tests/utils/server.py: New server helper

#135

tests/utils/server.py

+# Copyright (C) 2018 Bloomberg LP
+#
+# 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.
+
+
+from contextlib import contextmanager
+import multiprocessing
+import signal
+
+import pytest_cov
+
+from buildgrid._app.settings import parser
+from buildgrid.server.instance import BuildGridServer
+
+
+@contextmanager
+def serve(configuration):
+    server = Server(configuration)
+    try:
+        yield server
+    finally:
+        server.quit()
+
+
+class Server:
+
+    def __init__(self, configuration):
+
+        self.configuration = configuration
+
+        self.__queue = multiprocessing.Queue()
+        self.__process = multiprocessing.Process(
+            target=Server.serve,
+            args=(self.__queue, self.configuration))
+        self.__process.start()
+
+        self.port = self.__queue.get()
+        self.remote = 'localhost:{}'.format(self.port)
+
+    @classmethod
+    def serve(cls, queue, configuration):
+        pytest_cov.embed.cleanup_on_sigterm()
+
+        server = BuildGridServer()
+
+        def __signal_handler(signum, frame):
+            server.stop()
+
+        signal.signal(signal.SIGINT, signal.SIG_IGN)
+        signal.signal(signal.SIGTERM, __signal_handler)
+
+        instances = parser.get_parser().safe_load(configuration)['instances']
+        for instance in instances:
+            instance_name = instance['name']
+            services = instance['services']
+            for service in services:
+                service.register_instance_with_server(instance_name, server)
+
+        port = server.add_port('localhost:0', None)
+
+        queue.put(port)
+
+        server.start()
+
+    def quit(self):
+        if self.__process:
+            self.__process.terminate()
+            self.__process.join()