From 72672c98cb63eb953a9bb29fc9ea7cae2eeaa6df Mon Sep 17 00:00:00 2001 From: Cyril Galibern Date: Mon, 19 Apr 2021 18:31:33 +0200 Subject: [PATCH] Initial commit from opensvc flock --- .gitignore | 1 + LICENCE | 339 ++++++++++++++++++++++++++++++++++++++++++++++++++ flock_test.go | 111 +++++++++++++++++ go.mod | 11 ++ go.sum | 33 +++++ main.go | 79 ++++++++++++ 6 files changed, 574 insertions(+) create mode 100644 .gitignore create mode 100644 LICENCE create mode 100644 flock_test.go create mode 100644 go.mod create mode 100644 go.sum create mode 100644 main.go diff --git a/.gitignore b/.gitignore new file mode 100644 index 0000000..485dee6 --- /dev/null +++ b/.gitignore @@ -0,0 +1 @@ +.idea diff --git a/LICENCE b/LICENCE new file mode 100644 index 0000000..010a71a --- /dev/null +++ b/LICENCE @@ -0,0 +1,339 @@ + GNU GENERAL PUBLIC LICENSE + Version 2, June 1991 + + Copyright (C) 1989, 1991 Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA + Everyone is permitted to copy and distribute verbatim copies + of this license document, but changing it is not allowed. + + Preamble + + The licenses for most software are designed to take away your +freedom to share and change it. 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See the + GNU General Public License for more details. + + You should have received a copy of the GNU General Public License along + with this program; if not, write to the Free Software Foundation, Inc., + 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA. + +Also add information on how to contact you by electronic and paper mail. + +If the program is interactive, make it output a short notice like this +when it starts in an interactive mode: + + Gnomovision version 69, Copyright (C) year name of author + Gnomovision comes with ABSOLUTELY NO WARRANTY; for details type 'show w'. + This is free software, and you are welcome to redistribute it + under certain conditions; type 'show c' for details. + +The hypothetical commands 'show w' and 'show c' should show the appropriate +parts of the General Public License. Of course, the commands you use may +be called something other than 'show w' and 'show c'; they could even be +mouse-clicks or menu items--whatever suits your program. + +You should also get your employer (if you work as a programmer) or your +school, if any, to sign a "copyright disclaimer" for the program, if +necessary. Here is a sample; alter the names: + + Yoyodyne, Inc., hereby disclaims all copyright interest in the program + 'Gnomovision' (which makes passes at compilers) written by James Hacker. + + , 1 April 1989 + Ty Coon, President of Vice + +This General Public License does not permit incorporating your program into +proprietary programs. If your program is a subroutine library, you may +consider it more useful to permit linking proprietary applications with the +library. If this is what you want to do, use the GNU Lesser General +Public License instead of this License. diff --git a/flock_test.go b/flock_test.go new file mode 100644 index 0000000..628e7f7 --- /dev/null +++ b/flock_test.go @@ -0,0 +1,111 @@ +package flock + +import ( + "encoding/json" + "errors" + "github.com/golang/mock/gomock" + "github.com/opensvc/fcntllock" + "github.com/opensvc/locker" + mockLocker "github.com/opensvc/locker/mock_locker" + "github.com/opensvc/testhelper" + "github.com/stretchr/testify/assert" + "os" + "path/filepath" + "testing" + "time" +) + +func setup(t *testing.T) (prov func(string) locker.Locker, lck *mockLocker.MockLocker) { + ctrl := gomock.NewController(t) + lck = mockLocker.NewMockLocker(ctrl) + prov = func(string) locker.Locker { + return lck + } + return +} + +func TestLock(t *testing.T) { + t.Run("Ensure write data to lock file when lock succeed", func(t *testing.T) { + prov, mockLck := setup(t) + lck := New("foo.lck", "session1", prov) + var b []byte + mockLck.EXPECT().LockContext(gomock.Any(), 500*time.Millisecond).Return(nil) + mockLck.EXPECT(). + Write(gomock.AssignableToTypeOf(b)). + Do(func(arg []byte) { + b = arg + }). + Return(0, nil) + + err := lck.Lock(100*time.Millisecond, "intent1") + assert.Equal(t, nil, err) + + found := meta{} + if err := json.Unmarshal(b, &found); err != nil { + t.Fatalf("expected written data : %+v\n", b) + } + assert.Equal(t, "intent1", found.Intent) + assert.Equal(t, "session1", found.SessionID) + }) + + t.Run("Ensure return error if lock fail", func(t *testing.T) { + prov, mockLck := setup(t) + + mockLck.EXPECT().LockContext(gomock.Any(), gomock.Any()).Return(errors.New("can't lock")) + + err := New("foo.lck", "sessionId2", prov).Lock(100*time.Millisecond, "intent1") + assert.Equal(t, errors.New("can't lock"), err) + }) + + t.Run("can write, seek, read on locked file", func(t *testing.T) { + lockfile, tfCleanup := testhelper.TempFile(t) + defer tfCleanup() + l := New(lockfile, "sessionId3", fcntllock.New) + err := l.Lock(1*time.Second, "plop") + assert.Equal(t, nil, err) + dataToWrite := []byte("{}") + writeLen, err := l.Write(dataToWrite) + assert.Nil(t, err) + assert.Equal(t, 2, writeLen) + _, err = l.Seek(0, 0) + assert.Nil(t, err) + data := make([]byte, 200) + assert.Nil(t, err) + readLen, err := l.Read(data) + assert.Greater(t, readLen, 50) + _, err = os.Stat(lockfile) + assert.Nil(t, err) + }) + + t.Run("lock fail if lock dir doesn't exists", func(t *testing.T) { + lockDir, cleanup := testhelper.Tempdir(t) + defer cleanup() + defaultRetryInterval := retryInterval + defer func() { retryInterval = defaultRetryInterval }() + retryInterval = 5 * time.Millisecond + l := New(filepath.Join(lockDir, "dir", "lockfile"), "sessionOne", fcntllock.New) + err := l.Lock(15*time.Millisecond, "plop") + assert.NotNil(t, err) + assert.Equal(t, "lock timeout exceeded", err.Error()) + }) +} + +func TestUnLock(t *testing.T) { + t.Run("Ensure unlock succeed", func(t *testing.T) { + prov, mockLck := setup(t) + + mockLck.EXPECT().UnLock().Return(nil) + l := New("foo.lck", "sessionX", prov) + + err := l.UnLock() + assert.Equal(t, nil, err) + }) + t.Run("Ensure unlock (fcntl lock) succeed even if file is not locked", func(t *testing.T) { + lockfile, tfCleanup := testhelper.TempFile(t) + defer tfCleanup() + l := New(lockfile, "", fcntllock.New) + + err := l.UnLock() + assert.Equal(t, nil, err) + }) +} diff --git a/go.mod b/go.mod new file mode 100644 index 0000000..89023c9 --- /dev/null +++ b/go.mod @@ -0,0 +1,11 @@ +module github.com/opensvc/flock + +go 1.13 + +require ( + github.com/golang/mock v1.5.0 + github.com/opensvc/fcntllock v0.0.2 + github.com/opensvc/locker v0.0.2 + github.com/opensvc/testhelper v0.0.2 + github.com/stretchr/testify v1.7.0 +) diff --git a/go.sum b/go.sum new file mode 100644 index 0000000..a704b8d --- /dev/null +++ b/go.sum @@ -0,0 +1,33 @@ +github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8= +github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= +github.com/golang/mock v1.5.0 h1:jlYHihg//f7RRwuPfptm04yp4s7O6Kw8EZiVYIGcH0g= +github.com/golang/mock v1.5.0/go.mod h1:CWnOUgYIOo4TcNZ0wHX3YZCqsaM1I1Jvs6v3mP3KVu8= +github.com/opensvc/fcntllock v0.0.2 h1:2THz4s8LLuQKaT0Vq6PJyB8ccrRhR5rUHDDi9UcRrN8= +github.com/opensvc/fcntllock v0.0.2/go.mod h1:6roTI/HnYo0BTlu6p4mMDDzqkRRwKYOnINmdI8Ytbs0= +github.com/opensvc/locker v0.0.1 h1:LC2B8NF5jwAUynQvBOC0zMWCnOCE31hD3lwa//04CAM= +github.com/opensvc/locker v0.0.1/go.mod h1:EGM9u/OLJjie1vkNTaTlgj80+PpaH2zBUK/iPPOMCjY= +github.com/opensvc/locker v0.0.2 h1:q7CylV9/7vG8YjS/Poa2WmDr2Jo62aIGWTiaCgxIxG0= +github.com/opensvc/locker v0.0.2/go.mod h1:H/QSU7f5bULf/5PVOHZ58uEkyMF7RNkPfSEmP+E8qoM= +github.com/opensvc/testhelper v0.0.2 h1:RjajedHeA7cew1tfYGxytJklNpDoiV34KIqwl0qKW8k= +github.com/opensvc/testhelper v0.0.2/go.mod h1:fUJRZPmQs6iu4/gDlU8oTuTH7+c8vJ3uVOljkR6anL0= +github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= +github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= +github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= +github.com/stretchr/testify v1.7.0 h1:nwc3DEeHmmLAfoZucVR881uASk0Mfjw8xYJ99tb5CcY= +github.com/stretchr/testify v1.7.0/go.mod h1:6Fq8oRcR53rry900zMqJjRRixrwX3KX962/h/Wwjteg= +golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w= +golang.org/x/crypto v0.0.0-20191011191535-87dc89f01550/go.mod h1:yigFU9vqHzYiE8UmvKecakEJjdnWj3jj499lnFckfCI= +golang.org/x/mod v0.3.0/go.mod h1:s0Qsj1ACt9ePp/hMypM3fl4fZqREWJwdYDEqhRiZZUA= +golang.org/x/net v0.0.0-20190404232315-eb5bcb51f2a3/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg= +golang.org/x/net v0.0.0-20190620200207-3b0461eec859/go.mod h1:z5CRVTTTmAJ677TzLLGU+0bjPO0LkuOLi4/5GtJWs/s= +golang.org/x/sync v0.0.0-20190423024810-112230192c58/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM= +golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY= +golang.org/x/sys v0.0.0-20190412213103-97732733099d/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs= +golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ= +golang.org/x/tools v0.0.0-20191119224855-298f0cb1881e/go.mod h1:b+2E5dAYhXwXZwtnZ6UAqBI28+e2cm9otk0dWdXHAEo= +golang.org/x/xerrors v0.0.0-20190717185122-a985d3407aa7/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= +golang.org/x/xerrors v0.0.0-20191011141410-1b5146add898/go.mod h1:I/5z698sn9Ka8TeJc9MKroUUfqBBauWjQqLJ2OPfmY0= +gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM= +gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= +gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c h1:dUUwHk2QECo/6vqA44rthZ8ie2QXMNeKRTHCNY2nXvo= +gopkg.in/yaml.v3 v3.0.0-20200313102051-9f266ea9e77c/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM= diff --git a/main.go b/main.go new file mode 100644 index 0000000..33f5d22 --- /dev/null +++ b/main.go @@ -0,0 +1,79 @@ +package flock + +import ( + "context" + "encoding/json" + "errors" + "github.com/opensvc/locker" + "io" + "os" + "time" +) + +type ( + // T wraps flock and dumps a json data in the lock file + // hinting about what holds the lock. + T struct { + locker.Locker + Path string + sessionId string + } + + meta struct { + PID int `json:"pid"` + Intent string `json:"intent"` + SessionID string `json:"session_id"` + } +) + +var ( + truncate = os.Truncate + remove = os.Remove + //defaultLockProvider = fcntllock.New + retryInterval = 500 * time.Millisecond +) + +// New allocate a file lock struct from Locker provider. +func New(p string, sessionId string, lockP func(string) locker.Locker) *T { + return &T{ + Locker: lockP(p), + Path: p, + sessionId: sessionId, + } +} + +// +// Lock acquires an exclusive file lock on the file and write a json +// formatted structure hinting who holds the lock and with what +// intention. +// +func (t *T) Lock(timeout time.Duration, intent string) (err error) { + ctx, cancel := context.WithTimeout(context.Background(), timeout) + defer cancel() + err = t.LockContext(ctx, retryInterval) + if err != nil { + if errors.Is(err, context.DeadlineExceeded) { + return errors.New("lock timeout exceeded") + } + return + } + err = t.writeMeta(t, intent) + return +} + +func (t T) writeMeta(w io.Writer, intent string) error { + m := meta{ + PID: os.Getpid(), + Intent: intent, + SessionID: t.sessionId, + } + enc := json.NewEncoder(w) + return enc.Encode(m) +} + +// UnLock releases the file lock acquired by Lock. +func (t *T) UnLock() error { + _ = truncate(t.Path, 0) + _ = remove(t.Path) + return t.Locker.UnLock() +}