Optimizing Bazel Projects with Harness CI Intelligence

As software projects scale, build times often become a major bottleneck, especially when using tools like Bazel. Bazel is known for its speed and scalability, handling large codebases with ease. However, even the most optimized build tools can be slowed down by inefficient CI pipelines. In this blog, we’ll dive into how Bazel’s build capabilities can be taken to the next level with Harness CI. By leveraging features like Build Intelligence and caching, Harness CI helps maximize Bazel's performance, ensuring faster builds and a more efficient development cycle.

How Harness CI Enhances Bazel Builds

Harness CI integrates seamlessly with Bazel, taking full advantage of its strengths and enhancing performance. The best part? As a user, you don’t have to provide any additional configuration to leverage the build intelligence feature. Harness CI automatically configures the remote cache for your Bazel builds, optimizing the process from day one. 

Build Intelligence: Speeding Up Bazel Builds

Harness CI’s Build Intelligence ensures that Bazel builds are as fast and efficient as possible. While Bazel has its own caching mechanisms, Harness CI takes this a step further by automatically configuring and optimizing the remote cache, reducing build times without any manual setup.

This automatic configuration means that you can benefit from faster, more efficient builds right away—without having to tweak cache settings or worry about how to handle build artifacts across multiple machines.

How It Works with Bazel

Harness CI seamlessly integrates with Bazel’s caching system, automatically handling the configuration of remote caches. So, when you run a build, Harness CI makes sure that any unchanged files are skipped, and only the necessary tasks are executed. If there are any changes, only those parts of the project are rebuilt, making the process significantly faster.

For example, when building the bazel-gazelle project, Harness CI ensures that any unchanged files are cached and reused in subsequent builds, reducing the need for unnecessary recompilation. All this happens automatically in the background without requiring any special configuration from the user.

Benefits for Bazel Projects

• Automatic Remote Caching: No manual configuration needed—Harness CI configures the remote cache for you.
• Faster Builds: Builds run faster by reusing previously built outputs and skipping redundant tasks.
• Optimized Resource Usage: Reduces the use of CPU and memory by only running the tasks that are necessary.

Sample Pipeline: Harness CI with Bazel

pipeline:
  name: YOUR_PIPELINE_NAME
  identifier: YOUR_PIPELINE_ID
  projectIdentifier: YOUR_PROJECT_ID
  orgIdentifier: YOUR_ORG_ID
  tags: {}
  properties:
    ci:
      codebase:
        connectorRef: bazel_gazelle_connector
        build: <+input>
        sparseCheckout: []
  stages:
    - stage:
        name: build_stage
        identifier: build_stage
        description: ""
        type: CI
        spec:
          cloneCodebase: true
          platform:
            os: Linux
            arch: Amd64
          runtime:
            type: Cloud
            spec: {}
          execution:
            steps:
              - step:
                  type: Run
                  name: Bazel_Build_Step
                  identifier: bazel_build_step
                  spec:
                    shell: Sh
                    command: bazel build //...
          caching:
            enabled: false
            paths: []
          buildIntelligence:
            enabled: true

Benchmarking: Harness CI vs. GitHub Actions with Bazel

We compared the performance of Bazel builds using Harness CI and GitHub Actions, and the results were clear: Harness CI, with its automatic configuration and optimized caching, delivered up to 4x faster builds than GitHub Actions. The automatic configuration of the remote cache made a significant difference, helping Bazel avoid redundant tasks and speeding up the build process.

Results:

• Harness CI with Bazel: Builds were up to 4x faster, thanks to automatic remote cache configuration and build optimization.
• GitHub Actions with Bazel: Slower builds due to less efficient caching and redundant task execution.

Next Steps

Bazel is an excellent tool for large-scale builds, but it becomes even more powerful when combined with Harness CI and Harness Cloud. By automatically configuring remote caches and applying build intelligence, Harness CI ensures that your Bazel builds are as fast and efficient as possible, without requiring any additional configuration from you.

By combining other Harness CI intelligence features like Cache Intelligence, Docker Layer Caching, and Test Intelligence, you can speed up your Bazel projects by up to 8x.With the hyper optimized build infrastructure, you can experience lightning-fast builds on Harness Cloud at reasonable costs. This seamless integration allows you to spend less time waiting for builds and more time focusing on delivering quality code.

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