Merge pull request #114 from itamarst/signatures

Better signatures on decorated methods, by using wrapt.

Fixes #55.

Author: itamarst

crochet/__init__.py

@@ -66,7 +66,4 @@ def _importReactor():
     "wait_for",
     "ReactorStopped",
     "__version__",
-    # Backwards compatibility:
-    "DeferredResult",
-    "in_reactor",
-    "wait_for_reactor", ]
+]

crochet/_eventloop.py

@@ -5,6 +5,7 @@
 from __future__ import absolute_import
 
 import select
+import sys
 import threading
 import weakref
 import warnings
@@ -19,6 +20,8 @@
 from twisted.internet.defer import maybeDeferred
 from twisted.internet.task import LoopingCall
 
+import wrapt
+
 from ._util import synchronized
 from ._resultstore import ResultStore
 
@@ -434,10 +437,11 @@ def no_setup(self):
                 "using crochet are imported and call setup().")
         self._common_setup()
 
-    def run_in_reactor(self, function):
+    @wrapt.decorator
+    def _run_in_reactor(self, function, _, args, kwargs):
         """
-        A decorator that ensures the wrapped function runs in the reactor
-        thread.
+        Implementation: A decorator that ensures the wrapped function runs in
+        the reactor thread.
 
         When the wrapped function is called, an EventualResult is returned.
         """
@@ -446,15 +450,29 @@ def runs_in_reactor(result, args, kwargs):
             d = maybeDeferred(function, *args, **kwargs)
             result._connect_deferred(d)
 
-        @wraps(function)
-        def wrapper(*args, **kwargs):
-            result = EventualResult(None, self._reactor)
-            self._registry.register(result)
-            self._reactor.callFromThread(runs_in_reactor, result, args, kwargs)
-            return result
+        result = EventualResult(None, self._reactor)
+        self._registry.register(result)
+        self._reactor.callFromThread(runs_in_reactor, result, args, kwargs)
+        return result
+
+    def run_in_reactor(self, function):
+        """
+        A decorator that ensures the wrapped function runs in the
+        reactor thread.
 
-        wrapper.wrapped_function = function
-        return wrapper
+        When the wrapped function is called, an EventualResult is returned.
+        """
+        result = self._run_in_reactor(function)
+        # Backwards compatibility; we could have used wrapt's version, but
+        # older Crochet code exposed different attribute name:
+        try:
+            result.wrapped_function = function
+        except AttributeError:
+            if sys.version_info[0] == 3:
+                raise
+            # In Python 2 e.g. classmethod has some limitations where you can't
+            # set stuff on it.
+        return result
 
     def wait_for_reactor(self, function):
         """
@@ -486,8 +504,8 @@ def wait_for(self, timeout):
         """
 
         def decorator(function):
-            @wraps(function)
-            def wrapper(*args, **kwargs):
+            @wrapt.decorator
+            def wrapper(function, _, args, kwargs):
                 @self.run_in_reactor
                 def run():
                     return function(*args, **kwargs)
@@ -499,8 +517,16 @@ def run():
                     eventual_result.cancel()
                     raise
 
-            wrapper.wrapped_function = function
-            return wrapper
+            result = wrapper(function)
+            # Expose underling function for testing purposes:
+            try:
+                result.wrapped_function = function
+            except AttributeError:
+                if sys.version_info[0] == 3:
+                    raise
+                # In Python 2 e.g. classmethod has some limitations where you
+                # can't set stuff on it.
+            return result
 
         return decorator
 

crochet/_util.py

@@ -2,18 +2,20 @@
 Utility functions and classes.
 """
 
-from functools import wraps
+import wrapt
+
+
+@wrapt.decorator
+def _synced(method, self, args, kwargs):
+    """Underlying synchronized wrapper."""
+    with self._lock:
+        return method(*args, **kwargs)
 
 
 def synchronized(method):
     """
     Decorator that wraps a method with an acquire/release of self._lock.
     """
-
-    @wraps(method)
-    def synced(self, *args, **kwargs):
-        with self._lock:
-            return method(self, *args, **kwargs)
-
-    synced.synchronized = True
-    return synced
+    result = _synced(method)
+    result.synchronized = True
+    return result

crochet/tests/test_api.py

@@ -13,6 +13,7 @@
 import tempfile
 import os
 import imp
+import inspect
 
 from twisted.trial.unittest import TestCase
 from twisted.internet.defer import succeed, Deferred, fail, CancelledError
@@ -641,6 +642,19 @@ class RunInReactorTests(TestCase):
     Tests for the run_in_reactor decorator.
     """
 
+    def test_signature(self):
+        """
+        The function decorated with the run_in_reactor decorator has the same
+        signature as the original function.
+        """
+        c = EventLoop(lambda: FakeReactor(), lambda f, g: None)
+
+        def some_name(arg1, arg2, karg1=2, *args, **kw):
+            pass
+        decorated = c.run_in_reactor(some_name)
+        self.assertEqual(inspect.getargspec(some_name),
+                         inspect.getargspec(decorated))
+
     def test_name(self):
         """
         The function decorated with run_in_reactor has the same name as the
@@ -672,6 +686,48 @@ def func(a, b, c):
         func(1, 2, c=3)
         self.assertEqual(calls, [(1, 2, 3)])
 
+    def test_method(self):
+        """
+        The function decorated with the wait decorator can be a method.
+        """
+        myreactor = FakeReactor()
+        c = EventLoop(lambda: myreactor, lambda f, g: None)
+        c.no_setup()
+        calls = []
+
+        class C(object):
+            @c.run_in_reactor
+            def func(self, a, b, c):
+                calls.append((self, a, b, c))
+
+        o = C()
+        o.func(1, 2, c=3)
+        self.assertEqual(calls, [(o, 1, 2, 3)])
+
+    def test_classmethod(self):
+        """
+        The function decorated with the wait decorator can be a classmethod.
+        """
+        myreactor = FakeReactor()
+        c = EventLoop(lambda: myreactor, lambda f, g: None)
+        c.no_setup()
+        calls = []
+
+        class C(object):
+            @c.run_in_reactor
+            @classmethod
+            def func(cls, a, b, c):
+                calls.append((cls, a, b, c))
+
+            @classmethod
+            @c.run_in_reactor
+            def func2(cls, a, b, c):
+                calls.append((cls, a, b, c))
+
+        C.func(1, 2, c=3)
+        C.func2(1, 2, c=3)
+        self.assertEqual(calls, [(C, 1, 2, 3), (C, 1, 2, 3)])
+
     def make_wrapped_function(self):
         """
         Return a function wrapped with run_in_reactor that returns its first
@@ -809,6 +865,19 @@ def some_name(argument):
 
         self.assertEqual(some_name.__name__, "some_name")
 
+    def test_signature(self):
+        """
+        The function decorated with the wait decorator has the same signature
+        as the original function.
+        """
+        decorator = self.decorator()
+
+        def some_name(arg1, arg2, karg1=2, *args, **kw):
+            pass
+        decorated = decorator(some_name)
+        self.assertEqual(inspect.getargspec(some_name),
+                         inspect.getargspec(decorated))
+
     def test_wrapped_function(self):
         """
         The function wrapped by the wait decorator can be accessed via the
@@ -863,6 +932,28 @@ def func(a, b, c):
         func(1, 2, c=3)
         self.assertEqual(calls, [(1, 2, 3)])
 
+    def test_classmethod(self):
+        """
+        The function decorated with the wait decorator can be a classmethod.
+        """
+        calls = []
+        decorator = self.decorator()
+
+        class C(object):
+            @decorator
+            @classmethod
+            def func(cls, a, b, c):
+                calls.append((a, b, c))
+
+            @classmethod
+            @decorator
+            def func2(cls, a, b, c):
+                calls.append((a, b, c))
+
+        C.func(1, 2, c=3)
+        C.func2(1, 2, c=3)
+        self.assertEqual(calls, [(1, 2, 3), (1, 2, 3)])
+
     def test_deferred_success_result(self):
         """
         If the underlying function returns a Deferred, the wrapper returns a

docs/api-reference.rst

@@ -0,0 +1,12 @@
+API Reference
+=============
+
+.. autofunction:: crochet.setup()
+.. autofunction:: crochet.no_setup()
+.. autofunction:: crochet.run_in_reactor(function)
+.. autofunction:: crochet.wait_for(timeout)
+.. autoclass:: crochet.EventualResult
+   :members:
+.. autofunction:: crochet.retrieve_result(result_id)
+.. autoexception:: crochet.TimeoutError
+.. autoexception:: crochet.ReactorStopped

docs/conf.py

@@ -23,7 +23,7 @@
 
 # Add any Sphinx extension module names here, as strings. They can be extensions
 # coming with Sphinx (named 'sphinx.ext.*') or your custom ones.
-extensions = []
+extensions = ["sphinx.ext.autodoc"]
 
 # Add any paths that contain templates here, relative to this directory.
 templates_path = ['_templates']

docs/index.rst

@@ -32,4 +32,5 @@ Table of Contents
    using
    workarounds
    async
+   api-reference
    news

docs/news.rst

@@ -4,11 +4,19 @@ What's New
 1.8.0
 ^^^^^
 
+New features:
+
+* Signatures on decorated functions now match the original functions.
+  Thanks to Mikhail Terekhov for the original patch.
+* Documentation improvements, including an API reference.
+
 Bug fixes:
 
 * Switched to EPoll reactor for logging thread.
   Anecdotal evidence suggests this fixes some issues on AWS Lambda, but it's not clear why.
   Thanks to Rolando Espinoza for the patch.
+* It's now possible to call ``@run_in_reactor`` and ``@wait_for`` above a ``@classmethod``.
+  Thanks to vak for the bug report.
 
 1.7.0
 ^^^^^

setup.py

@@ -13,6 +13,7 @@ def read(path):
     with open(path) as f:
         return f.read()
 
+
 setup(
     classifiers=[
         'Intended Audience :: Developers',
@@ -32,6 +33,7 @@ def read(path):
     description="Use Twisted anywhere!",
     install_requires=[
         "Twisted>=15.0",
+        "wrapt",
     ],
     keywords="twisted threading",
     license="MIT",