Add the wrap_greenthread() function

4 files changed, 86 insertions, 19 deletions

diff --git a/README b/README
index 27ea8c9..5d0dc60 100644
--- a/README
+++ b/README
@@ -72,6 +72,38 @@ Hello World::
     loop.close()
 
 
+Use a greenthread in a coroutine
+--------------------------------
+
+Use the ``wrap_greenthread()`` function to wrap a greenthread into a Future
+object. The Future object waits for the completion of a greenthread.
+
+Example with asyncio::
+
+    def slow_sum(x, y):
+        eventlet.sleep(1.0)
+        return x + y
+
+    @asyncio.coroutine
+    def coro_sum():
+        gt = eventlet.spawn(slow_sum, 1, 2)
+        fut = aiogreen.wrap_greenthread(gt, loop=loop)
+        result = yield from fut
+        return result
+
+Note: In debug mode, when a greenthread raises an exception, the exception is
+logged to sys.stderr by eventlet, even if it is correctly copied to the Future
+object.
+
+
+API
+===
+
+Functions which are not in asyncio:
+
+* ``wrap_greenthread(gt)``: wrap a greenthread into a Future object
+
+
 Installation
 ============
 
@@ -139,6 +171,7 @@ only call the callback once per loop iteration.
 
 Changes:
 
+* Add the ``wrap_greenthread()`` function to wrap a greenthread into a Future
 * Support also eventlet 0.14, not only eventlet 0.15 or newer
 * Support eventlet with monkey-patching
 * Rewrite the code handling file descriptors to ensure that the listener is
diff --git a/aiogreen.py b/aiogreen.py
index 5c45635..e7558c3 100644
--- a/aiogreen.py
+++ b/aiogreen.py
@@ -68,6 +68,24 @@ class _TpoolExecutor(object):
         self._tpool.killall()
 
 
+def wrap_greenthread(gt, loop=None):
+    """Wrap an eventlet greenthread into a Future object."""
+    if loop is None:
+        loop = asyncio.get_event_loop()
+    fut = asyncio.Future(loop=loop)
+
+    def copy_result(gt):
+        try:
+            value = gt.wait()
+        except Exception as exc:
+            loop.call_soon(fut.set_exception, exc)
+        else:
+            loop.call_soon(fut.set_result, value)
+
+    gt.link(copy_result)
+    return fut
+
+
 class _Selector(asyncio.selectors._BaseSelectorImpl):
     def __init__(self, loop, hub):
         super(_Selector, self).__init__()
diff --git a/tests/test_eventlet.py b/tests/test_eventlet.py
index eb428d7..4ff9e8c 100644
--- a/tests/test_eventlet.py
+++ b/tests/test_eventlet.py
@@ -1,5 +1,8 @@
+import aiogreen
 import eventlet
 import tests
+from tests import unittest
+
 
 def eventlet_slow_append(result, value, delay):
     eventlet.sleep(delay)
@@ -33,22 +36,25 @@ try:
             return value
 
         @asyncio.coroutine
-        def coro_chain_greenthread():
+        def coro_wrap_greenthread():
             result = []
             loop = asyncio.get_event_loop()
 
             g1 = eventlet.spawn(eventlet_slow_append, result, 1, 0.2)
 
-            value = yield from wait_greenthread(g1, loop=loop)
+            fut = aiogreen.wrap_greenthread(g1, loop=loop)
+            value = yield from fut
             result.append(value)
 
             g2 = eventlet.spawn(eventlet_slow_append, result, 2, 0.1)
-            value = yield from wait_greenthread(g2, loop=loop)
+            fut = aiogreen.wrap_greenthread(g2, loop=loop)
+            value = yield from fut
             result.append(value)
 
             g3 = eventlet.spawn(eventlet_slow_error, 0.001)
+            fut = aiogreen.wrap_greenthread(g3, loop=loop)
             try:
-                yield from wait_greenthread(g3, loop=loop)
+                yield from fut
             except ValueError as exc:
                 result.append(str(exc))
 
@@ -89,22 +95,24 @@ except ImportError:
         raise Return(value)
 
     @asyncio.coroutine
-    def coro_chain_greenthread():
+    def coro_wrap_greenthread():
         result = []
         loop = asyncio.get_event_loop()
 
         g1 = eventlet.spawn(eventlet_slow_append, result, 1, 0.2)
-
-        value = yield From(wait_greenthread(g1, loop=loop))
+        fut = aiogreen.wrap_greenthread(g1, loop=loop)
+        value = yield From(fut)
         result.append(value)
 
         g2 = eventlet.spawn(eventlet_slow_append, result, 2, 0.1)
-        value = yield From(wait_greenthread(g2, loop=loop))
+        fut = aiogreen.wrap_greenthread(g2, loop=loop)
+        value = yield From(fut)
         result.append(value)
 
         g3 = eventlet.spawn(eventlet_slow_error, 0.001)
+        fut = aiogreen.wrap_greenthread(g3, loop=loop)
         try:
-            yield From(wait_greenthread(g3, loop=loop))
+            yield From(fut)
         except ValueError as exc:
             result.append(str(exc))
 
@@ -123,7 +131,7 @@ except ImportError:
         raise ValueError("error")
 
 
-def wait_task(task):
+def link_task(task):
     event = eventlet.event.Event()
     def done(fut):
         try:
@@ -137,19 +145,19 @@ def wait_task(task):
     task.add_done_callback(done)
     return event.wait()
 
-def greenthread_chain_coro(result, loop):
+def greenthread_link_task(result, loop):
     try:
         t1 = asyncio.async(coro_slow_append(result, 1, 0.2), loop=loop)
-        value = wait_task(t1)
+        value = link_task(t1)
         result.append(value)
 
         t2 = asyncio.async(coro_slow_append(result, 2, 0.1), loop=loop)
-        value = wait_task(t2)
+        value = link_task(t2)
         result.append(value)
 
         t3 = asyncio.async(coro_slow_error(0.001), loop=loop)
         try:
-            value = wait_task(t3)
+            value = link_task(t3)
         except ValueError as exc:
             result.append(str(exc))
 
@@ -204,13 +212,14 @@ class EventletTests(tests.TestCase):
         self.loop.run_forever()
         self.assertEqual(result, ["spawn", "spawn_after"])
 
-    def test_coro_chain_greenthread(self):
-        result = self.loop.run_until_complete(coro_chain_greenthread())
+    def test_coro_wrap_greenthread(self):
+        result = self.loop.run_until_complete(coro_wrap_greenthread())
         self.assertEqual(result, [1, 10, 2, 20, 'error', 4])
 
-    def test_greenthread_chain_coro(self):
+    def test_greenthread_link_task(self):
         result = []
-        self.loop.call_soon(eventlet.spawn, greenthread_chain_coro, result, self.loop)
+        self.loop.call_soon(eventlet.spawn,
+                            greenthread_link_task, result, self.loop)
         self.loop.run_forever()
         self.assertEqual(result, [1, 10, 2, 20, 'error', 4])
 
diff --git a/tox.ini b/tox.ini
index 86aed81..6b6f983 100644
--- a/tox.ini
+++ b/tox.ini
@@ -1,5 +1,5 @@
 [tox]
-envlist = py26,py27,py27_patch,py32,py33,py34
+envlist = py26,py27,py27_patch,py32,py33,py34,py35
 
 [testenv:py26]
 setenv =
@@ -49,3 +49,10 @@ setenv =
 deps=
    eventlet
 commands=python runtests.py -r
+
+[testenv:py35]
+setenv =
+   PYTHONASYNCIODEBUG = 1
+deps=
+   eventlet
+commands=python runtests.py -r