Merge pull request #24326 from gnossen/fix_fork_interop

Remove uses of PIPE in Fork Interop Tests

src/python/grpcio_tests/tests/fork/_fork_interop_test.py

@@ -16,6 +16,7 @@
 import six
 import subprocess
 import sys
+import tempfile
 import threading
 import unittest
 from grpc._cython import cygrpc
@@ -69,15 +70,23 @@ class ForkInteropTest(unittest.TestCase):
             while True:
                 time.sleep(1)
         """
+        streams = tuple(tempfile.TemporaryFile() for _ in range(2))
         self._server_process = subprocess.Popen(
             [sys.executable, '-c', start_server_script],
-            stdout=subprocess.PIPE,
-            stderr=subprocess.PIPE)
+            stdout=streams[0],
+            stderr=streams[1])
         timer = threading.Timer(_SUBPROCESS_TIMEOUT_S,
                                 self._server_process.kill)
         try:
             timer.start()
-            self._port = int(self._server_process.stdout.readline())
+            while True:
+                streams[0].seek(0)
+                s = streams[0].readline()
+                if not s:
+                    continue
+                else:
+                    self._port = int(s)
+                    break
         except ValueError:
             raise Exception('Failed to get port from server')
         finally:
@@ -125,26 +134,22 @@ class ForkInteropTest(unittest.TestCase):
 
     def _verifyTestCase(self, test_case):
         script = _CLIENT_FORK_SCRIPT_TEMPLATE % (test_case.name, self._port)
+        streams = tuple(tempfile.TemporaryFile() for _ in range(2))
         process = subprocess.Popen([sys.executable, '-c', script],
-                                   stdout=subprocess.PIPE,
-                                   stderr=subprocess.PIPE)
+                                   stdout=streams[0],
+                                   stderr=streams[1])
         timer = threading.Timer(_SUBPROCESS_TIMEOUT_S, process.kill)
-        try:
-            timer.start()
-            try:
-                out, err = process.communicate(timeout=_SUBPROCESS_TIMEOUT_S)
-            except TypeError:
-                # The timeout parameter was added in Python 3.3.
-                out, err = process.communicate()
-        except subprocess.TimeoutExpired:
-            process.kill()
-            raise RuntimeError('Process failed to terminate')
-        finally:
-            timer.cancel()
+        timer.start()
+        process.wait()
+        timer.cancel()
+        outputs = []
+        for stream in streams:
+            stream.seek(0)
+            outputs.append(stream.read())
         self.assertEqual(
             0, process.returncode,
-            'process failed with exit code %d (stdout: %s, stderr: %s)' %
-            (process.returncode, out, err))
+            'process failed with exit code %d (stdout: "%s", stderr: "%s")' %
+            (process.returncode, outputs[0], outputs[1]))
 
 
 if __name__ == '__main__':

src/python/grpcio_tests/tests/fork/methods.py

@@ -142,7 +142,8 @@ class _ChildProcess(object):
                              self._process.exitcode)
         try:
             exception = self._exceptions.get(block=False)
-            raise ValueError('Child process failed: %s' % exception)
+            raise ValueError('Child process failed: "%s": "%s"' %
+                             (repr(exception), exception))
         except queue.Empty:
             pass