How to fix Error in Docker?

Question

Python

there are two containers, one with a python script, the second mysql
in the logs, I see that the docker with python has an error connecting to the database, please tell me what I'm doing wrong?

version: "3.5"
services:
  db:
    image: mysql:latest
    command: --default-authentication-plugin=mysql_native_password
    volumes:
      - ./db_data:/var/lib/mysql
    ports:
      - "3307:3306"
    environment:
      MYSQL_ROOT_PASSWORD: fil
      MYSQL_DATABASE: doc
      MYSQL_USER: fil
      MYSQL_PASSWORD: fil
  python-test:
    image: python:3
    build: .
    links:
      - db
volumes:
  db_data:

FROM python:3
WORKDIR /usr/src/app
COPY . .
RUN pip install --no-cache-dir -r requirements.txt

CMD ["python", "main.py"]

from sqlalchemy import create_engine, Table, MetaData, Column, BIGINT, String, Integer, FLOAT
from sqlalchemy.ext.declarative import declarative_base
from sqlalchemy.orm import sessionmaker, relationship
import pymysql

pymysql.install_as_MySQLdb()
engine = create_engine("mysql://fil:[email protected]:3306/doc", encoding="utf8")

Base = declarative_base()
Session = sessionmaker(bind=engine)


class Doc(Base):
    __tablename__ = 'Docker'

    def __init__(self, text):
        self.text = text

    id = Column(BIGINT, primary_key=True, autoincrement=True)
    text = Column(String(100))


Base.metadata.create_all(engine)
session = Session()

session.add(Doc('text'))
session.commit()

Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 613, in connect
    sock = socket.create_connection(
  File "/usr/local/lib/python3.9/socket.py", line 843, in create_connection
    raise err
  File "/usr/local/lib/python3.9/socket.py", line 831, in create_connection
    sock.connect(sa)
ConnectionRefusedError: [Errno 111] Connection refused

During handling of the above exception, another exception occurred:

Traceback (most recent call last):
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2336, in _wrap_pool_connect
    return fn()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 364, in connect
    return _ConnectionFairy._checkout(self)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 778, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 495, in checkout
    rec = pool._do_get()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 140, in _do_get
    self._dec_overflow()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 68, in __exit__
    compat.raise_(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 137, in _do_get
    return self._create_connection()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 309, in _create_connection
    return _ConnectionRecord(self)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 440, in __init__
    self.__connect(first_connect_check=True)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 661, in __connect
    pool.logger.debug("Error on connect(): %s", e)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 68, in __exit__
    compat.raise_(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 656, in __connect
    connection = pool._invoke_creator(self)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/strategies.py", line 114, in connect
    return dialect.connect(*cargs, **cparams)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 509, in connect
    return self.dbapi.connect(*cargs, **cparams)
  File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__
    self.connect()
  File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 664, in connect
    raise exc
pymysql.err.OperationalError: (2003, "Can't connect to MySQL server on 'db' ([Errno 111] Connection refused)")

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "/usr/src/app/main.py", line 23, in <module>
    Base.metadata.create_all(engine)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/sql/schema.py", line 4553, in create_all
    bind._run_visitor(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2094, in _run_visitor
    with self._optional_conn_ctx_manager(connection) as conn:
  File "/usr/local/lib/python3.9/contextlib.py", line 117, in __enter__
    return next(self.gen)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2086, in _optional_conn_ctx_manager
    with self._contextual_connect() as conn:
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2302, in _contextual_connect
    self._wrap_pool_connect(self.pool.connect, None),
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2339, in _wrap_pool_connect
    Connection._handle_dbapi_exception_noconnection(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 1583, in _handle_dbapi_exception_noconnection
    util.raise_(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/base.py", line 2336, in _wrap_pool_connect
    return fn()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 364, in connect
    return _ConnectionFairy._checkout(self)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 778, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 495, in checkout
    rec = pool._do_get()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 140, in _do_get
    self._dec_overflow()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 68, in __exit__
    compat.raise_(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/impl.py", line 137, in _do_get
    return self._create_connection()
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 309, in _create_connection
    return _ConnectionRecord(self)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 440, in __init__
    self.__connect(first_connect_check=True)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 661, in __connect
    pool.logger.debug("Error on connect(): %s", e)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/langhelpers.py", line 68, in __exit__
    compat.raise_(
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/util/compat.py", line 182, in raise_
    raise exception
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/pool/base.py", line 656, in __connect
    connection = pool._invoke_creator(self)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/strategies.py", line 114, in connect
    return dialect.connect(*cargs, **cparams)
  File "/usr/local/lib/python3.9/site-packages/sqlalchemy/engine/default.py", line 509, in connect
    return self.dbapi.connect(*cargs, **cparams)
  File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 353, in __init__
    self.connect()
  File "/usr/local/lib/python3.9/site-packages/pymysql/connections.py", line 664, in connect
    raise exc
sqlalchemy.exc.OperationalError: (pymysql.err.OperationalError) (2003, "Can't connect to MySQL server on 'db' ([Errno 111] Connection refused)")
(Background on this error at: http://sqlalche.me/e/13/e3q8)

CONTAINER ID   IMAGE          COMMAND                  CREATED         STATUS                     PORTS                               NAMES
84ac8cd290fa   python:3       "python main.py"         6 minutes ago   Exited (1) 6 minutes ago                                       docker_python-test_1
30c6438df401   mysql:latest   "docker-entrypoint.s…"   6 minutes ago   Up 6 minutes               33060/tcp, 0.0.0.0:3307->3306/tcp   docker_db_1

Answer 1

Forward port 3307 and connect to 3306