CI CD And Automation

CI/CD and Automation

Overview

Shift left: catch problems early through automated checks. A well-structured CI pipeline runs sequential quality gates — from fast checks (lint, compile) to slow checks (instrumented tests, security audit) — so feedback arrives quickly and issues are caught before merging.

When to Use

• Setting up CI for a new Android project
• Adding quality gates to an existing pipeline
• CI pipeline exceeds 10 minutes (needs optimization)
• Automating deployment to Play Store or Firebase App Distribution
• Feature flag management for staged rollouts

Skip when: The project has no CI (start with ci-cd-and-automation first).

Core Process

Step 1: Sequential Quality Gates

1. Gate order (fastest to slowest):

# .github/workflows/android-ci.yml
name: Android CI

on:
  pull_request:
    branches: [main]
  push:
    branches: [main]

jobs:
  lint-and-compile:
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: 17

      - name: Setup Gradle
        uses: gradle/actions/setup-gradle@v4

      # Gate 1: Format check (~30s)
      - name: Check formatting
        run: ./gradlew spotlessCheck

      # Gate 2: Static analysis (~1min)
      - name: Run detekt
        run: ./gradlew detekt

      # Gate 3: Compile (~2min)
      - name: Compile
        run: ./gradlew assembleDebug

      # Gate 4: Android Lint (~3min)
      - name: Lint
        run: ./gradlew lint

  unit-tests:
    needs: lint-and-compile
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: 17
      - uses: gradle/actions/setup-gradle@v4

      # Gate 5: Unit tests (~3min)
      - name: Unit tests
        run: ./gradlew test

      - name: Upload test results
        if: always()
        uses: actions/upload-artifact@v4
        with:
          name: test-results
          path: '**/build/reports/tests/'

  instrumented-tests:
    needs: unit-tests
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4
      - uses: actions/setup-java@v4
        with:
          distribution: temurin
          java-version: 17

      # Gate 6: Instrumented tests (~10min)
      - name: Run instrumented tests
        uses: reactivecircus/android-emulator-runner@v2
        with:
          api-level: 36   # Play target floor; add API 37 to the matrix for latest-behavior testing
          arch: x86_64
          script: ./gradlew connectedAndroidTest

  security-check:
    needs: unit-tests
    runs-on: ubuntu-latest
    steps:
      - uses: actions/checkout@v4

      # Gate 7: Dependency vulnerability scan
      - name: Security audit
        run: ./gradlew dependencyCheckAnalyze

      # Gate 8: Secrets scan
      - name: Check for secrets
        uses: trufflesecurity/trufflehog@main
        with:
          extra_args: --only-verified

2. No gate skipping — fix the code, don't disable the rule:

// BAD: suppressing lint
@Suppress("MagicNumber")
val timeout = 5000

// GOOD: use a named constant
private const val NETWORK_TIMEOUT_MS = 5_000L

Step 2: Gradle Caching

3. Cache Gradle dependencies and build outputs:

# Gradle caching is handled by gradle/actions/setup-gradle@v4
# It automatically caches:
# - ~/.gradle/caches
# - ~/.gradle/wrapper
# - .gradle (project-level)
# - Build outputs

- uses: gradle/actions/setup-gradle@v4
  with:
    cache-read-only: ${{ github.event_name == 'pull_request' }}

4. Gradle build optimization:

# gradle.properties
org.gradle.caching=true
org.gradle.parallel=true
org.gradle.configureondemand=true
org.gradle.jvmargs=-Xmx4g -XX:+UseParallelGC

Step 3: Emulator Testing in CI

5. Use android-emulator-runner for instrumented tests:

- name: Run instrumented tests
  uses: reactivecircus/android-emulator-runner@v2
  with:
    api-level: 36
    arch: x86_64
    target: google_apis
    profile: pixel_6
    emulator-options: -no-snapshot-save -no-window -gpu swiftshader_indirect -noaudio
    disable-animations: true
    script: ./gradlew connectedAndroidTest

If the repo has committed Maestro flows (.maestro/), run them in the same emulator job after installing the debug build — ./gradlew installDebug && maestro test .maestro/ — so every shipped acceptance criterion is regression-checked per PR (see android-e2e-verification).

When the android CLI is present in the runner image, android sdk install is a leaner alternative to setup-android for declarative platform/build-tools provisioning:

- name: Install Android platforms
  run: |
    android sdk install \
      platforms/android-35 \
      build-tools/35.0.0 \
      platform-tools

Stick with reactivecircus/android-emulator-runner for the emulator itself — android emulator is disabled on Windows and the runner action handles snapshot caching, hardware acceleration, and animation disabling that you'd otherwise rebuild by hand. See ../../references/android-cli-reference.md.

6. Test sharding for large test suites:

strategy:
  matrix:
    shard: [0, 1, 2, 3]
steps:
  - name: Run tests (shard ${{ matrix.shard }})
    run: |
      ./gradlew connectedAndroidTest \
        -Pandroid.testInstrumentationRunnerArguments.numShards=4 \
        -Pandroid.testInstrumentationRunnerArguments.shardIndex=${{ matrix.shard }}

Step 4: Feature Flags

7. Decouple deployment from release:

// Build-time flags (for CI/staging)
// build.gradle.kts
android {
    buildTypes {
        debug {
            buildConfigField("Boolean", "FEATURE_NEW_UI", "true")
        }
        release {
            buildConfigField("Boolean", "FEATURE_NEW_UI", "false")
        }
    }
}

// Runtime flags (for gradual rollout)
// Using Firebase Remote Config
class FeatureFlagRepository @Inject constructor(
    private val remoteConfig: FirebaseRemoteConfig,
) {
    fun isEnabled(key: String): Flow<Boolean> = callbackFlow {
        val listener = ConfigUpdateListener { trySend(remoteConfig.getBoolean(key)) }
        remoteConfig.addOnConfigUpdateListener(listener)
        trySend(remoteConfig.getBoolean(key))
        awaitClose { /* cleanup */ }
    }
}

Step 5: Deployment Automation

8. Firebase App Distribution (internal testing):

deploy-internal:
  needs: [unit-tests, instrumented-tests, security-check]
  if: github.ref == 'refs/heads/main'
  runs-on: ubuntu-latest
  steps:
    - uses: actions/checkout@v4
    - uses: actions/setup-java@v4
      with:
        distribution: temurin
        java-version: 17

    - name: Build release APK
      run: ./gradlew assembleRelease

    - name: Upload to Firebase App Distribution
      uses: wzieba/Firebase-Distribution-Github-Action@v1
      with:
        appId: ${{ secrets.FIREBASE_APP_ID }}
        serviceCredentialsFileContent: ${{ secrets.FIREBASE_CREDENTIALS }}
        groups: internal-testers
        file: app/build/outputs/apk/release/app-release.apk

9. Play Store (production):

deploy-production:
  needs: [deploy-internal]  # After internal testing
  if: startsWith(github.ref, 'refs/tags/v')
  runs-on: ubuntu-latest
  steps:
    - name: Upload to Play Store
      uses: r0adkll/upload-google-play@v1
      with:
        serviceAccountJsonPlainText: ${{ secrets.PLAY_STORE_CREDENTIALS }}
        packageName: com.example.app
        releaseFiles: app/build/outputs/bundle/release/app-release.aab
        track: internal  # internal → alpha → beta → production
        status: completed

Step 6: Feedback Loops

10. When CI fails, use the agent feedback loop:
    1. Read the failure output
    2. Identify the gate that failed
    3. Fix the specific issue (don't disable the gate)
    4. Re-run the pipeline
    5. If the fix introduces new failures, revert and investigate

Step 7: Pipeline Optimization

11. If pipeline exceeds 10 minutes:
    • Cache dependencies (Gradle, SDK components)
    • Parallelize independent gates (lint + unit tests simultaneously)
    • Selective testing (only run affected modules)
    • Test sharding (split instrumented tests across emulators)
    • Build cache (enable Gradle build cache)

Environment Separation

Environment	Secrets Source	Build Type
Local	local.properties (gitignored)	Debug
CI	GitHub Secrets / Vault	Debug + Release
Staging	Firebase Remote Config	Release (staging flavor)
Production	Play Store + Firebase	Release

Common Rationalizations

Shortcut	Why It Fails
"CI is too slow, I'll push without waiting"	Pushing broken code blocks the team. Optimize the pipeline instead.
"Lint warnings aren't real errors"	Lint catches real bugs (unused resources, API compatibility, security issues).
"Instrumented tests are too flaky for CI"	Flaky tests have root causes. Fix them or isolate them — don't skip them.
"We'll add CI later"	Later means tech debt. Start with lint + compile + unit tests on day one.

Red Flags

• No CI pipeline
• CI gates disabled or skipped (@Suppress, -x lint)
• No Gradle caching in CI
• Instrumented tests not running in CI
• Secrets in repository (use GitHub Secrets)
• No deployment automation
• Pipeline exceeds 15 minutes without optimization
• Feature flags without cleanup plan

Verification

• CI runs on every PR and push to main
• Gates run in order: format → lint → compile → unit tests → instrumented tests → security
• No gates skipped or disabled
• Gradle caching configured
• Instrumented tests run on emulator in CI
• Secrets stored in CI environment (not in repo)
• Deployment automated (Firebase App Distribution and/or Play Store)
• Pipeline completes in < 15 minutes
• Failed gates produce actionable error messages