使用 Docker-Compose 连接 FastAPI 服务器和 MySQL 数据库时出现问题
Problem in Connecting FastAPI Server and MySQL databse using Docker-Compose
我一直在尝试使用 Docker-compose 连接我的 FastAPI 服务器和 MySQL 数据库。但是，当我 运行 docker-compose up --build.
时，它一直显示以下错误
网上和Whosebug的一些帖子（如Post1）建议将DB_HOST的值改成类似于MySQL服务名，在[=18]中指定=] 文件。我也试过那个选项，但我仍然遇到同样的错误。
能否请您帮助我，我需要做哪些更改才能 运行 MySQL 和使用 docker-compose 的 FastAPI 服务器？
以下是我的docker-compose.yml文件
version: '3.8'
services:
mysql-db:
container_name: mysql-db
image: mysql:latest
platform: linux/amd64
environment:
- MYSQL_DATABASE='admin'
- MYSQL_ROOT_PASSWORD='admin'
expose:
- "3306"
ports:
- "3306:3306"
backend-server:
container_name: "backend-server"
build: .
ports:
- "8000:8000"
depends_on:
- mysql-db
我的数据库配置文件如下
from sqlalchemy import create_engine, MetaData
DB_USER = "root"
DB_PASSWORD = "admin"
DB_HOST = "mysql-db"
DB_PORT = "3306"
DATABASE = "admin"
connect_string = 'mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8'.format(DB_USER, DB_PASSWORD, DB_HOST, DB_PORT, DATABASE)
engine = create_engine(connect_string)
meta = MetaData()
conn = engine.connect()
我的 DockerFastAPI 服务器文件
FROM python:3.9
WORKDIR '/backend'
COPY ./requirements.txt ./
RUN pip install --trusted-host pypi.python.org -r requirements.txt
COPY . .
CMD ["uvicorn", "main:app"]
我的错误日志如下：
Starting mysql-db ... done
Recreating backend-server ... done
Attaching to mysql-db, backend-server
mysql-db | 2022-03-20 20:57:57+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.28-1debian10 started.
backend-server | Traceback (most recent call last):
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 613, in connect
backend-server | sock = socket.create_connection(
backend-server | File "/usr/local/lib/python3.9/socket.py", line 844, in create_connection
backend-server | raise err
backend-server | File "/usr/local/lib/python3.9/socket.py", line 832, in create_connection
backend-server | sock.connect(sa)
backend-server | ConnectionRefusedError: [Errno 111] Connection refused
backend-server |
backend-server | During handling of the above exception, another exception occurred:
backend-server |
backend-server | Traceback (most recent call last):
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3256, in _wrap_pool_connect
backend-server | return fn()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 310, in connect
backend-server | return _ConnectionFairy._checkout(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 868, in _checkout
backend-server | fairy = _ConnectionRecord.checkout(pool)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 476, in checkout
backend-server | rec = pool._do_get()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 146, in _do_get
backend-server | self._dec_overflow()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 143, in _do_get
backend-server | return self._create_connection()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 256, in _create_connection
backend-server | return _ConnectionRecord(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 371, in __init__
backend-server | self.__connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 666, in __connect
backend-server | pool.logger.debug("Error on connect(): %s", e)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 661, in __connect
backend-server | self.dbapi_connection = connection = pool._invoke_creator(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/create.py", line 590, in connect
backend-server | return dialect.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 597, in connect
backend-server | return self.dbapi.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__
backend-server | self.connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 664, in connect
backend-server | raise exc
backend-server | pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'mysql-db' ([Errno 111] Connection refused)")
backend-server |
backend-server | The above exception was the direct cause of the following exception:
backend-server |
backend-server | Traceback (most recent call last):
backend-server | File "/usr/local/bin/uvicorn", line 8, in <module>
backend-server | sys.exit(main())
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 1128, in __call__
backend-server | return self.main(*args, **kwargs)
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 1053, in main
backend-server | rv = self.invoke(ctx)
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 1395, in invoke
backend-server | return ctx.invoke(self.callback, **ctx.params)
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 754, in invoke
backend-server | return __callback(*args, **kwargs)
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/main.py", line 437, in main
backend-server | run(app, **kwargs)
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/main.py", line 463, in run
backend-server | server.run()
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/server.py", line 60, in run
backend-server | return asyncio.run(self.serve(sockets=sockets))
backend-server | File "/usr/local/lib/python3.9/asyncio/runners.py", line 44, in run
backend-server | return loop.run_until_complete(main)
backend-server | File "/usr/local/lib/python3.9/asyncio/base_events.py", line 647, in run_until_complete
backend-server | return future.result()
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/server.py", line 67, in serve
backend-server | config.load()
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/config.py", line 458, in load
backend-server | self.loaded_app = import_from_string(self.app)
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/importer.py", line 21, in import_from_string
backend-server | module = importlib.import_module(module_str)
backend-server | File "/usr/local/lib/python3.9/importlib/__init__.py", line 127, in import_module
backend-server | return _bootstrap._gcd_import(name[level:], package, level)
backend-server | File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
backend-server | File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
backend-server | File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
backend-server | File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
backend-server | File "<frozen importlib._bootstrap_external>", line 850, in exec_module
backend-server | File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
backend-server | File "/backend/./main.py", line 2, in <module>
backend-server | from models.dbschema import dbExceptionMessage, dbMaterialMaster
backend-server | File "/backend/./models/dbschema.py", line 3, in <module>
backend-server | from config.db import meta, engine
backend-server | File "/backend/./config/db.py", line 15, in <module>
backend-server | conn = engine.connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3210, in connect
backend-server | return self._connection_cls(self, close_with_result=close_with_result)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 96, in __init__
backend-server | else engine.raw_connection()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3289, in raw_connection
backend-server | return self._wrap_pool_connect(self.pool.connect, _connection)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3259, in _wrap_pool_connect
backend-server | Connection._handle_dbapi_exception_noconnection(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2106, in _handle_dbapi_exception_noconnection
backend-server | util.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3256, in _wrap_pool_connect
backend-server | return fn()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 310, in connect
backend-server | return _ConnectionFairy._checkout(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 868, in _checkout
backend-server | fairy = _ConnectionRecord.checkout(pool)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 476, in checkout
backend-server | rec = pool._do_get()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 146, in _do_get
backend-server | self._dec_overflow()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 143, in _do_get
backend-server | return self._create_connection()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 256, in _create_connection
backend-server | return _ConnectionRecord(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 371, in __init__
backend-server | self.__connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 666, in __connect
backend-server | pool.logger.debug("Error on connect(): %s", e)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 661, in __connect
backend-server | self.dbapi_connection = connection = pool._invoke_creator(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/create.py", line 590, in connect
backend-server | return dialect.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 597, in connect
backend-server | return self.dbapi.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__
backend-server | self.connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 664, in connect
backend-server | raise exc
backend-server | sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2003, "Can't connect to MySQL server on 'mysql-db' ([Errno 111] Connection refused)")
backend-server | (Background on this error at: https://sqlalche.me/e/14/e3q8)
backend-server exited with code 1
mysql-db | 2022-03-20 20:57:57+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
mysql-db | 2022-03-20 20:57:57+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.28-1debian10 started.
mysql-db | 2022-03-20T20:57:59.047590Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.28) starting as process 1
mysql-db | 2022-03-20T20:57:59.145611Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
mysql-db | 2022-03-20T20:57:59.171249Z 1 [ERROR] [MY-012585] [InnoDB] Linux Native AIO interface is not supported on this platform. Please check your OS documentation and install appropriate binary of InnoDB.
mysql-db | 2022-03-20T20:57:59.171538Z 1 [Warning] [MY-012654] [InnoDB] Linux Native AIO disabled.
mysql-db | 2022-03-20T20:57:59.678151Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.
mysql-db | 2022-03-20T20:58:00.317516Z 0 [System] [MY-010229] [Server] Starting XA crash recovery...
mysql-db | 2022-03-20T20:58:00.330970Z 0 [System] [MY-010232] [Server] XA crash recovery finished.
mysql-db | 2022-03-20T20:58:00.475268Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.
mysql-db | 2022-03-20T20:58:00.476155Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.
mysql-db | 2022-03-20T20:58:00.481201Z 0 [Warning] [MY-011810] [Server] Insecure configuration for --pid-file: Location '/var/run/mysqld' in the path is accessible to all OS users. Consider choosing a different directory.
mysql-db | 2022-03-20T20:58:00.599555Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /var/run/mysqld/mysqlx.sock
mysql-db | 2022-03-20T20:58:00.601446Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.28' socket: '/var/run/mysqld/mysqld.sock' port: 3306 MySQL Community Server - GPL.
如日志中所述，数据库服务器拒绝连接，因此问题似乎既不在 FastAPI 也不在 docker-compose；因为你的配置是正确的。
（假设您尝试从其他代码或服务器连接 MySQL 数据库。换句话说，您确定可以从客户端连接到数据库。）
您正在为 SQLAlchemy 使用 PyMySQL 连接。因此，如 the documentation 中所述，您的数据库连接字符串应如下所示：
mysql+pymysql://<username>:<password>@<host>/<dbname>[?<options>]
区别在于端口属性。
因此，如果您尝试如下所示的连接字符串，您应该能够连接到数据库：
connect_string = 'mysql+pymysql://{}:{}@{}/{}?port={}?charset=utf8'.format(DB_USER, DB_PASSWORD, DB_HOST, DATABASE, DB_PORT)
注意： 此外，在某些示例中，我看到除了 port 之外还添加了 ?host= 选项；所以如果它不起作用，你也可以尝试使用它。
我一直在尝试使用 Docker-compose 连接我的 FastAPI 服务器和 MySQL 数据库。但是，当我 运行 docker-compose up --build.
网上和Whosebug的一些帖子（如Post1）建议将DB_HOST的值改成类似于MySQL服务名，在[=18]中指定=] 文件。我也试过那个选项，但我仍然遇到同样的错误。
能否请您帮助我，我需要做哪些更改才能 运行 MySQL 和使用 docker-compose 的 FastAPI 服务器？
以下是我的docker-compose.yml文件
version: '3.8'
services:
mysql-db:
container_name: mysql-db
image: mysql:latest
platform: linux/amd64
environment:
- MYSQL_DATABASE='admin'
- MYSQL_ROOT_PASSWORD='admin'
expose:
- "3306"
ports:
- "3306:3306"
backend-server:
container_name: "backend-server"
build: .
ports:
- "8000:8000"
depends_on:
- mysql-db
我的数据库配置文件如下
from sqlalchemy import create_engine, MetaData
DB_USER = "root"
DB_PASSWORD = "admin"
DB_HOST = "mysql-db"
DB_PORT = "3306"
DATABASE = "admin"
connect_string = 'mysql+pymysql://{}:{}@{}:{}/{}?charset=utf8'.format(DB_USER, DB_PASSWORD, DB_HOST, DB_PORT, DATABASE)
engine = create_engine(connect_string)
meta = MetaData()
conn = engine.connect()
我的 DockerFastAPI 服务器文件
FROM python:3.9
WORKDIR '/backend'
COPY ./requirements.txt ./
RUN pip install --trusted-host pypi.python.org -r requirements.txt
COPY . .
CMD ["uvicorn", "main:app"]
我的错误日志如下：
Starting mysql-db ... done
Recreating backend-server ... done
Attaching to mysql-db, backend-server
mysql-db | 2022-03-20 20:57:57+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.28-1debian10 started.
backend-server | Traceback (most recent call last):
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 613, in connect
backend-server | sock = socket.create_connection(
backend-server | File "/usr/local/lib/python3.9/socket.py", line 844, in create_connection
backend-server | raise err
backend-server | File "/usr/local/lib/python3.9/socket.py", line 832, in create_connection
backend-server | sock.connect(sa)
backend-server | ConnectionRefusedError: [Errno 111] Connection refused
backend-server |
backend-server | During handling of the above exception, another exception occurred:
backend-server |
backend-server | Traceback (most recent call last):
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3256, in _wrap_pool_connect
backend-server | return fn()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 310, in connect
backend-server | return _ConnectionFairy._checkout(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 868, in _checkout
backend-server | fairy = _ConnectionRecord.checkout(pool)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 476, in checkout
backend-server | rec = pool._do_get()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 146, in _do_get
backend-server | self._dec_overflow()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 143, in _do_get
backend-server | return self._create_connection()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 256, in _create_connection
backend-server | return _ConnectionRecord(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 371, in __init__
backend-server | self.__connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 666, in __connect
backend-server | pool.logger.debug("Error on connect(): %s", e)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 661, in __connect
backend-server | self.dbapi_connection = connection = pool._invoke_creator(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/create.py", line 590, in connect
backend-server | return dialect.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 597, in connect
backend-server | return self.dbapi.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__
backend-server | self.connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 664, in connect
backend-server | raise exc
backend-server | pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'mysql-db' ([Errno 111] Connection refused)")
backend-server |
backend-server | The above exception was the direct cause of the following exception:
backend-server |
backend-server | Traceback (most recent call last):
backend-server | File "/usr/local/bin/uvicorn", line 8, in <module>
backend-server | sys.exit(main())
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 1128, in __call__
backend-server | return self.main(*args, **kwargs)
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 1053, in main
backend-server | rv = self.invoke(ctx)
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 1395, in invoke
backend-server | return ctx.invoke(self.callback, **ctx.params)
backend-server | File "/usr/local/lib/python3.9/site-packages/click/core.py", line 754, in invoke
backend-server | return __callback(*args, **kwargs)
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/main.py", line 437, in main
backend-server | run(app, **kwargs)
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/main.py", line 463, in run
backend-server | server.run()
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/server.py", line 60, in run
backend-server | return asyncio.run(self.serve(sockets=sockets))
backend-server | File "/usr/local/lib/python3.9/asyncio/runners.py", line 44, in run
backend-server | return loop.run_until_complete(main)
backend-server | File "/usr/local/lib/python3.9/asyncio/base_events.py", line 647, in run_until_complete
backend-server | return future.result()
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/server.py", line 67, in serve
backend-server | config.load()
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/config.py", line 458, in load
backend-server | self.loaded_app = import_from_string(self.app)
backend-server | File "/usr/local/lib/python3.9/site-packages/uvicorn/importer.py", line 21, in import_from_string
backend-server | module = importlib.import_module(module_str)
backend-server | File "/usr/local/lib/python3.9/importlib/__init__.py", line 127, in import_module
backend-server | return _bootstrap._gcd_import(name[level:], package, level)
backend-server | File "<frozen importlib._bootstrap>", line 1030, in _gcd_import
backend-server | File "<frozen importlib._bootstrap>", line 1007, in _find_and_load
backend-server | File "<frozen importlib._bootstrap>", line 986, in _find_and_load_unlocked
backend-server | File "<frozen importlib._bootstrap>", line 680, in _load_unlocked
backend-server | File "<frozen importlib._bootstrap_external>", line 850, in exec_module
backend-server | File "<frozen importlib._bootstrap>", line 228, in _call_with_frames_removed
backend-server | File "/backend/./main.py", line 2, in <module>
backend-server | from models.dbschema import dbExceptionMessage, dbMaterialMaster
backend-server | File "/backend/./models/dbschema.py", line 3, in <module>
backend-server | from config.db import meta, engine
backend-server | File "/backend/./config/db.py", line 15, in <module>
backend-server | conn = engine.connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3210, in connect
backend-server | return self._connection_cls(self, close_with_result=close_with_result)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 96, in __init__
backend-server | else engine.raw_connection()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3289, in raw_connection
backend-server | return self._wrap_pool_connect(self.pool.connect, _connection)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3259, in _wrap_pool_connect
backend-server | Connection._handle_dbapi_exception_noconnection(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2106, in _handle_dbapi_exception_noconnection
backend-server | util.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 3256, in _wrap_pool_connect
backend-server | return fn()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 310, in connect
backend-server | return _ConnectionFairy._checkout(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 868, in _checkout
backend-server | fairy = _ConnectionRecord.checkout(pool)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 476, in checkout
backend-server | rec = pool._do_get()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 146, in _do_get
backend-server | self._dec_overflow()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 143, in _do_get
backend-server | return self._create_connection()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 256, in _create_connection
backend-server | return _ConnectionRecord(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 371, in __init__
backend-server | self.__connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 666, in __connect
backend-server | pool.logger.debug("Error on connect(): %s", e)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 70, in __exit__
backend-server | compat.raise_(
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 207, in raise_
backend-server | raise exception
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 661, in __connect
backend-server | self.dbapi_connection = connection = pool._invoke_creator(self)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/create.py", line 590, in connect
backend-server | return dialect.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 597, in connect
backend-server | return self.dbapi.connect(*cargs, **cparams)
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__
backend-server | self.connect()
backend-server | File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 664, in connect
backend-server | raise exc
backend-server | sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2003, "Can't connect to MySQL server on 'mysql-db' ([Errno 111] Connection refused)")
backend-server | (Background on this error at: https://sqlalche.me/e/14/e3q8)
backend-server exited with code 1
mysql-db | 2022-03-20 20:57:57+00:00 [Note] [Entrypoint]: Switching to dedicated user 'mysql'
mysql-db | 2022-03-20 20:57:57+00:00 [Note] [Entrypoint]: Entrypoint script for MySQL Server 8.0.28-1debian10 started.
mysql-db | 2022-03-20T20:57:59.047590Z 0 [System] [MY-010116] [Server] /usr/sbin/mysqld (mysqld 8.0.28) starting as process 1
mysql-db | 2022-03-20T20:57:59.145611Z 1 [System] [MY-013576] [InnoDB] InnoDB initialization has started.
mysql-db | 2022-03-20T20:57:59.171249Z 1 [ERROR] [MY-012585] [InnoDB] Linux Native AIO interface is not supported on this platform. Please check your OS documentation and install appropriate binary of InnoDB.
mysql-db | 2022-03-20T20:57:59.171538Z 1 [Warning] [MY-012654] [InnoDB] Linux Native AIO disabled.
mysql-db | 2022-03-20T20:57:59.678151Z 1 [System] [MY-013577] [InnoDB] InnoDB initialization has ended.
mysql-db | 2022-03-20T20:58:00.317516Z 0 [System] [MY-010229] [Server] Starting XA crash recovery...
mysql-db | 2022-03-20T20:58:00.330970Z 0 [System] [MY-010232] [Server] XA crash recovery finished.
mysql-db | 2022-03-20T20:58:00.475268Z 0 [Warning] [MY-010068] [Server] CA certificate ca.pem is self signed.
mysql-db | 2022-03-20T20:58:00.476155Z 0 [System] [MY-013602] [Server] Channel mysql_main configured to support TLS. Encrypted connections are now supported for this channel.
mysql-db | 2022-03-20T20:58:00.481201Z 0 [Warning] [MY-011810] [Server] Insecure configuration for --pid-file: Location '/var/run/mysqld' in the path is accessible to all OS users. Consider choosing a different directory.
mysql-db | 2022-03-20T20:58:00.599555Z 0 [System] [MY-011323] [Server] X Plugin ready for connections. Bind-address: '::' port: 33060, socket: /var/run/mysqld/mysqlx.sock
mysql-db | 2022-03-20T20:58:00.601446Z 0 [System] [MY-010931] [Server] /usr/sbin/mysqld: ready for connections. Version: '8.0.28' socket: '/var/run/mysqld/mysqld.sock' port: 3306 MySQL Community Server - GPL.
如日志中所述，数据库服务器拒绝连接，因此问题似乎既不在 FastAPI 也不在 docker-compose；因为你的配置是正确的。
（假设您尝试从其他代码或服务器连接 MySQL 数据库。换句话说，您确定可以从客户端连接到数据库。）
您正在为 SQLAlchemy 使用 PyMySQL 连接。因此，如 the documentation 中所述，您的数据库连接字符串应如下所示：
mysql+pymysql://<username>:<password>@<host>/<dbname>[?<options>]
区别在于端口属性。
因此，如果您尝试如下所示的连接字符串，您应该能够连接到数据库：
connect_string = 'mysql+pymysql://{}:{}@{}/{}?port={}?charset=utf8'.format(DB_USER, DB_PASSWORD, DB_HOST, DATABASE, DB_PORT)
注意： 此外，在某些示例中，我看到除了 port 之外还添加了 ?host= 选项；所以如果它不起作用，你也可以尝试使用它。