fix(storage): specify credentials with STORAGE_EMULATOR_HOST (#7271)

Encountered the same problem with googleapis/google-api-go-client#558 when specifying STORAGE_EMULATOR_HOST. For our case, we'd like to pass option.WithTokenSource, and it raises the following error with STORAGE_EMULATOR_HOST during the test. To avoid the error, we should pass internaloption.SkipDialSettingsValidation as the Spanner client does.

Co-authored-by: Chris Cotter <cjcotter@google.com>

storage/storage.go

@@ -179,10 +179,12 @@ func NewClient(ctx context.Context, opts ...option.ClientOption) (*Client, error
 		endpoint := hostURL.String()
 
 		// Append the emulator host as default endpoint for the user
-		opts = append([]option.ClientOption{option.WithoutAuthentication()}, opts...)
-
-		opts = append(opts, internaloption.WithDefaultEndpoint(endpoint))
-		opts = append(opts, internaloption.WithDefaultMTLSEndpoint(endpoint))
+		opts = append([]option.ClientOption{
+			option.WithoutAuthentication(),
+			internaloption.SkipDialSettingsValidation(),
+			internaloption.WithDefaultEndpoint(endpoint),
+			internaloption.WithDefaultMTLSEndpoint(endpoint),
+		}, opts...)
 	}
 
 	// htransport selects the correct endpoint among WithEndpoint (user override), WithDefaultEndpoint, and WithDefaultMTLSEndpoint.

storage/storage_test.go

@@ -1992,6 +1992,17 @@ func TestAttrToFieldMapCoverage(t *testing.T) {
 	}
 }
 
+func TestEmulatorWithCredentialsFile(t *testing.T) {
+	t.Setenv("STORAGE_EMULATOR_HOST", "localhost:1234")
+
+	client, err := NewClient(context.Background(), option.WithCredentialsFile("/path/to/key.json"))
+	if err != nil {
+		t.Fatalf("failed creating a client with credentials file when running agains an emulator: %v", err)
+		return
+	}
+	client.Close()
+}
+
 // Create a client using a combination of custom endpoint and
 // STORAGE_EMULATOR_HOST env variable and verify that raw.BasePath (used
 // for writes) and readHost and scheme (used for reads) are all set correctly.