在docker中发布查询之前检查MySQL数据库是否已经启动的例子

我们知道启动数据库有时需要时间，所以如果你想在发出任何查询之前知道它是否已经启动，你可以使用下面的例子。

docker-compose.yml

version: '3'

services:

    mysql:
        build:
            context: ./docker/mysql
        ...
        volumes:
            - ./docker/mysql/init.sh:/docker-entrypoint-initdb.d/init.sh

Docker文件

FROM mysql:5.7.22

COPY init.sh /docker-entrypoint-initdb.d/init.sh

init.sh

#!/bin/bash

echo "Checking if the database is up ..."
while ! mysqladmin ping -h"localhost" --silent; do
    echo "Waiting for the database to come up ..."
    sleep 2
done
echo "Database is up ..."

# Run an example query
mysql -u root -proot -e "USE mysql;"

测试

$ docker-compose up -d
...
mysql_1  | Checking if the database is up ...
mysql_1  | Waiting for the database to come up ...
mysql_1  | Waiting for the database to come up ...
mysql_1  | Database is up ...
...