dvc: switch to flufl lock

dvc/analytics.py

@@ -66,7 +66,7 @@ def __init__(self, info=None):
                 raise
 
         self.user_id_file = os.path.join(cdir, self.USER_ID_FILE)
-        self.user_id_file_lock = Lock(cdir, self.USER_ID_FILE + ".lock")
+        self.user_id_file_lock = Lock(self.user_id_file + ".lock")
 
     @staticmethod
     def load(path):
@@ -113,7 +113,7 @@ def _get_user_id(self):
                 return user_id
         except LockError:
             msg = "Failed to acquire '{}'"
-            logger.debug(msg.format(self.user_id_file_lock.lock_file))
+            logger.debug(msg.format(self.user_id_file_lock.lockfile))
 
     def _collect_windows(self):
         import sys

dvc/lock.py

@@ -3,58 +3,118 @@
 from __future__ import unicode_literals
 
 import os
+import hashlib
 import time
-import zc.lockfile
-
-from dvc.exceptions import DvcException
+from datetime import timedelta
 
+from funcy.py3 import lkeep
 
-class LockError(DvcException):
-    """Thrown when unable to acquire the lock for dvc repo."""
+from dvc.exceptions import DvcException
+from dvc.utils import makedirs
+from dvc.utils.compat import is_py3
 
 
-class Lock(object):
-    """Class for dvc repo lock.
+DEFAULT_TIMEOUT = 5
 
-    Args:
-        dvc_dir (str): path to the directory that the lock should be created
-            in.
-        name (str): name of the lock file.
-    """
 
-    LOCK_FILE = "lock"
-    TIMEOUT = 5
+class LockError(DvcException):
+    """Thrown when unable to acquire the lock for dvc repo."""
 
-    def __init__(self, dvc_dir, name=LOCK_FILE):
-        self.lock_file = os.path.join(dvc_dir, name)
-        self._lock = None
 
-    def _do_lock(self):
-        try:
-            self._lock = zc.lockfile.LockFile(self.lock_file)
-        except zc.lockfile.LockError:
-            raise LockError(
-                "cannot perform the cmd since DVC is busy and "
-                "locked. Please retry the cmd later."
-            )
+if is_py3:
+    import flufl.lock
+
+    class Lock(flufl.lock.Lock):
+        """Class for dvc repo lock.
+
+        Args:
+            lockfile (str): the lock filename
+                in.
+            lifetime (int | timedelta): hold the lock for so long.
+            tmp_dir (str): a directory to store claim files.
+        """
+
+        def __init__(self, lockfile, lifetime=None, tmp_dir=None):
+            if lifetime is None:
+                lifetime = timedelta(days=365)  # Lock for good by default
+            elif isinstance(lifetime, int):
+                lifetime = timedelta(seconds=lifetime)
+
+            self._tmp_dir = tmp_dir
+            if self._tmp_dir is not None:
+                makedirs(self._tmp_dir, exist_ok=True)
+
+            super(Lock, self).__init__(lockfile, lifetime=lifetime)
+
+        @property
+        def lockfile(self):
+            return self._lockfile
+
+        @property
+        def files(self):
+            return lkeep([self._lockfile, self._tmp_dir])
+
+        def lock(self):
+            try:
+                super(Lock, self).lock(timedelta(seconds=DEFAULT_TIMEOUT))
+            except flufl.lock.TimeOutError:
+                raise LockError(
+                    "cannot perform the cmd since DVC is busy and "
+                    "locked. Please retry the cmd later."
+                )
+
+        def _set_claimfile(self, pid=None):
+            super(Lock, self)._set_claimfile(pid)
+
+            if self._tmp_dir is not None:
+                # Under Windows file path length is limited so we hash it
+                filename = hashlib.md5(self._claimfile.encode()).hexdigest()
+                self._claimfile = os.path.join(
+                    self._tmp_dir, filename + ".lock"
+                )
+
+
+else:
+    import zc.lockfile
+
+    class Lock(object):
+        """Class for dvc repo lock.
+
+        Uses zc.lockfile as backend.
+        """
+
+        def __init__(self, lockfile, lifetime=None, tmp_dir=None):
+            self.lockfile = lockfile
+            self._lock = None
+
+        @property
+        def files(self):
+            return [self.lockfile]
+
+        def _do_lock(self):
+            try:
+                self._lock = zc.lockfile.LockFile(self.lockfile)
+            except zc.lockfile.LockError:
+                raise LockError(
+                    "cannot perform the cmd since DVC is busy and "
+                    "locked. Please retry the cmd later."
+                )
+
+        def lock(self):
+            try:
+                self._do_lock()
+                return
+            except LockError:
+                time.sleep(DEFAULT_TIMEOUT)
 
-    def lock(self):
-        """Acquire lock for dvc repo."""
-        try:
             self._do_lock()
-            return
-        except LockError:
-            time.sleep(self.TIMEOUT)
-
-        self._do_lock()
 
-    def unlock(self):
-        """Release lock for dvc repo."""
-        self._lock.close()
-        self._lock = None
+        def unlock(self):
+            self._lock.close()
+            self._lock = None
 
-    def __enter__(self):
-        self.lock()
+        def __enter__(self):
+            self.lock()
 
-    def __exit__(self, typ, value, tbck):
-        self.unlock()
+        def __exit__(self, typ, value, tbck):
+            self.unlock()

dvc/logger.py

@@ -196,6 +196,10 @@ def setup(level=logging.INFO):
                     "level": logging.CRITICAL,
                     "handlers": ["console", "console_errors"],
                 },
+                "flufl.lock": {
+                    "level": logging.CRITICAL,
+                    "handlers": ["console", "console_errors"],
+                },
             },
         }
     )

dvc/repo/__init__.py

@@ -70,7 +70,10 @@ def __init__(self, root_dir=None):
 
         self.tree = WorkingTree(self.root_dir)
 
-        self.lock = Lock(self.dvc_dir)
+        self.lock = Lock(
+            os.path.join(self.dvc_dir, "lock"),
+            tmp_dir=os.path.join(self.dvc_dir, "tmp"),
+        )
         # NOTE: storing state and link_state in the repository itself to avoid
         # any possible state corruption in 'shared cache dir' scenario.
         self.state = State(self, self.config.config)
@@ -128,12 +131,12 @@ def _ignore(self):
 
         updater = Updater(self.dvc_dir)
 
-        flist = [
-            self.lock.lock_file,
-            self.config.config_local_file,
-            updater.updater_file,
-            updater.lock.lock_file,
-        ] + self.state.files
+        flist = (
+            [self.config.config_local_file, updater.updater_file]
+            + self.state.files
+            + self.lock.files
+            + updater.lock.files
+        )
 
         if self.cache.local.cache_dir.startswith(self.root_dir):
             flist += [self.cache.local.cache_dir]

dvc/state.py

@@ -3,14 +3,16 @@
 from __future__ import unicode_literals
 
 import os
+import re
 import sqlite3
 import logging
 
 from dvc.config import Config
 from dvc.utils import remove, current_timestamp, relpath, to_chunks
 from dvc.exceptions import DvcException
 from dvc.utils.fs import get_mtime_and_size, get_inode
-from dvc.utils.compat import fspath_py35
+from dvc.utils.compat import fspath_py35, urlencode, urlunparse, is_py2
+
 
 SQLITE_MAX_VARIABLES_NUMBER = 999
 
@@ -213,7 +215,11 @@ def load(self):
             assert self.cursor is None
             assert self.inserts == 0
             empty = not os.path.exists(self.state_file)
-            self.database = sqlite3.connect(self.state_file)
+            # NOTE: we use nolock option because fcntl() lock sqlite uses
+            # doesn't work on some older NFS/CIFS filesystems.
+            # This opens a possibility of data corruption by concurrent writes,
+            # which is prevented by repo lock.
+            self.database = _connect_sqlite(self.state_file, {"nolock": 1})
             self.cursor = self.database.cursor()
 
             # Try loading once to check that the file is indeed a database
@@ -473,3 +479,25 @@ def remove_unused_links(self, used):
                 self.LINK_STATE_TABLE, ",".join(["?"] * len(chunk_unused))
             )
             self._execute(cmd, tuple(chunk_unused))
+
+
+def _connect_sqlite(filename, options):
+    # Connect by URI was added in Python 3.4 and sqlite 3.7.7,
+    # we ignore options, which should be fine unless repo is on old NFS/CIFS
+    if is_py2 or sqlite3.sqlite_version_info < (3, 7, 7):
+        return sqlite3.connect(filename)
+
+    uri = _build_sqlite_uri(filename, options)
+    return sqlite3.connect(uri, uri=True)
+
+
+def _build_sqlite_uri(filename, options):
+    # Convert filename to uri according to https://www.sqlite.org/uri.html, 3.1
+    uri_path = filename.replace("?", "%3f").replace("#", "%23")
+    if os.name == "nt":
+        uri_path = uri_path.replace("\\", "/")
+        uri_path = re.sub(r"^([a-z]:)", "/\\1", uri_path, flags=re.I)
+    uri_path = re.sub(r"/+", "/", uri_path)
+
+    # Empty netloc, params and fragment
+    return urlunparse(("file", "", uri_path, "", urlencode(options), ""))

dvc/updater.py

@@ -25,7 +25,9 @@ class Updater(object):  # pragma: no cover
     def __init__(self, dvc_dir):
         self.dvc_dir = dvc_dir
         self.updater_file = os.path.join(dvc_dir, self.UPDATER_FILE)
-        self.lock = Lock(dvc_dir, self.updater_file + ".lock")
+        self.lock = Lock(
+            self.updater_file + ".lock", tmp_dir=os.path.join(dvc_dir, "tmp")
+        )
         self.current = parse_version(__version__).base_version
 
     def _is_outdated_file(self):
@@ -41,7 +43,7 @@ def _with_lock(self, func, action):
                 func()
         except LockError:
             msg = "Failed to acquire '{}' before {} updates"
-            logger.debug(msg.format(self.lock.lock_file, action))
+            logger.debug(msg.format(self.lock.lockfile, action))
 
     def check(self):
         if os.getenv("CI") or os.getenv("DVC_TEST"):

dvc/utils/compat.py

@@ -101,7 +101,8 @@ def ignore_file_not_found():
 
 
 if is_py2:
-    from urlparse import urlparse, urljoin, urlsplit, urlunsplit  # noqa: F401
+    from urlparse import urlparse, urlunparse, urljoin  # noqa: F401
+    from urllib import urlencode  # noqa: F401
     from BaseHTTPServer import HTTPServer  # noqa: F401
     from SimpleHTTPServer import SimpleHTTPRequestHandler  # noqa: F401
     import ConfigParser  # noqa: F401
@@ -144,9 +145,9 @@ def __exit__(self, *args):
     from os import makedirs  # noqa: F401
     from urllib.parse import (  # noqa: F401
         urlparse,  # noqa: F401
+        urlunparse,  # noqa: F401
+        urlencode,  # noqa: F401
         urljoin,  # noqa: F401
-        urlsplit,  # noqa: F401
-        urlunsplit,  # noqa: F401
     )
     from io import StringIO, BytesIO  # noqa: F401
     from http.server import (  # noqa: F401

setup.py

@@ -39,7 +39,6 @@ def run(self):
 install_requires = [
     "ply>=3.9",  # See https://github.com/pyinstaller/pyinstaller/issues/1945
     "configparser>=3.5.0",
-    "zc.lockfile>=1.2.1",
     "future>=0.16.0",
     "colorama>=0.3.9",
     "configobj>=5.0.6",
@@ -139,7 +138,12 @@ def run(self):
         "ssh_gssapi": ssh_gssapi,
         "hdfs": hdfs,
         # NOTE: https://github.com/inveniosoftware/troubleshooting/issues/1
-        ":python_version=='2.7'": ["futures", "pathlib2"],
+        ":python_version=='2.7'": [
+            "futures",
+            "pathlib2",
+            "zc.lockfile>=1.2.1",
+        ],
+        ":python_version>='3.0'": ["flufl.lock>=3.2"],
         "tests": tests_requirements,
     },
     keywords="data science, data version control, machine learning",

tests/func/test_lock.py

@@ -1,3 +1,5 @@
+import os
+
 from dvc.lock import LockError
 from dvc.main import main
 from dvc.lock import Lock
@@ -7,15 +9,17 @@
 
 class TestLock(TestDvc):
     def test_with(self):
-        lock = Lock(self.dvc.dvc_dir)
+        lockfile = os.path.join(self.dvc.dvc_dir, "lock")
+        lock = Lock(lockfile)
         with lock:
             with self.assertRaises(LockError):
-                lock2 = Lock(self.dvc.dvc_dir)
+                lock2 = Lock(lockfile)
                 with lock2:
                     self.assertTrue(False)
 
     def test_cli(self):
-        lock = Lock(self.dvc.dvc_dir)
+        lockfile = os.path.join(self.dvc.dvc_dir, "lock")
+        lock = Lock(lockfile)
         with lock:
             ret = main(["add", self.FOO])
             self.assertEqual(ret, 1)