br: fix S3 backup endpoint suffix

br/pkg/storage/parse_test.go

@@ -57,7 +57,7 @@ func (r *testStorageSuite) TestCreateStorage(c *C) {
 	c.Assert(s3, NotNil)
 	c.Assert(s3.Bucket, Equals, "bucket2")
 	c.Assert(s3.Prefix, Equals, "prefix")
-	c.Assert(s3.Endpoint, Equals, "https://s3.example.com/")
+	c.Assert(s3.Endpoint, Equals, "https://s3.example.com")
 	c.Assert(s3.ForcePathStyle, IsFalse)
 
 	// nolint:lll

br/pkg/storage/s3.go

@@ -155,7 +155,7 @@ func (options *S3BackendOptions) Apply(s3 *backuppb.S3) error {
 		return errors.Annotate(berrors.ErrStorageInvalidConfig, "secret_access_key not found")
 	}
 
-	s3.Endpoint = options.Endpoint
+	s3.Endpoint = strings.TrimSuffix(options.Endpoint, "/")
 	s3.Region = options.Region
 	// StorageClass, SSE and ACL are acceptable to be empty
 	s3.StorageClass = options.StorageClass
@@ -189,6 +189,7 @@ func (options *S3BackendOptions) parseFromFlags(flags *pflag.FlagSet) error {
 	if err != nil {
 		return errors.Trace(err)
 	}
+	options.Endpoint = strings.TrimSuffix(options.Endpoint, "/")
 	options.Region, err = flags.GetString(s3RegionOption)
 	if err != nil {
 		return errors.Trace(err)