什么是Jenkins

Jenkins是开源CI&CD软件领导者，提供超过1000个插件来支持构建、部署、自动化，满足任何项目的需要。

为什么需要Jenkins(DevOps)

我们日常开发一般流程: Commit -> Push -> Merge -> Build. 基本就算完成. 而Jenkins的存在就是代替这一些系列从而实现自动化,侧重在于后面几个阶段,我们可以做很多的事情. 自动化的过程是确保构建编译都是正确的,平时我们手动编译不同版本的时候难免可能会出错,有了它可以降低编译错误,提高构建速度. 然而一般我们Jenkins都是需要配合Docker来完成的,所以需要具备一定的Docker的基础与了解. 文末有Github地址,共享了DockerFile及JenkinsFile. Why Pipeline?

有Jenkins在Android能实现什么:

当push一个commit到服务器,将构建结果提交到MR/PR上(MR/PR存在)
当push一个commit到服务器,执行构建-->多渠道-->签名-->发布到各大市场-->通知相关人员
当push一个commit到服务器,在指定的branch做一些freestyle
当push一个commit到服务器,创建一个TAG
....

详细如图(Gitlab CI/CD):

在MergeRequest/PullRequest中应用如下:

一个DevOps基本序列

一个DevOps的工作序列基本主要区分与Jenkins Server两种工作模式,这两种工作模式分为:

Webhook的方式(在Gitlab/Github配置event触发后的地址,即当Gitlab/Gtihub产生事件会通过HTTP/HTTPS的方式将一个事件详细发送给Jenkins Service,随后Jenkins Service收到该消息会解析并做定义的处理);
轮训方式;(即无需侵入Gitlab/Github,由Jenkins定期轮训对应仓库的代码,如果发生改变则立即出发构建.)

下面主要介绍一下以Webhook工作方式的时序图如下:

sequenceDiagram
User ->> Gitlab/Github: push a commit
Gitlab/Github-->>Jekins: push a message via webhook
Jenkins -->> Jenkins: Sync with branchs and do a build with freestyle if there are changes
Jenkins --x Gitlab/Github: Feedback some comments on MR or IM/EMAIL

这将产生一个流程图。:

graph LR
A(User) --Push a commit --> B(Gitlab/Github)
B --Push a message via webhook --> C(Jenkins)

构建一个的Android应用多分支步骤

配置一个Jenkins Server;(由于文章主要讲解Jenkins脚本高级应用,所以还请网上搜索相关环境搭建)
在Jenkins 里面创建一个应用如下图:
配置好对应的远程仓库地址后,我们需要指定Jenkins脚本路径如下:
由于Jenkins配置的路径是在项目路径下,所以我们Android Studio也得配置在对应跟布局下:
最后以Gitlab为例子配置Webhook如下:

所有的配置完毕后,接下来就是详解Jenkins脚本.

Jenkins脚本详解(直接声明的方式):

pipeline {
    agent any 
    stages {
        stage('Build') { 
            steps {
                // Do the build with gradle../gradlew build
            }
        }
        stage('Test') { 
            steps {
                // Do some test script
            }
        }
        stage('Deploy') { 
            steps {
                // Deploy your project to other place
            }
        }
    }
}

高级特性详解:

想要提交comment在MR/PR上: 一般是通过调用Gitlab/Github开放的API来实现,以Gitlab为例:

/**
 * Add the comment to gitlab on MR if the MR is exist and state is OPEN
 */
def addCommentToGitLabMR(String commentContent) {
    branchHasMRID = sh(script: "curl --header \"PRIVATE-TOKEN: ${env.gitUserToken}\" ${GITLAB_SERVER_URL}/api/v4/projects/${XXPROJECT_ID}/merge_requests?source_branch=${env.BRANCH_NAME} | grep -o 'iid\":[^,]*' | head -n 1 | cut -b 6-", returnStdout: true).trim()
    echo 'Current Branch has MR id : ' + branchHasMRID
    if (branchHasMRID == '') {
        echo "The id of MR doesn't exist on the gitlab. skip the comment on MR"
    } else {
        // TODO : Should be handled on first time.
        TheMRState = sh(script: "curl --header \"PRIVATE-TOKEN: ${env.gitUserToken}\" ${GITLAB_SERVER_URL}/api/v4/projects/${XXPROJECT_ID}/merge_requests?source_branch=${env.BRANCH_NAME} | grep -o 'state\":[^,]*' | head -n 1 | cut -b 9-14", returnStdout: true).trim()
        echo 'Current MR state is : ' + TheMRState
        if (TheMRState == 'opened') {
            sh "curl -d \"id=${XXPROJECT_ID}&merge_request_iid=${branchHasMRID}&body=${commentContent}\" --header \"PRIVATE-TOKEN: ${env.gitUserToken}\" ${GITLAB_SERVER_URL}/api/v4//projects/${XXPROJECT_ID}/merge_requests/${branchHasMRID}/notes"
        } else {
            echo 'The MR not is opened, skip the comment on MR'
        }
    }
}

自动创建一个TAG且有CHANGELOG: 因为我们通过git tag创建的TAG一般是没有描述的,有时候比较难跟踪,所以我们可以调用Gitlab/Github API来创建一个TAG,效果如下:

def pushTag(String gitTagName, String gitTagContent) {
    sh "curl -d \"id=${XXPROJECT_ID}&tag_name=${gitTagName}&ref=development&release_description=${gitTagContent}\" --header \"PRIVATE-TOKEN: ${env.gitUserToken}\" ${GITLAB_SERVER_URL}/api/v4/projects/${XXPROJECT_ID}/repository/tags"
}

将Gradle 缓存共享给Docker,这样每次构建的时候就不会在Docker里面每次去下载依赖包:

environment {
    GRADLE_CACHE = '/tmp/gradle-user-cache'
}
...
agent {
    dockerfile {
        filename 'Dockerfile'
        // https://github.com/gradle/gradle/issues/851
        args '-v $GRADLE_CACHE/.gradle:$HOME/.gradle --net=host'
    }
}

完整的JenkinsFile;

#!/usr/bin/env groovy

//This JenkinsFile is based on a declarative format
//https://jenkins.io/doc/book/pipeline/#declarative-versus-scripted-pipeline-syntax
def CSD_DEPLOY_BRANCH = 'development'
// Do not add the `def` for these fields
XXPROJECT_ID = 974
GITLAB_SERVER_URL = 'http://gitlab.com'// Or your server

pipeline {
    // 默认代理用主机,意味着用Jenkins主机来运行一下块
    agent any
    options {
        // 配置当前branch不支持同时构建,为了避免资源竞争,当一个新的commit到来,会进入排队如果之前的构建还在进行
        disableConcurrentBuilds()
        // 链接到Gitlab的服务器,用于访问Gitlab一些API
        gitLabConnection('Jenkins_CI_CD')
    }
    environment {
        // 配置缓存路径在主机
        GRADLE_CACHE = '/tmp/gradle-user-cache'
    }
    stages {
        // 初始化阶段
        stage('Setup') {
            steps {
                // 将初始化阶段修改到这次commit即Gitlab会展示对应的UI
                gitlabCommitStatus(name: 'Setup') {
                    // 通过SLACK工具推送一个通知
                    notifySlack('STARTED')
                    echo "Setup Stage Starting. Depending on the Docker cache this may take a few " +
                            "seconds to a couple of minutes."
                    echo "${env.BRANCH_NAME} is the branch.  Subsequent steps may not run on branches that are not ${CSD_DEPLOY_BRANCH}."
                    script {
                        cacheFileExist = sh(script: "[ -d ${GRADLE_CACHE} ]  && echo 'true' || echo 'false' ", returnStdout: true).trim()
                        echo 'Current cacheFile is exist : ' + cacheFileExist
                        // Make dir if not exist
                        if (cacheFileExist == 'false') sh "mkdir ${GRADLE_CACHE}/ || true"
                    }
                }
            }
        }

        // 构建阶段
        stage('Build') {
            agent {
                dockerfile {
                    // 构建的时候指定一个DockerFile,该DockerFile有Android的构建环境
                    filename 'Dockerfile'
                    // https://github.com/gradle/gradle/issues/851
                    args '-v $GRADLE_CACHE/.gradle:$HOME/.gradle --net=host'
                }
            }

            steps {
                gitlabCommitStatus(name: 'Build') {

                    script {
                        echo "Build Stage Starting"
                        echo "Building all types (debug, release, etc.) with lint checking"
                        getGitAuthor()

                        if (env.BRANCH_NAME == CSD_DEPLOY_BRANCH) {

                            // TODO : Do some checks on your style

                            // https://docs.gradle.org/current/userguide/gradle_daemon.html
                            sh 'chmod +x gradlew'
                            // Try with the all build types.
                            sh "./gradlew build"
                        } else {
                            // https://docs.gradle.org/current/userguide/gradle_daemon.html
                            sh 'chmod +x gradlew'
                            // Try with the production build type.
                            sh "./gradlew compileReleaseJavaWithJavac"
                        }
                    }
                }

                /* Comment out the inner cache rsync logic
                gitlabCommitStatus(name: 'Sync Gradle Cache') {
                    script {
                        if (env.BRANCH_NAME != CSD_DEPLOY_BRANCH) {
                            // TODO : The max cache file should be added.
                            echo 'Write updates to the Gradle cache back to the host'
                            // Write updates to the Gradle cache back to the host

                            // -W, --whole-file:
                            // With this option rsync's delta-transfer algorithm is not used and the whole file is sent as-is instead.
                            // The transfer may be faster if this option is used when the bandwidth between the source and
                            // destination machines is higher than the bandwidth to disk (especially when the lqdiskrq is actually a networked filesystem).
                            // This is the default when both the source and destination are specified as local paths.
                            sh "rsync -auW ${HOME}/.gradle/caches ${HOME}/.gradle/wrapper ${GRADLE_CACHE}/ || true"
                        } else {
                            echo 'Not on the Deploy branch , Skip write updates to the Gradle cache back to the host'
                        }
                    }
                }*/

                script {
                    // Only the development branch can be triggered
                    if (env.BRANCH_NAME == CSD_DEPLOY_BRANCH) {
                        gitlabCommitStatus(name: 'Signature') {
                            // signing the apks with the platform key
                            signAndroidApks(
                                    keyStoreId: "platform",
                                    keyAlias: "platform",
                                    apksToSign: "**/*.apk",
                                    archiveSignedApks: false,
                                    skipZipalign: true
                            )
                        }

                        gitlabCommitStatus(name: 'Deploy') {
                            script {
                                echo "Debug finding apks"
                                // debug statement to show the signed apk's
                                sh 'find . -name "*.apk"'

                                // TODO : Deploy your apk to other place

                                //Specific deployment to Production environment
                                //echo "Deploying to Production environment"
                                //sh './gradlew app:publish -DbuildType=proCN'
                            }
                        }
                    } else {
                        echo 'Current branch of the build not on the development branch, Skip the next steps!'
                    }
                }
            }
            // This post working on the docker. not on the jenkins of local
            post {
                // The workspace should be cleaned if the build is failure.
                failure {
                    // notFailBuild : if clean failed that not tell Jenkins failed.
                    cleanWs notFailBuild: true
                }
                // The APKs should be deleted when the server is successfully built.
                success {
                    script {
                        // Only the development branch can be deleted these APKs.
                        if (env.BRANCH_NAME == CSD_DEPLOY_BRANCH) {
                            cleanWs notFailBuild: true, patterns: [[pattern: '**/*.apk', type: 'INCLUDE']]
                        }
                    }
                }
            }
        }
    }

    post {
        always { deleteDir() }
        failure {
            addCommentToGitLabMR("\\:negative_squared_cross_mark\\: Jenkins Build \\`FAILURE\\` <br /><br /> Results available at:[[#${env.BUILD_NUMBER} ${env.JOB_NAME}](${env.BUILD_URL})]")
            notifySlack('FAILED')
        }
        success {
            addCommentToGitLabMR("\\:white_check_mark\\: Jenkins Build \\`SUCCESS\\` <br /><br /> Results available at:[[#${env.BUILD_NUMBER} ${env.JOB_NAME}](${env.BUILD_URL})]")
            notifySlack('SUCCESS')
        }
        unstable { notifySlack('UNSTABLE') }
        changed { notifySlack('CHANGED') }
    }
}

def addCommentToGitLabMR(String commentContent) {
    branchHasMRID = sh(script: "curl --header \"PRIVATE-TOKEN: ${env.gitTagPush}\" ${GITLAB_SERVER_URL}/api/v4/projects/${XXPROJECT_ID}/merge_requests?source_branch=${env.BRANCH_NAME} | grep -o 'iid\":[^,]*' | head -n 1 | cut -b 6-", returnStdout: true).trim()
    echo 'Current Branch has MR id : ' + branchHasMRID
    if (branchHasMRID == '') {
        echo "The id of MR doesn't exist on the gitlab. skip the comment on MR"
    } else {
        // TODO : Should be handled on first time.
        TheMRState = sh(script: "curl --header \"PRIVATE-TOKEN: ${env.gitTagPush}\" ${GITLAB_SERVER_URL}/api/v4/projects/${XXPROJECT_ID}/merge_requests?source_branch=${env.BRANCH_NAME} | grep -o 'state\":[^,]*' | head -n 1 | cut -b 9-14", returnStdout: true).trim()
        echo 'Current MR state is : ' + TheMRState
        if (TheMRState == 'opened') {
            sh "curl -d \"id=${XXPROJECT_ID}&merge_request_iid=${branchHasMRID}&body=${commentContent}\" --header \"PRIVATE-TOKEN: ${env.gitTagPush}\" ${GITLAB_SERVER_URL}/api/v4//projects/${XXPROJECT_ID}/merge_requests/${branchHasMRID}/notes"
        } else {
            echo 'The MR not is opened, skip the comment on MR'
        }
    }
}

def pushTag(String gitTagName, String gitTagContent) {
    sh "curl -d \"id=${XXPROJECT_ID}&tag_name=${gitTagName}&ref=development&release_description=${gitTagContent}\" --header \"PRIVATE-TOKEN: ${env.gitTagPush}\" ${GITLAB_SERVER_URL}/api/v4/projects/${XXPROJECT_ID}/repository/tags"
}

//Helper methods
//TODO Probably can extract this into a JenkinsFile shared library
def getGitAuthor() {
    def commitSHA = sh(returnStdout: true, script: 'git rev-parse HEAD')
    author = sh(returnStdout: true, script: "git --no-pager show -s --format='%an' ${commitSHA}").trim()
    echo "Commit author: " + author
}

def notifySlack(String buildStatus = 'STARTED') {
    // Build status of null means success.
    buildStatus = buildStatus ?: 'SUCCESS'

    def color
    if (buildStatus == 'STARTED') {
        color = '#D4DADF'
    } else if (buildStatus == 'SUCCESS') {
        color = 'good'
    } else if (buildStatus == 'UNSTABLE' || buildStatus == 'CHANGED') {
        color = 'warning'
    } else {
        color = 'danger'
    }

    def msg = "${buildStatus}: `${env.JOB_NAME}` #${env.BUILD_NUMBER}:\n${env.BUILD_URL}"

    slackSend(color: color, message: msg)
}

DockerFile支持Android构建环境(包含JNI,API:26.0.3+)及JenkinsFile开源在Github: JenkinsWithDockerInAndroid