vxcontrol/pentagi · error

failed to create exec process: %w

Error message

failed to create exec process: %w

What it means

ExecCommand calls dockerClient.ContainerExecCreate to spawn the sh -c process inside the terminal container. If the Docker API rejects the exec creation, the call fails with "failed to create exec process: %w" wrapping the Docker error.

Source

Thrown at backend/pkg/tools/terminal.go:233

	// Format command with working directory and ANSI styling
	styledCommand := fmt.Sprintf("%s $ %s%s%s%s", cwd, ansiColorInputCmd, command, ansiColorReset, ansiLineTerminator)
	_, err = t.tlp.PutMsg(ctx, database.TermlogTypeStdin, styledCommand, t.containerID, t.taskID, t.subtaskID)
	if err != nil {
		return "", fmt.Errorf("failed to put terminal log (stdin): %w", err)
	}

	timeout = t.normalizeExecTimeout(timeout)

	createResp, err := t.dockerClient.ContainerExecCreate(ctx, containerName, client.ExecCreateOptions{
		Cmd:          cmd,
		AttachStdout: true,
		AttachStderr: true,
		WorkingDir:   cwd,
		TTY:          true,
	})
	if err != nil {
		return "", fmt.Errorf("failed to create exec process: %w", err)
	}

	if detach {
		resultChan := make(chan execResult, 1)
		detachedCtx := context.WithoutCancel(ctx)

		go func() {
			output, err := t.getExecResult(detachedCtx, createResp.ID, timeout)
			resultChan <- execResult{output: output, err: err}
		}()

		select {
		case result := <-resultChan:
			if result.err != nil {
				return "", fmt.Errorf("command failed: %w: %s", result.err, result.output)
			}
			if result.output == "" {
				return "Command completed in background with exit code 0", nil

View on GitHub (pinned to ea665308ba)

Solutions

1. Read the wrapped Docker error for the specific API cause
2. Confirm the container (PrimaryTerminalName result) still exists and is running right before exec
3. Validate that the cwd path exists inside the container image
4. Recreate the terminal container and retry; check daemon health (docker info)

Example fix

// before
ExecCreateOptions{WorkingDir: "/nonexistent", ...} // failed to create exec process: ... no such directory
// after
cwd := docker.WorkFolderPathInContainer // guaranteed to exist in the image
createResp, err := dockerClient.ContainerExecCreate(ctx, containerName, client.ExecCreateOptions{WorkingDir: cwd, ...})

exists, err := dockerClient.IsContainerRunning(ctx, containerLID)
if err != nil || !exists {
    return fmt.Errorf("container not ready for exec: %w", err)
}
if cwd != "" {
    if err := ensureDirInContainer(ctx, containerName, cwd); err != nil {
        return fmt.Errorf("cwd %q missing in container: %w", cwd, err)
    }
}

out, err := term.ExecCommand(ctx, cwd, cmd, false, timeout)
if err != nil && strings.HasPrefix(err.Error(), "failed to create exec process:") {
    // likely a race with container exit or bad cwd — recreate sandbox, then retry once
    if rerr := term.EnsureRunning(ctx); rerr == nil {
        out, err = term.ExecCommand(ctx, cwd, cmd, false, timeout)
    }
}

When it happens

Trigger: ContainerExecCreate failing because the container name doesn't resolve (container removed/renamed), the container just stopped between the running-check and this call, an invalid working directory (cwd doesn't exist in the container), or the Docker daemon erroring/being unreachable.

Common situations: Race where the container exits between IsContainerRunning and exec creation; PrimaryTerminalName container removed externally; cwd pointing to a path not present in the image; Docker daemon OOM or restarting; malformed command leading to API rejection.

Related errors

• failed to attach file-check exec: %w
• failed to inspect file-check exec: %w
• failed to stat container path '%s': %w
• failed to create list exec for '%s': %w
• failed to attach list exec for '%s': %w

AI-assisted analysis of vxcontrol/pentagi@ea665308ba (2026-09-01). Data as JSON: /api/errors/791698a2fcd379af. Report an issue: GitHub.