Fix deadlock

incus/main.go

@@ -47,30 +47,47 @@ func (d *IncusDriver) pipeToRestic(incusCmd *exec.Cmd, filename string, tags []s
 	resticCmd.Stderr = os.Stderr
 	resticCmd.Env = os.Environ()
 
-	// Start the incus export command
+	// Start both commands
 	if err := incusCmd.Start(); err != nil {
 		return fmt.Errorf("failed to start incus export: %w", err)
 	}
 
-	// Start the restic backup command
 	if err := resticCmd.Start(); err != nil {
 		log.Println("DEBUG", resticCmd.String())
 		return fmt.Errorf("failed to start restic backup: %w", err)
 	}
 
-	// Wait for the incus export command to finish
-	if err := incusCmd.Wait(); err != nil {
-		log.Printf("incus export command failed: %v", err)
-	}
+	// Wait for both commands concurrently
+	var incusErr, resticErr error
+	done := make(chan struct{}, 2)
 
-	if err := w.Close(); err != nil {
-		log.Printf("failed to close pipe: %v", err)
-	}
+	go func() {
+		incusErr = incusCmd.Wait()
+		if incusErr != nil {
+			log.Printf("incus export command failed: %v", incusErr)
+		}
+		w.Close() // Close the write end when incus is done
+		done <- struct{}{}
+	}()
 
-	// Wait for the restic backup command to finish
-	if err := resticCmd.Wait(); err != nil {
-		log.Println("DEBUG", resticCmd.String())
-		return fmt.Errorf("restic backup command failed: %w", err)
+	go func() {
+		resticErr = resticCmd.Wait()
+		if resticErr != nil {
+			log.Println("DEBUG", resticCmd.String())
+		}
+		done <- struct{}{}
+	}()
+
+	// Wait for both commands to finish
+	<-done
+	<-done
+
+	// Return the first error encountered
+	if incusErr != nil {
+		return fmt.Errorf("incus export command failed: %w", incusErr)
+	}
+	if resticErr != nil {
+		return fmt.Errorf("restic backup command failed: %w", resticErr)
 	}
 
 	return nil