Accelerating Gradle Builds with Harness CI Build Intelligence

When building complex software projects, slow build times can become a major bottleneck, impacting developer productivity and resource efficiency. The goal of this blog post is to demonstrate that Harness CI is fast for building large-scale projects. Using benchmarks and a sample Gradle project, we’ll showcase how Harness CI optimizes build performance with Build Intelligence.

Gradle is a powerful build automation tool widely used across different programming languages and platforms. Whether you're building Java, Kotlin, or Android projects—or even large-scale distributed systems—Gradle’s flexibility and efficiency make it a go-to choice for developers. However, as projects grow in complexity, build times can become a major bottleneck, leading to wasted resources and slower development cycles.

This is where Harness CI comes in, providing Build Intelligence, Test Intelligence, and Cache Intelligence to optimize and accelerate Gradle builds. In this blog, we’ll explore how Build Intelligence works, using the Spring Framework as an example of a large Java project that benefits from Harness CI’s optimizations.

Why Harness CI for Gradle?

Gradle is designed to handle complex dependency management and incremental builds, but traditional CI pipelines often don’t take full advantage of its optimizations. Common issues include:

• Slow builds due to redundant compilation and dependency resolution.
• Inefficient test execution where all tests run, even when only a subset is impacted.
• Lack of caching for build outputs, leading to unnecessary recomputation.

Harness CI Intelligence helps solve these issues by reusing build artifacts, running only relevant tests, and caching dependencies efficiently. Let’s dive into how these features enhance Gradle builds.

Build Intelligence: Reusing Build Outputs for Faster Builds

What is Build Intelligence?

Build Intelligence in Harness CI speeds up Gradle builds by caching outputs of previous runs and retrieving them when inputs haven’t changed. This avoids redundant work, significantly reducing build times.

How It Works with Gradle

Harness CI integrates with Gradle’s caching mechanism to store and reuse outputs from cacheable tasks, such as compiling source code and generating artifacts.

Example with Spring Framework:

1. First Build: Gradle compiles the Spring Framework codebase from scratch, caching task outputs.
2. Subsequent Builds: If no relevant code changes are detected, Harness CI reuses the cached outputs, skipping redundant tasks.

Benefits for Gradle Projects

- Faster Builds: Reduces build times by reusing cached outputs.

- Efficient Resource Usage: Minimizes CPU and memory usage by skipping redundant tasks.

- Seamless Integration: Works out-of-the-box with Gradle and Bazel.

Sample Pipeline

Here’s a sample pipeline with build intelligence in action:

- stage:
       name: build_stage
       identifier: build_stage
       description: ""
       type: CI
       spec:
         cloneCodebase: true
         platform:
           os: Linux
           arch: Amd64
         runtime:
           type: Cloud
           spec: {}
         caching:
           enabled: false
           paths: []
         buildIntelligence:
           enabled: true
         execution:
           steps:
             - step:
                 type: Action
                 name: Setup JDK
                 identifier: Setup_JDK
                 spec:
                   uses: actions/setup-java@v3
                   with:
                     java-version: "17"
                     distribution: temurin
             - step:
                 type: Action
                 name: Set up Gradle
                 identifier: Set_up_Gradle
                 spec:
                   uses: gradle/gradle-build-action@v2
                   with:
                     gradle-version: "8.5"
             - step:
                 type: Run
                 name: Spring Framework Build
                 identifier: Spring_Framework_Build
                 spec:
                   shell: Sh
                   command: gradle unitTest -PmaxParallelForks=32 -PignoreFailures=true --profile

Benchmarking: Harness CI vs. GitHub Actions

To demonstrate the performance improvements provided by Harness CI’s Build Intelligence, we benchmarked build times for a Spring Framework Gradle build across different CI platforms. The test involved multiple builds with incremental changes to measure caching efficiency and execution speed. Here’s one of those benchmarks when compared against GitHub Actions.

Results

Key Takeaways

• Harness CI significantly reduces build times by leveraging Build Intelligence to reuse previous outputs efficiently.
• Subsequent builds in Harness CI are nearly 6 times as fast as those in GitHub Actions, thanks to its caching and optimized task execution.

Next Steps

Gradle’s powerful build system enables efficient dependency management and incremental builds, but traditional CI pipelines often fail to take full advantage of these optimizations. Harness CI bridges this gap with Build Intelligence, Test Intelligence, and Cache Intelligence, significantly reducing build times and improving efficiency.

From our benchmarks, Harness CI not only accelerates Gradle builds but also optimizes resource usage, making it an ideal choice for teams working on large-scale projects like Spring Framework. By integrating Harness CI with Gradle, developers can spend less time waiting for builds and more time delivering high-quality code.

If you're looking to speed up your Gradle builds, give Harness CI a try today and experience the difference!