Add Retries to the Payment Client: Code Review Practice

Charges sometimes fail on a flaky network, and checkout shows an error. This retries the charge with exponential backoff and moves the API key and retry count into config.py.

Mpayments/client.py1 of 3

Files Changed

payments/

tests/

payments/client.py

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@@ -1,20 +1,28 @@

import logging

import os

import time

import requests

from payments.config import API_KEY, MAX_RETRIES

log = logging.getLogger(__name__)

BASE_URL = "https://api.payments.example.com/v1"

class PaymentClient:

def __init__(self, http=None):

self.http = http or requests.Session()

self.http.headers["Authorization"] = f"Bearer {os.environ['PAYMENTS_API_KEY']}"

self.http.headers["Authorization"] = f"Bearer {API_KEY}"

def charge(self, amount_cents, card_token):

body = {"amount": amount_cents, "currency": "usd", "source": card_token}

resp = self.http.post(f"{BASE_URL}/charges", json=body, timeout=10)

for attempt in range(MAX_RETRIES):

try:

resp = self.http.post(f"{BASE_URL}/charges", json=body, timeout=10)

break

except Exception:

log.warning("charge failed, retrying (attempt %d)", attempt)

time.sleep(2 ** attempt)

resp.raise_for_status()

return resp.json()

payments/client.py

payments/config.py

tests/test_client.py