无法连接到'localhost‘上的MySQL服务器([Errno 99]地址不可用)

Question

当我试图从外部docker容器连接到MariaDB时，我得到了上面的错误。下面是我的docker-compose.yml文件：

version: '3'
services:
    mariadb:
        image: mariadb
        ports:
            - "127.0.0.1:3309:3306"
        volumes: 
            - mariadb_volume:/var/lib/mysql
        environment: 
            MYSQL_ROOT_PASSWORD: mypassword
            MYSQL_DATABASE: mydatabase
            MYSQL_USER: myuser
            MYSQL_PASSWORD: mypassword
        networks:
            - fastapi_network
            
    fastapi-dev:
        build: 
            context: .
            dockerfile: Dockerfile
        image: fastapi-dev:latest
        container_name: fastapi-dev
        command: /start-reload.sh
        volumes: 
            - ./src:/app/src
        ports:
            - 5000:80
        depends_on:
            - mariadb
        networks:
            - fastapi_network
     
volumes:
    mariadb_volume:
        driver: local
                      
networks:
  fastapi_network:
    external: true

数据库连接的数据库配置如下：

class DbSettings(BaseSettings):
    db_username:str = 'myuser'
    db_password: str = 'mypassword'
    db_host: str = 'localhost'
    db_port: int = '3306'
    db_name: str = 'mydatabase'

    engine_echo = True
    session_autocommit = False
    session_autoflush = False

    @property
    def db_conn_str(self) -> AnyUrl:
        return AnyUrl.build(
            scheme="mysql+pymysql",
            user=self.db_username,
            password=self.db_password,
            host=self.db_host,
            port=str(self.db_port),
            path=f"/{self.db_name}"
        )

在使用'docker-compose up‘部署容器后，我可以看到服务器完全启动并运行，如下所示：

mariadb_1              | 2021-09-06  8:24:10 0 [Note] mysqld: ready for connections.
mariadb_1              | Version: '10.6.4-MariaDB-1:10.6.4+maria~focal'  socket: '/run/mysqld/mysqld.sock'  port: 3306  mariadb.org binary distribution

考虑到服务器正在运行并接受连接，我不太明白代码出了什么问题。有人能在这方面给我一些建议吗？

Answer 1

我刚刚发现了一个错误，db_host应该是'mariadb‘而不是'localhost’。在此更改之后，它现在可以工作了。