Resolving AWS CodeDeploy CDK Lambda Java in Docker Build Error

Uncover how to fix the AWS CodeDeploy build return code 125 for your CDK Lambda Java Docker project, ensuring smooth deployments every time.
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Fixing AWS CodeDeploy CDK Lambda Java Build Error: Understanding Return Code 125

Deploying applications can sometimes come with unexpected challenges, particularly when working with services like AWS CodeDeploy and CDK. A common issue developers face is when the build fails with a return code 125 while trying to package Lambda functions using Docker. In this guide, we will walk through a specific case and demonstrate how to resolve this issue effectively.

The Problem

In this case, we have a multi-modal Maven project that consists of two modules:

LambdaService - This module contains our Lambda function implementation.

CDK infrastructure - This module is responsible for the infrastructure as code, including the deployment pipeline.

The developer is successfully able to run the cdk synth command from both local Windows and Cygwin (Linux) environments, but encounters a failure when the code is pushed to GitHub, triggering the CI/CD pipeline. The error message received indicates that Docker exited with status 125, which typically points to a problem occurring during the build phase.

Error Excerpt:

The specific error from the log reads as follows:

[[See Video to Reveal this Text or Code Snippet]]

The Solution

Upon investigation, it was found that the root cause of the problem lay in the pipeline configuration. Specifically, the pipeline was not properly enabling Docker for the synthesis step. The solution involved a simple adjustment to the pipeline definition.

Modifying the Pipeline Code

The original pipeline code looks like this:

[[See Video to Reveal this Text or Code Snippet]]

Adding Docker Support

To resolve the issue, one line needed to be added to enable Docker support during the synthesis phase:

[[See Video to Reveal this Text or Code Snippet]]

Here’s how the updated code looks after adding the required line for Docker enrichment:

[[See Video to Reveal this Text or Code Snippet]]

Why This Change Matters

Enabling Docker for the synth step is crucial as it allows the CodeBuild environment to execute commands inside a Docker container, which matches the environment where the Lambda function will eventually run. This adjustment helps ensure that all dependencies are properly bundled, and the build can complete successfully, thereby avoiding the dreaded return code 125 error.

Conclusion

Facing a return code 125 during AWS CodeDeploy when bundling a Lambda function can be frustrating, but as we’ve explored, the solution can sometimes be as simple as enabling Docker support in your pipeline configuration. By making sure you're properly configuring your AWS CDK pipeline, you can eliminate these errors and achieve smooth and successful deployments.

Feel free to share your experiences or any questions you might have regarding AWS CodeDeploy, CDK, or Docker in the comments below!