Use personal fork of nightlyone/filelock

This commit is contained in:
Marius 2016-09-30 12:03:49 +02:00
parent 5fceb7eb77
commit 9753aae065
9 changed files with 149 additions and 208 deletions

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@ -25,7 +25,7 @@ import (
"github.com/tus/tusd"
"github.com/tus/tusd/uid"
"github.com/nightlyone/lockfile"
"gopkg.in/Acconut/lockfile.v1"
)
var defaultFilePerm = os.FileMode(0664)

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@ -1,196 +0,0 @@
// Package lockfile handles pid file based locking.
package lockfile
import (
"errors"
"fmt"
"io"
"io/ioutil"
"os"
"path/filepath"
)
// Lockfile is a pid file which can be locked
type Lockfile string
// TemporaryError is a type of error where a retry after a random amount of sleep should help to mitigate it.
type TemporaryError string
func (t TemporaryError) Error() string { return string(t) }
// Temporary returns always true.
// It exists, so you can detect it via
// if te, ok := err.(interface{ Temporary() bool }); ok {
// fmt.Println("I am a temporay error situation, so wait and retry")
// }
func (t TemporaryError) Temporary() bool { return true }
// Various errors returned by this package
var (
ErrBusy = TemporaryError("Locked by other process") // If you get this, retry after a short sleep might help
ErrNotExist = TemporaryError("Lockfile created, but doesn't exist") // If you get this, retry after a short sleep might help
ErrNeedAbsPath = errors.New("Lockfiles must be given as absolute path names")
ErrInvalidPid = errors.New("Lockfile contains invalid pid for system")
ErrDeadOwner = errors.New("Lockfile contains pid of process not existent on this system anymore")
ErrRogueDeletion = errors.New("Lockfile owned by me has been removed unexpectedly")
)
// New describes a new filename located at the given absolute path.
func New(path string) (Lockfile, error) {
if !filepath.IsAbs(path) {
return Lockfile(""), ErrNeedAbsPath
}
return Lockfile(path), nil
}
// GetOwner returns who owns the lockfile.
func (l Lockfile) GetOwner() (*os.Process, error) {
name := string(l)
// Ok, see, if we have a stale lockfile here
content, err := ioutil.ReadFile(name)
if err != nil {
return nil, err
}
// try hard for pids. If no pid, the lockfile is junk anyway and we delete it.
pid, err := scanPidLine(content)
if err != nil {
return nil, err
}
running, err := isRunning(pid)
if err != nil {
return nil, err
}
if running {
proc, err := os.FindProcess(pid)
if err != nil {
return nil, err
}
return proc, nil
}
return nil, ErrDeadOwner
}
// TryLock tries to own the lock.
// It Returns nil, if successful and and error describing the reason, it didn't work out.
// Please note, that existing lockfiles containing pids of dead processes
// and lockfiles containing no pid at all are simply deleted.
func (l Lockfile) TryLock() error {
name := string(l)
// This has been checked by New already. If we trigger here,
// the caller didn't use New and re-implemented it's functionality badly.
// So panic, that he might find this easily during testing.
if !filepath.IsAbs(name) {
panic(ErrNeedAbsPath)
}
tmplock, err := ioutil.TempFile(filepath.Dir(name), "")
if err != nil {
return err
}
cleanup := func() {
_ = tmplock.Close()
_ = os.Remove(tmplock.Name())
}
defer cleanup()
if err := writePidLine(tmplock, os.Getpid()); err != nil {
return err
}
// return value intentionally ignored, as ignoring it is part of the algorithm
_ = os.Link(tmplock.Name(), name)
fiTmp, err := os.Lstat(tmplock.Name())
if err != nil {
return err
}
fiLock, err := os.Lstat(name)
if err != nil {
// tell user that a retry would be a good idea
if os.IsNotExist(err) {
return ErrNotExist
}
return err
}
// Success
if os.SameFile(fiTmp, fiLock) {
return nil
}
proc, err := l.GetOwner()
switch err {
default:
// Other errors -> defensively fail and let caller handle this
return err
case nil:
if proc.Pid != os.Getpid() {
return ErrBusy
}
case ErrDeadOwner, ErrInvalidPid:
// cases we can fix below
}
// clean stale/invalid lockfile
err = os.Remove(name)
if err != nil {
// If it doesn't exist, then it doesn't matter who removed it.
if !os.IsNotExist(err) {
return err
}
}
// now that the stale lockfile is gone, let's recurse
return l.TryLock()
}
// Unlock a lock again, if we owned it. Returns any error that happend during release of lock.
func (l Lockfile) Unlock() error {
proc, err := l.GetOwner()
switch err {
case ErrInvalidPid, ErrDeadOwner:
return ErrRogueDeletion
case nil:
if proc.Pid == os.Getpid() {
// we really own it, so let's remove it.
return os.Remove(string(l))
}
// Not owned by me, so don't delete it.
return ErrRogueDeletion
default:
// This is an application error or system error.
// So give a better error for logging here.
if os.IsNotExist(err) {
return ErrRogueDeletion
}
// Other errors -> defensively fail and let caller handle this
return err
}
}
func writePidLine(w io.Writer, pid int) error {
_, err := io.WriteString(w, fmt.Sprintf("%d\n", pid))
return err
}
func scanPidLine(content []byte) (int, error) {
if len(content) == 0 {
return 0, ErrInvalidPid
}
var pid int
if _, err := fmt.Sscanln(string(content), &pid); err != nil {
return 0, ErrInvalidPid
}
if pid <= 0 {
return 0, ErrInvalidPid
}
return pid, nil
}

135
vendor/gopkg.in/Acconut/lockfile.v1/lockfile.go generated vendored Normal file
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@ -0,0 +1,135 @@
// Handle pid file based locking.
package lockfile
import (
"errors"
"fmt"
"io/ioutil"
"os"
"path/filepath"
)
type Lockfile string
var (
ErrBusy = errors.New("Locked by other process") // If you get this, retry after a short sleep might help
ErrNeedAbsPath = errors.New("Lockfiles must be given as absolute path names")
ErrInvalidPid = errors.New("Lockfile contains invalid pid for system")
ErrDeadOwner = errors.New("Lockfile contains pid of process not existent on this system anymore")
)
// Describe a new filename located at path. It is expected to be an absolute path
func New(path string) (Lockfile, error) {
if !filepath.IsAbs(path) {
return Lockfile(""), ErrNeedAbsPath
}
return Lockfile(path), nil
}
// Who owns the lockfile?
func (l Lockfile) GetOwner() (*os.Process, error) {
name := string(l)
// Ok, see, if we have a stale lockfile here
content, err := ioutil.ReadFile(name)
if err != nil {
return nil, err
}
var pid int
_, err = fmt.Sscanln(string(content), &pid)
if err != nil {
return nil, ErrInvalidPid
}
// try hard for pids. If no pid, the lockfile is junk anyway and we delete it.
if pid > 0 {
running, err := isRunning(pid)
if err != nil {
return nil, err
}
if running {
proc, err := os.FindProcess(pid)
if err != nil {
return nil, err
}
return proc, nil
} else {
return nil, ErrDeadOwner
}
} else {
return nil, ErrInvalidPid
}
panic("Not reached")
}
// Try to get Lockfile lock. Returns nil, if successful and and error describing the reason, it didn't work out.
// Please note, that existing lockfiles containing pids of dead processes and lockfiles containing no pid at all
// are deleted.
func (l Lockfile) TryLock() error {
name := string(l)
// This has been checked by New already. If we trigger here,
// the caller didn't use New and re-implemented it's functionality badly.
// So panic, that he might find this easily during testing.
if !filepath.IsAbs(string(name)) {
panic(ErrNeedAbsPath)
}
tmplock, err := ioutil.TempFile(filepath.Dir(name), "")
if err != nil {
return err
} else {
defer tmplock.Close()
defer os.Remove(tmplock.Name())
}
_, err = tmplock.WriteString(fmt.Sprintf("%d\n", os.Getpid()))
if err != nil {
return err
}
// return value intentionally ignored, as ignoring it is part of the algorithm
_ = os.Link(tmplock.Name(), name)
fiTmp, err := os.Lstat(tmplock.Name())
if err != nil {
return err
}
fiLock, err := os.Lstat(name)
if err != nil {
return err
}
// Success
if os.SameFile(fiTmp, fiLock) {
return nil
}
_, err = l.GetOwner()
switch err {
default:
// Other errors -> defensively fail and let caller handle this
return err
case nil:
return ErrBusy
case ErrDeadOwner, ErrInvalidPid:
// cases we can fix below
}
// clean stale/invalid lockfile
err = os.Remove(name)
if err != nil {
return err
}
// now that we cleaned up the stale lockfile, let's recurse
return l.TryLock()
}
// Release a lock again. Returns any error that happend during release of lock.
func (l Lockfile) Unlock() error {
return os.Remove(string(l))
}

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@ -11,10 +11,12 @@ func isRunning(pid int) (bool, error) {
proc, err := os.FindProcess(pid)
if err != nil {
return false, err
}
if err := proc.Signal(syscall.Signal(0)); err != nil {
} else {
err := proc.Signal(syscall.Signal(0))
if err == nil {
return true, nil
} else {
return false, nil
}
return true, nil
}
}

12
vendor/vendor.json vendored
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@ -38,12 +38,6 @@
"revision": "c12348ce28de40eed0136aa2b644d0ee0650e56c",
"revisionTime": "2016-04-24T11:30:07Z"
},
{
"checksumSHA1": "dSCW0yEU+VThfWk5v/GkSdrjIu4=",
"path": "github.com/nightlyone/lockfile",
"revision": "3d299f51e376213fcdcfd213a76afce6b290bf9d",
"revisionTime": "2016-06-19T19:46:32Z"
},
{
"checksumSHA1": "LuFv4/jlrmFNnDb/5SCSEPAM9vU=",
"path": "github.com/pmezard/go-difflib/difflib",
@ -91,6 +85,12 @@
"path": "github.com/stretchr/testify/assert",
"revision": "d77da356e56a7428ad25149ca77381849a6a5232",
"revisionTime": "2016-06-15T09:26:46Z"
},
{
"checksumSHA1": "0zBf3a7Gzqypt1sWefwx4NkOEIc=",
"path": "gopkg.in/Acconut/lockfile.v1",
"revision": "941fc61ce4d67dd432b94ed0bd445ad5fb9391a9",
"revisionTime": "2016-05-20T15:30:20Z"
}
],
"rootPath": "github.com/tus/tusd"