浅谈Docker-compose中的depends_on顺序的问题解决

FROM openjdk:8-jre	// 基于 openjdk COPY wait-for .		// 将 wait-for 拷贝到虚拟机中RUN apt-get update	// 更新源，RUN apt-get install netcat -y // 安装 netcat， wait-for 需要使用到WORKDIR /app				// 设置落脚点ADD course.jar course.jar	// 将 jar 文件 添加到 虚拟机中EXPOSE 8002					// 需要暴露的端口

version: '3.0'services:  nacos:    image: nacos/nacos-server:1.1.4    container_name: nacos    ports:      - "8848:8848"    environment:      MODE: standalone   # nacos 单节点运行  course:    build: /root/    container_name: course    ports:      - "18002:18002"    depends_on:      - nacos    command: ["sh","wait-for","nacos:8848","--","java","-jar","course.jar"]

#!/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.set -- "$@" -- "$TIMEOUT" "$QUIET" "$PROTOCOL" "$HOST" "$PORT" "$result"TIMEOUT=60QUIET=0# The protocol to make the request with, either "tcp" or "http"PROTOCOL="tcp"echoerr() {  if [ "$QUIET" -ne 1 ]; then printf "%s/n" "$*" 1>&2; fi}usage() {  exitcode="$1"  cat << USAGE >&2Usage:  $0 host:port|url [-t timeout] [-- command args]  -q | --quiet                        Do not output any status messages  -t TIMEOUT | --timeout=timeout      Timeout in seconds, zero for no timeout  -- COMMAND ARGS                     Execute command with args after the test finishesUSAGE  exit "$exitcode"}wait_for() {  case "$PROTOCOL" in    tcp)      if ! command -v nc >/dev/null; then        echoerr 'nc command is missing!'        exit 1      fi      ;;    wget)      if ! command -v wget >/dev/null; then        echoerr 'wget command is missing!'        exit 1      fi      ;;  esac  while :; do    case "$PROTOCOL" in      tcp)         nc -w 1 -z "$HOST" "$PORT" > /dev/null 2>&1        ;;      http)        wget --timeout=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 [ "$TIMEOUT" -le 0 ]; then      break    fi    TIMEOUT=$((TIMEOUT - 1))    sleep 1  done  echo "Operation timed out" >&2  exit 1}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    ;;    -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: $1"    usage 1    ;;  esacdoneif ! [ "$TIMEOUT" -ge 0 ] 2>/dev/null; then  echoerr "Error: invalid timeout '$TIMEOUT'"  usage 3ficase "$PROTOCOL" in  tcp)    if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then      echoerr "Error: you need to provide a host and port to test."      usage 2    fi  ;;  http)    if [ "$HOST" = "" ]; then      echoerr "Error: you need to provide a host to test."      usage 2    fi  ;;esacwait_for "$@"