Docker：docker-compose设置启动顺序
前言
项目的技术栈vue+nodejs+redis+rabbitmq，由于vue服务依赖于redis+rabbitmq组件，所以需要先启动redis+rabbitmq组件，之后在运行vue服务。
属性设置
version: "3"
services:
## redis
redis:
image: redis:latest
ports:
- "6379:6379"
container_name: im-redis-compose
restart: always
command: redis-server --appendonly yes
## rabbitmq
rabbitmq:
image: rabbitmq:management
ports:
- "5672:5672"
- "15672:15672"
container_name: im-rabbitmq-compose
environment:
RABBITMQ_DEFAULT_USER: guest
RABBITMQ_DEFAULT_PASS: guest
RABBITMQ_DEFAULT_VHOST: my_vhost
## vue服务
backend:
build: .
links:
- redis
- rabbitmq
container_name: im-server-compose
restart: on-failure
## 设置启动顺序
depends_on:
- rabbitmq
- redis
ports:
- "3000:3000"问题
运行 docker-compose up 命令的时候却报错，发现是vue服务的nodejs报的错，启动的时候报错connect refused，连接rabbitmq的时候出错；明明设置depends_on属性启动顺序，结果没有生效。
原因
depends_on 在启动 vue 服务容器前，并不会等待 rabbitmq 和 redis 这两个容器进入ready状态，而只是等到它们被启动状态(被启动，但不关心是否启动完成)；所以导致 rabbitmq 和 redis 这个两个容器虽然先启动，但是在 vue 服务容器之后才启动完成。
具体内容可以自己去看https://docs.docker.com/compose/startup-order/
解决方法
在容器启动命令执行前，跑一个shell脚本，这个脚本会去访问依赖服务的页面或者ping api来判断底层的服务有没有ready，随后再去启动真正的服务。
GitHub有现成的方案：wait-for
1. 修改vue服务的DockerFile文件(需要联网)
添加 RUN apt-get -q update && apt-get -qy install netcat 命令
#基础镜像
FROM nginx:stable
##定义工作目录
ENV WORK_PATH /etc/nginx
#
##定义conf文件名
ENV CONF_FILE_NAME nginx.conf
#
##更新apt-get 下载netcat服务
RUN apt-get -q update && apt-get -qy install netcat
#
##删除原有配置文件
RUN rm $WORK_PATH/$CONF_FILE_NAME
#
##复制新的配置文件
COPY ./$CONF_FILE_NAME $WORK_PATH/
#
##给shell文件赋读权限
RUN chmod a+r $WORK_PATH/$CONF_FILE_NAME2. 将wait-for.sh复制到当前文件夹
wait-for.sh
查看代码
#!/bin/sh
# The MIT License (MIT)
#
# Copyright (c) 2017 Eficode Oy
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.
VERSION="2.2.4"
set -- "$@" -- "$TIMEOUT" "$QUIET" "$PROTOCOL" "$HOST" "$PORT" "$result"
TIMEOUT=15
QUIET=0
# The protocol to make the request with, either "tcp" or "http"
PROTOCOL="tcp"
echoerr() {
if [ "$QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi
}
usage() {
exitcode="$1"
cat << USAGE >&2
Usage:
$0 host:port|url [-t timeout] [-- command args]
-q | --quiet Do not output any status messages
-t TIMEOUT | --timeout=timeout Timeout in seconds, zero for no timeout
Defaults to 15 seconds
-v | --version Show the version of this tool
-- COMMAND ARGS Execute command with args after the test finishes
USAGE
exit "$exitcode"
}
wait_for() {
case "$PROTOCOL" in
tcp)
if ! command -v nc >/dev/null; then
echoerr 'nc command is missing!'
exit 1
fi
;;
http)
if ! command -v wget >/dev/null; then
echoerr 'wget command is missing!'
exit 1
fi
;;
esac
TIMEOUT_END=$(($(date +%s) + TIMEOUT))
while :; do
case "$PROTOCOL" in
tcp)
nc -w 1 -z "$HOST" "$PORT" > /dev/null 2>&1
;;
http)
wget --timeout=1 --tries=1 -q "$HOST" -O /dev/null > /dev/null 2>&1
;;
*)
echoerr "Unknown protocol '$PROTOCOL'"
exit 1
;;
esac
result=$?
if [ $result -eq 0 ] ; then
if [ $# -gt 7 ] ; then
for result in $(seq $(($# - 7))); do
result=$1
shift
set -- "$@" "$result"
done
TIMEOUT=$2 QUIET=$3 PROTOCOL=$4 HOST=$5 PORT=$6 result=$7
shift 7
exec "$@"
fi
exit 0
fi
if [ $TIMEOUT -ne 0 -a $(date +%s) -ge $TIMEOUT_END ]; then
echo "Operation timed out" >&2
exit 1
fi
sleep 1
done
}
while :; do
case "$1" in
http://*|https://*)
HOST="$1"
PROTOCOL="http"
shift 1
;;
*:* )
HOST=$(printf "%s\n" "$1"| cut -d : -f 1)
PORT=$(printf "%s\n" "$1"| cut -d : -f 2)
shift 1
;;
-v | --version)
echo $VERSION
exit
;;
-q | --quiet)
QUIET=1
shift 1
;;
-q-*)
QUIET=0
echoerr "Unknown option: $1"
usage 1
;;
-q*)
QUIET=1
result=$1
shift 1
set -- -"${result#-q}" "$@"
;;
-t | --timeout)
TIMEOUT="$2"
shift 2
;;
-t*)
TIMEOUT="${1#-t}"
shift 1
;;
--timeout=*)
TIMEOUT="${1#*=}"
shift 1
;;
--)
shift
break
;;
--help)
usage 0
;;
-*)
QUIET=0
echoerr "Unknown option: $1"
usage 1
;;
*)
QUIET=0
echoerr "Unknown argument: $1"
usage 1
;;
esac
done
if ! [ "$TIMEOUT" -ge 0 ] 2>/dev/null; then
echoerr "Error: invalid timeout '$TIMEOUT'"
usage 3
fi
case "$PROTOCOL" in
tcp)
if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then
echoerr "Error: you need to provide a host and port to test."
usage 2
fi
;;
http)
if [ "$HOST" = "" ]; then
echoerr "Error: you need to provide a host to test."
usage 2
fi
;;
esac
wait_for "$@"
Footer3. 修改docker-compose.yml文件
version: "3"
services:
redis:
image: redis:latest
ports:
- "6379:6379"
container_name: im-redis-compose
restart: always
command: redis-server --appendonly yes
rabbitmq:
image: rabbitmq:management
ports:
- "5672:5672"
- "15672:15672"
container_name: im-rabbitmq-compose
environment:
RABBITMQ_DEFAULT_USER: guest
RABBITMQ_DEFAULT_PASS: guest
RABBITMQ_DEFAULT_VHOST: my_vhost
backend:
build: .
links:
- redis
- rabbitmq
container_name: im-server-compose
restart: on-failure
depends_on:
- rabbitmq
- redis
ports:
- "3000:3000"
## 添加运行脚本的命令
command: sh -c './wait-for.sh rabbitmq:15672 -- npm run start'
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作者：怒吼的萝卜
链接：http://www.cnblogs.com/nhdlb/
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