Stuck on an issue?

Lightrun Answers was designed to reduce the constant googling that comes with debugging 3rd party libraries. It collects links to all the places you might be looking at while hunting down a tough bug.

And, if you’re still stuck at the end, we’re happy to hop on a call to see how we can help out.

Feature Request: Support large event payload input to Lambda

See original GitHub issue

I’m trying to build an API endpoint lambda function that accepts an uploaded binary file.

Try this:

git clone git@github.com:awslabs/aws-sam-local.git
cd aws-sam-local/samples/api-event-source
sam local start-api

and then in a new shell, from the aws-sam-local folder:

curl --request POST --url 'http://localhost:3000/' --data-binary '@./sam-banner.png'

The response I get to curl is { "message": "Internal server error" }.

Back in the first shell, I see this output:

2017/11/01 23:05:55 Connected to Docker 1.32
2017/11/01 23:05:55 Fetching lambci/lambda:nodejs6.10 image for nodejs6.10 runtime...
nodejs6.10: Pulling from lambci/lambda
Digest: sha256:7eb4ced6a15ae3c30effc4ec0cd3aabb2bd57c9a8330b37920c3d5d722d81083
Status: Image is up to date for lambci/lambda:nodejs6.10

Mounting index.handler (nodejs6.10) at http://127.0.0.1:3000/ [OPTIONS GET HEAD POST PUT DELETE TRACE CONNECT]
Mounting static files from public at /

You can now browse to the above endpoints to invoke your functions.
You do not need to restart/reload SAM CLI while working on your functions,
changes will be reflected instantly/automatically. You only need to restart
SAM CLI if you update your AWS SAM template.

2017/11/01 23:06:19 Invoking index.handler (nodejs6.10)
standard_init_linux.go:185: exec user process caused "argument list too long"
2017/11/01 23:06:25 Function index.handler timed out after 3 seconds
2017/11/01 23:06:25 Error invoking nodejs6.10 runtime: io: read/write on closed pipe

If I remove the --data-binary, to send a POST request without a body, I get the expected OK response.

If I change --data-binary '@./sam-banner.png' to --data-binary '@./README.md', replacing the 129 KB file with a 21 KB one, I also get the OK response. So I gather that there must be some (fairly low) limit on request size? Is there some way I can increase it?

Also, I feel like aws-sam-local should print an informative error message, rather than (I presume) passing invalid parameters onward to Docker for it to throw an exception on.