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Android Build ​

This page covers building and distributing the Medipal Android app to Google Play internal testing using mp-mobile-app-builder and Fastlane.

Overview ​

mp-mobile-app-builder is a separate repository from mp-mobile-app. It exists solely for producing signed, distributable native app packages. The main development repo stays clean of app store build tooling.

See Mobile App Builder Architecture for an explanation of why the repos are separated.

Prerequisites ​

  • Android Studio (Flamingo or newer) with SDK platform for the target API level
  • JDK 17 — required by Gradle
  • Fastlane — brew install fastlane or gem install fastlane
  • Node.js / npm — for the Nuxt static generation step
  • Google Play service account credentials JSON (see Credentials)

Repository Structure ​

mp-mobile-app-builder/
  android/                      ← git submodule → mp-mobile-app-android-native
    fastlane/
      Fastfile                  ← Fastlane lane definitions
      Appfile                   ← Package name and credentials path
  ios/                          ← git submodule → mp-mobile-app-ios-native
  ...nuxt.config.ts / package.json

The android/ directory is a git submodule pointing to mp-mobile-app-android-native. Always initialize submodules after cloning:

bash
git clone --recurse-submodules <mp-mobile-app-builder>
# or after a plain clone:
git submodule update --init --recursive

Building ​

Manual (step by step) ​

bash
# 1. Generate static web bundle
npm run build

# 2. Sync web bundle into the Android native project
npx cap sync android

# 3. Open in Android Studio (optional — for manual inspection / signing)
npx cap open android

Shortcut ​

bash
npm run build:android

This single command runs the Nuxt static generation and Capacitor sync in sequence.

Fastlane Internal Lane ​

The internal lane automates the full Google Play internal track upload. Run it from the root of mp-mobile-app-builder:

bash
fastlane android internal

What the lane does (android/fastlane/Fastfile) ​

ruby
lane :internal do
  gradle(
    task: "clean bundle",
    build_type: "Release"
  )
  upload_to_play_store(
    track: "internal",
    release_status: "draft",
    json_key: "medipal-play-console.json"
  )
end
StepPurpose
gradle(task: "clean bundle", build_type: "Release")Clean build + produce signed .aab (Android App Bundle)
upload_to_play_storeUpload .aab to the internal testing track as a draft release

Output artifact: app-release.aab — Android App Bundle format (required by Play Store).

The release is uploaded as release_status: "draft", meaning it does not roll out to testers automatically. A human must promote the draft to active in the Play Console.

Required Env Vars ​

VariablePurpose
ANDROID_KEYSTORE_FILEPath to the .jks / .keystore signing file
ANDROID_KEYSTORE_PASSWORDKeystore password
ANDROID_KEY_ALIASKey alias within the keystore
ANDROID_KEY_PASSWORDKey password
API_URLBackend API base URL embedded in the generated bundle
API_KEYAPI key embedded in the bundle
CRYPTO_KEYAES key for deep-link authentication token decryption
LIVE_UPDATE_URLOTA update endpoint (when USE_LIVE_UPDATE=true)

Keep CRYPTO_KEY in sync

CRYPTO_KEY must match the value configured in the backend. A mismatch causes silent decryption failures during patient deep-link authentication.

Credentials ​

Google Play service account ​

The Play Store upload uses a Google service account JSON key: medipal-play-console.json.

To set up the service account:

  1. Create a service account in Google Cloud Console with the Service Account User role
  2. In Google Play Console → Setup → API access, link the service account and grant Release Manager permissions
  3. Download the JSON key and store it securely — reference its path in json_key (Fastfile) or SUPPLY_JSON_KEY env var

Do not commit credentials

medipal-play-console.json must never be committed to version control. Store it in CI secrets and inject it at build time (e.g., write the base64-decoded content to a temp file).

Android signing keystore ​

The release keystore is used by Gradle's signingConfig to sign the .aab. Store the keystore file and its passwords in CI secrets:

bash
# Example: decode base64-encoded keystore from CI secret
echo "$KEYSTORE_BASE64" | base64 --decode > android/app/release.keystore

Package Name ​

FieldValue
Package namecom.medipal.sigil
Distribution targetGoogle Play internal testing track
Min SDKAndroid 8.0 (API 26)

CI Integration ​

In CI (GitHub Actions via mp-github-actions), the internal lane runs automatically. Required secrets:

  • ANDROID_KEYSTORE_FILE (base64-encoded keystore content)
  • ANDROID_KEYSTORE_PASSWORD
  • ANDROID_KEY_ALIAS
  • ANDROID_KEY_PASSWORD
  • GOOGLE_PLAY_JSON_KEY (base64-encoded service account JSON)
  • Runtime env vars (API_URL, API_KEY, CRYPTO_KEY, LIVE_UPDATE_URL)

Promoting a Release ​

After the internal lane runs successfully:

  1. Open Google Play Console → com.medipal.sigil
  2. Testing → Internal testing → find the uploaded draft release
  3. Click Promote release to make it available to internal testers
  4. To promote further: Internal → Closed → Open → Production

See Also ​