pghoard: rename prefetched WAL in pghoard_postgres_command_go

golang/pghoard_postgres_command_go.go

@@ -81,7 +81,7 @@ func run() (int, error) {
 		retry_seconds := *riPtr
 		for {
 			attempt += 1
-			rc, err := restore_command(url, *outputPtr)
+			rc, err := restore_command(url, *outputPtr, *xlogPtr)
 			if rc != EXIT_RESTORE_FAIL {
 				return rc, err
 			}
@@ -100,7 +100,7 @@ func archive_command(url string) (int, error) {
 	return EXIT_ABORT, errors.New("archive_command not yet implemented")
 }
 
-func restore_command(url string, output string) (int, error) {
+func restore_command(url string, output string, xlog string) (int, error) {
 	var output_path string
 	var req *http.Request
 	var err error
@@ -120,6 +120,16 @@ func restore_command(url string, output string) (int, error) {
 			}
 			output_path = path.Join(cwd, output)
 		}
+		// if file "<xlog>.pghoard.prefetch" exists, just move it to destination
+		xlogPrefetchPath := path.Join(path.Dir(output_path), xlog+".pghoard.prefetch")
+		_, err = os.Stat(xlogPrefetchPath)
+		if err == nil {
+			err := os.Rename(xlogPrefetchPath, output_path)
+			if err != nil {
+				return EXIT_ABORT, err
+			}
+			return EXIT_OK, nil
+		}
 		req, err = http.NewRequest("GET", url, nil)
 		req.Header.Set("x-pghoard-target-path", output_path)
 	}