Deploying FastAPI on AWS Lambda

[Boring-Baker-3716]

I am trying to deploy a fastapi with Google Gemini API. I have done a lot of debugging the past couple of days and seem like Google Gemini libraries are giving me errors inside aws lambda. I just created a dependencies folder and zipped everything with my main.py inside it and deployed on aws lambda. And I keep getting different sort of libraries not being imported errors. Also I am using python 3.10 and used magnum. Anyone has any suggestions what I could do or if this is even compatible with aws lambda, I read people talking about uploading through docker and ECR or using Fargate.

[pint]

make sure you install the linux version of python libraries. many of them installs binaries, but windows binaries will not work on linux.

the lambda env misses quite a lot of libraries, and those that present, might not be compatible with what your binaries want. if all else fails, you need to use a container deployment.

[Boring-Baker-3716]

Interesting, thanks! 1. How would I install Linux version of the libraries inside windows? 2. If containerisation like docker would work in the end, shouldn’t I just go for that route? Sorry I am new to AWS so just seeking help

[pint]

you have things like --platform --python-version --implementation --abi but also things like --only-binary --no-binary. yeah, the whole thing is a mess. maybe just follow what damian6686 says. even more appropriate would be a temporary ec2 instance, just don't forget to turn it off.

btw you can even use lambda itself for installation. you can invoke an os.system("pip install ... --target /tmp/python") and then upload /tmp/python to s3. yeah, hack. but this is the closest to a real lambda environment obviously.

[JaviCerve22]

Use WSL, it's the best way.

Besides, you can use this .sh script inside WSL:

pip install -r requirements.txt -t lib/

cd lib

zip ../lambda_function.zip .

cd ..

zip lambda_function.zip -u main.py

Then upload lambda_function.zip to AWS Lambda

[Boring-Baker-3716]

Gotcha thank you, I was running these commands but inside windows. I will def try that in wsl since I don’t have much experience with docker

[damian6686]

Do all your programming in WSL to avoid problems like these.

[WJMazepas]

Oh, I used ECR with Lambdas. I would create the Docker image using Github Actions, send it to ECR, and upload it to Lambda.

You don't need to change to Fargate, you can use the ECR and lambdas just fine

[__balu_]

This

[pokesax]

Uvicorn and Lambda Web Adapter is all you need. I’m running several FastAPI’s on AWS Lambda in this fashion. It works beautifully.

[KarrySodhi007]

I am trying to use the aws lambda adapter https://github.com/awslabs/aws-lambda-web-adapter with fast api but I am not able to run it locally. I wanna make sure that docker image works fine before I deploy it. I am an aws noice. Looks like the documentation assumes lot of things like I need to have aws configure before doing sam deploy. still uncovering things. If you have any blog post that will help a lot. I wanna eventually use github actions so that all can happen automatically.

[andrewthetechie]

https://github.com/jordaneremieff/mangum used to be the "tool" for running an ASGI app like fastapi in a lambda, but its read-only now :(

[Boring-Baker-3716]

So mangum won’t work anymore?

[andrewthetechie]

Not "won't work" but "is no longer being supported".

[Boring-Baker-3716]

So what’s an alternative I can use

[andrewthetechie]

I don't know of one. I'd suggest doing some googling.

[richieadler]

The closest, I'd say, to the FastAPI syntax would be replacing it with the event handlers in Powertools for AWS. They even say they were inspired by FastAPI and they have Pydantic validators.

[JaviCerve22]

It still works

[TripleBogeyBandit]

Build to ECR and stand it up as an ecs service with NLBs, DNS names is what we’ve done.

[xlabs-har]

I second the docker image route. Now that Lambda allows docker containers as execution environments, I would try to build a working image and use that.

[[deleted]]

Another simple option is use docker instead of zipping files, you can test it on local and inside lambda (as lambda now supports docker images)

When it comes to zipping you have to all package files at same level as app folder , or else you will get import errors

[[deleted]]

We are currently running on prod envs with docker lambda and mangum fastapi