cinder api启动过程源码分析
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1、启动cinder-api服务
当你通过cinder-api命令(如:/usr/bin/cinder-api --config-file /etc/cinder/cinder.conf)启动api服务时,执行的实际上是
cinder/cmd/api.py/main()函数, 如下:
[root@xgto02n010027244133 ~]# cat /usr/bin/cinder-api #!/usr/bin/python2 # PBR Generated from u‘console_scripts‘ import sys from cinder.cmd.api import main if __name__ == "__main__": sys.exit(main())
cinder/cmd/api.py/main()函数,内容如下:
def main(): objects.register_all() #加载辅助对象,封装与数据库相关的操作 gmr_opts.set_defaults(CONF) #oslo_reports模块,用于生成错误报告,如内存泄漏等 CONF(sys.argv[1:], project=‘cinder‘, version=version.version_string()) config.set_middleware_defaults() logging.setup(CONF, "cinder") python_logging.captureWarnings(True) utils.monkey_patch() # monkey-patch,替换库比如socket、thread等,不改变import的行为,改变的是操作的指向函数 gmr.TextGuruMeditation.setup_autorun(version, conf=CONF) """初始化rpc: 设置全局Transport和Notifier,Transport是 oslo_messaging/transport.py/Transport实例,我采用的是默认的 rpc_backend=rabbit,所以Transport采用的driver=oslo_messaging/ _drivers/impl_rabbit.py/RabbitDriver;Notifier是一个通知消息发 送器,它借助Transport将通知发送发送给ceilometer """ rpc.init(CONF) #通过服务启动器启动WSGI服务(`osapi_volume`)并等待服务启动成功 #在初始化WSGI服务时,会设置路由映射以及加载WSGI应用程序 #在启动WSGI服务时,会启动http监听 launcher = service.process_launcher() server = service.WSGIService(‘osapi_volume‘) #创建一个名为`osapi_volume`的`WSGIService`服务对象 ,2里面详解 launcher.launch_service(server, workers=server.workers) launcher.wait()
2、创建 WSGIService 服务对象
from oslo_service import wsgi from cinder import service cinder/service.py:class WSGIService(service.ServiceBase): class WSGIService(service.ServiceBase): """Provides ability to launch API from a ‘paste‘ configuration.""" def __init__(self, name, loader=None): """Initialize, but do not start the WSGI server. 初始化,但是并不启动wsgi server服务 :param name: The name of the WSGI server given to the loader. :param loader: Loads the WSGI application using the given name. :returns: None """ self.name = name #服务名`osapi_volume` self.manager = self._get_manager() #加载名为(`osapi_volume_manager`)的管理器,返回值为None) #创建WSGI应用加载器,并根据配置文件(`cinder.conf`)设置应用配置路径,config_path` = `/etc/cinder/api-paste.ini‘ self.loader = loader or wsgi.Loader(CONF) #该函数会寻找cinder.conf文件中 api_paste_config 参数对应的配置文件,并保存到变量中 self.app = self.loader.load_app(name) #加载WSGI应用并设置路由映射,return paste.urlmap.URLMap """ 根据配置文件(`cinder.conf`)设置监听地址及工作线程数 如果未指定监听ip及端口就分别设置为`0.0.0.0`及`0` 如果为指定工作线程数就设置为cpu个数 如果设置的工作线程数小于1,则抛异常 """ self.host = getattr(CONF, ‘%s_listen‘ % name, "0.0.0.0") self.port = getattr(CONF, ‘%s_listen_port‘ % name, 0) self.use_ssl = getattr(CONF, ‘%s_use_ssl‘ % name, False) self.workers = (getattr(CONF, ‘%s_workers‘ % name, None) or processutils.get_worker_count()) if self.workers and self.workers < 1: worker_name = ‘%s_workers‘ % name msg = (_("%(worker_name)s value of %(workers)d is invalid, " "must be greater than 0.") % {‘worker_name‘: worker_name, ‘workers‘: self.workers}) raise exception.InvalidInput(msg) """如果CONF.profiler.enabled = True就开启性能分析 创建一个类型为`Messaging`的通知器(`_notifier`),将性能数据发送给 ceilometer """ setup_profiler(name, self.host) ##创建WSGI服务器对象 self.server = wsgi.Server(CONF, name, self.app, host=self.host, port=self.port, use_ssl=self.use_ssl)
在cinder.conf配置文件中与cinder api服务有关的参数
# File name for the paste.deploy config for api service (string value)
api_paste_config = /etc/cinder/api-paste.ini
在初始化WSGIService服务对象过程中,主要完成了如下操作:
1)加载WSGI Application(Python Paste Deployment)
2)设置路由映射(Python Routes)
3)创建WSGI服务器对象并完成初始化
2.1 对wsgi的使用
oslo_service/wsgi.py class Loader(object): """Used to load WSGI applications from paste configurations.""" def __init__(self, conf): """Initialize the loader, and attempt to find the config. :param conf: Application config :returns: None """ conf.register_opts(_options.wsgi_opts) self.config_path = None config_path = conf.api_paste_config if not os.path.isabs(config_path): self.config_path = conf.find_file(config_path) elif os.path.exists(config_path): self.config_path = config_path if not self.config_path: raise ConfigNotFound(path=config_path) def load_app(self, name): """Return the paste URLMap wrapped WSGI application. :param name: Name of the application to load. :returns: Paste URLMap object wrapping the requested application. :raises: PasteAppNotFound """ try: LOG.debug("Loading app %(name)s from %(path)s", {‘name‘: name, ‘path‘: self.config_path}) return deploy.loadapp("config:%s" % self.config_path, name=name) except LookupError: LOG.exception("Couldn‘t lookup app: %s", name) raise PasteAppNotFound(name=name, path=self.config_path)
配置文件api-paste.ini内容如下
[composite:osapi_volume] use = call:cinder.api:root_app_factory /: apiversions /v1: openstack_volume_api_v1 /v2: openstack_volume_api_v2 /v3: openstack_volume_api_v3 [composite:openstack_volume_api_v1] use = call:cinder.api.middleware.auth:pipeline_factory noauth = cors http_proxy_to_wsgi request_id faultwrap sizelimit osprofiler noauth apiv1 keystone = cors http_proxy_to_wsgi request_id faultwrap sizelimit osprofiler authtoken keystonecontext apiv1 keystone_nolimit = cors http_proxy_to_wsgi request_id faultwrap sizelimit osprofiler authtoken keystonecontext apiv1 [composite:openstack_volume_api_v2] use = call:cinder.api.middleware.auth:pipeline_factory noauth = cors http_proxy_to_wsgi request_id faultwrap sizelimit osprofiler noauth apiv2 keystone = cors http_proxy_to_wsgi request_id faultwrap sizelimit osprofiler authtoken keystonecontext apiv2 keystone_nolimit = cors http_proxy_to_wsgi request_id faultwrap sizelimit osprofiler authtoken keystonecontext apiv2 cinder.conf文件中的api启动的配置 这三个参数控制的是api 版本的控制 # DEPRECATED: Deploy v1 of the Cinder API. (boolean value) # This option is deprecated for remoervice_down_timeal. # Its value may be silently ignored in the future. #enable_v1_api = false--------不加载v1对应的app # DEPRECATED: Deploy v2 of the Cinder API. (boolean value) # This option is deprecated for removal. # Its value may be silently ignored in the future. #enable_v2_api = True------------加载v2对应的app # Deploy v3 of the Cinder API. (boolean value) enable_v3_api = True-------------加载v3对应的app # The strategy to use for auth. Supports noauth or keystone. (string value) # Allowed values: noauth, keystone auth_strategy = keystone----------这个参数控制的api-paste.ini中选择哪一种认证方式
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