How to Publish an Ionic Android App with Docker

For the sake of brevity, we're going to operate under the assumption that you already have docker and docker-compose running on your Mac.

If you don't, here are some instructions: Installing Docker for Mac

Docker for Mac is one of the new kids on the Docker block. It uses a lightweight VM instead of relying on Virtualbox or Vagrant. I find this approach appealing, since it's a one button install, and self-updating.

Sadly, like all new tech, it's not all roses. There is a speed issue when dealing with the Filesystem. It's resulted in me running a hybrid Mac host/Docker setup for my development environment. I run all filesystem intensive apps on my Mac, then dockerize all external services that it depends on (like MySQL and ElasticSearch).

Why Docker for Android Builds?

I find the docker approach so much cleaner than installing a million android build dependencies. Just set up a simple container, run a few commands, and you've got a signed APK ready for Google Play.

Important Note: This approach doesn't work for iOS development, which still requires going full Mac.

Getting Dockerized

We're going to use the ionic-framework base image as a jumping off point and follow along the Ionic docs for publishing your ionic app.

Let's start by making a local directory for gradle, so you don't have to install it each time you run your ionic docker container.

mkdir ~/.gradle

I like to use docker and docker-compose so I don't need to include a long string of commands each time I'm working with the build process. Docker compose isn't a hard requirement, but more of a personal preference. I like to start containers with docker-compose ... instead of docker ...9 million commands.

Example Dockerfile

You could probably get away with just using the docker image instead of having a local Dockerfile, but I felt more comfortable with it, in case I need to customize it down the road.

FROM agileek/ionic-framework:2.0.0

Docker Compose Configuration

version: '2'
services:
  app:
    container_name: karma2_ionic
    build:
      context: .
      dockerfile: Dockerfile
    volumes:
      - .:/myApp
      - ~/.gradle:/root/.gradle

Building the App

Ok so we have it all setup. Let's get it built!

docker-compose build
docker-compose run app ionic build android --release

You should see output similar to this:

BUILD SUCCESSFUL
Total time: XX seconds

Generating a Release Key

Next, you'll need to generate a keystore for signing your app:

keytool -genkey -v -keystore my-release-key.keystore -alias alias_name -keyalg RSA -keysize 2048 -validity 10000

Signing the APK

Sign your APK with the generated keystore:

jarsigner -verbose -sigalg SHA1withRSA -digestalg SHA1 -keystore my-release-key.keystore android-release-unsigned.apk alias_name

Running Zipalign

Finally, run zipalign to optimize your APK:

zipalign -v 4 android-release-unsigned.apk YourApp.apk

Uploading to Google Play

Now you're ready to upload your signed APK to the Google Play Store! 🐳✨

Conclusion

Using Docker for Ionic Android app builds eliminates the hassle of managing Android build dependencies on your local machine. While it doesn't solve iOS development (you still need a Mac for that), it makes the Android build process much cleaner and more reproducible.

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Originally published on July 14, 2022