Frank-Mich's Blog

Printing an Aware Date in Python

Posted on 2023/09/072023/11/08 by Frank-Mich L'Heureux

A handy code sample that I keep forgetting about.

from datetime import datetime, timezone

now = datetime.now(tz=timezone.utc)
print(now.astimezone().isoformat())

FastAPI Stripe Webhook Template

Posted on 2023/08/302023/08/30 by Frank-Mich L'Heureux

A FastAPI equivalent for verify-events-came-from-stripe.

import os

from http import HTTPStatus
from typing import Annotated

import stripe
from fastapi import Depends, FastAPI, Header, HTTPException, Request


app = FastAPI()


async def get_body(request: Request) -> bytes:
    return await request.body()


@app.post("/webhook", status_code=HTTPStatus.NO_CONTENT)
def post_report(
    stripe_signature: Annotated[str, Header(alias="stripe-signature")],
    body: bytes = Depends(get_body),
) -> None:
    endpoint_secret = os.environ["ENDPOINT_SECRET"]

    try:
        # signature validation
        event = stripe.Webhook.construct_event(body, stripe_signature, endpoint_secret)
    except ValueError as e:
        # Invalid payload
        raise HTTPException(status_code=HTTPStatus.BAD_REQUEST) from e
    except stripe.error.SignatureVerificationError as e:
        # Invalid signature
        raise HTTPException(status_code=HTTPStatus.UNPROCESSABLE_ENTITY) from e

    print(event)

    return

A possible catch, one that I ran into, is that I had FastAPI convert the request.body to a dictionary in the function parameters (so body: dict). Then I serialized it to a string for the validation step… and it failed because it was no longer identical to what came in.

Serverless: How to share the ids of an existing API Gateway

Posted on 2023/01/312023/01/31 by Frank-Mich L'Heureux

The serverless documentation indicates how to share the ids of an API Gateway, but the technique described there seems to work only for a new deployment. (In my case, following this technique created a 2nd empty API Gateway whose ids were shared, which was, unsurprisingly, not fulfilling my needs).

Here is how to do it for an existing deployment.

Python Type Hinting: To hint or to cast?

Posted on 2022/12/062022/12/06 by Frank-Mich L'Heureux

During a code review, a colleague, Zachary Paden, asked me why I was calling the typing.cast function on my variables rather than creating temporary variables just to type hint. Well, just as he didn’t know about cast, I didn’t know that this approach worked. Being the nerdz that we are, he decided to measure the performance of each approach.

boto3 – From monkeypatch to moto

Posted on 2022/11/182022/11/18 by Frank-Mich L'Heureux

Today, at the suggestion of a college (Zachary Paden), I contemplated the idea of migrating my tests using python/monkeypatch to moto. Here I will share my journey and observations.

Minimize the size of lambdas by deleting boto3 from the deployment package

Posted on 2022/08/292022/08/30 by Frank-Mich L'Heureux

Last April, I wrote a post about managing boto3 in deployed packages. (See Minimizing the size of lambdas by avoiding having boto3 and its stubs in the deployment package). This approach works when all dependencies can be set in the development section.

But, what about when dependencies are required in production? For example, we recently had to deploy a lambda that depends on awswrangler. So the technique suggested in the previous post did not work. Here I will cover a different approach that allows to remove boto3 from the package to be deployed in the example context. It is however less flexible and based on a specific technology: serverless.

Recipe: Run a local copy of a WordPress site with Docker

Posted on 2022/06/212022/06/21 by Frank-Mich L'Heureux

I recently decided to publish my articles in French and in English. First, I had to find and test plugins in order to choose one. So I spent some time, more than I expected, to make it work locally through Docker. Since I encountered some pitfalls, I decided to share the recipe.

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