Add custom initializer argument to multiprocess.Manager*, courtesy of lekma
diff --git a/Doc/library/multiprocessing.rst b/Doc/library/multiprocessing.rst
index 18e81a7..a36836e 100644
--- a/Doc/library/multiprocessing.rst
+++ b/Doc/library/multiprocessing.rst
@@ -1130,9 +1130,10 @@
``current_process().authkey``. Otherwise *authkey* is used and it
must be a string.
- .. method:: start()
+ .. method:: start([initializer[, initargs]])
- Start a subprocess to start the manager.
+ Start a subprocess to start the manager. If *initializer* is not ``None``
+ then the subprocess will call ``initializer(*initargs)`` when it starts.
.. method:: serve_forever()
diff --git a/Lib/multiprocessing/managers.py b/Lib/multiprocessing/managers.py
index 02e96b9..fde0e40 100644
--- a/Lib/multiprocessing/managers.py
+++ b/Lib/multiprocessing/managers.py
@@ -475,12 +475,15 @@
dispatch(conn, None, 'dummy')
self._state.value = State.STARTED
- def start(self):
+ def start(self, initializer=None, initargs=()):
'''
Spawn a server process for this manager object
'''
assert self._state.value == State.INITIAL
+ if initializer is not None and not hasattr(initializer, '__call__'):
+ raise TypeError('initializer must be a callable')
+
# pipe over which we will retrieve address of server
reader, writer = connection.Pipe(duplex=False)
@@ -488,7 +491,7 @@
self._process = Process(
target=type(self)._run_server,
args=(self._registry, self._address, self._authkey,
- self._serializer, writer),
+ self._serializer, writer, initializer, initargs),
)
ident = ':'.join(str(i) for i in self._process._identity)
self._process.name = type(self).__name__ + '-' + ident
@@ -509,10 +512,14 @@
)
@classmethod
- def _run_server(cls, registry, address, authkey, serializer, writer):
+ def _run_server(cls, registry, address, authkey, serializer, writer,
+ initializer=None, initargs=()):
'''
Create a server, report its address and run it
'''
+ if initializer is not None:
+ initializer(*initargs)
+
# create server
server = cls._Server(registry, address, authkey, serializer)
diff --git a/Lib/multiprocessing/pool.py b/Lib/multiprocessing/pool.py
index 9da27d4..bc7e8f1 100644
--- a/Lib/multiprocessing/pool.py
+++ b/Lib/multiprocessing/pool.py
@@ -92,6 +92,9 @@
except NotImplementedError:
processes = 1
+ if initializer is not None and not hasattr(initializer, '__call__'):
+ raise TypeError('initializer must be a callable')
+
self._pool = []
for i in range(processes):
w = self.Process(
diff --git a/Lib/test/test_multiprocessing.py b/Lib/test/test_multiprocessing.py
index 8ef2e2f..cbcb630 100644
--- a/Lib/test/test_multiprocessing.py
+++ b/Lib/test/test_multiprocessing.py
@@ -1831,7 +1831,37 @@
multiprocessing.connection.answer_challenge,
_FakeConnection(), b'abc')
-testcases_other = [OtherTest, TestInvalidHandle]
+#
+# Test Manager.start()/Pool.__init__() initializer feature - see issue 5585
+#
+
+def initializer(ns):
+ ns.test += 1
+
+class TestInitializers(unittest.TestCase):
+ def setUp(self):
+ self.mgr = multiprocessing.Manager()
+ self.ns = self.mgr.Namespace()
+ self.ns.test = 0
+
+ def tearDown(self):
+ self.mgr.shutdown()
+
+ def test_manager_initializer(self):
+ m = multiprocessing.managers.SyncManager()
+ self.assertRaises(TypeError, m.start, 1)
+ m.start(initializer, (self.ns,))
+ self.assertEqual(self.ns.test, 1)
+ m.shutdown()
+
+ def test_pool_initializer(self):
+ self.assertRaises(TypeError, multiprocessing.Pool, initializer=1)
+ p = multiprocessing.Pool(1, initializer, (self.ns,))
+ p.close()
+ p.join()
+ self.assertEqual(self.ns.test, 1)
+
+testcases_other = [OtherTest, TestInvalidHandle, TestInitializers]
#
#
diff --git a/Misc/NEWS b/Misc/NEWS
index 8a50059..7de7b8a 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -202,6 +202,9 @@
Library
-------
+- Issue 5585: Add the ability to call an initializer to mulitiprocessing.manager
+ so that users can install custonm handlers/etc.
+
- Issue 3551: Patch multiprocessing to raise a proper exception if the size of the
object when writefile is called causes a ERROR_NO_SYSTEM_RESOURCES. Added docs
to note the limitation