module-detector-task.yaml

apiVersion: tekton.dev/v1
kind: Task
metadata:
  name: detect-java-module
  namespace: tap-tasks
  annotations:
    kapp.k14s.io/create-strategy: fallback-on-update
spec:
  description: |-
    A task to detect which java module is impacted by the commit and will return
    the url and revision if it should be built
  stepTemplate:
    securityContext:
      allowPrivilegeEscalation: false
      runAsUser: 1001
      capabilities:
        drop:
          - ALL
      seccompProfile:
        type: "RuntimeDefault"
      runAsNonRoot: true
  params:
    - name: source-url
    - name: source-revision
    - name: prior-url
    - name: prior-revision
    - name: git-url
    - name: git-branch
    - name: module
  results:
    - name: url
    - name: revision
  steps:
    - name: detect
      image: cxscssa.azurecr.io/utils/module-detector-pipeline-image:0.2.6
      env:
        - name: "HOME"
          value: "/tekton/home/"
      script: |-
        #!/usr/bin/env bash
        
        # new workload/no history, lets short circuit and build no matter what
        if [ -z "$(params.prior-url)" ]; then
          echo -n "$(params.source-url)" > $(results.url.path)
          echo -n "$(params.source-revision)" > $(results.revision.path)
        else
          # need to re-assign to temp var due to tekton script substitution
          rev=$(params.prior-revision)
          url=$(params.prior-url)
          
          # need to cleanup the prior run inputs due to having new lines within it
          priorRevision=$(echo -n $rev | tr -d '\n')
          priorUrl=$(echo -n $url | tr -d '\n')

          # lets check to see if we are re-running with the same inputs/outputs to short circuit 
          if [[ "$(params.source-revision)" == "priorRevision" ]]; then
            echo -n "$(params.source-url)" > $(results.url.path)
            echo -n "$(params.source-revision)" > $(results.revision.path)
          else
            # prepare credentials
            ssh_config_file=$(mktemp)
        
            echo "
            UserKnownHostsFile /tekton/creds/.ssh/known_hosts
            Include $(credentials.path)/.ssh/config
            " > $ssh_config_file
            
            export GIT_SSH_COMMAND="ssh -F $ssh_config_file"
            
            cd `mktemp -d`
            
            # clone our repo and adjust to expected branch
            git clone "$(params.git-url)" ./repo && cd ./repo
            git checkout "$(params.git-branch)"
            
            # run gradle and store output
            GRADLE_OUTPUT=$(gradle printProjectsImpacted -Paffected_module_detector.enable -Dorg.gradle.welcome=never --no-daemon)
            MODULE_DETECTED=$(echo $GRADLE_OUTPUT | grep -i $(params.module))
            
            # print for logging
            echo "$GRADLE_OUTPUT"
        
            # determine if we need to build based on this change or not
            if [ -z "$MODULE_DETECTED" ]; then
              echo "$(params.module) not detected"
              # return prior url/revision to ensure the supply chain stays healthy
              # and no additional work is completed after this step
              if [ -n "$(params.prior-url)" ]; then
                echo -n "$priorUrl" > $(results.url.path)
                echo -n "$priorRevision" > $(results.revision.path)        
              fi
            else
              echo "$(params.module) is detected"
              # return the input url/revision from the new commit so we pass it along
              # to test, build, etc.
              echo -n "$(params.source-url)" > $(results.url.path)
              echo -n "$(params.source-revision)" > $(results.revision.path)
            fi  
          fi
        fi