Handling API rate limits

When making requests to APIs, it's common to encounter rate limits that restrict the number of calls you can make within a certain time frame. Copilot Chat can help you handle these limits by suggesting code to detect rate limit responses and automatically retry requests after a delay.

The following Python code fetches weather data from an external API. If the API has rate limits, requests may fail when limits are exceeded, and your app may need a way to handle these responses gracefully by implementing retry logic.

from flask import Flask, request
import requests

app = Flask(__name__)

WEATHER_API_URL = "https://api.example.com/weather"

@app.route('/get_weather', methods=['GET'])
def get_weather():
    city = request.args.get('city')
    # Simulate an API request to the external weather service
    response = requests.get(WEATHER_API_URL, params={"city": city})
    weather_data = response.json()

    return weather_data

How can I handle API rate limits within get_weather().

Copilot might suggest code that implements a retry mechanism with exponential backoff to limit the frequency of retry attempts.

For example:

import requests
from flask import Flask, request
from requests.adapters import HTTPAdapter
from requests.packages.urllib3.util.retry import Retry

app = Flask(__name__)

WEATHER_API_URL = "https://api.example.com/weather"

def requests_retry_session(
    retries=3,
    backoff_factor=0.3,
    status_forcelist=(500, 502, 504),
    session=None,
):
    session = session or requests.Session()
    retry = Retry(
        total=retries,
        read=retries,
        connect=retries,
        backoff_factor=backoff_factor,
        status_forcelist=status_forcelist,
    )
    adapter = HTTPAdapter(max_retries=retry)
    session.mount("http://", adapter)
    session.mount("https://", adapter)
    return session

@app.route('/get_weather', methods=['GET'])
def get_weather():
    city = request.args.get('city')
    try:
        response = requests_retry_session().get(WEATHER_API_URL, params={"city": city})
        response.raise_for_status()
        weather_data = response.json()
    except requests.exceptions.RequestException as e:
        return {"error": str(e)}, 500

    return weather_data

In this example, Copilot's suggestions include setting up a retry session that allows the code to automatically retry requests if they fail due to specific status codes (500, 502, 504). The backoff_factor gradually increases the delay between retries, helping avoid exceeding the API's rate limit further.

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