backend/remote-state/gcloud: Add the "path" config option.

This config option was used by the legacy "gcs" client. If set, we're
using it for the default state -- all other states still use the
"state_dir" setting.

backend/remote-state/gcloud/backend.go

@@ -24,8 +24,9 @@ type gcsBackend struct {
 	storageClient  *storage.Client
 	storageContext context.Context
 
-	bucketName string
-	stateDir   string
+	bucketName       string
+	stateDir         string
+	defaultStateFile string
 }
 
 func New() backend.Backend {
@@ -39,6 +40,12 @@ func New() backend.Backend {
 				Description: "The name of the Google Cloud Storage bucket",
 			},
 
+			"path": {
+				Type:        schema.TypeString,
+				Optional:    true,
+				Description: "(Legacy) Path of the default state file; use state_dir instead",
+			},
+
 			"state_dir": {
 				Type:        schema.TypeString,
 				Optional:    true,
@@ -73,6 +80,8 @@ func (b *gcsBackend) configure(ctx context.Context) error {
 	b.bucketName = data.Get("bucket").(string)
 	b.stateDir = strings.TrimLeft(data.Get("state_dir").(string), "/")
 
+	b.defaultStateFile = strings.TrimLeft(data.Get("path").(string), "/")
+
 	var tokenSource oauth2.TokenSource
 
 	if credentials := data.Get("credentials").(string); credentials != "" {

backend/remote-state/gcloud/backend_state.go

@@ -77,8 +77,8 @@ func (b *gcsBackend) client(name string) (*remoteClient, error) {
 		storageContext: b.storageContext,
 		storageClient:  b.storageClient,
 		bucketName:     b.bucketName,
-		stateFilePath:  path.Join(b.stateDir, name+stateFileSuffix),
-		lockFilePath:   path.Join(b.stateDir, name+lockFileSuffix),
+		stateFilePath:  b.stateFile(name),
+		lockFilePath:   b.lockFile(name),
 	}, nil
 }
 
@@ -139,3 +139,17 @@ the initial state file is created.`
 
 	return st, nil
 }
+
+func (b *gcsBackend) stateFile(name string) string {
+	if name == backend.DefaultStateName && b.defaultStateFile != "" {
+		return b.defaultStateFile
+	}
+	return path.Join(b.stateDir, name+stateFileSuffix)
+}
+
+func (b *gcsBackend) lockFile(name string) string {
+	if name == backend.DefaultStateName && b.defaultStateFile != "" {
+		return strings.TrimSuffix(b.defaultStateFile, stateFileSuffix) + lockFileSuffix
+	}
+	return path.Join(b.stateDir, name+lockFileSuffix)
+}