allow changing user id by setting TSURU_OS_UID env

internal/user/user.go

@@ -0,0 +1,111 @@
+// Copyright 2017 deploy-agent authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package user
+
+import (
+	"bytes"
+	"fmt"
+	"os"
+	"os/user"
+	"strconv"
+	"strings"
+	"text/template"
+
+	"github.com/tsuru/tsuru/app/bind"
+	"github.com/tsuru/tsuru/exec"
+)
+
+const (
+	defaultUserIfRoot = "ubuntu"
+	oldUserPrefix     = "tsuru.old."
+	tsuruUIDEnv       = "TSURU_OS_UID"
+)
+
+var sudoFixTemplate *template.Template
+
+func init() {
+	sudoFixTemplate, _ = template.New("userfix").Parse(`
+usermod -u {{.newUID}} {{.username}};
+groupmod -g {{.newUID}} {{.username}};
+useradd -M -U -u {{.oldUID}} {{.oldUserPrefix}}{{.username}};
+echo "{{.oldUserPrefix}}{{.username}} ALL=(#{{.newUID}}) NOPASSWD:ALL" >>/etc/sudoers;
+find / \( -name proc -o -name dev -o -name sys \) -prune -o \( -user {{.oldUID}} -exec chown -h {{.newUID}}:{{.newUID}} {} + \);
+`)
+}
+
+var testProcessCurrentUser func(*user.User) = nil
+
+func ChangeUser(executor exec.Executor, envs []bind.EnvVar) (exec.Executor, error) {
+	user, err := user.Current()
+	if err != nil {
+		return nil, err
+	}
+	if testProcessCurrentUser != nil {
+		testProcessCurrentUser(user)
+	}
+	username := user.Username
+	if username == "" {
+		username = user.Name
+	}
+	if username == "root" {
+		username = defaultUserIfRoot
+	}
+	oldUID := os.Getuid()
+	newUID, _ := strconv.ParseUint(getEnv(envs, tsuruUIDEnv), 10, 32)
+	if newUID == 0 ||
+		oldUID == int(newUID) ||
+		user.Uid == string(newUID) {
+		return executor, nil
+	}
+	newExecutor := &userExecutor{
+		baseExecutor: executor,
+		uid:          int(newUID),
+	}
+	if strings.HasPrefix(username, oldUserPrefix) {
+		return newExecutor, nil
+	}
+	buf := bytes.NewBuffer(nil)
+	err = sudoFixTemplate.Execute(buf, map[string]interface{}{
+		"newUID":        newUID,
+		"oldUID":        oldUID,
+		"oldUserPrefix": oldUserPrefix,
+		"username":      username,
+	})
+	if err != nil {
+		return nil, err
+	}
+	return newExecutor, executor.Execute(exec.ExecuteOptions{
+		Cmd: "sudo",
+		Args: []string{
+			"--", "sh", "-c", buf.String(),
+		},
+		Dir:    "/",
+		Stdout: os.Stdout,
+		Stderr: os.Stderr,
+	})
+}
+
+type userExecutor struct {
+	baseExecutor exec.Executor
+	uid          int
+}
+
+func (e *userExecutor) Execute(opts exec.ExecuteOptions) error {
+	args := []string{
+		"-u", fmt.Sprintf("#%d", e.uid), "--", opts.Cmd,
+	}
+	opts.Args = append(args, opts.Args...)
+	opts.Cmd = "sudo"
+	return e.baseExecutor.Execute(opts)
+}
+
+func getEnv(envs []bind.EnvVar, key string) string {
+	for _, e := range envs {
+		if e.Name == key {
+			return e.Value
+		}
+	}
+	return ""
+}

internal/user/user_test.go

@@ -0,0 +1,106 @@
+// Copyright 2017 deploy-agent authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+package user
+
+import (
+	"os/user"
+	"testing"
+
+	"github.com/tsuru/tsuru/app/bind"
+	"github.com/tsuru/tsuru/exec"
+	"github.com/tsuru/tsuru/exec/exectest"
+	"gopkg.in/check.v1"
+)
+
+func Test(t *testing.T) { check.TestingT(t) }
+
+type S struct {
+	exec *exectest.FakeExecutor
+}
+
+var _ = check.Suite(&S{})
+
+func (s *S) SetUpTest(c *check.C) {
+	s.exec = &exectest.FakeExecutor{}
+}
+
+func (s *S) TestChangeUserWithAnotherUID(c *check.C) {
+	executor, err := ChangeUser(s.exec, []bind.EnvVar{
+		{Name: "TSURU_OS_UID", Value: "1234"},
+	})
+	c.Assert(err, check.IsNil)
+	c.Assert(executor, check.DeepEquals, &userExecutor{
+		baseExecutor: s.exec,
+		uid:          1234,
+	})
+	cmds := s.exec.GetCommands("sudo")
+	c.Assert(cmds, check.HasLen, 1)
+	args := cmds[0].GetArgs()
+	c.Assert(args, check.HasLen, 4)
+	c.Assert(args[:3], check.DeepEquals, []string{"--", "sh", "-c"})
+	c.Assert(args[3], check.Matches, `(?s)
+usermod -u 1234 .+?;
+groupmod -g 1234 .+?;
+useradd -M -U -u \d+ tsuru\.old\..+?;
+echo "tsuru\.old\..+? ALL=\(#1234\) NOPASSWD:ALL" >>/etc/sudoers;
+find / \\\( -name proc -o -name dev -o -name sys \\\) -prune -o \\\( -user \d+ -exec chown -h 1234:1234 \{\} \+ \\\);
+`)
+}
+
+func (s *S) TestChangeUserNoEnvs(c *check.C) {
+	executor, err := ChangeUser(s.exec, nil)
+	c.Assert(err, check.IsNil)
+	c.Assert(executor, check.Equals, s.exec)
+	cmds := s.exec.GetCommands("sudo")
+	c.Assert(cmds, check.HasLen, 0)
+}
+
+func (s *S) TestChangeUserSameUser(c *check.C) {
+	u, err := user.Current()
+	c.Assert(err, check.IsNil)
+	executor, err := ChangeUser(s.exec, []bind.EnvVar{
+		{Name: "TSURU_OS_UID", Value: u.Uid},
+	})
+	c.Assert(err, check.IsNil)
+	c.Assert(executor, check.Equals, s.exec)
+	cmds := s.exec.GetCommands("sudo")
+	c.Assert(cmds, check.HasLen, 0)
+}
+
+func (s *S) TestChangeUserWithOldUser(c *check.C) {
+	testProcessCurrentUser = func(u *user.User) {
+		u.Name = "tsuru.old.myuser"
+		u.Username = u.Name
+	}
+	defer func() { testProcessCurrentUser = nil }()
+	executor, err := ChangeUser(s.exec, []bind.EnvVar{
+		{Name: "TSURU_OS_UID", Value: "9998"},
+	})
+	c.Assert(err, check.IsNil)
+	c.Assert(executor, check.DeepEquals, &userExecutor{
+		baseExecutor: s.exec,
+		uid:          9998,
+	})
+	cmds := s.exec.GetCommands("sudo")
+	c.Assert(cmds, check.HasLen, 0)
+}
+
+func (s *S) TestUserExecutorExecute(c *check.C) {
+	exe := userExecutor{
+		baseExecutor: s.exec,
+		uid:          999,
+	}
+	err := exe.Execute(exec.ExecuteOptions{
+		Cmd:  "mycmd",
+		Args: []string{"arg1", "arg2"},
+	})
+	c.Assert(err, check.IsNil)
+	cmds := s.exec.GetCommands("sudo")
+	c.Assert(cmds, check.HasLen, 1)
+	args := cmds[0].GetArgs()
+	c.Assert(args, check.DeepEquals, []string{
+		"-u", "#999", "--", "mycmd", "arg1", "arg2",
+	})
+}

tasks.go

@@ -12,6 +12,7 @@ import (
 	"regexp"
 	"strings"
 
+	"github.com/tsuru/deploy-agent/internal/user"
 	"github.com/tsuru/tsuru/app/bind"
 	"github.com/tsuru/tsuru/exec"
 	"github.com/tsuru/tsuru/fs"
@@ -41,10 +42,15 @@ func executor() exec.Executor {
 	}
 	return osExecutor
 }
+
 func execScript(cmds []string, envs []bind.EnvVar, w io.Writer) error {
 	if w == nil {
 		w = ioutil.Discard
 	}
+	currentExecutor, err := user.ChangeUser(executor(), envs)
+	if err != nil {
+		return err
+	}
 	workingDir := defaultWorkingDir
 	if _, err := filesystem().Stat(defaultWorkingDir); err != nil {
 		if os.IsNotExist(err) {
@@ -69,7 +75,7 @@ func execScript(cmds []string, envs []bind.EnvVar, w io.Writer) error {
 			Stderr: os.Stderr,
 		}
 		fmt.Fprintf(w, " ---> Running %q\n", cmd)
-		err := executor().Execute(execOpts)
+		err := currentExecutor.Execute(execOpts)
 		if err != nil {
 			return fmt.Errorf("error running %q: %s\n", cmd, err)
 		}