "github.com/json-iterator/go"
@@ -146,6 +147,41 @@ func (iamOS *IAMObjectStore) deleteIAMConfig(ctx context.Context, path string) e
 	return deleteConfig(ctx, iamOS.objAPI, path)
 }
 
+func (iamOS *IAMObjectStore) loadPolicyDocWithRetry(ctx context.Context, policy string, m map[string]PolicyDoc, retries int) error {
+	for {
+	retry:
+		data, objInfo, err := iamOS.loadIAMConfigBytesWithMetadata(ctx, getPolicyDocPath(policy))
+		if err != nil {
+			if err == errConfigNotFound {
+				return errNoSuchPolicy
+			}
+			retries--
+			if retries <= 0 {
+				return err
+			}
+			time.Sleep(500 * time.Millisecond)
+			goto retry
+		}
+
+		var p PolicyDoc
+		err = p.parseJSON(data)
+		if err != nil {
+			return err
+		}
+
+		if p.Version == 0 {
+			// This means that policy was in the old version (without any
+			// timestamp info). We fetch the mod time of the file and save
+			// that as create and update date.
+			p.CreateDate = objInfo.ModTime
+			p.UpdateDate = objInfo.ModTime
+		}
+
+		m[policy] = p
+		return nil
+	}
+}
+
 func (iamOS *IAMObjectStore) loadPolicyDoc(ctx context.Context, policy string, m map[string]PolicyDoc) error {
 	data, objInfo, err := iamOS.loadIAMConfigBytesWithMetadata(ctx, getPolicyDocPath(policy))
 	if err != nil {
@@ -289,6 +325,30 @@ func (iamOS *IAMObjectStore) loadGroups(ctx context.Context, m map[string]GroupI
 	return nil
 }
 
+func (iamOS *IAMObjectStore) loadMappedPolicyWithRetry(ctx context.Context, name string, userType IAMUserType, isGroup bool,
+	m map[string]MappedPolicy, retries int,
+) error {
+	for {
+	retry:
+		var p MappedPolicy
+		err := iamOS.loadIAMConfig(ctx, &p, getMappedPolicyPath(name, userType, isGroup))
+		if err != nil {
+			if err == errConfigNotFound {
+				return errNoSuchPolicy
+			}
+			retries--
+			if retries <= 0 {
+				return err
+			}
+			time.Sleep(500 * time.Millisecond)
+			goto retry
+		}
+
+		m[name] = p
+		return nil
+	}
+}
+
 func (iamOS *IAMObjectStore) loadMappedPolicy(ctx context.Context, name string, userType IAMUserType, isGroup bool,
 	m map[string]MappedPolicy,
 ) error {
@@ -300,6 +360,7 @@ func (iamOS *IAMObjectStore) loadMappedPolicy(ctx context.Context, name string,
 		}
 		return err
 	}
+
 	m[name] = p
 	return nil
 }