Initial commit moving openolt adapter from voltha-go to the new repo.
This version works with ponsim rather than openolt, this is temporary.
It is currently being fixed to work with openolt.
Change-Id: I34a800c98f050140b367e2d474b7aa8b79f34b9a
Signed-off-by: William Kurkian <wkurkian@cisco.com>
diff --git a/python/common/utils/grpc_utils.py b/python/common/utils/grpc_utils.py
new file mode 100644
index 0000000..8df630e
--- /dev/null
+++ b/python/common/utils/grpc_utils.py
@@ -0,0 +1,109 @@
+#
+# Copyright 2017 the original author or 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.
+#
+
+"""
+Utilities to handle gRPC server and client side code in a Twisted environment
+"""
+import structlog
+from concurrent.futures import Future
+from twisted.internet import reactor
+from twisted.internet.defer import Deferred
+from twisted.python.threadable import isInIOThread
+
+
+log = structlog.get_logger()
+
+
+def twisted_async(func):
+ """
+ This decorator can be used to implement a gRPC method on the twisted
+ thread, allowing asynchronous programming in Twisted while serving
+ a gRPC call.
+
+ gRPC methods normally are called on the futures.ThreadPool threads,
+ so these methods cannot directly use Twisted protocol constructs.
+ If the implementation of the methods needs to touch Twisted, it is
+ safer (or mandatory) to wrap the method with this decorator, which will
+ call the inner method from the external thread and ensure that the
+ result is passed back to the foreign thread.
+
+ Example usage:
+
+ When implementing a gRPC server, typical pattern is:
+
+ class SpamService(SpamServicer):
+
+ def GetBadSpam(self, request, context):
+ '''this is called from a ThreadPoolExecutor thread'''
+ # generally unsafe to make Twisted calls
+
+ @twisted_async
+ def GetSpamSafely(self, request, context):
+ '''this method now is executed on the Twisted main thread
+ # safe to call any Twisted protocol functions
+
+ @twisted_async
+ @inlineCallbacks
+ def GetAsyncSpam(self, request, context):
+ '''this generator can use inlineCallbacks Twisted style'''
+ result = yield some_async_twisted_call(request)
+ returnValue(result)
+
+ """
+ def in_thread_wrapper(*args, **kw):
+
+ if isInIOThread():
+
+ return func(*args, **kw)
+
+ f = Future()
+
+ def twisted_wrapper():
+ try:
+ d = func(*args, **kw)
+ if isinstance(d, Deferred):
+
+ def _done(result):
+ f.set_result(result)
+ f.done()
+
+ def _error(e):
+ f.set_exception(e)
+ f.done()
+
+ d.addCallback(_done)
+ d.addErrback(_error)
+
+ else:
+ f.set_result(d)
+ f.done()
+
+ except Exception, e:
+ f.set_exception(e)
+ f.done()
+
+ reactor.callFromThread(twisted_wrapper)
+ try:
+ result = f.result()
+ except Exception, e:
+ log.exception(e=e, func=func, args=args, kw=kw)
+ raise
+
+ return result
+
+ return in_thread_wrapper
+
+