Guide to Setup Gitlab CI/CD for Android

Continuous Integration and Continuous Deployment System let you automatically build and test your app every time. The goal of the article is how to automatically build Android APK, then upload the generated APK to Slack.

Get Started

Building Docker images with GitLab CI/CD

First, we need to create a package install configuration file Dockerfile.

Docker configuration

Next, we need to create a Docker Image through written the Dockerfile.

docker build -t registry.example.com/group/project:tag .

e.g. docker build -t registry.silkrode.com.tw/team_mobile/jys:1.0.1 .

Finally, we push the Docker image to Gitlab Container Registry.

docker push registry.example.com/group/project:tag

e.g. docker push registry.silkrode.com.tw/team_mobile/jys:1.0.1

Docker Images for Gitlab

Setup GitLab CI/CD Pipelines

We add a Gitlab CI configuration file .gitlab-ci.yml inside our Android project root. This file essentially contains all the instructions for our CI/CD pipeline.

Let’s understand some of the basic GitLab CI keywords and the code in the YML config file.

• image：Gitlab runners will use specify a Docker image to run the pipeline.
• stages：These are globally defined levels that a pipeline run. It is used by jobs and run in the same order as their definition and each stage can contain different jobs. When one job fails the rest of the jobs in other stages will not be executed.
• stage：This signifies which stage the job belongs to.
• tags：List of tags that are used to select a runner.
• script：The shell script executed by the Gitlab Runner.
• cache：List of files that should be cached between subsequent runs.
• untracked：Cache all files that are untracked in your Git repository.
• only：Define all the branch names for which the job will run.

YML file for Gitlab CI

pipelines for Gitlab CI

Setup Fastlane Scripts

Navigate your terminal to your project’s directory and run

fastlane init

It will automatically generate a configuration. You can see the newly created ./fastlane directory, with the following files:

• Appfile：Defines configuration information that is global to your app.

Appfile for Fastlane

• Fastfile：Defines the lanes that drive the behavior of fastlane.

How to automatically build Android APK, then upload the generated APK to Slack?

First, create local.properties file and clean project, define init_env lane：

Step 1：Writing Android SDK path in local.properties file.

Step 2：Delete the contents of the build directory, and run

gradle(task: "clean")

Next, build Android APK.

gradle(
  task: "assemble",
  flavor: options[:flavor],
  build_type: options[:build_type],
  properties: {
    "android.injected.signing.store.file" => ENV["KEYSTORE_PATH"],
    "android.injected.signing.store.password" => ENV["KEY_PASSWORD"],
    "android.injected.signing.key.alias" => ENV["KEY_ALIAS"],
    "android.injected.signing.key.password" => ENV["KEY_PASSWORD"],
  }
)

Finally, upload the generated APK to Slack.

file_path = lane_context[SharedValues::GRADLE_APK_OUTPUT_PATH]
file_name = file_path.gsub(/\/.*\//,"")
sh "echo Uploading " + file_name + " to Slack"
sh "curl https://slack.com/api/files.upload -F token=[SLACK_TOKEN] -F channels=\"#team_mobile\" -F title=\"" + file_name + "\" -F filename=\"" + file_name + "\" -F file=@" + file_path

Fastfile for Fastlane

Generated Android APK for Slack

Thanks for reading this and I hope this helped you in setting up CI/CD for your project.