Method ExecSync

internal/cri/server/container_execsync.go:72–99

ExecSync executes a command in the container, and returns the stdout output. If command exits with a non-zero exit code, an error is returned.

(ctx context.Context, r *runtime.ExecSyncRequest)

// ExecSync executes a command in the container, and returns the stdout output.
// If command exits with a non-zero exit code, an error is returned.
func (c *criService) ExecSync(ctx context.Context, r *runtime.ExecSyncRequest) (*runtime.ExecSyncResponse, error) {
	const maxStreamSize = 1024 * 1024 * 16

	var stdout, stderr bytes.Buffer

	// cappedWriter truncates the output. In that case, the size of
	// the ExecSyncResponse will hit the CRI plugin's gRPC response limit.
	// Thus the callers outside of the containerd process (e.g. Kubelet) never see
	// the truncated output.
	cout := &cappedWriter{w: cioutil.NewNopWriteCloser(&stdout), remain: maxStreamSize}
	cerr := &cappedWriter{w: cioutil.NewNopWriteCloser(&stderr), remain: maxStreamSize}

	exitCode, err := c.execInContainer(ctx, r.GetContainerId(), execOptions{
		cmd:     r.GetCmd(),
		stdout:  cout,
		stderr:  cerr,
		timeout: time.Duration(r.GetTimeout()) * time.Second,
	})
	if err != nil {
		return nil, fmt.Errorf("failed to exec in container: %w", err)
	}

	return &runtime.ExecSyncResponse{
		Stdout:   stdout.Bytes(),
		Stderr:   stderr.Bytes(),
		ExitCode: int32(*exitCode),
	}, nil
}

// execOptions specifies how to execute command in container.
type execOptions struct {