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neutron-server作为Neutron看的唯一的服务进程,承担着接收用户restful api请求并分发处理的任务
neutron-server的启动入口在neutron/server/__init__.py中,分别启动neutron-api和neutron-rpc两个服务,neutron-api负责处理其它模块或者用户的restful请求,neutron-rpc处理neutron-server与neutron agent 之间的通信
启动代码:
def main():
eventlet.monkey_patch()
# the configuration will be read into the cfg.CONF global data structure
config.parse(sys.argv[1:])
if not cfg.CONF.config_file:
sys.exit(_("ERROR: Unable to find configuration file via the default"
" search paths (~/.neutron/, ~/, /etc/neutron/, /etc/) and"
" the '--config-file' option!"))
try:
pool = eventlet.GreenPool()
neutron_api = service.serve_wsgi(service.NeutronApiService)
api_thread = pool.spawn(neutron_api.wait)
try:
neutron_rpc = service.serve_rpc()
except NotImplementedError:
LOG.info(_("RPC was already started in parent process by plugin."))
else:
rpc_thread = pool.spawn(neutron_rpc.wait)
# api and rpc should die together. When one dies, kill the other.
rpc_thread.link(lambda gt: api_thread.kill())
api_thread.link(lambda gt: rpc_thread.kill())
pool.waitall()
except KeyboardInterrupt:
pass
except RuntimeError as e:
sys.exit(_("ERROR: %s") % e)neutron_api 根据/etc/neutron/api-paste.ini文件设置加载application,如下配置Paste Deploy会在这个WSGI Server创建时参与进来,完成下面配置的所有composite filter app的配置,并将配置的类通过factory初始化
[composite:neutron]
use = egg:Paste#urlmap
/: neutronversions
/v2.0: neutronapi_v2_0
[composite:neutronapi_v2_0]
use = call:neutron.auth:pipeline_factory
noauth = request_id catch_errors extensions neutronapiapp_v2_0
keystone = request_id catch_errors authtoken keystonecontext extensions neutronapiapp_v2_0
[filter:request_id]
paste.filter_factory = neutron.openstack.common.middleware.request_id:RequestIdMiddleware.factory
[filter:catch_errors]
paste.filter_factory = neutron.openstack.common.middleware.catch_errors:CatchErrorsMiddleware.factory
[filter:keystonecontext]
paste.filter_factory = neutron.auth:NeutronKeystoneContext.factory
[filter:authtoken]
paste.filter_factory = keystoneclient.middleware.auth_token:filter_factory
[filter:extensions]
paste.filter_factory = neutron.api.extensions:plugin_aware_extension_middleware_factory
[app:neutronversions]
paste.app_factory = neutron.api.versions:Versions.factory
[app:neutronapiapp_v2_0]
paste.app_factory = neutron.api.v2.router:APIRouter.factoryneutron为了优化neutron并行处理能力,加入了worker的配置,如果配置为worker小于1直接启动,否则会通过 Processlauncher fork几个子进程来并行处理rest请求
if workers < 1:
# For the case where only one process is required.
self._server = self.pool.spawn(self._run, application,
self._socket)
else:
# Minimize the cost of checking for child exit by extending the
# wait interval past the default of 0.01s.
self._launcher = ProcessLauncher(wait_interval=1.0)
self._server = WorkerService(self, application)
self._launcher.launch_service(self._server, workers=workers)所有的core api 和extension api 的加载与路由规则的创建都是通过APIRouter类完成的 ,server在初始化的时候会通过api-paste.ini的配置将APIRouter通过factory()初始化,初始化的流程如下代码,会将neutron里的core api以及extension api加到mapper中
class APIRouter(wsgi.Router):
@classmethod
def factory(cls, global_config, **local_config):
return cls(**local_config)
def __init__(self, **local_config):
mapper = routes_mapper.Mapper()
plugin = manager.NeutronManager.get_plugin()
ext_mgr = extensions.PluginAwareExtensionManager.get_instance()
ext_mgr.extend_resources("2.0", attributes.RESOURCE_ATTRIBUTE_MAP)
col_kwargs = dict(collection_actions=COLLECTION_ACTIONS,
member_actions=MEMBER_ACTIONS)
def _map_resource(collection, resource, params, parent=None):
allow_bulk = cfg.CONF.allow_bulk
allow_pagination = cfg.CONF.allow_pagination
allow_sorting = cfg.CONF.allow_sorting
controller = base.create_resource(
collection, resource, plugin, params, allow_bulk=allow_bulk,
parent=parent, allow_pagination=allow_pagination,
allow_sorting=allow_sorting)
path_prefix = None
if parent:
path_prefix = "/%s/{%s_id}/%s" % (parent['collection_name'],
parent['member_name'],
collection)
mapper_kwargs = dict(controller=controller,
requirements=REQUIREMENTS,
path_prefix=path_prefix,
**col_kwargs)
return mapper.collection(collection, resource,
**mapper_kwargs)
mapper.connect('index', '/', controller=Index(RESOURCES))
for resource in RESOURCES:
_map_resource(RESOURCES[resource], resource,
attributes.RESOURCE_ATTRIBUTE_MAP.get(
RESOURCES[resource], dict()))
for resource in SUB_RESOURCES:
_map_resource(SUB_RESOURCES[resource]['collection_name'], resource,
attributes.RESOURCE_ATTRIBUTE_MAP.get(
SUB_RESOURCES[resource]['collection_name'],
dict()),
SUB_RESOURCES[resource]['parent'])
# Certain policy checks require that the extensions are loaded
# and the RESOURCE_ATTRIBUTE_MAP populated before they can be
# properly initialized. This can only be claimed with certainty
# once this point in the code has been reached. In the event
# that the policies have been initialized before this point,
# calling reset will cause the next policy check to
# re-initialize with all of the required data in place.
policy.reset()
super(APIRouter, self).__init__(mapper)core api对应L2层的network/subnet/port三种抽象,其余的各层抽象都涵盖在Extension API的范围
三个核心资源使用base.py文件中的类Controller去实现,只是在封装成WSGI Application的时候调用这个文件中的create_resource()函数根据不同参数动态创建对应的Controller对象
def create_resource(collection, resource, plugin, params, allow_bulk=False,
member_actions=None, parent=None, allow_pagination=False,
allow_sorting=False):
controller = Controller(plugin, collection, resource, params, allow_bulk,
member_actions=member_actions, parent=parent,
allow_pagination=allow_pagination,
allow_sorting=allow_sorting)
return wsgi_resource.Resource(controller, FAULT_MAP)对于其余的扩展资源,Neutron仍然使用了传统的方式来实现,它们在neutron/extensions/目录下都分别有对应的实现和对应的Controller类位于neutron/api/目录下的extension.py文件只是一些基类和共用的代码