refactor(app): improve command execution with proper goroutine synchronization

refactor(app): improve command execution with proper goroutine synchronization

Author: sgaunet

files.go.bak

@@ -3,9 +3,12 @@ package app
 
 import (
 	"bufio"
+	"context"
 	"fmt"
+	"io"
 	"log/slog"
 	"os/exec"
+	"sync"
 
 	"github.com/sgaunet/gitlab-backup2s3/pkg/logger"
 )
@@ -55,37 +58,79 @@ func (a *App) Run() error {
 // execCommand executes a command.
 // It wraps all errors from external packages.
 func (a *App) execCommand(cmdToExec []string) error {
-	cmd := exec.Command(cmdToExec[0], cmdToExec[1:]...) // #nosec G204
+	cmd := exec.CommandContext(context.Background(), cmdToExec[0], cmdToExec[1:]...) // #nosec G204
+
 	stderr, err := cmd.StderrPipe()
 	if err != nil {
 		return fmt.Errorf("error creating stderr pipe: %w", err)
 	}
+
 	stdout, err := cmd.StdoutPipe()
 	if err != nil {
 		return fmt.Errorf("error creating stdout pipe: %w", err)
 	}
+
 	err = cmd.Start()
 	if err != nil {
 		return fmt.Errorf("error starting command: %w", err)
 	}
 
-	go func() {
-		scanner := bufio.NewScanner(stderr)
-		for scanner.Scan() {
-			m := scanner.Text()
-			a.logger.Error(m)
-		}
-	}()
-	go func() {
-		scanner := bufio.NewScanner(stdout)
-		for scanner.Scan() {
-			m := scanner.Text()
-			a.logger.Info(m)
-		}
-	}()
-	err = cmd.Wait()
+	return a.handleCommandOutput(cmd, stderr, stdout)
+}
+
+// handleCommandOutput handles the output streams from the command.
+func (a *App) handleCommandOutput(cmd *exec.Cmd, stderr, stdout io.ReadCloser) error {
+	var stderrErr, stdoutErr error
+	var wg sync.WaitGroup
+
+	// Add wait group counter for both stdout and stderr goroutines
+	const numGoroutines = 2
+	wg.Add(numGoroutines)
+
+	go a.processStderr(stderr, &wg, &stderrErr)
+	go a.processStdout(stdout, &wg, &stdoutErr)
+
+	err := cmd.Wait()
 	if err != nil {
 		return fmt.Errorf("error waiting for command: %w", err)
 	}
+
+	wg.Wait()
+
+	if stderrErr != nil {
+		return stderrErr
+	}
+	if stdoutErr != nil {
+		return stdoutErr
+	}
+
 	return nil
 }
+
+// processStderr processes the stderr stream.
+func (a *App) processStderr(stderr io.ReadCloser, wg *sync.WaitGroup, stderrErr *error) {
+	defer wg.Done()
+	scanner := bufio.NewScanner(stderr)
+	for scanner.Scan() {
+		m := scanner.Text()
+		a.logger.Error(m)
+	}
+	scannerErr := scanner.Err()
+	if scannerErr != nil {
+		*stderrErr = fmt.Errorf("stderr scanner error: %w", scannerErr)
+	}
+}
+
+// processStdout processes the stdout stream.
+func (a *App) processStdout(stdout io.ReadCloser, wg *sync.WaitGroup, stdoutErr *error) {
+	defer wg.Done()
+	scanner := bufio.NewScanner(stdout)
+	for scanner.Scan() {
+		m := scanner.Text()
+		a.logger.Info(m)
+	}
+	scannerErr := scanner.Err()
+	if scannerErr != nil {
+		*stdoutErr = fmt.Errorf("stdout scanner error: %w", scannerErr)
+	}
+}