判断Git是否有新的提交

 公司要搭建CI，有这样一个需求：判断Git是否有新的提交，如果有的话拉取代码构建，如果没有不构建，Jenkins的搭建这里就不赘述了，主要讲一下判断这里。

Jenkins需要安装插件Conditional BuildStep，地址https://wiki.jenkins-ci.org/display/JENKINS/Conditional+BuildStep+Plugin

配置如下：

执行脚本：

#!/bin/bash
if [ ! $GIT_PREVIOUS_SUCCESSFUL_COMMIT ];then
    echo "GIT_PREVIOUS_SUCCESSFUL_COMMIT is not exists."
    exit 0
else
    echo "GIT_COMMIT=[$GIT_COMMIT],GIT_PREVIOUS_SUCCESSFUL_COMMIT=[$GIT_PREVIOUS_SUCCESSFUL_COMMIT]"
    if [ $GIT_PREVIOUS_SUCCESSFUL_COMMIT == $GIT_COMMIT ];then
        echo "GIT_COMMIT is equals to GIT_PREVIOUS_SUCCESSFUL_COMMIT,skip build."
        exit -1
    else
        echo "GIT_COMMIT is not equals to GIT_PREVIOUS_SUCCESSFUL_COMMIT"
        sh build_using_xctool.sh//这里是有代码更新的条件下需要执行的代码，我这里是跑一个脚本
        exit 0
    fi
fi

判断的条件是本地的Git_Commit跟远端进行对比，不一致就代表有新的代码提交，执行操作，否则exit