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Swift的Account Server、Container Server和Object Server通过Paste Deploy加载WSGI Application，分别由AccountController、ContainerController和ObjectController处理用户的HTTP请求。这些服务与Proxy Server类似，均通过run_wsgi()函数启动。Account Server的配置文件位于/etc/swift/account-server/目录下。

Paste Deploy的配置文件中，[pipeline:main]管道定义了健康检查和重建功能，接着调用account-server模块。setup.cfg文件定义了entry_points，指定了各个服务的app_factory函数，包括swift.account.server、swift.container.server等。

结合配置文件和setup.cfg，Paste Deploy最终使用swift.account.server模块的app_factory函数加载Account Server的WSGI Application，即swift.account.server.AccountController。该Controller与swift/proxy/controllers目录下的Controller不同，后者负责将HTTP请求转发给Account Server，而AccountController则是对请求的最终处理。

以PUT操作为例，Account PUT请求有两种语义：一种是创建Account，另一种是创建Account中的Container。两者的区别在于路径参数是否包含Container信息。

AccountController的实现如下：

class AccountController(object):    """WSGI controller for the account server."""    def PUT(self, req):        """Handle HTTP PUT request."""        # 从请求参数中获取drive, part, account, container信息        drive, part, account, container = split_and_validate_path(req, 3, 4)        if self.mount_check and not check_mount(self.root, drive):            return HTTPInsufficientStorage(drive=drive, request=req)                if container:            # PUT account container            if 'x-timestamp' not in req.headers:                timestamp = Timestamp(time.time())            else:                timestamp = valid_timestamp(req)                        pending_timeout = None            container_policy_index = req.headers.get('X-Backend-Storage-Policy-Index', 0)            if 'x-trans-id' in req.headers:                pending_timeout = 3                        broker = self._get_account_broker(drive, part, account, pending_timeout=pending_timeout)            if account.startswith(self.auto_create_account_prefix) and not os.path.exists(broker.db_file):                try:                    broker.initialize(timestamp.internal)                except DatabaseAlreadyExists:                    pass            if req.headers.get('x-account-override-deleted', 'no').lower() != 'yes' and broker.is_deleted():                return HTTPNotFound(request=req)                        broker.put_container(container, req.headers['x-put-timestamp'],                                  req.headers['x-delete-timestamp'],                                  req.headers['x-object-count'],                                  req.headers['x-bytes-used'],                                  container_policy_index)            if req.headers['x-delete-timestamp'] > req.headers['x-put-timestamp']:                return HTTPNoContent(request=req)            else:                return HTTPCreated(request=req)        else:            # PUT account            timestamp = valid_timestamp(req)            broker = self._get_account_broker(drive, part, account)            if not os.path.exists(broker.db_file):                try:                    broker.initialize(timestamp.internal)                    created = True                except DatabaseAlreadyExists:                    created = False            elif broker.is_status_deleted():                return self._deleted_response(broker, req, HTTPForbidden, body='Recently deleted')            else:                created = broker.is_deleted()                broker.update_put_timestamp(timestamp.internal)                if broker.is_deleted():                    return HTTPConflict(request=req)                        metadata = {}            metadata.update((key, (value, timestamp.internal)) for key, value in req.headers.iteritems() if is_sys_or_user_meta('account', key))            if metadata:                broker.update_metadata(metadata, validate_metadata=True)                        if created:                return HTTPCreated(request=req)            else:                return HTTPAccepted(request=req)

该Controller通过路径参数分割和验证请求，检查存储位置并调用相应的Broker进行操作。Broker负责处理具体的账户操作，包括创建账户和账户中的容器。

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