Chameleon outline: a REST-to-GRPC gateway
diff --git a/__init__.py b/__init__.py
new file mode 100644
index 0000000..e69de29
--- /dev/null
+++ b/__init__.py
diff --git a/chameleon.yml b/chameleon.yml
new file mode 100644
index 0000000..2b1d69e
--- /dev/null
+++ b/chameleon.yml
@@ -0,0 +1,44 @@
+logging:
+    version: 1
+
+    formatters:
+      brief:
+        format: '%(message)s'
+      default:
+        format: '%(asctime)s.%(msecs)03d %(levelname)-8s %(module)s.%(funcName)s %(message)s'
+        datefmt: '%Y%m%dT%H%M%S'
+      fluent_fmt:
+        '()': fluent.handler.FluentRecordFormatter
+        format:
+          level: '%(levelname)s'
+          hostname: '%(hostname)s'
+          where: '%(module)s.%(funcName)s'
+
+    handlers:
+        console:
+            class : logging.StreamHandler
+            level: DEBUG
+            formatter: default
+            stream: ext://sys.stdout
+        fluent:
+            class: fluent.handler.FluentHandler
+            host: localhost
+            port: 24224
+            tag: voltha.logging
+            formatter: fluent_fmt
+            level: DEBUG
+        null:
+            class: logging.NullHandler
+
+    loggers:
+        amqp:
+            handlers: [null]
+            propagate: False
+        conf:
+            handlers: [null]
+            propagate: False
+        '': # root logger
+            handlers: [console, fluent]
+            level: INFO # this can be bumped up/down by -q and -v command line
+                        # options
+            propagate: False
diff --git a/dockerhelpers.py b/dockerhelpers.py
new file mode 100644
index 0000000..0927711
--- /dev/null
+++ b/dockerhelpers.py
@@ -0,0 +1,50 @@
+#
+# 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.
+#
+
+"""
+Some docker related convenience functions
+"""
+
+import os
+from structlog import get_logger
+
+from docker import Client
+
+
+log = get_logger()
+
+
+def get_my_containers_name():
+    """
+    Return the docker containers name in which this process is running.
+    To look up the container name, we use the container ID extracted from the
+    $HOSTNAME environment variable (which is set by docker conventions).
+    :return: String with the docker container name (or None if any issue is
+             encountered)
+    """
+    my_container_id = os.environ.get('HOSTNAME', None)
+
+    try:
+        docker_cli = Client(base_url='unix://tmp/docker.sock')
+        info = docker_cli.inspect_container(my_container_id)
+
+    except Exception, e:
+        log.exception('failed', my_container_id=my_container_id, e=e)
+        raise
+
+    name = info['Name'].lstrip('/')
+
+    return name
diff --git a/main.py b/main.py
new file mode 100755
index 0000000..fa63210
--- /dev/null
+++ b/main.py
@@ -0,0 +1,224 @@
+#!/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()
diff --git a/nethelpers.py b/nethelpers.py
new file mode 100644
index 0000000..52f7f4c
--- /dev/null
+++ b/nethelpers.py
@@ -0,0 +1,46 @@
+#
+# 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.
+#
+
+"""
+Some network related convenience functions
+"""
+
+from netifaces import AF_INET
+
+import netifaces as ni
+
+
+def get_my_primary_interface():
+    gateways = ni.gateways()
+    assert 'default' in gateways, \
+        ("No default gateway on host/container, "
+         "cannot determine primary interface")
+    default_gw_index = gateways['default'].keys()[0]
+    # gateways[default_gw_index] has the format (example):
+    # [('10.15.32.1', 'en0', True)]
+    interface_name = gateways[default_gw_index][0][1]
+    return interface_name
+
+
+def get_my_primary_local_ipv4(ifname=None):
+    ifname = get_my_primary_interface() if ifname is None else ifname
+    addresses = ni.ifaddresses(ifname)
+    ipv4 = addresses[AF_INET][0]['addr']
+    return ipv4
+
+
+if __name__ == '__main__':
+    print get_my_primary_local_ipv4()
diff --git a/structlog_setup.py b/structlog_setup.py
new file mode 100644
index 0000000..d4b2e8e
--- /dev/null
+++ b/structlog_setup.py
@@ -0,0 +1,113 @@
+#
+# 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.
+#
+
+"""Setting up proper logging for Voltha"""
+
+import logging
+import logging.config
+from collections import OrderedDict
+
+import structlog
+from structlog.stdlib import BoundLogger, INFO
+
+try:
+    from thread import get_ident as _get_ident
+except ImportError:
+    from dummy_thread import get_ident as _get_ident
+
+
+class FluentRenderer(object):
+    def __call__(self, logger, name, event_dict):
+        # in order to keep structured log data in event_dict to be forwarded as
+        # is to the fluent logger, we need to pass it into the logger framework
+        # as the first positional argument.
+        args = (event_dict, )
+        kwargs = {}
+        return args, kwargs
+
+
+class PlainRenderedOrderedDict(OrderedDict):
+    """Our special version of OrderedDict that renders into string as a dict,
+       to make the log stream output cleaner.
+    """
+    def __repr__(self, _repr_running={}):
+        'od.__repr__() <==> repr(od)'
+        call_key = id(self), _get_ident()
+        if call_key in _repr_running:
+            return '...'
+        _repr_running[call_key] = 1
+        try:
+            if not self:
+                return '{}'
+            return '{%s}' % ", ".join("%s: %s" % (k, v)
+                                      for k, v in self.items())
+        finally:
+            del _repr_running[call_key]
+
+
+def setup_logging(log_config, instance_id, verbosity_adjust=0, fluentd=None):
+    """
+    Set up logging such that:
+    - The primary logging entry method is structlog
+      (see http://structlog.readthedocs.io/en/stable/index.html)
+    - By default, the logging backend is Python standard lib logger
+    - Alternatively, fluentd can be configured with to be the backend,
+      providing direct bridge to a fluent logging agent.
+    """
+
+    def add_exc_info_flag_for_exception(_, name, event_dict):
+        if name == 'exception':
+            event_dict['exc_info'] = True
+        return event_dict
+
+    def add_instance_id(_, __, event_dict):
+        event_dict['instance_id'] = instance_id
+        return event_dict
+
+    # if fluentd is specified, we need to override the config data with
+    # its host and port info
+    if fluentd is not None:
+        fluentd_host = fluentd.split(':')[0].strip()
+        fluentd_port = int(fluentd.split(':')[1].strip())
+
+        handlers = log_config.get('handlers', None)
+        if isinstance(handlers, dict):
+            for _, defs in handlers.iteritems():
+                if isinstance(defs, dict):
+                    if defs.get('class', '').endswith('FluentHandler'):
+                        defs['host'] = fluentd_host
+                        defs['port'] = fluentd_port
+
+    # Configure standard logging
+    logging.config.dictConfig(log_config)
+    logging.root.level -= 10 * verbosity_adjust
+
+    processors = [
+        add_exc_info_flag_for_exception,
+        structlog.processors.StackInfoRenderer(),
+        structlog.processors.format_exc_info,
+        add_instance_id,
+        FluentRenderer(),
+    ]
+    structlog.configure(logger_factory=structlog.stdlib.LoggerFactory(),
+                        context_class=PlainRenderedOrderedDict,
+                        wrapper_class=BoundLogger,
+                        processors=processors)
+
+    # Mark first line of log
+    log = structlog.get_logger()
+    log.info("first-line")
+    return log