Gitlab CI script for Medium article: https://medium.com/evenbit/e51aba6ba53e

.gitlab-ci.yml

.package_template: &package_template_def
  before_script:
    - export VERSION_NAME=`egrep '^[[:blank:]]+versionName[[:blank:]]'  app/build.gradle | awk '{print $2}' | sed s/\"//g`
    - export VERSION_CODE=`egrep '^[[:blank:]]+versionCode[[:blank:]]'  app/build.gradle | awk '{print $2}'`
    - mkdir -p deliverables

    # Store some information about the build
    - touch ./deliverables/info.txt
    - echo "Build date          $(date)"                >> ./deliverables/info.txt
    - echo "App version name    ${VERSION_NAME}"        >> ./deliverables/info.txt
    - echo "App version code    ${VERSION_CODE}"        >> ./deliverables/info.txt
    - echo "Git branch          ${CI_COMMIT_REF_NAME}"  >> ./deliverables/info.txt
    - echo "Git commit          ${CI_COMMIT_SHA}"       >> ./deliverables/info.txt
    - echo "Gitlab pipeline     ${CI_PIPELINE_ID}"      >> ./deliverables/info.txt

package_develop:
  <<: *package_template_def
  stage: package
  environment: Development
  only:
    - develop
  script:
    - mv app/build/outputs/apk/app-debug.apk ./deliverables/NameOfTheApp-v$VERSION_NAME-$VERSION_CODE-debug.apk
  artifacts:
    expire_in: 3 days
    paths:
    - deliverables

package_release:
  <<: *package_template_def
  stage: package
  environment: Release
  only:
    - master
  script:
    - mv app/build/outputs/apk/app-release.apk ./deliverables/NameOfTheApp-v$VERSION_NAME-$VERSION_CODE-release.apk
  artifacts:
    expire_in: 4 weeks
    paths:
    - deliverables