chameleon/grpc_client/grpc_client.py - voltha - Gitiles

 #
 # Copyright 2016 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.
 #

 """
 gRPC client meant to connect to a gRPC server endpoint, and query the
 end-point's schema by calling SchemaService.Schema(NullMessage) and all of its
 semantics are derived from the recovered schema.
 """

 import os
 import sys
 from random import randint
 from zlib import decompress

 import grpc
 from consul import Consul
 from grpc._channel import _Rendezvous
 from structlog import get_logger
 from twisted.internet import reactor
 from twisted.internet.defer import inlineCallbacks
 from werkzeug.exceptions import ServiceUnavailable

 from chameleon.asleep import asleep
 from chameleon.protos.schema_pb2 import NullMessage, SchemaServiceStub

 log = get_logger()


 class GrpcClient(object):
     """
     Connect to a gRPC server, fetch its schema, and process the downloaded
     schema files to drive the customization of the north-bound interface(s)
     of Chameleon.
     """
     RETRY_BACKOFF = [0.05, 0.1, 0.2, 0.5, 1, 2, 5]

     def __init__(self, consul_endpoint, work_dir, endpoint='localhost:50055'):
         self.consul_endpoint = consul_endpoint
         self.endpoint = endpoint
         self.work_dir = work_dir
         self.plugin_dir = os.path.abspath(os.path.join(
             os.path.dirname(__file__), '../protoc_plugins'))

         self.channel = None
         self.schema = None
         self.retries = 0
         self.on_reconnect = None
         self.shutting_down = False
         self.connected = False

     def run(self, on_reconnect=None):
         self.on_reconnect = on_reconnect
         if not self.connected:
             reactor.callLater(0, self.connect)
         return self

     def shutdown(self):
         if self.shutting_down:
             return
         self.shutting_down = True
         pass

     @inlineCallbacks
     def connect(self):
         """
         (Re-)Connect to end-point
         """

         if self.shutting_down or self.connected:
             return

         try:
             if self.endpoint.startswith('@'):
                 _endpoint = self._get_endpoint_from_consul(self.endpoint[1:])
             else:
                 _endpoint = self.endpoint

             log.info('connecting', endpoint=_endpoint)
             self.channel = grpc.insecure_channel(_endpoint)

             self._retrieve_schema()
             self._compile_proto_files()
             self._clear_backoff()

             self.connected = True
             if self.on_reconnect is not None:
                 reactor.callLater(0, self.on_reconnect)

             return

         except _Rendezvous, e:
             if e.code() == grpc.StatusCode.UNAVAILABLE:
                 log.info('grpc-endpoint-not-available')
             else:
                 log.exception(e)
             yield self._backoff('not-available')

         except Exception, e:
             if not self.shutting_down:
                 log.exception('cannot-connect', endpoint=_endpoint)
             yield self._backoff('unknown-error')

         reactor.callLater(0, self.connect)

     def _backoff(self, msg):
         wait_time = self.RETRY_BACKOFF[min(self.retries,
                                            len(self.RETRY_BACKOFF) - 1)]
         self.retries += 1
         log.error(msg, retry_in=wait_time)
         return asleep(wait_time)

     def _clear_backoff(self):
         if self.retries:
             log.info('reconnected', after_retries=self.retries)
             self.retries = 0

     def _get_endpoint_from_consul(self, service_name):
         """
         Look up an appropriate grpc endpoint (host, port) from
         consul, under the service name specified by service-name
         """
         host = self.consul_endpoint.split(':')[0].strip()
         port = int(self.consul_endpoint.split(':')[1].strip())

         consul = Consul(host=host, port=port)
         _, services = consul.catalog.service(service_name)

         if len(services) == 0:
             raise Exception('Cannot find service %s in consul' % service_name)

         # pick a random entry
         # TODO should we prefer local IP addresses? Probably.

         service = services[randint(0, len(services) - 1)]
         endpoint = '{}:{}'.format(service['ServiceAddress'],
                                   service['ServicePort'])
         return endpoint

     def _retrieve_schema(self):
         """
         Retrieve schema from gRPC end-point, and save all *.proto files in
         the work directory.
         """
         assert isinstance(self.channel, grpc.Channel)
         stub = SchemaServiceStub(self.channel)
         # try:
         schema = stub.GetSchema(NullMessage())
         # except _Rendezvous, e:
         #     if e.code == grpc.StatusCode.UNAVAILABLE:
         #
         #     else:
         #         raise e

         os.system('mkdir -p %s' % self.work_dir)
         os.system('rm -fr /tmp/%s/*' %
                   self.work_dir.replace('/tmp/', ''))  # safer

         for fname in schema.protos:
             content = schema.protos[fname]
             log.debug('saving-proto',
                       fname=fname, dir=self.work_dir, length=len(content))
             with open(os.path.join(self.work_dir, fname), 'w') as f:
                 f.write(content)

         for fname in schema.descriptors:
             content = decompress(schema.descriptors[fname])
             log.debug('saving-descriptor',
                       fname=fname, dir=self.work_dir, length=len(content))
             with open(os.path.join(self.work_dir, fname), 'wb') as f:
                 f.write(content)

     def _compile_proto_files(self):
         """
         For each *.proto file in the work directory, compile the proto
         file into the respective *_pb2.py file as well as generate the
         web server gateway python file *_gw.py.
         :return: None
         """
         google_api_dir = os.path.abspath(os.path.join(
             os.path.dirname(__file__), '../protos/third_party'
         ))

         chameleon_base_dir = os.path.abspath(os.path.join(
             os.path.dirname(__file__), '../..'
         ))

         for fname in [f for f in os.listdir(self.work_dir)
                       if f.endswith('.proto')]:

             log.debug('compiling', file=fname)
             cmd = (
                 'cd %s && '
                 'env PATH=%s PYTHONPATH=%s '
                 'python -m grpc.tools.protoc '
                 '-I. '
                 '-I%s '
                 '--python_out=. '
                 '--grpc_python_out=. '
                 '--plugin=protoc-gen-gw=%s/gw_gen.py '
                 '--gw_out=. '
                 '--plugin=protoc-gen-swagger=%s/swagger_gen.py '
                 '--swagger_out=. '
                 '%s' % (
                     self.work_dir,
                     ':'.join([os.environ['PATH'], self.plugin_dir]),
                     ':'.join([google_api_dir, chameleon_base_dir]),
                     google_api_dir,
                     self.plugin_dir,
                     self.plugin_dir,
                     fname)
             )
             log.debug('executing', cmd=cmd, file=fname)
             os.system(cmd)
             log.info('compiled', file=fname)

         # test-load each _pb2 file to see all is right
         if self.work_dir not in sys.path:
             sys.path.insert(0, self.work_dir)

         for fname in [f for f in os.listdir(self.work_dir)
                       if f.endswith('_pb2.py')]:
             modname = fname[:-len('.py')]
             log.debug('test-import', modname=modname)
             _ = __import__(modname)

     def invoke(self, stub, method_name, request):
         """
         Invoke a gRPC call to the remote server and return the response.
         :param stub: Reference to the *_pb2 service stub
         :param method_name: The method name inside the service stub
         :param request: The request protobuf message
         :return: The response protobuf message
         """

         if not self.connected:
             raise ServiceUnavailable()

         try:
             response = getattr(stub(self.channel), method_name)(request)
             return response

         except grpc._channel._Rendezvous, e:
             if e.code() == grpc.StatusCode.UNAVAILABLE:
                 e = ServiceUnavailable()
             else:
                 log.exception(e)

             if self.connected :
                 self.connected = False
                 reactor.callLater(0, self.connect)

             raise e
	#
	# Copyright 2016 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.
	#

	"""
	gRPC client meant to connect to a gRPC server endpoint, and query the
	end-point's schema by calling SchemaService.Schema(NullMessage) and all of its
	semantics are derived from the recovered schema.
	"""

	import os
	import sys
	from random import randint
	from zlib import decompress

	import grpc
	from consul import Consul
	from grpc._channel import _Rendezvous
	from structlog import get_logger
	from twisted.internet import reactor
	from twisted.internet.defer import inlineCallbacks
	from werkzeug.exceptions import ServiceUnavailable

	from chameleon.asleep import asleep
	from chameleon.protos.schema_pb2 import NullMessage, SchemaServiceStub

	log = get_logger()


	class GrpcClient(object):
	"""
	Connect to a gRPC server, fetch its schema, and process the downloaded
	schema files to drive the customization of the north-bound interface(s)
	of Chameleon.
	"""
	RETRY_BACKOFF = [0.05, 0.1, 0.2, 0.5, 1, 2, 5]

	def __init__(self, consul_endpoint, work_dir, endpoint='localhost:50055'):
	self.consul_endpoint = consul_endpoint
	self.endpoint = endpoint
	self.work_dir = work_dir
	self.plugin_dir = os.path.abspath(os.path.join(
	os.path.dirname(__file__), '../protoc_plugins'))

	self.channel = None
	self.schema = None
	self.retries = 0
	self.on_reconnect = None
	self.shutting_down = False
	self.connected = False

	def run(self, on_reconnect=None):
	self.on_reconnect = on_reconnect
	if not self.connected:
	reactor.callLater(0, self.connect)
	return self

	def shutdown(self):
	if self.shutting_down:
	return
	self.shutting_down = True
	pass

	@inlineCallbacks
	def connect(self):
	"""
	(Re-)Connect to end-point
	"""

	if self.shutting_down or self.connected:
	return

	try:
	if self.endpoint.startswith('@'):
	_endpoint = self._get_endpoint_from_consul(self.endpoint[1:])
	else:
	_endpoint = self.endpoint

	log.info('connecting', endpoint=_endpoint)
	self.channel = grpc.insecure_channel(_endpoint)

	self._retrieve_schema()
	self._compile_proto_files()
	self._clear_backoff()

	self.connected = True
	if self.on_reconnect is not None:
	reactor.callLater(0, self.on_reconnect)

	return

	except _Rendezvous, e:
	if e.code() == grpc.StatusCode.UNAVAILABLE:
	log.info('grpc-endpoint-not-available')
	else:
	log.exception(e)
	yield self._backoff('not-available')

	except Exception, e:
	if not self.shutting_down:
	log.exception('cannot-connect', endpoint=_endpoint)
	yield self._backoff('unknown-error')

	reactor.callLater(0, self.connect)

	def _backoff(self, msg):
	wait_time = self.RETRY_BACKOFF[min(self.retries,
	len(self.RETRY_BACKOFF) - 1)]
	self.retries += 1
	log.error(msg, retry_in=wait_time)
	return asleep(wait_time)

	def _clear_backoff(self):
	if self.retries:
	log.info('reconnected', after_retries=self.retries)
	self.retries = 0

	def _get_endpoint_from_consul(self, service_name):
	"""
	Look up an appropriate grpc endpoint (host, port) from
	consul, under the service name specified by service-name
	"""
	host = self.consul_endpoint.split(':')[0].strip()
	port = int(self.consul_endpoint.split(':')[1].strip())

	consul = Consul(host=host, port=port)
	_, services = consul.catalog.service(service_name)

	if len(services) == 0:
	raise Exception('Cannot find service %s in consul' % service_name)

	# pick a random entry
	# TODO should we prefer local IP addresses? Probably.

	service = services[randint(0, len(services) - 1)]
	endpoint = '{}:{}'.format(service['ServiceAddress'],
	service['ServicePort'])
	return endpoint

	def _retrieve_schema(self):
	"""
	Retrieve schema from gRPC end-point, and save all *.proto files in
	the work directory.
	"""
	assert isinstance(self.channel, grpc.Channel)
	stub = SchemaServiceStub(self.channel)
	# try:
	schema = stub.GetSchema(NullMessage())
	# except _Rendezvous, e:
	# if e.code == grpc.StatusCode.UNAVAILABLE:
	#
	# else:
	# raise e

	os.system('mkdir -p %s' % self.work_dir)
	os.system('rm -fr /tmp/%s/*' %
	self.work_dir.replace('/tmp/', '')) # safer

	for fname in schema.protos:
	content = schema.protos[fname]
	log.debug('saving-proto',
	fname=fname, dir=self.work_dir, length=len(content))
	with open(os.path.join(self.work_dir, fname), 'w') as f:
	f.write(content)

	for fname in schema.descriptors:
	content = decompress(schema.descriptors[fname])
	log.debug('saving-descriptor',
	fname=fname, dir=self.work_dir, length=len(content))
	with open(os.path.join(self.work_dir, fname), 'wb') as f:
	f.write(content)

	def _compile_proto_files(self):
	"""
	For each *.proto file in the work directory, compile the proto
	file into the respective *_pb2.py file as well as generate the
	web server gateway python file *_gw.py.
	:return: None
	"""
	google_api_dir = os.path.abspath(os.path.join(
	os.path.dirname(__file__), '../protos/third_party'
	))

	chameleon_base_dir = os.path.abspath(os.path.join(
	os.path.dirname(__file__), '../..'
	))

	for fname in [f for f in os.listdir(self.work_dir)
	if f.endswith('.proto')]:

	log.debug('compiling', file=fname)
	cmd = (
	'cd %s && '
	'env PATH=%s PYTHONPATH=%s '
	'python -m grpc.tools.protoc '
	'-I. '
	'-I%s '
	'--python_out=. '
	'--grpc_python_out=. '
	'--plugin=protoc-gen-gw=%s/gw_gen.py '
	'--gw_out=. '
	'--plugin=protoc-gen-swagger=%s/swagger_gen.py '
	'--swagger_out=. '
	'%s' % (
	self.work_dir,
	':'.join([os.environ['PATH'], self.plugin_dir]),
	':'.join([google_api_dir, chameleon_base_dir]),
	google_api_dir,
	self.plugin_dir,
	self.plugin_dir,
	fname)
	)
	log.debug('executing', cmd=cmd, file=fname)
	os.system(cmd)
	log.info('compiled', file=fname)

	# test-load each _pb2 file to see all is right
	if self.work_dir not in sys.path:
	sys.path.insert(0, self.work_dir)

	for fname in [f for f in os.listdir(self.work_dir)
	if f.endswith('_pb2.py')]:
	modname = fname[:-len('.py')]
	log.debug('test-import', modname=modname)
	_ = __import__(modname)

	def invoke(self, stub, method_name, request):
	"""
	Invoke a gRPC call to the remote server and return the response.
	:param stub: Reference to the *_pb2 service stub
	:param method_name: The method name inside the service stub
	:param request: The request protobuf message
	:return: The response protobuf message
	"""

	if not self.connected:
	raise ServiceUnavailable()

	try:
	response = getattr(stub(self.channel), method_name)(request)
	return response

	except grpc._channel._Rendezvous, e:
	if e.code() == grpc.StatusCode.UNAVAILABLE:
	e = ServiceUnavailable()
	else:
	log.exception(e)

	if self.connected :
	self.connected = False
	reactor.callLater(0, self.connect)

	raise e