gradle-ci-cd-integration

What this skill does

# Gradle CI/CD Integration

## Table of Contents

- [Purpose](#purpose)
- [When to Use](#when-to-use)
- [Quick Start](#quick-start)
- [Instructions](#instructions)
- [Requirements](#requirements)
- [See Also](#see-also)

## Purpose

Configure Gradle builds for continuous integration and deployment with caching, artifact management, test reporting, and Docker image building. Covers GitHub Actions, GitLab CI, Jenkins, and CircleCI with production-ready optimizations.

## When to Use

Use this skill when you need to:
- Set up automated builds in GitHub Actions, GitLab CI, Jenkins, or CircleCI
- Configure dependency and build caching for faster CI pipelines
- Generate and publish test reports in CI/CD
- Build and push Docker images in automated pipelines
- Optimize CI build performance with parallel execution
- Handle build artifacts and code coverage reports

## Quick Start

**GitHub Actions** `.github/workflows/build.yml`:

```yaml
name: Build

on: [push, pull_request]

jobs:
  build:
    runs-on: ubuntu-latest

    steps:
    - uses: actions/checkout@v4

    - uses: actions/setup-java@v4
      with:
        java-version: '21'
        distribution: 'temurin'

    - uses: gradle/actions/setup-gradle@v4
      with:
        cache-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}

    - run: ./gradlew build --parallel --build-cache --scan
```

**GitLab CI** `.gitlab-ci.yml`:

```yaml
image: gradle:8.11-jdk21-alpine

variables:
  GRADLE_OPTS: "-Dorg.gradle.daemon=false -Dorg.gradle.caching=true"

build:
  script:
    - ./gradlew build --parallel --build-cache
  cache:
    paths:
      - .gradle/wrapper
      - .gradle/caches
```

## Instructions

### Step 1: Use Gradle Wrapper in CI

Always use the Gradle wrapper for consistent versions:

```bash
# Use wrapper (recommended)
./gradlew build

# Not this
gradle build
```

Ensure wrapper is executable:
```bash
chmod +x ./gradlew
git add gradlew
```

### Step 2: Configure Build Caching

Enable caching in your CI configuration:

**GitHub Actions:**
```yaml
- uses: gradle/actions/setup-gradle@v4
  with:
    cache-encryption-key: ${{ secrets.GRADLE_ENCRYPTION_KEY }}
    cache-read-only: ${{ github.ref != 'refs/heads/main' }}
```

**GitLab CI:**
```yaml
cache:
  key: "$CI_COMMIT_REF_SLUG"
  paths:
    - .gradle/wrapper
    - .gradle/caches
```

**Jenkins:**
```groovy
agent {
    docker {
        image 'gradle:8.11-jdk21'
        args '-v $HOME/.gradle:/home/gradle/.gradle'
    }
}
```

See [references/detailed-guide.md](./references/detailed-guide.md) for complete caching strategies.

### Step 3: Optimize Build Performance

Use these flags for faster CI builds:

```bash
./gradlew build \
  --parallel \              # Parallel execution
  --build-cache \          # Remote build cache
  --configuration-cache \  # Configuration cache (Gradle 8+)
  --scan                   # Build scan for analysis
```

Configure in `gradle.properties`:
```properties
org.gradle.parallel=true
org.gradle.caching=true
org.gradle.daemon=false  # Disable for CI
```

### Step 4: Configure Test Reporting

**JUnit XML reports:**

```yaml
# GitHub Actions
- name: Publish Test Results
  uses: mikepenz/action-junit-report@v4
  if: always()
  with:
    report_paths: '**/build/test-results/test/TEST-*.xml'
```

**GitLab CI:**
```yaml
test:
  script:
    - ./gradlew test
  artifacts:
    reports:
      junit: build/test-results/test/TEST-*.xml
```

See [references/detailed-guide.md](./references/detailed-guide.md) for coverage reporting with JaCoCo.

### Step 5: Build and Push Docker Images

**GitHub Actions with Jib:**

```yaml
- name: Build Docker Image (PR)
  if: github.event_name == 'pull_request'
  run: ./gradlew jibDockerBuild

- name: Build and Push (Main)
  if: github.ref == 'refs/heads/main'
  run: ./gradlew jib
  env:
    DOCKER_USERNAME: ${{ secrets.DOCKER_USERNAME }}
    DOCKER_PASSWORD: ${{ secrets.DOCKER_PASSWORD }}
```

**GitLab CI:**
```yaml
docker-build:
  stage: deploy
  only:
    - main
  script:
    - ./gradlew jib
  environment:
    name: production
```

See [references/detailed-guide.md](./references/detailed-guide.md) for Jenkins and CircleCI configurations.

### Step 6: Handle Build Artifacts

**Upload artifacts:**

```yaml
# GitHub Actions
- name: Upload Build Artifacts
  uses: actions/upload-artifact@v4
  with:
    name: build-artifacts
    path: |
      build/libs/
      build/reports/
```

**GitLab CI:**
```yaml
build:
  artifacts:
    paths:
      - build/libs/
    expire_in: 1 day
```

### Step 7: Implement Build Scans

Enable build scans for troubleshooting:

```kotlin
// build.gradle.kts
plugins {
    id("com.gradle.enterprise") version "3.16.1"
}

gradleEnterprise {
    buildScan {
        termsOfServiceUrl = "https://gradle.com/terms-of-service"
        termsOfServiceAgree = "yes"
        publishAlways()
    }
}
```

Run with `--scan`:
```bash
./gradlew build --scan
```

## Requirements

- **Gradle Wrapper:** 8.11+ recommended
- **Java:** JDK 17+ (21 recommended for latest features)
- **CI Platform:** GitHub Actions, GitLab CI, Jenkins, or CircleCI
- **Dependencies:**
  - `gradle/actions/setup-gradle@v4` for GitHub Actions
  - Docker for container-based builds
- **Secrets:** Store credentials securely
  - `GRADLE_ENCRYPTION_KEY` for cache encryption
  - `DOCKER_USERNAME`, `DOCKER_PASSWORD` for registry auth

## See Also

- [references/detailed-guide.md](./references/detailed-guide.md) - Comprehensive examples for all CI platforms, commands reference, best practices, and troubleshooting
- [gradle-performance-optimization](../gradle-performance-optimization/SKILL.md) - Optimize build caching
- [gradle-docker-jib](../gradle-docker-jib/SKILL.md) - Build Docker images
- [gradle-testing-setup](../gradle-testing-setup/SKILL.md) - Configure test reporting
- [GitHub Actions Gradle Setup](https://github.com/gradle/actions) - Official Gradle Actions