Chameleon outline: a REST-to-GRPC gateway
diff --git a/main.py b/main.py
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+++ b/main.py
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+#!/usr/bin/env python
+#
+# 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.
+#
+
+"""A REST protocol gateway to self-describing GRPC end-points"""
+
+import argparse
+import os
+import sys
+import time
+import yaml
+from twisted.internet.defer import inlineCallbacks
+
+base_dir = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
+sys.path.append(base_dir)
+
+from chameleon.structlog_setup import setup_logging
+from chameleon.nethelpers import get_my_primary_local_ipv4
+from chameleon.dockerhelpers import get_my_containers_name
+
+
+defs = dict(
+ #consul=os.environ.get('CONSUL', 'localhost:8500'),
+ instance_id=os.environ.get('INSTANCE_ID', os.environ.get('HOSTNAME', '1')),
+ config=os.environ.get('CONFIG', './chameleon.yml'),
+ internal_host_address=os.environ.get('INTERNAL_HOST_ADDRESS',
+ get_my_primary_local_ipv4()),
+ external_host_address=os.environ.get('EXTERNAL_HOST_ADDRESS',
+ get_my_primary_local_ipv4()),
+ fluentd=os.environ.get('FLUENTD', None),
+ rest_port=os.environ.get('REST_PORT', 8881),
+)
+
+
+def parse_args():
+
+ parser = argparse.ArgumentParser()
+
+ _help = ('Path to chameleon.yml config file (default: %s). '
+ 'If relative, it is relative to main.py of chameleon.'
+ % defs['config'])
+ parser.add_argument('-c', '--config',
+ dest='config',
+ action='store',
+ default=defs['config'],
+ help=_help)
+
+ '''
+ _help = '<hostname>:<port> to consul agent (default: %s)' % defs['consul']
+ parser.add_argument(
+ '-C', '--consul', dest='consul', action='store',
+ default=defs['consul'],
+ help=_help)
+ '''
+
+ _help = ('<hostname> or <ip> at which Chameleon is reachable from outside '
+ 'the cluster (default: %s)' % defs['external_host_address'])
+ parser.add_argument('-E', '--external-host-address',
+ dest='external_host_address',
+ action='store',
+ default=defs['external_host_address'],
+ help=_help)
+
+ _help = ('<hostname>:<port> to fluentd server (default: %s). (If not '
+ 'specified (None), the address from the config file is used'
+ % defs['fluentd'])
+ parser.add_argument('-F', '--fluentd',
+ dest='fluentd',
+ action='store',
+ default=defs['fluentd'],
+ help=_help)
+
+ _help = ('<hostname> or <ip> at which Chameleon is reachable from inside'
+ 'the cluster (default: %s)' % defs['internal_host_address'])
+ parser.add_argument('-H', '--internal-host-address',
+ dest='internal_host_address',
+ action='store',
+ default=defs['internal_host_address'],
+ help=_help)
+
+ _help = ('unique string id of this Chameleon instance (default: %s)'
+ % defs['instance_id'])
+ parser.add_argument('-i', '--instance-id',
+ dest='instance_id',
+ action='store',
+ default=defs['instance_id'],
+ help=_help)
+
+ _help = 'omit startup banner log lines'
+ parser.add_argument('-n', '--no-banner',
+ dest='no_banner',
+ action='store_true',
+ default=False,
+ help=_help)
+
+ _help = ('port number for the rest service (default: %d)'
+ % defs['rest_port'])
+ parser.add_argument('-R', '--rest-port',
+ dest='rest_port',
+ action='store',
+ type=int,
+ default=defs['rest_port'],
+ help=_help)
+
+ _help = "suppress debug and info logs"
+ parser.add_argument('-q', '--quiet',
+ dest='quiet',
+ action='count',
+ help=_help)
+
+ _help = 'enable verbose logging'
+ parser.add_argument('-v', '--verbose',
+ dest='verbose',
+ action='count',
+ help=_help)
+
+ _help = ('use docker container name as Chameleon instance id'
+ ' (overrides -i/--instance-id option)')
+ parser.add_argument('--instance-id-is-container-name',
+ dest='instance_id_is_container_name',
+ action='store_true',
+ default=False,
+ help=_help)
+
+ args = parser.parse_args()
+
+ # post-processing
+
+ if args.instance_id_is_container_name:
+ args.instance_id = get_my_containers_name()
+
+ return args
+
+
+def load_config(args):
+ path = args.config
+ if path.startswith('.'):
+ dir = os.path.dirname(os.path.abspath(__file__))
+ path = os.path.join(dir, path)
+ path = os.path.abspath(path)
+ with open(path) as fd:
+ config = yaml.load(fd)
+ return config
+
+banner = r'''
+ ____ _ _
+ / ___| | |__ __ _ _ __ ___ ___ | | ___ ___ _ __
+ | | | '_ \ / _` | | '_ ` _ \ / _ \ | | / _ \ / _ \ | '_ \
+ | |___ | | | | | (_| | | | | | | | | __/ | | | __/ | (_) | | | | |
+ \____| |_| |_| \__,_| |_| |_| |_| \___| |_| \___| \___/ |_| |_|
+
+'''
+def print_banner(log):
+ for line in banner.strip('\n').splitlines():
+ log.info(line)
+ log.info('(to stop: press Ctrl-C)')
+
+
+class Main(object):
+
+ def __init__(self):
+
+ self.args = args = parse_args()
+ self.config = load_config(args)
+
+ verbosity_adjust = (args.verbose or 0) - (args.quiet or 0)
+ self.log = setup_logging(self.config.get('logging', {}),
+ args.instance_id,
+ verbosity_adjust=verbosity_adjust,
+ fluentd=args.fluentd)
+
+ # components
+ self.rest_server = None
+ self.grpc_client = None
+
+ if not args.no_banner:
+ print_banner(self.log)
+
+ self.startup_components()
+
+ def start(self):
+ self.start_reactor() # will not return except Keyboard interrupt
+
+ def startup_components(self):
+ self.log.info('starting-internal-components')
+
+ # TODO init client
+ # TODO init server
+
+ self.log.info('started-internal-services')
+
+ @inlineCallbacks
+ def shutdown_components(self):
+ """Execute before the reactor is shut down"""
+ self.log.info('exiting-on-keyboard-interrupt')
+ if self.rest_server is not None:
+ yield self.rest_server.shutdown()
+ if self.grpc_client is not None:
+ yield self.grpc_client.shutdown()
+
+ def start_reactor(self):
+ from twisted.internet import reactor
+ reactor.callWhenRunning(
+ lambda: self.log.info('twisted-reactor-started'))
+ reactor.addSystemEventTrigger('before', 'shutdown',
+ self.shutdown_components)
+ reactor.run()
+
+
+if __name__ == '__main__':
+ Main().start()