Add zc.lockfile.LockError handling to locks.file_lock (#42)

Following the fix for #38 by #39, I added a timeout loop and exception handling for the exception raised by zc.lockfile

Add myself to AUTHORS.rst as contributor
Include description of #42 in CHANGES.rst as Unreleased

Author: mshriver

AUTHORS.rst

@@ -10,6 +10,7 @@ These people have contributed to `pytest-services`, in alphabetical order:
 * `Dmitrijs Milajevs <[email protected]>`_
 * `Jason R. Coombs <[email protected]>`_
 * `Joep van Dijken <[email protected]>`_
+* `Magnus Staberg <[email protected]>`_
+* `Michael Shriver <[email protected]>`_
 * `Oleg Pidsadnyi <[email protected]>`_
 * `Zac Hatfield-Dodds <[email protected]>`_
-* `Magnus Staberg <[email protected]>`_

CHANGES.rst

@@ -1,6 +1,11 @@
 Changelog
 =========
 
+Unreleased
+-----
+
+- #42: Retry on ``zc.lockfile.LockError`` in ``file_lock``, use existing timeout kwarg
+
 2.2.0
 -----
 

pytest_services/locks.py

@@ -24,10 +24,21 @@ def file_lock(filename, remove=True, timeout=20):
     """A lock that is shared across processes.
 
     :param filename: the name of the file that will be locked.
-
+    :param remove: whether or not to remove the file on context close
+    :param timeout: Amount of time to retry the file lock if a :class:`zc.lockfile.LockError` is hit
     """
-    with contextlib.closing(zc.lockfile.SimpleLockFile(filename)) as lockfile:
-        yield lockfile._fp
+    total_seconds_slept = 0
+    while True:
+        try:
+            with contextlib.closing(zc.lockfile.SimpleLockFile(filename)) as lockfile:
+                yield lockfile._fp
+                break
+        except zc.lockfile.LockError as err:
+            if total_seconds_slept >= timeout:
+                raise err
+        seconds_to_sleep = random() * 0.1 + 0.05
+        total_seconds_slept += seconds_to_sleep
+        time.sleep(seconds_to_sleep)
 
     remove and try_remove(filename)