Jenkins Pipeline 官方文档 https://jenkins.io/doc/book/pipeline/
1. 创建一个Pipeline项目 Getting Started with Pipeline
1.1 前提 prerequisites：Jenkins 2.x以上+Pipeline plugin（已包含在推荐的插件中）
1.2 创建Pipline项目步骤 Defining a Pipeline in the Web UI
2. pipeline script 语法
2.1 pipeline script与 Groovy语言有点关系. 可以简单看一下语法 Groovy syntax.
2.2 Pipeline Syntax可以生成代码
2.3 Using a Jenkinsfile包含一些例子，node ／stage／sh／Deploy 的currentBuild.result == null || currentBuild.result == 'SUCCESS'等
3. 执行pipeline script
Jenkins job执行pipeline script，有两种方式：
- By entering a script directly in the Jenkins web UI，直接在Script输入框（web UI）里面输入pipeline script，语法参考Pipeline Syntax。
- pipeline script from SCM，脚本文件要存放在Git/SVN工程地址下。脚本名字默认叫
Jenkinsfile，在Git/SVN工程根目录下。Script Path可配置。测试使用：github UnityJenkins工程地址
Relative location (/-separated regardless of platform) within the checkout of your Pipeline script. Note that it will always be run inside a Groovy sandbox. Jenkinsfile is conventional and allows you to switch easily to a multibranch project (just use checkout scm to retrieve sources from the same location as is configured here).
报错处理
pipeline script from SCM方式下：
Started by user ***
java.io.FileNotFoundException
at jenkins.plugins.git.GitSCMFile$3.invoke(GitSCMFile.java:167)
at jenkins.plugins.git.GitSCMFile$3.invoke(GitSCMFile.java:159)
at jenkins.plugins.git.GitSCMFileSystem$3.invoke(GitSCMFileSystem.java:193)
...
Finished: FAILURE
原因是git工程下，没有找到Script Path路径下的脚本文件。
