ci: use github-integration plugin for PR's only (vmware-archive#589)

The github-integration plugin provides nice features that allow us to control the
behaviour of CI using github comments and labels. However we have been noticing issues
where build on branches and tags are randomly triggered.

To work around this issue, we are switching to processing only tags using this plugin while
processing branches and tags with the regular jenkins github integration.

(cherry picked from commit e019cad)

Jenkinsfile

@@ -17,48 +17,57 @@ def parentZoneResourceGroup = 'jenkins-bkpr-rg'
 def label = env.BUILD_TAG.replaceAll(/[^a-zA-Z0-9-]/, '-').toLowerCase()
 
 def scmCheckout() {
-    def repo_url = env.GITHUB_REPO_GIT_URL
-    def sha = env.GITHUB_PR_HEAD_SHA ?: (env.GITHUB_BRANCH_HEAD_SHA ?: env.GITHUB_TAG_HEAD_SHA)
-
-    sh """
-    git init --quiet
-    git remote add origin ${repo_url}
-    git config --add remote.origin.fetch '+refs/pull/*/head:refs/remotes/origin/pr/*'
-    git fetch origin --quiet
-    git checkout ${sha} --quiet
-    git submodule update --init
-    """
+    // PR builds are handled using the github-integration plugin to
+    // control builds from github comments and labels
+    if(env.GITHUB_PR_HEAD_SHA) {
+        def repo_url = env.GITHUB_REPO_GIT_URL
+        def sha = env.GITHUB_PR_HEAD_SHA
+        sh """
+        git init --quiet
+        git remote add origin ${repo_url}
+        git config --add remote.origin.fetch '+refs/pull/*/head:refs/remotes/origin/pr/*'
+        git fetch origin --quiet
+        git checkout ${sha} --quiet
+        """
+    } else {
+        checkout scm
+    }
+    sh 'git submodule update --init'
 }
 
 def scmPostCommitStatus(String state) {
-    def target_url = env.BUILD_URL + 'display/redirect'
-    def sha = env.GITHUB_PR_HEAD_SHA ?: (env.GITHUB_BRANCH_HEAD_SHA ?: env.GITHUB_TAG_HEAD_SHA)
-    def context = 'continuous-integration/jenkins/' + (env.GITHUB_BRANCH_NAME ? 'branch' : (env.GITHUB_TAG_NAME ? 'tag' : 'pr-merge'))
-    def params = (env.GITHUB_PR_URL ?: (env.GITHUB_BRANCH_URL ?: env.GITHUB_TAG_URL)).replaceAll('https://github.com/', '').split('/')
-    def repo = params[0] + '/' + params[1]
-    def desc = ''
-
-    switch(state) {
-        case 'success':
-            desc = 'This commit looks good'
-            break
-        case 'error':
-        case 'failure':
-            desc = 'This commit cannot be built'
-            break
-        case 'pending':
-            desc = 'Waiting for status to be reported'
-            break
-        default:
-            return
-    }
+    // PR builds are handled using the github-integration plugin to
+    // control builds from github comments and labels
+    if(env.GITHUB_PR_HEAD_SHA) {
+        def target_url = env.BUILD_URL + 'display/redirect'
+        def sha = env.GITHUB_PR_HEAD_SHA
+        def context = 'continuous-integration/jenkins/pr-merge'
+        def params = (env.GITHUB_PR_URL).replaceAll('https://github.com/', '').split('/')
+        def repo = params[0] + '/' + params[1]
+        def desc = ''
+
+        switch(state) {
+            case 'success':
+                desc = 'This commit looks good'
+                break
+            case 'error':
+            case 'failure':
+                desc = 'This commit cannot be built'
+                break
+            case 'pending':
+                desc = 'Waiting for status to be reported'
+                break
+            default:
+                return
+        }
 
-    withCredentials([usernamePassword(credentialsId: 'github-bitnami-bot', passwordVariable: 'GITHUB_TOKEN', usernameVariable: '')]) {
-        sh """
-        curl -sSf \"https://api.github.com/repos/${repo}/statuses/${sha}?access_token=${GITHUB_TOKEN}\" \
-            -H \"Content-Type: application/json\" -X POST -o /dev/null \
-            -d \"{\\\"state\\\": \\\"${state}\\\",\\\"context\\\": \\\"${context}\\\", \\\"description\\\": \\\"${desc}\\\", \\\"target_url\\\": \\\"${target_url}\\\"}\"
-        """
+        withCredentials([usernamePassword(credentialsId: 'github-bitnami-bot', passwordVariable: 'GITHUB_TOKEN', usernameVariable: '')]) {
+            sh """
+            curl -sSf \"https://api.github.com/repos/${repo}/statuses/${sha}?access_token=${GITHUB_TOKEN}\" \
+                -H \"Content-Type: application/json\" -X POST -o /dev/null \
+                -d \"{\\\"state\\\": \\\"${state}\\\",\\\"context\\\": \\\"${context}\\\", \\\"description\\\": \\\"${desc}\\\", \\\"target_url\\\": \\\"${target_url}\\\"}\"
+            """
+        }
     }
 }
 
@@ -672,7 +681,7 @@ spec:
                     parallel platforms
 
                     stage('Release') {
-                        if (env.GITHUB_TAG_NAME) {
+                        if(env.TAG_NAME) {
                             dir("${env.WORKSPACE}/src/github.com/bitnami/kube-prod-runtime") {
                                 withGo() {
                                     withCredentials([
@@ -686,16 +695,16 @@ spec:
                                             "PATH+AWLESS=${tool 'awless'}",
                                             "GITHUB_USER=bitnami",
                                         ]) {
-                                            sh "make dist VERSION=${GITHUB_TAG_NAME}"
-                                            sh "make publish VERSION=${GITHUB_TAG_NAME}"
+                                            sh "make dist VERSION=${TAG_NAME}"
+                                            sh "make publish VERSION=${TAG_NAME}"
                                         }
                                     }
                                 }
 
                                 container(name: 'kaniko', shell: '/busybox/sh') {
                                     withEnv(['PATH+KANIKO=/busybox:/kaniko']) {
                                         sh """#!/busybox/sh
-                                        /kaniko/executor --dockerfile `pwd`/Dockerfile --build-arg BKPR_VERSION=${GITHUB_TAG_NAME} --context `pwd` --destination kubeprod/kubeprod:${GITHUB_TAG_NAME}
+                                        /kaniko/executor --dockerfile `pwd`/Dockerfile --build-arg BKPR_VERSION=${TAG_NAME} --context `pwd` --destination kubeprod/kubeprod:${TAG_NAME}
                                         """
                                     }
                                 }
@@ -704,7 +713,6 @@ spec:
                             Utils.markStageSkippedForConditional(STAGE_NAME)
                         }
                     }
-
                     scmPostCommitStatus("success")
                 } catch (error) {
                     scmPostCommitStatus("failure")