Add context manager to GreenPipe.

eventlet/greenio.py

@@ -461,6 +461,12 @@ class GreenPipe(object):
     def __iter__(self):
         return self.xreadlines()
 
+    def __enter__(self):
+        return self
+
+    def __exit__(self, *exc_info):
+        self.close()
+
     def xreadlines(self, size=None):
         if size is None:
             while True:

tests/greenio_test.py

@@ -483,6 +483,26 @@ class TestGreenIo(LimitedTestCase):
 
         gt.wait()
 
+    def test_pipe_context(self):
+        # ensure using a pipe as a context actually closes it.
+        r, w = os.pipe()
+
+        r = os.fdopen(r)
+        w = os.fdopen(w, 'w')
+
+        r = greenio.GreenPipe(r)
+        w = greenio.GreenPipe(w)
+
+        with r:
+            pass
+
+        assert r.closed and not w.closed
+
+        with w as f:
+            assert f == w
+
+        assert r.closed and w.closed
+
 
 class TestGreenIoLong(LimitedTestCase):
     TEST_TIMEOUT=10  # the test here might take a while depending on the OS