Add shared filelock

Currently each driver in tooz only support exclusive lock, it is
inefficient in some scenarios which only need shared lock.

This patch adds shared lock in file driver.

Change-Id: I55a528977e74b27da736f421d2eee28c7aae8aa3
Implements: blueprint support-shared-lock
Co-Authored-By: Julien Danjou <julien@danjou.info>

1 files changed, 56 insertions, 0 deletions

diff --git a/tooz/tests/test_coordination.py b/tooz/tests/test_coordination.py
index 74a74b1..c177100 100644
--- a/tooz/tests/test_coordination.py
+++ b/tooz/tests/test_coordination.py
@@ -712,6 +712,62 @@ class TestAPI(tests.TestWithCoordinator):
         with lock:
             pass
 
+    def test_get_shared_lock(self):
+        lock = self._coord.get_lock(tests.get_random_uuid())
+        self.assertTrue(lock.acquire(shared=True))
+        self.assertTrue(lock.release())
+        with lock(shared=True):
+            pass
+
+    def test_get_shared_lock_locking_same_lock_twice(self):
+        lock = self._coord.get_lock(tests.get_random_uuid())
+        self.assertTrue(lock.acquire(shared=True))
+        self.assertTrue(lock.acquire(shared=True))
+        self.assertTrue(lock.release())
+        self.assertTrue(lock.release())
+        self.assertFalse(lock.release())
+        with lock(shared=True):
+            pass
+
+    def test_get_shared_lock_locking_two_lock(self):
+        name = tests.get_random_uuid()
+        lock1 = self._coord.get_lock(name)
+        coord = tooz.coordination.get_coordinator(
+            self.url, tests.get_random_uuid())
+        coord.start()
+        lock2 = coord.get_lock(name)
+
+        self.assertTrue(lock1.acquire(shared=True))
+        self.assertTrue(lock2.acquire(shared=True))
+        self.assertTrue(lock1.release())
+        self.assertTrue(lock2.release())
+
+    def test_get_lock_locking_shared_and_exclusive(self):
+        name = tests.get_random_uuid()
+        lock1 = self._coord.get_lock(name)
+        coord = tooz.coordination.get_coordinator(
+            self.url, tests.get_random_uuid())
+        coord.start()
+        lock2 = coord.get_lock(name)
+
+        self.assertTrue(lock1.acquire(shared=True))
+        self.assertFalse(lock2.acquire(blocking=False))
+        self.assertTrue(lock1.release())
+        self.assertFalse(lock2.release())
+
+    def test_get_lock_locking_exclusive_and_shared(self):
+        name = tests.get_random_uuid()
+        lock1 = self._coord.get_lock(name)
+        coord = tooz.coordination.get_coordinator(
+            self.url, tests.get_random_uuid())
+        coord.start()
+        lock2 = coord.get_lock(name)
+
+        self.assertTrue(lock1.acquire())
+        self.assertFalse(lock2.acquire(shared=True, blocking=False))
+        self.assertTrue(lock1.release())
+        self.assertFalse(lock2.release())
+
     def test_get_lock_concurrency_locking_same_lock(self):
         lock = self._coord.get_lock(tests.get_random_uuid())