diff_tracer 0.0.1

No project description provided

DIFF TRACER

A FastAPI utility designed to compare two API responses, making it easier to validate behavior and ensure accuracy during refactoring.

[!WARNING] Please keep in mind that Diff Tracer is still under active development

Installation

❯ pip install diff_tracer

Basic Usage

To compare two results:

from diff_tracer import compare_async

@app.get("/")
async def get_data():
    return await compare_async(
        current_fn=lambda: currentUseCase(), # current function in production
        new_fn=lambda: newUseCase(), # new refactored function
        percentage=80, # percentage of requests to compare, good to control expensive endpoints
    )

Active the dashboard endpoint in your main file:

from fastapi import FastAPI
from diff_tracer import init_web_view


app = FastAPI()


init_web_view(app=app, security_token="362a9b3f302542deb3184671bbc3e7da")

Access http://localhost:{PORT}/diff-tracer-view/362a9b3f302542deb3184671bbc3e7da to view the dashboard.

Check a full working example on ./diff_tracer/fastapi_example.py

Why

I used this aproach while working on a major endpoint refactor at my current company. The endpoint was critical but lacked comprehensive tests, making it challenging to ensure the refactored function behaved identically to the original. While I wrote some tests, I wanted an extra layer of confidence before deploying to production.

Known issues

• The dashboard endpoint is not secure. You can set a token to make it harder to access, but it's still not secure.
• The files are saved local on your API, so everytime you make a new deploy they will be erased.
  
  

Contributing

For local development just install the libraries and start the FastAPI example file:

❯ poetry install
❯ poetry run task start_api

Access http://localhost:8000/users to simulate requests.

Access http://localhost:8000/diff-tracer-view/1234 to view de dashboard. 1234 is the default token.

To run the tests:

❯ poetry run task test

Thanks to

The code that makes the comparison is from Google Diff, Match and Patch Library written by Neil Fraser Copyright (c) 2006 Google Inc. http://code.google.com/p/google-diff-match-patch/