GitHub Action - Android Emulator Runner

A GitHub Action for installing, configuring and running hardware-accelerated Android Emulators on macOS virtual machines.

The old ARM-based emulators were slow and are no longer supported by Google. The modern Intel Atom (x86 and x86_64) emulators require hardware acceleration (HAXM on Mac & Windows, QEMU on Linux) from the host to run fast. This presents a challenge on CI as to be able to run hardware accelerated emulators within a docker container, KVM must be supported by the host VM which isn't the case for cloud-based CI providers due to infrastructural limits. If you want to learn more about this, here's an article I wrote: Running Android Instrumented Tests on CI.

The macOS VM provided by GitHub Actions has HAXM installed so we are able to create a new AVD instance, launch an emulator with hardware acceleration, and run our Android tests directly on the VM. You can also achieve this on a self-hosted Linux runner, but it will need to be on a compatible instance that allows you to enable KVM - for example AWS EC2 Bare Metal instances.

This action automates the process by doing the following:

• Install / update the required Android SDK components including build-tools, platform-tools, platform (for the required API level), emulator and system-images (for the required API level).
• Create a new instance of AVD with the provided configurations.
• Launch a new Emulator with the provided configurations.
• Wait until the Emulator is booted and ready for use.
• Run a custom script provided by user once the Emulator is up and running - e.g. ./gradlew connectedCheck.
• Kill the Emulator and finish the action.

Usage

It is recommended to run this action on a macOS VM, e.g. macos-latest or macos-10.15 to take advantage of hardware accleration support provided by HAXM.

A workflow that uses android-emulator-runner to run your instrumented tests on API 29:

jobs:
  test:
    runs-on: macos-latest
    steps:
      - name: checkout
        uses: actions/checkout@v2

      - name: run tests
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: 29
          script: ./gradlew connectedCheck

We can also leverage GitHub Actions's build matrix to test across multiple configurations:

jobs:
  test:
    runs-on: macos-latest
    strategy:
      matrix:
        api-level: [21, 23, 29]
        target: [default, google_apis]
    steps:
      - name: checkout
        uses: actions/checkout@v2

      - name: run tests
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: ${{ matrix.api-level }}
          target: ${{ matrix.target }}
          arch: x86_64
          profile: Nexus 6
          script: ./gradlew connectedCheck

If you need specific versions of NDK and CMake installed:

jobs:
  test:
    runs-on: macos-latest
    steps:
      - name: checkout
        uses: actions/checkout@v2

      - name: run tests
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: 29
          ndk: 21.0.6113669
          cmake: 3.10.2.4988404
          script: ./gradlew connectedCheck

We can significantly reduce emulator startup time by setting up AVD snapshot caching:

1. add an actions/cache@v2 step for caching the avd
2. add a reactivecircus/android-emulator-runner@v2 step to generate a clean snapshot - specify emulator-options without no-snapshot
3. add another reactivecircus/android-emulator-runner@v2 step to run your tests using existing AVD / snapshot - specify emulator-options with no-snapshot-save

jobs:
  test:
    runs-on: macos-latest
    strategy:
      matrix:
        api-level: [21, 23, 29]
    steps:
      - name: checkout
        uses: actions/checkout@v2

      - name: Gradle cache
        uses: actions/cache@v2
        with:
          path: |
            ~/.gradle/caches
            ~/.gradle/wrapper
          key: gradle-${{ runner.os }}-${{ hashFiles('**/*.gradle*') }}-${{ hashFiles('**/gradle/wrapper/gradle-wrapper.properties') }}-${{ hashFiles('**/buildSrc/**/*.kt') }}

      - name: AVD cache
        uses: actions/cache@v2
        id: avd-cache
        with:
          path: |
            ~/.android/avd/*
            ~/.android/adb*
          key: avd-${{ matrix.api-level }}

      - name: create AVD and generate snapshot for caching
        if: steps.avd-cache.outputs.cache-hit != 'true'
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: ${{ matrix.api-level }}
          force-avd-creation: false
          emulator-options: -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
          disable-animations: false
          script: echo "Generated AVD snapshot for caching."

      - name: run tests
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: ${{ matrix.api-level }}
          force-avd-creation: false
          emulator-options: -no-snapshot-save -no-window -gpu swiftshader_indirect -noaudio -no-boot-anim -camera-back none
          disable-animations: true
          script: ./gradlew connectedCheck

Configurations

Input	Required	Default	Description
api-level	Required	N/A	API level of the platform system image - e.g. 23 for Android Marshmallow, 29 for Android 10. Minimum API level supported is 15.
target	Optional	default	Target of the system image - default, google_apis or playstore.
arch	Optional	x86	CPU architecture of the system image - x86, x86_64 or arm64-v8a. Note that x86_64 image is only available for API 21+. arm64-v8a images require Android 4.2+ and are limited to fewer API levels (e.g. 30).
profile	Optional	N/A	Hardware profile used for creating the AVD - e.g. Nexus 6. For a list of all profiles available, run avdmanager list and refer to the results under "Available Android Virtual Devices".
cores	Optional	2	Number of cores to use for the emulator (hw.cpu.ncore in config.ini).
ram-size	Optional	N/A	Size of RAM to use for this AVD, in KB or MB, denoted with K or M. - e.g. 2048M
sdcard-path-or-size	Optional	N/A	Path to the SD card image for this AVD or the size of a new SD card image to create for this AVD, in KB or MB, denoted with K or M. - e.g. path/to/sdcard, or 1000M.
avd-name	Optional	test	Custom AVD name used for creating the Android Virtual Device.
force-avd-creation	Optional	true	Whether to force create the AVD by overwriting an existing AVD with the same name as avd-name - true or false.
emulator-options	Optional	See below	Command-line options used when launching the emulator (replacing all default options) - e.g. -no-window -no-snapshot -camera-back emulated.
disable-animations	Optional	true	Whether to disable animations - true or false.
disable-spellchecker	Optional	false	Whether to disable spellchecker - true or false.
disable-linux-hw-accel	Optional	true	Whether to disable hardware acceleration on Linux machines - true or false. Note that this is true by default as Github-hosted Linux runners do not support hardware acceleration.
emulator-build	Optional	N/A	Build number of a specific version of the emulator binary to use e.g. 6061023 for emulator v29.3.0.0.
working-directory	Optional	./	A custom working directory - e.g. ./android if your root Gradle project is under the ./android sub-directory within your repository.
ndk	Optional	N/A	Version of NDK to install - e.g. 21.0.6113669
cmake	Optional	N/A	Version of CMake to install - e.g. 3.10.2.4988404
channel	Optional	stable	Channel to download the SDK components from - stable, beta, dev, canary
script	Required	N/A	Custom script to run - e.g. to run Android instrumented tests on the emulator: ./gradlew connectedCheck

Default emulator-options: -no-window -gpu swiftshader_indirect -no-snapshot -noaudio -no-boot-anim.

Can I use this action on Linux VMs?

The short answer is yes but on Github-hosted Linux runners it's expected to be a much worse experience (on some newer API levels it might not work at all) than running it on macOS. You can get it running much faster on self-hosted Linux runners but only if the underlying instances support KVM (which most don't).

For a longer answer please refer to this issue.

Who is using Android Emulator Runner?

These are some of the open-source projects using (or used) Android Emulator Runner:

• coil-kt/coil
• cashapp/sqldelight
• square/workflow-kotlin
• square/retrofit
• natario1/CameraView
• natario1/Transcoder
• chrisbanes/insetter
• slackhq/keeper
• android/compose-samples
• ReactiveCircus/streamlined
• ReactiveCircus/FlowBinding
• JakeWharton/RxBinding
• vinaygaba/Learn-Jetpack-Compose-By-Example
• ashishb/adb-enhanced
• vgaidarji/ci-matters
• simpledotorg/simple-android
• cashapp/copper
• square/radiography
• Shopify/android-testify
• square/leakcanary
• hash-checker/hash-checker
• hash-checker/hash-checker-lite
• Kiwix/kiwix-android
• wikimedia/apps-android-wikipedia
• google/android-fhir
• google/accompanist
• dotanuki-labs/norris
• tinylog-org/tinylog

If you are using Android Emulator Runner and want your project included in the list, please feel free to create an issue or open a pull request.