From 0d0848b807d560aa490a9ad8fb692e2a6b84ea88 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Andr=C3=A9=20Carvalho?= <asantostc@gmail.com>
Date: Thu, 22 Mar 2018 14:44:44 -0300
Subject: [PATCH] docker/executor: support running commands as user

---
 internal/docker/executor.go | 9 ++++++---
 internal/user/user.go       | 5 +++++
 main.go                     | 7 ++++++-
 3 files changed, 17 insertions(+), 4 deletions(-)

diff --git a/internal/docker/executor.go b/internal/docker/executor.go
index 963ac76..73de41e 100644
--- a/internal/docker/executor.go
+++ b/internal/docker/executor.go
@@ -16,13 +16,15 @@ import (
 type Executor struct {
 	ContainerID string
 	Client      *Client
+	DefaultUser string
 }
 
 func (d *Executor) Execute(opts exec.ExecuteOptions) error {
+	return d.ExecuteAsUser(d.DefaultUser, opts)
+}
+
+func (d *Executor) ExecuteAsUser(user string, opts exec.ExecuteOptions) error {
 	cmd := append([]string{opts.Cmd}, opts.Args...)
-	if cmd[0] != "/bin/sh" && (opts.Dir != "" || len(opts.Envs) > 0) {
-		cmd = append([]string{"/bin/sh", "-c"}, strings.Join(cmd, " "))
-	}
 	if opts.Dir != "" {
 		cmd = append(cmd[:2], fmt.Sprintf("cd %s && %s", opts.Dir, strings.Join(cmd[2:], " ")))
 	}
@@ -35,6 +37,7 @@ func (d *Executor) Execute(opts exec.ExecuteOptions) error {
 		AttachStdin:  opts.Stdin != nil,
 		AttachStdout: opts.Stdout != nil,
 		AttachStderr: opts.Stderr != nil,
+		User:         user,
 	})
 	if err != nil {
 		return err
diff --git a/internal/user/user.go b/internal/user/user.go
index e90b87d..3f29e31 100644
--- a/internal/user/user.go
+++ b/internal/user/user.go
@@ -93,6 +93,11 @@ type userExecutor struct {
 }
 
 func (e *userExecutor) Execute(opts exec.ExecuteOptions) error {
+	if ue, ok := e.baseExecutor.(interface {
+		ExecuteAsUser(string, exec.ExecuteOptions) error
+	}); ok {
+		return ue.ExecuteAsUser(strconv.Itoa(e.uid), opts)
+	}
 	args := []string{
 		"-u", fmt.Sprintf("#%d", e.uid), "--", opts.Cmd,
 	}
diff --git a/main.go b/main.go
index 3f44c4b..a6261b6 100644
--- a/main.go
+++ b/main.go
@@ -34,6 +34,7 @@ type Config struct {
 	RegistryAuthPass    string `split_words:"true"`
 	RegistryAuthUser    string `split_words:"true"`
 	RegistryAddress     string `split_words:"true"`
+	RunAsUser           string `split_words:"true"`
 }
 
 func main() {
@@ -76,7 +77,11 @@ func main() {
 		if err != nil {
 			fatal("failed to get main container: %v", err)
 		}
-		executor = &docker.Executor{Client: dockerClient, ContainerID: mainContainer.ID}
+		executor = &docker.Executor{
+			Client:      dockerClient,
+			ContainerID: mainContainer.ID,
+			DefaultUser: config.RunAsUser,
+		}
 		filesystem = &executorFS{executor: executor}
 		err = uploadFile(context.Background(), dockerClient, mainContainer.ID, config.InputFile)
 		if err != nil {