[GitHub Guide](https://github.com/jenkinsci/github-branch-source-plugin/blob/master/docs/github-app.adoc)
一.使用Github App Jenkins Plugin訪問Github
1.設定Github

`Settings/Developer Settings/GitHub Apps` => New GitHub App

只有這兩個值必填
Github App name, Homepage URL

產生private key => Generate a private key

將private key格式從pkcs1轉換成pkcs8
[下載openssl](https://www.openssl.org/source/)，使用命令提示字元進行轉換

產生完成GithubApp後選擇左邊InstallApp，

安裝完成後，Applications選擇repositories access權限

2.建立Jenkins Credentials
`管理Jenkins/Credentials/System/Global credentials`

將Github App產生的資料帶入，
填入openssl轉換後的pkcs8格式的private key

[參考](https://blog.csdn.net/a7442358/article/details/127888512)

3.使用建立好的Credentials進行git同步

`git branch: 'main', credentialsId: 'GaiaGitHub', url:'https://github.com/CannonUFO/Gaia.git'`

script區塊用來執行Groovy語法
checkout = Jenkins Git Plugin提供語法，執行Git相關操作

stage('Source') {
    steps{
        script {
            checkout([$class: 'GitSCM', 
            branches: [[name: 'main']], 
            userRemoteConfigs: [[url:'https://github.com/CannonUFO/Gaia.git', credentialsId: 'GaiaGitHub']], 
            extensions: [[$class: 'CloneOption', shallow: true], [$class: 'RelativeTargetDirectory',relativeTargetDir: 'Dev']], poll: true])
        }
    }
}

[groovy語法](https://wiki.eryajf.net/pages/3298.html#_6-when)
[Jenkinsfile同使存取多個Git庫](https://www.cnblogs.com/fengyinxu/p/jenkins-parallel-checkout-multiple-git-repositories.html)
[Jenkins程式碼打包](https://juejin.cn/post/7228855520566919227)

3.Webhook
[GitHub Webhook](https://plugins.jenkins.io/github/)
[GitHub Webhook](https://hevodata.com/learn/jenkins-github-webhook/)
todo:目前使用外部私人GitHub連線被擋，等換公司GitHub再試

二.[GitHub Authentication](https://plugins.jenkins.io/github-oauth/) 使用Github訪問Jenkins

設定Github
Settings/Developer Settings/OAuth Apps => new OAuth App
只有Client ID、ClientSecrets有用

Jenkins設定
管理Jenkins/Security/Authentication/安全性領域