Python Docker Client无法正确执行MySQL命令，求助排查解决

Let's break down why your initialization script isn't running and fix it step by step:

1. Shell Redirection Isn't Being Processed (The Most Likely Culprit) #

When you use exec_run() without specifying shell=True, Docker executes the command directly without passing it through a shell. That means the < redirection symbol isn't interpreted—it's just treated as a regular argument to the mysql command, which is why your script isn't being loaded.

Fixes: #

Option 1: Enable shell execution to let the shell handle the redirection:

er = container.exec_run(
    'mysql -h localhost < /data/init.sql',
    shell=True  # This is the key addition
)

Option 2: Avoid shell redirection entirely by using MySQL's built-in source command:

er = container.exec_run(
    ['mysql', '-h', 'localhost', '-e', 'source /data/init.sql']
)

2. MySQL Might Not Be Ready When You Run the Script #

Docker containers start quickly, but MySQL needs a few seconds to initialize its data directory and start accepting connections. If you run exec_run() immediately after starting the container, the database might not be up yet.

Fix: Add a wait loop to check if MySQL is ready #

import time

def wait_for_mysql(container):
    while True:
        # Use mysqladmin to check if the server is responsive
        result = container.exec_run('mysqladmin ping -h localhost --silent')
        if result.exit_code == 0:
            print("MySQL is ready!")
            break
        print("Waiting for MySQL to start...")
        time.sleep(1)

# Wait for MySQL to be ready before running the script
wait_for_mysql(container)
er = container.exec_run('mysql -h localhost < /data/init.sql', shell=True)

3. Better Alternative: Use MySQL Docker Image's Built-in Initialization #

The official MySQL Docker image has a built-in feature that automatically runs scripts placed in /docker-entrypoint-initdb.d/ when the container starts for the first time. This is more reliable because the image handles waiting for MySQL to be ready before executing the scripts.

How to implement this: #

Modify your volumes configuration to mount your init.sql directly into this directory:

volumes={
    f"{path_to_current_dir}/init.sql": {
        'bind': '/docker-entrypoint-initdb.d/init.sql',
        'mode': 'ro'
    },
}

With this setup, you can remove the exec_run() call entirely—MySQL will run your script automatically during initialization.

内容的提问来源于stack exchange，提问作者Most Wanted