Fix a crash with Python 3.4 when you stop IOU

http://bugs.python.org/issue23140

gns3server/modules/iou/iou_vm.py

@@ -483,18 +483,19 @@ class IOUVM(BaseVM):
                 self._ioucon_thread = None
 
             self._terminate_process_iou()
-            try:
-                yield from asyncio.wait_for(self._iou_process.wait(), timeout=3)
-            except asyncio.TimeoutError:
-                self._iou_process.kill()
-                if self._iou_process.returncode is None:
-                    log.warn("IOU process {} is still running".format(self._iou_process.pid))
+            if self._iou_process.returncode is None:
+                try:
+                    yield from gns3server.utils.asyncio.wait_for_process_termination(self._iou_process, timeout=3)
+                except asyncio.TimeoutError:
+                    self._iou_process.kill()
+                    if self._iou_process.returncode is None:
+                        log.warn("IOU process {} is still running".format(self._iou_process.pid))
             self._iou_process = None
 
             if self._iouyap_process is not None:
                 self._terminate_process_iouyap()
                 try:
-                    yield from asyncio.wait_for(self._iouyap_process.wait(), timeout=3)
+                    yield from gns3server.utils.asyncio.wait_for_process_termination(self._iouyap_process, timeout=3)
                 except asyncio.TimeoutError:
                     self._iouyap_process.kill()
                     if self._iouyap_process.returncode is None:

gns3server/utils/asyncio.py

@@ -53,3 +53,27 @@ def subprocess_check_output(*args, cwd=None, env=None):
     if output is None:
         return ""
     return output.decode("utf-8")
+
+
+@asyncio.coroutine
+def wait_for_process_termination(process, timeout=10):
+    """
+    Wait for a process terminate, and raise asyncio.TimeoutError in case of
+    timeout.
+
+    In theory this can be implemented by just:
+    yield from asyncio.wait_for(self._iou_process.wait(), timeout=100)
+
+    But it's broken before Python 3.4:
+    http://bugs.python.org/issue23140
+
+    :param process: An asyncio subprocess
+    :param timeout: Timeout in seconds
+    """
+
+    while timeout > 0:
+        if process.returncode is not None:
+            return
+        yield from asyncio.sleep(0.1)
+        timeout -= 0.1
+    raise asyncio.TimeoutError()

tests/utils/test_asyncio.py

@@ -18,8 +18,9 @@
 
 import asyncio
 import pytest
+from unittest.mock import MagicMock
 
-from gns3server.utils.asyncio import wait_run_in_executor, subprocess_check_output
+from gns3server.utils.asyncio import wait_run_in_executor, subprocess_check_output, wait_for_process_termination
 
 
 def test_wait_run_in_executor(loop):
@@ -50,3 +51,17 @@ def test_subprocess_check_output(loop, tmpdir, restore_original_path):
     exec = subprocess_check_output("cat", path)
     result = loop.run_until_complete(asyncio.async(exec))
     assert result == "TEST"
+
+
+def test_wait_for_process_termination(loop):
+
+    process = MagicMock()
+    process.returncode = 0
+    exec = wait_for_process_termination(process)
+    loop.run_until_complete(asyncio.async(exec))
+
+    process = MagicMock()
+    process.returncode = None
+    exec = wait_for_process_termination(process, timeout=0.5)
+    with pytest.raises(asyncio.TimeoutError):
+        loop.run_until_complete(asyncio.async(exec))