如何在Bash函数中使用局部变量

库尔特·皮克

我正在尝试编写一个Bash脚本，该脚本将停止Docker容器的存储库，重新构建它们，并对它们运行一些测试（使用Pytest）。为了使代码干燥，我尝试定义一个函数wait_for_container，如下所示：

docker stop $(docker ps -a -q)

docker-compose build

docker-compose up -d

function wait_for_container {
    local CONTAINER=$1
    local PORT=$2

    ADDR=$(docker inspect --format '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $CONTAINER)

    until nc -z $CONTAINER $PORT
    do
        echo "Waiting for the $CONTAINER container..."
        sleep 0.5
    done
    echo "$CONTAINER listening at $ADDR:$PORT"
}

RETHINKDB_CONTAINER=ipercroncompose_rethinkdb_1
RETHINKDB_PORT=28015
wait_for_container $RETHINKDB_CONTAINER $RETHINKDB_PORT

RABBITMQ_CONTAINER=ipercroncompose_rabbitmq_1
RABBITMQ_PORT=5672
wait_for_container $RABBITMQ_CONTAINER $RABBITMQ_PORT

cd test
pytest

但是，我发现这行不通：我反复得到

nc: getaddrinfo: Temporary failure in name resolution
Waiting for the ipercroncompose_rethinkdb_1 container...

另一方面，以下非DRY脚本可以正常工作：

docker stop $(docker ps -a -q)

docker-compose build

docker-compose up -d

RETHINKDB_CONTAINER=ipercroncompose_rethinkdb_1
RETHINKDB_ADDR=$(docker inspect --format '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $RETHINKDB_CONTAINER)
RETHINKDB_PORT=28015

until nc -z $RETHINKDB_ADDR $RETHINKDB_PORT
do
    echo "Waiting for the RethinkDB container..."
    sleep 0.5
done
echo "RethinkDB listening at ${RETHINKDB_ADDR}:${RETHINKDB_PORT}."

RABBITMQ_CONTAINER=ipercroncompose_rabbitmq_1
RABBITMQ_ADDR=$(docker inspect --format '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $RABBITMQ_CONTAINER)
RABBITMQ_PORT=5672

until nc -z $RABBITMQ_ADDR $RABBITMQ_PORT
do
    echo "Waiting for the RabbitMQ container..."
    sleep 0.5
done
echo "RabbitMQ listening at ${RABBITMQ_ADDR}:${RABBITMQ_PORT}."

cd test
pytest

和回声

RethinkDB listening at 172.18.0.2:28015.
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
Waiting for the RabbitMQ container...
RabbitMQ listening at 172.19.0.2:5672.

其次是Pytests的结果。如何改善wait_for_container功能以达到相同的效果？

库尔特·皮克

在Grisha Levit和Fred的评论之后，以下是改编的脚本：

docker stop $(docker ps -a -q)
docker-compose build
docker-compose up -d

function wait_for_container {
    local CONTAINER=$1
    local PORT=$2

    local ADDR=$(docker inspect --format '{{range .NetworkSettings.Networks}}{{.IPAddress}}{{end}}' $CONTAINER)
    echo $ADDR

    until nc -z $ADDR $PORT
    do
        echo "Waiting for the $CONTAINER container..."
        sleep 0.5
    done
    echo "$CONTAINER listening at $ADDR:$PORT"
}

wait_for_container ipercroncompose_rethinkdb_1 28015
wait_for_container ipercroncompose_rabbitmq_1 5672

cd test
pytest

问题的确确实是netcat需要IP地址作为其第一个输入，而不是Docker容器名称。（我也将ADDR变量设置为局部变量）。

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