Implement test for example

examples/python/multiprocessing/BUILD

@@ -24,10 +24,11 @@ py_binary(
 )
 
 py_test(
-    name = "_multiprocessing_example_test",
+    name = "test/_multiprocessing_example_test",
     srcs = ["test/_multiprocessing_example_test.py"],
     data = [
         ":client",
         ":server"
-    ]
+    ],
+    size = "small",
 )

examples/python/multiprocessing/README.md

@@ -0,0 +1,3 @@
+TODO: Describe the example.
+TODO: Describe how to run the example.
+TODO: Describe how to run the test.

examples/python/multiprocessing/client.py

@@ -25,6 +25,7 @@ import multiprocessing
 import operator
 import os
 import time
+import sys
 
 import prime_pb2
 import prime_pb2_grpc
@@ -36,11 +37,13 @@ _MAXIMUM_CANDIDATE = 10000
 _worker_channel_singleton = None
 _worker_stub_singleton = None
 
+_LOGGER = logging.getLogger(__name__)
+
 
 def _initialize_worker(server_address):
     global _worker_channel_singleton
     global _worker_stub_singleton
-    logging.warning('[PID {}] Initializing worker process.'.format(
+    _LOGGER.info('[PID {}] Initializing worker process.'.format(
             os.getpid()))
     _worker_channel_singleton = grpc.insecure_channel(server_address)
     _worker_stub_singleton = prime_pb2_grpc.PrimeCheckerStub(
@@ -49,25 +52,26 @@ def _initialize_worker(server_address):
 
 
 def _shutdown_worker():
-    logging.warning('[PID {}] Shutting worker process down.'.format(
+    _LOGGER.info('[PID {}] Shutting worker process down.'.format(
             os.getpid()))
     if _worker_channel_singleton is not None:
         _worker_channel_singleton.stop()
 
 
 def _run_worker_query(primality_candidate):
-    logging.warning('[PID {}] Checking primality of {}.'.format(
+    _LOGGER.info('[PID {}] Checking primality of {}.'.format(
             os.getpid(), primality_candidate))
     return _worker_stub_singleton.check(
             prime_pb2.PrimeCandidate(candidate=primality_candidate))
 
+
 def _calculate_primes(server_address):
     worker_pool = multiprocessing.Pool(processes=_PROCESS_COUNT,
                     initializer=_initialize_worker, initargs=(server_address,))
     check_range = range(2, _MAXIMUM_CANDIDATE)
     primality = worker_pool.map(_run_worker_query, check_range)
     primes = zip(check_range, map(operator.attrgetter('isPrime'), primality))
-    logging.warning(tuple(primes))
+    _LOGGER.info(tuple(primes))
 
 
 def main():
@@ -77,7 +81,16 @@ def main():
     parser.add_argument('server_address', help='The address of the server (e.g. localhost:50051)')
     args = parser.parse_args()
     _calculate_primes(args.server_address)
+    sys.stdout.flush()
+
 
 if __name__ == '__main__':
-    logging.basicConfig()
+    # TODO(rbellevi): Add PID to formatter
+    fh = logging.FileHandler('/tmp/client.log')
+    fh.setLevel(logging.INFO)
+    ch = logging.StreamHandler(sys.stdout)
+    ch.setLevel(logging.INFO)
+    _LOGGER.addHandler(fh)
+    _LOGGER.addHandler(ch)
+    _LOGGER.setLevel(logging.INFO)
     main()

examples/python/multiprocessing/server.py

@@ -27,10 +27,13 @@ import multiprocessing
 import os
 import time
 import socket
+import sys
 
 import prime_pb2
 import prime_pb2_grpc
 
+_LOGGER = logging.getLogger(__name__)
+
 _ONE_DAY = datetime.timedelta(days=1)
 _PROCESS_COUNT = 8
 _THREAD_CONCURRENCY = 10
@@ -47,7 +50,7 @@ def is_prime(n):
 class PrimeChecker(prime_pb2_grpc.PrimeCheckerServicer):
 
     def check(self, request, context):
-        logging.warning(
+        _LOGGER.info(
             '[PID {}] Determining primality of {}'.format(
                     os.getpid(), request.candidate))
         return prime_pb2.Primality(isPrime=is_prime(request.candidate))
@@ -63,7 +66,7 @@ def _wait_forever(server):
 
 def _run_server(bind_address):
     """Start a server in a subprocess."""
-    logging.warning( '[PID {}] Starting new server.'.format(os.getpid()))
+    _LOGGER.info( '[PID {}] Starting new server.'.format(os.getpid()))
     options = (('grpc.so_reuseport', 1),)
 
     # WARNING: This example takes advantage of SO_REUSEPORT. Due to the
@@ -99,7 +102,8 @@ def _reserve_port():
 def main():
     with _reserve_port() as port:
         bind_address = '[::]:{}'.format(port)
-        logging.warning("Binding to {}".format(bind_address))
+        _LOGGER.info("Binding to '{}'".format(bind_address))
+        sys.stdout.flush()
         workers = []
         for _ in range(_PROCESS_COUNT):
             # NOTE: It is imperative that the worker subprocesses be forked before
@@ -111,7 +115,13 @@ def main():
         for worker in workers:
             worker.join()
 
-
 if __name__ == '__main__':
-    logging.basicConfig()
+    # TODO(rbellevi): Add PID to formatter
+    fh = logging.FileHandler('/tmp/server.log')
+    fh.setLevel(logging.INFO)
+    ch = logging.StreamHandler(sys.stdout)
+    ch.setLevel(logging.INFO)
+    _LOGGER.addHandler(fh)
+    _LOGGER.addHandler(ch)
+    _LOGGER.setLevel(logging.INFO)
     main()

examples/python/multiprocessing/test/_multiprocessing_example_test.py

@@ -0,0 +1,74 @@
+# Copyright 2019 the gRPC authors.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+"""Test for multiprocessing example."""
+
+import datetime
+import logging
+import math
+import os
+import re
+import subprocess
+import tempfile
+import time
+import unittest
+
+_BINARY_DIR = os.path.realpath(
+    os.path.join(
+        os.path.dirname(os.path.abspath(__file__)), '..'))
+_SERVER_PATH = os.path.join(_BINARY_DIR, 'server')
+_CLIENT_PATH = os.path.join(_BINARY_DIR, 'client')
+
+
+def is_prime(n):
+    for i in range(2, int(math.ceil(math.sqrt(n)))):
+        if n % i == 0:
+            return False
+    else:
+        return True
+
+
+def _get_server_address(server_stream):
+    while True:
+        server_stream.seek(0)
+        line = server_stream.readline()
+        while line:
+            matches = re.search('Binding to \'(.+)\'', line)
+            if matches is not None:
+                return matches.groups()[0]
+            line = server_stream.readline()
+
+
+class MultiprocessingExampleTest(unittest.TestCase):
+
+    def test_multiprocessing_example(self):
+        server_stdout = tempfile.TemporaryFile(mode='r')
+        server_process = subprocess.Popen((_SERVER_PATH,),
+                                          stdout=server_stdout)
+        server_address = _get_server_address(server_stdout)
+        client_stdout = tempfile.TemporaryFile(mode='r')
+        client_process = subprocess.Popen((_CLIENT_PATH, server_address,),
+                                          stdout=client_stdout)
+        client_process.wait()
+        server_process.terminate()
+        client_stdout.seek(0)
+        results = eval(client_stdout.read().strip().split('\n')[-1])
+        values = tuple(result[0] for result in results)
+        self.assertSequenceEqual(range(2, 10000), values)
+        for result in results:
+            self.assertEqual(is_prime(result[0]), result[1])
+
+
+if __name__ == '__main__':
+    logging.basicConfig()
+    unittest.main(verbosity=2)