Merge pull request #36 from vikingco/VD-463/automatic-unlock-updates

VD-463: document and test LOCK_MAX_AGE

.gitignore

@@ -26,5 +26,12 @@ coverage.xml
 .mr.developer.cfg
 
 # Virtualenvs
+/venv
 .venv*
 .cache/
+
+# IDE junk
+/.idea
+
+# SQLite test db
+/db.sqlite3

README.rst

@@ -35,20 +35,15 @@ yourself, you can do that too::
     do_something()
     lock.release()
 
+Note that locks can expire automatically. There is a `LOCK_MAX_AGE` settings where you can specify a default lock release value for locks in your entire Django codebase. This value can be overridden per lock by setting the `max_age` parameter.
+
 Test
 -----
 You can run the tests with
 ::
 
     tox
 
-Wishlist
---------
-- Add lock time-out (try to aquire a lock for up to a given TIME_OUT), like
-  `lockfile's <http://packages.python.org/lockfile/>`_ `FileLock.aquire
-  <http://packages.python.org/lockfile/lockfile.html#lockfile.FileLock.acquire>`_
-- Global locks (for instance on a whole Model not just an object)
-
 Releases
 --------
 v2.0.0:

locking/migrations/0006_auto_20170609_1342.py

@@ -0,0 +1,20 @@
+# -*- coding: utf-8 -*-
+# Generated by Django 1.11.2 on 2017-06-09 13:42
+from __future__ import unicode_literals
+
+from django.db import migrations, models
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('locking', '0005_merge_20170504_1024'),
+    ]
+
+    operations = [
+        migrations.AlterField(
+            model_name='nonblockinglock',
+            name='max_age',
+            field=models.PositiveIntegerField(default=0, help_text='The age of a lock before it can be overwritten. 0 means indefinitely.', verbose_name='Maximum lock age'),
+        ),
+    ]

locking/models.py

@@ -188,7 +188,7 @@ class NonBlockingLock(models.Model):
     #: The age of a lock before it can be overwritten. If it's ``MAX_AGE_FOREVER``, it will
     #: never expire.
     max_age = models.PositiveIntegerField(
-        default=DEFAULT_MAX_AGE, verbose_name=_('Maximum lock age'),
+        default=MAX_AGE_FOREVER, verbose_name=_('Maximum lock age'),
         help_text=_('The age of a lock before it can be overwritten. '
                     '%s means indefinitely.' % MAX_AGE_FOREVER)
     )

locking/tests.py

@@ -4,10 +4,13 @@
 from __future__ import absolute_import
 import uuid
 
+from datetime import datetime, timedelta
+from django.conf import settings
+
 from freezegun import freeze_time
 
 from django.contrib.auth.models import User
-from django.test import TestCase
+from django.test import TestCase, override_settings
 
 from .exceptions import AlreadyLocked, RenewalError, NonexistentLock, NotLocked, Expired
 from .models import NonBlockingLock, _get_lock_name
@@ -143,3 +146,36 @@ def test_clean(self):
             # Only the non-expired lock should remain
             clean_expired_locks()
             self.assertEqual(NonBlockingLock.objects.get(), lock_to_be_released)
+
+    def test_implicit_cleaning_disabled(self):
+        """If no max_age parameter is given and locks aren't configured to autoexpire, don't clean them up."""
+        assert hasattr(settings, 'LOCK_MAX_AGE') is False
+        initial_timestamp = datetime(2017, 1, 1)
+
+        with freeze_time(initial_timestamp):
+            lock_to_remain = NonBlockingLock.objects.acquire_lock(self.user)
+        with freeze_time(initial_timestamp + timedelta(days=9600)):
+            clean_expired_locks()
+            assert NonBlockingLock.objects.get() == lock_to_remain
+
+    @override_settings(LOCK_MAX_AGE=0)
+    def test_implicit_cleaning_set_to_zero(self):
+        """If the LOCK_MAX_AGE setting is set to 0, no locks should autoexpire."""
+        initial_timestamp = datetime(2017, 1, 1)
+
+        with freeze_time(initial_timestamp):
+            lock_to_remain = NonBlockingLock.objects.acquire_lock(self.user)
+        with freeze_time(initial_timestamp + timedelta(days=9600)):
+            clean_expired_locks()
+            assert NonBlockingLock.objects.get() == lock_to_remain
+
+    @override_settings(LOCK_MAX_AGE=1)
+    def test_implicit_cleaning_set_to_nonzero(self):
+        """If the LOCK_MAX_AGE setting is bigger than 0, locks should autoexpire."""
+        initial_timestamp = datetime(2017, 1, 1)
+
+        with freeze_time(initial_timestamp):
+            NonBlockingLock.objects.acquire_lock(self.user)
+        with freeze_time(initial_timestamp + timedelta(seconds=1)):
+            clean_expired_locks()
+            assert NonBlockingLock.objects.count() == 0

pytest.ini

@@ -1,4 +1,4 @@
 [pytest]
 DJANGO_SETTINGS_MODULE=test_project.settings
 python_files = test*.py
-norecursedirs = .* *.egg *.egg-info wheel dist build artifacts
+norecursedirs = .* *.egg *.egg-info wheel dist build artifacts venv