Neutron 源码分析 --- Neutron-server创建_neutron-server源码-优快云博客

本文链接：https://blog.youkuaiyun.com/scucscheng/article/details/79045847

本文分析了Neutron-server在Pike版本中的启动入口，指出其核心函数位于`neutron/cmd/eventlet/server/__init__.py`，并详细解释了`pipeline_factory`函数如何根据`auth_strategy`配置加载Keystone认证管道。还提到了eventlet的协程机制与线程的区别，并提及GreenPool作为协程池的角色。最后，提到了Neutron的核心plugin为ML2以及其他的service_plugins。

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本文源码基于Pike版本.

通过setup.py里面:

[entry_points]

console_scripts =

....

neutron-server = neutron.cmd.eventlet.server:main

.....

可知,neutron-server的入口函数在neutron/cmd/eventlet/server/__init__.py:

def main():
    server.boot_server(wsgi_eventlet.eventlet_wsgi_server)


def main_rpc_eventlet():
    server.boot_server(rpc_eventlet.eventlet_rpc_server)

neutron/server/__init__.py:

def _init_configuration():
    # the configuration will be read into the cfg.CONF global data structure
    config.init(sys.argv[1:])   #此处传入的参数一般为 --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/plugins/ml2/ml2_conf.ini
    config.setup_logging()   #设置neutron的logging,就是以neutron为进程名的打印
    config.set_config_defaults()
    ...省略...


def boot_server(server_func):
    _init_configuration()
    try:
        server_func()
    ...省略...

server_func为传入的wsgi_eventlet.eventlet_wsgi_server,neutron/server/wsgi_eventlet.py:

def eventlet_wsgi_server():
    neutron_api = service.serve_wsgi(service.NeutronApiService) #创建neutron-server服务进程
    start_api_and_rpc_workers(neutron_api)


def start_api_and_rpc_workers(neutron_api):
    try:
        worker_launcher = service.start_all_workers()

        pool = eventlet.GreenPool()
        api_thread = pool.spawn(neutron_api.wait)
        plugin_workers_thread = pool.spawn(worker_launcher.wait)

        # api and other workers should die together. When one dies,
        # kill the other.
        api_thread.link(lambda gt: plugin_workers_thread.kill())
        plugin_workers_thread.link(lambda gt: api_thread.kill())

        pool.waitall()
    except NotImplementedError:
        LOG.info("RPC was already started in parent process by "
                 "plugin.")

        neutron_api.wait()

def serve_wsgi(cls):

    try:
        service = cls.create()
        service.start()

class NeutronApiService(WsgiService):
...省略....

class WsgiService(object):
    """Base class for WSGI based services.

    For each api you define, you must also define these flags:
    :<api>_listen: The address on which to listen
    :<api>_listen_port: The port on which to listen

    """

    def __init__(self, app_name):
        self.app_name = app_name
        self.wsgi_app = None

    def start(self):
        self.wsgi_app = _run_wsgi(self.app_name)  #加载/etc/neutron/api-paste.ini,启动WSGI服务器

    def wait(self):
        self.wsgi_app.wait()

def _run_wsgi(app_name):
    app = config.load_paste_app(app_name)
    if not app:
        LOG.error('No known API applications configured.')
        return
    return