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RuntimeDependenciesLayer rebuilding on every API request

See original GitHub issue

First of all, thank you @Envek and others for both the great writeup at and for this template repo.

This is my first time using AWS SAM in general, and it’s been tricky with Typescript.


When running sam local start-api, every request I make to triggers a rebuild of the dependency layer.

Steps to reproduce

The first visit will build the image as expected.

When refreshing the browse, based on this comment, I would expect the image not to rebuild since no source code would have changed.

However, on each request, the image appears to be rebuilt with the following log line:

RuntimeDependenciesLayer is a local Layer in the template

The time it takes to rebuild this image makes it difficult to develop my frontend.

The workaround I have right now is to just point my frontend at my dev environment in AWS, but I’d prefer to be able to run both front & backend locally.

Issue Analytics

  • State:open
  • Created 2 years ago
  • Comments:11 (2 by maintainers)

github_iconTop GitHub Comments

justintilsoncommented, Feb 5, 2022

One way I found that changes this behavior is to include the --warm-containers=EAGER flag when starting your local SAM API. Example:

sam local start-api --docker-network your-network --env-vars=env.json --warm-containers=EAGER

From: with some more relevant tidbits here:

ahurlburtcommented, Mar 12, 2022

@Envek done:

Maybe people coming across this can upvote 😃

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