写在前头，最近更新到了odoo13， 抽空看了一下odoo的源码，浏览了启动过程。

启动文件 odoo-bin.py

主要过程：
1.导入os，设置环境上下文
2.执行cli目录下的main()方法

#!/usr/bin/env python3

# set server timezone in UTC before time module imported
__import__('os').environ['TZ'] = 'UTC'  #此处是导入os模块并设置全局环境
import odoo

if __name__ == "__main__":
    odoo.cli.main()  #启动脚本, 执行main()函数

cli目录下的 command.py

cli.main()执行的是command.py中的 main()方法
主要过程：
1.获取系统启动参数
2.获取模块信息并导入
3.根据命令，实例化服务并启动

def main():
    args = sys.argv[1:]  # 此处是获取启动参数

    # The only shared option is '--addons-path=' needed to discover additional
    # commands from modules
    if len(args) > 1 and args[0].startswith('--addons-path=') and not args[1].startswith("-"):
        # parse only the addons-path, do not setup the logger...
        odoo.tools.config._parse_config([args[0]])
        args = args[1:]

    # Default legacy command
    command = "server"  # 默认启动命令的方式 为‘server’

    # TODO: find a way to properly discover addons subcommands without importing the world
    # Subcommand discovery
    if len(args) and not args[0].startswith("-"):
        logging.disable(logging.CRITICAL)
        for module in get_modules():  # 获取模块
            if isdir(joinpath(get_module_path(module), 'cli')):
                __import__('odoo.addons.' + module)  # 导入模块
        logging.disable(logging.NOTSET)
        command = args[0]
        args = args[1:]

    if command in commands:
        o = commands[command]()  #获取命令并执行， 实际是实例了一个 Server对象
        o.run(args)  # 调用Server的run()方法
    else:
        sys.exit('Unknow command %r' % (command,))

cli目录下的 server.py

Server类用于启动odoo服务，启动方法为run，而run 执行的是server.py中的 main()方法
主要过程：
1.检查用户（包括数据库用户）以及设置config参数
2.创建数据库（此处后续文章详细说明）
3.启动odoo的http服务，执行service目录下的server.py中的start()方法

def main(args):
    check_root_user()  #检查root用户
    odoo.tools.config.parse_config(args) #解析配置参数
    check_postgres_user() # 检查数据库用户, 针对 postgres用户
    report_configuration()  #记录配置的值

    config = odoo.tools.config

    # the default limit for CSV fields in the module is 128KiB, which is not
    # quite sufficient to import images to store in attachment. 500MiB is a
    # bit overkill, but better safe than sorry I guess
    csv.field_size_limit(500 * 1024 * 1024)

    preload = []
    if config['db_name']:
        preload = config['db_name'].split(',')
        for db_name in preload:
            try:
                odoo.service.db._create_empty_database(db_name)  #创建空的数据库
                config['init']['base'] = True
            except ProgrammingError as err:
                if err.pgcode == errorcodes.INSUFFICIENT_PRIVILEGE:
                    # We use an INFO loglevel on purpose in order to avoid
                    # reporting unnecessary warnings on build environment
                    # using restricted database access.
                    _logger.info("Could not determine if database %s exists, "
                                 "skipping auto-creation: %s", db_name, err)
                else:
                    raise err
            except odoo.service.db.DatabaseExists:
                pass

    if config["translate_out"]:
        export_translation()
        sys.exit(0)

    if config["translate_in"]:
        import_translation()
        sys.exit(0)

    # This needs to be done now to ensure the use of the multiprocessing
    # signaling mecanism for registries loaded with -d
    if config['workers']:
        odoo.multi_process = True

    stop = config["stop_after_init"]

    setup_pid_file()
    rc = odoo.service.server.start(preload=preload, stop=stop)  #启动odoo的http服务
    sys.exit(rc)

class Server(Command):
    """Start the odoo server (default command)"""
    def run(self, args):
        main(args)

service目录下的 server.py

start用于启动odoo的http服务
主要过程：
1.设置一个全局的server对象
2.实例server对象（wsgi_server）
3.启动wsgi_server(实际是实例化root对象，位于http.py中)
4.启动http服务后，便会加载模块，路由分发等等

def start(preload=None, stop=False):
    """ Start the odoo http server and cron processor.
    """
    global server

    load_server_wide_modules()
    odoo.service.wsgi_server._patch_xmlrpc_marshaller()

    if odoo.evented:
        server = GeventServer(odoo.service.wsgi_server.application)
    elif config['workers']:
        if config['test_enable'] or config['test_file']:
            _logger.warning("Unit testing in workers mode could fail; use --workers 0.")

        server = PreforkServer(odoo.service.wsgi_server.application)

        # Workaround for Python issue24291, fixed in 3.6 (see Python issue26721)
        if sys.version_info[:2] == (3,5):
            # turn on buffering also for wfile, to avoid partial writes (Default buffer = 8k)
            werkzeug.serving.WSGIRequestHandler.wbufsize = -1
    else:
        server = ThreadedServer(odoo.service.wsgi_server.application)

    watcher = None
    if 'reload' in config['dev_mode'] and not odoo.evented:
        if inotify:
            watcher = FSWatcherInotify()
            watcher.start()
        elif watchdog:
            watcher = FSWatcherWatchdog()
            watcher.start()
        else:
            if os.name == 'posix' and platform.system() != 'Darwin':
                module = 'inotify'
            else:
                module = 'watchdog'
            _logger.warning("'%s' module not installed. Code autoreload feature is disabled", module)
    if 'werkzeug' in config['dev_mode']:
        server.app = DebuggedApplication(server.app, evalex=True)

    rc = server.run(preload, stop)

    if watcher:
        watcher.stop()
    # like the legend of the phoenix, all ends with beginnings
    if getattr(odoo, 'phoenix', False):
        _reexec()

    return rc if rc else 0

以上，为启动的大致过程。其实加载模块，也是应用了python本身的导入机制。后续抽空研究odoo的模块加载机制，路由分发机制等等。

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