Pass parameters from AWS lambda to AWS CodePipeline

Question

I have a lambda that is initiating a CodePipeline execution via the AWS SDK startPipelineExecution function. Is there any mechanism available to pass a parameter to the CodePipeline build so that it may use the value within the CodeBuild build as an environment variable?

Answer 1

Update: The startPipelineExecution action now accepts a list of variables to override pipeline variables for a new execution.

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Original answer: Currently CodePipeline does not provide any functionality for passing parameters into the Source Stage. Depending on the CodePipeline setup, I would look into one of the following:

1. From your Lambda function, save the parameter to Amazon Systems Manager - Parameter Store and use CodeBuilds built-in approach to retrieve it during runtime. Buildspec:

    env:
      parameter-store:
        key: "value"

2. Instead of calling the CodePipeline directly, upload a file with all your parameters to an S3 bucket. Then set S3 as Source Action Provider, so the CodePipeline is triggered when the file is updated. This way you can pass the file as artifact to your CodeBuild project and use it there.
3. If you can redesign your flow to trigger CodeBuild directly from Lambda, it would be possible to call startBuild using the environment-variables-override flag.