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Merge pull request #140 from jonboulle/atomic

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fix(system): write all files atomically
This commit is contained in:
Jonathan Boulle 2014-06-06 10:37:09 -07:00
commit f127406d01
8 changed files with 75 additions and 48 deletions
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7
initialize/config.go
View File

@ -4,7 +4,6 @@ import (
"errors"
"fmt"
"log"
"path"
"github.com/coreos/coreos-cloudinit/third_party/launchpad.net/goyaml"
@ -221,11 +220,11 @@ func Apply(cfg CloudConfig, env *Environment) error {
}
for _, file := range cfg.WriteFiles {
file.Path = path.Join(env.Root(), file.Path)
if err := system.WriteFile(&file); err != nil {
path, err := system.WriteFile(&file, env.Root())
if err != nil {
return err
}
log.Printf("Wrote file %s to filesystem", file.Path)
log.Printf("Wrote file %s to filesystem", path)
}
commands := make(map[string]string, 0)

4
initialize/manage_etc_hosts_test.go
View File

@ -50,9 +50,7 @@ func TestEtcHostsWrittenToDisk(t *testing.T) {
t.Fatalf("manageEtcHosts returned nil file unexpectedly")
}
f.Path = path.Join(dir, f.Path)
if err := system.WriteFile(f); err != nil {
if _, err := system.WriteFile(f, dir); err != nil {
t.Fatalf("Error writing EtcHosts: %v", err)
}

3
initialize/oem_test.go
View File

@ -31,8 +31,7 @@ func TestOEMReleaseWrittenToDisk(t *testing.T) {
t.Fatalf("OEMRelease returned nil file unexpectedly")
}
f.Path = path.Join(dir, f.Path)
if err := system.WriteFile(f); err != nil {
if _, err := system.WriteFile(f, dir); err != nil {
t.Fatalf("Writing of OEMRelease failed: %v", err)
}

3
initialize/update_test.go
View File

@ -205,8 +205,7 @@ func TestUpdateConfWrittenToDisk(t *testing.T) {
t.Fatal("Unexpectedly got nil updateconfig file")
}
f.Path = path.Join(dir, f.Path)
if err := system.WriteFile(f); err != nil {
if _, err := system.WriteFile(f, dir); err != nil {
t.Fatalf("Error writing update config: %v", err)
}

17
initialize/workspace.go
View File

@ -3,6 +3,7 @@ package initialize
import (
"io/ioutil"
"path"
"strings"
"github.com/coreos/coreos-cloudinit/system"
)
@ -28,21 +29,23 @@ func PersistScriptInWorkspace(script system.Script, workspace string) (string, e
}
tmp.Close()
relpath := strings.TrimPrefix(tmp.Name(), workspace)
file := system.File{
Path: tmp.Name(),
Path: relpath,
RawFilePermissions: "0744",
Content: string(script),
Content: string(script),
}
err = system.WriteFile(&file)
return file.Path, err
return system.WriteFile(&file, workspace)
}
func PersistUnitNameInWorkspace(name string, workspace string) error {
file := system.File{
Path: path.Join(workspace, "scripts", "unit-name"),
Path: path.Join("scripts", "unit-name"),
RawFilePermissions: "0644",
Content: name,
Content: name,
}
return system.WriteFile(&file)
_, err := system.WriteFile(&file, workspace)
return err
}

42
system/file.go
View File

@ -31,33 +31,55 @@ func (f *File) Permissions() (os.FileMode, error) {
return os.FileMode(perm), nil
}
func WriteFile(f *File) error {
func WriteFile(f *File, root string) (string, error) {
if f.Encoding != "" {
return fmt.Errorf("Unable to write file with encoding %s", f.Encoding)
return "", fmt.Errorf("Unable to write file with encoding %s", f.Encoding)
}
if err := os.MkdirAll(path.Dir(f.Path), os.FileMode(0755)); err != nil {
return err
fullpath := path.Join(root, f.Path)
dir := path.Dir(fullpath)
if err := EnsureDirectoryExists(dir); err != nil {
return "", err
}
perm, err := f.Permissions()
if err != nil {
return err
return "", err
}
if err := ioutil.WriteFile(f.Path, []byte(f.Content), perm); err != nil {
return err
var tmp *os.File
// Create a temporary file in the same directory to ensure it's on the same filesystem
if tmp, err = ioutil.TempFile(dir, "cloudinit-temp"); err != nil {
return "", err
}
if err := ioutil.WriteFile(tmp.Name(), []byte(f.Content), perm); err != nil {
return "", err
}
if err := tmp.Close(); err != nil {
return "", err
}
// Ensure the permissions are as requested (since WriteFile can be affected by sticky bit)
if err := os.Chmod(tmp.Name(), perm); err != nil {
return "", err
}
if f.Owner != "" {
// We shell out since we don't have a way to look up unix groups natively
cmd := exec.Command("chown", f.Owner, f.Path)
cmd := exec.Command("chown", f.Owner, tmp.Name())
if err := cmd.Run(); err != nil {
return err
return "", err
}
}
return nil
if err := os.Rename(tmp.Name(), fullpath); err != nil {
return "", err
}
return fullpath, nil
}
func EnsureDirectoryExists(dir string) error {

43
system/file_test.go
View File

@ -4,7 +4,6 @@ import (
"io/ioutil"
"os"
"path"
"syscall"
"testing"
)
@ -13,18 +12,22 @@ func TestWriteFileUnencodedContent(t *testing.T) {
if err != nil {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer syscall.Rmdir(dir)
defer os.RemoveAll(dir)
fullPath := path.Join(dir, "tmp", "foo")
fn := "foo"
fullPath := path.Join(dir, fn)
wf := File{
Path: fullPath,
Content: "bar",
Path: fn,
Content: "bar",
RawFilePermissions: "0644",
}
if err := WriteFile(&wf); err != nil {
path, err := WriteFile(&wf, dir)
if err != nil {
t.Fatalf("Processing of WriteFile failed: %v", err)
} else if path != fullPath {
t.Fatalf("WriteFile returned bad path: want %s, got %s", fullPath, path)
}
fi, err := os.Stat(fullPath)
@ -51,15 +54,15 @@ func TestWriteFileInvalidPermission(t *testing.T) {
if err != nil {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer syscall.Rmdir(dir)
defer os.RemoveAll(dir)
wf := File{
Path: path.Join(dir, "tmp", "foo"),
Content: "bar",
Path: path.Join(dir, "tmp", "foo"),
Content: "bar",
RawFilePermissions: "pants",
}
if err := WriteFile(&wf); err == nil {
if _, err := WriteFile(&wf, dir); err == nil {
t.Fatalf("Expected error to be raised when writing file with invalid permission")
}
}
@ -69,17 +72,21 @@ func TestWriteFilePermissions(t *testing.T) {
if err != nil {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer syscall.Rmdir(dir)
defer os.RemoveAll(dir)
fullPath := path.Join(dir, "tmp", "foo")
fn := "foo"
fullPath := path.Join(dir, fn)
wf := File{
Path: fullPath,
Path: fn,
RawFilePermissions: "0755",
}
if err := WriteFile(&wf); err != nil {
path, err := WriteFile(&wf, dir)
if err != nil {
t.Fatalf("Processing of WriteFile failed: %v", err)
} else if path != fullPath {
t.Fatalf("WriteFile returned bad path: want %s, got %s", fullPath, path)
}
fi, err := os.Stat(fullPath)
@ -97,15 +104,15 @@ func TestWriteFileEncodedContent(t *testing.T) {
if err != nil {
t.Fatalf("Unable to create tempdir: %v", err)
}
defer syscall.Rmdir(dir)
defer os.RemoveAll(dir)
wf := File{
Path: path.Join(dir, "tmp", "foo"),
Content: "",
Path: path.Join(dir, "tmp", "foo"),
Content: "",
Encoding: "base64",
}
if err := WriteFile(&wf); err == nil {
if _, err := WriteFile(&wf, dir); err == nil {
t.Fatalf("Expected error to be raised when writing file with encoding")
}
}

4
system/systemd.go
View File

@ -78,12 +78,12 @@ func PlaceUnit(u *Unit, dst string) error {
}
file := File{
Path: dst,
Path: filepath.Base(dst),
Content: u.Content,
RawFilePermissions: "0644",
}
err := WriteFile(&file)
_, err := WriteFile(&file, dir)
if err != nil {
return err
}