在Python容器中运行蒸馏器是依赖于一个MySQL容器

Question

我有，我用下面的docker-compose.yml文件的项目：

version: '3' 
services: 
    python: 
     restart: always 
     build: ./budget/dockerfiles/python/ 
     ports: 
      - "5000:5000" 
     links: 
      - db 
     depends_on: 
      - db 
     volumes: 
      - ./budget/:/app:z 
     entrypoint: 
      - python 
      - -u 
      - /app/run.py 

    db: 
     build: ./budget/dockerfiles/mysql/ 
     environment: 
      MYSQL_ROOT_PASSWORD: rainmakers 
      MYSQL_DATABASE: forecast 
      MYSQL_USER: rain 
      MYSQL_PASSWORD: rainmakers 
     volumes: 
      - ./Dump.sql:/db/Dump.sql:z 
      - ./Dump_Test.sql:/db/Dump_Test.sql:z 
      - ./big_fc.sql:/db/big_fc.sql:z 
     ports: 
      - "3306:3306" 

我也有以下alembi.ini文件：

# A generic, single database configuration. 

[alembic] 
sqlalchemy.url = mysql://username:password@localhost/database_name 

# Logging configuration 
[loggers] 
keys = root,sqlalchemy,alembic 

[handlers] 
keys = console 

[formatters] 
keys = generic 

[logger_root] 
level = WARN 
handlers = console 
qualname = 

[logger_sqlalchemy] 
level = WARN 
handlers = 
qualname = sqlalchemy.engine 

[logger_alembic] 
level = INFO 
handlers = 
qualname = alembic 

[handler_console] 
class = StreamHandler 
args = (sys.stderr,) 
level = NOTSET 
formatter = generic 

[formatter_generic] 
format = %(levelname)-5.5s [%(name)s] %(message)s 
datefmt = %H:%M:%S 

我需要在我的Python容器中运行命令alembic upgrade head，但是当我运行它时，出现以下错误：

Traceback (most recent call last): 
    File "/usr/local/bin/alembic", line 11, in <module> 
    sys.exit(main()) 
    File "/usr/local/lib/python2.7/dist-packages/alembic/config.py", line 479, in main 
    CommandLine(prog=prog).main(argv=argv) 
    File "/usr/local/lib/python2.7/dist-packages/alembic/config.py", line 473, in main 
    self.run_cmd(cfg, options) 
    File "/usr/local/lib/python2.7/dist-packages/alembic/config.py", line 456, in run_cmd 
    **dict((k, getattr(options, k, None)) for k in kwarg) 
    File "/usr/local/lib/python2.7/dist-packages/alembic/command.py", line 254, in upgrade 
    script.run_env() 
    File "/usr/local/lib/python2.7/dist-packages/alembic/script/base.py", line 421, in run_env 
    util.load_python_file(self.dir, 'env.py') 
    File "/usr/local/lib/python2.7/dist-packages/alembic/util/pyfiles.py", line 93, in load_python_file 
    module = load_module_py(module_id, path) 
    File "/usr/local/lib/python2.7/dist-packages/alembic/util/compat.py", line 75, in load_module_py 
    mod = imp.load_source(module_id, path, fp) 
    File "alembic/env.py", line 70, in <module> 
    run_migrations_online() 
    File "alembic/env.py", line 58, in run_migrations_online 
    with connectable.connect() as connection: 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2085, in connect 
    return self._connection_cls(self, **kwargs) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 90, in __init__ 
    if connection is not None else engine.raw_connection() 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2171, in raw_connection 
    self.pool.unique_connection, _connection) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2145, in _wrap_pool_connect 
    e, dialect, self) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 1456, in _handle_dbapi_exception_noconnection 
    exc_info 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/util/compat.py", line 202, in raise_from_cause 
    reraise(type(exception), exception, tb=exc_tb, cause=cause) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/base.py", line 2141, in _wrap_pool_connect 
    return fn() 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 328, in unique_connection 
    return _ConnectionFairy._checkout(self) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 766, in _checkout 
    fairy = _ConnectionRecord.checkout(pool) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 516, in checkout 
    rec = pool._do_get() 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 1229, in _do_get 
    return self._create_connection() 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 333, in _create_connection 
    return _ConnectionRecord(self) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 461, in __init__ 
    self.__connect(first_connect_check=True) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/pool.py", line 651, in __connect 
    connection = pool._invoke_creator(self) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/strategies.py", line 105, in connect 
    return dialect.connect(*cargs, **cparams) 
    File "/usr/local/lib/python2.7/dist-packages/sqlalchemy/engine/default.py", line 385, in connect 
    return self.dbapi.connect(*cargs, **cparams) 
    File "/usr/local/lib/python2.7/dist-packages/MySQLdb/__init__.py", line 81, in Connect 
    return Connection(*args, **kwargs) 
    File "/usr/local/lib/python2.7/dist-packages/MySQLdb/connections.py", line 193, in __init__ 
    super(Connection, self).__init__(*args, **kwargs2) 
sqlalchemy.exc.OperationalError: (_mysql_exceptions.OperationalError) (2002, "Can't connect to local MySQL server through socket '/var/run/mysqld/mysqld.sock' (2)") 

我猜错误是这个命令试图在我的python容器里面找到mysql，但这不在这里，所以我想知道我能做些什么来使它正常运行。

Answer 1

从python容器的角度来看，mysql IP使用mysql服务的名称解析：db。解决问题为：

[alembic] 
sqlalchemy.url = mysql://username:password@db/database_name