Retry Strategies

import time
import requests

def api_call_with_retry(
    url: str,
    headers: dict,
    max_retries: int = 3,
    initial_delay: float = 1.0
) -> dict:
    """
    Call an API with exponential backoff retry.
    Retries only on transient errors (5xx, timeout, network).
    """
    delay = initial_delay

    for attempt in range(max_retries + 1):
        try:
            response = requests.get(url, headers=headers, timeout=10)

            if response.status_code == 200:
                return {"status": "success", "data": response.json()}

            if response.status_code == 429:
                # Rate limited — wait for server's suggested time
                retry_after = int(response.headers.get("Retry-After", delay))
                print(f"Rate limited. Waiting {retry_after}s...")
                time.sleep(retry_after)
                continue

            if 400 <= response.status_code < 500:
                # Client error — do NOT retry
                return {"status": "error", "error_type": "client",
                        "error": f"HTTP {response.status_code} — not retrying"}

            # 5xx — retry with backoff
            if attempt < max_retries:
                print(f"Server error {response.status_code}. Retry {attempt+1}/{max_retries} in {delay:.1f}s")
                time.sleep(delay)
                delay *= 2  # exponential backoff: 1s, 2s, 4s...

        except (requests.Timeout, requests.ConnectionError) as e:
            if attempt < max_retries:
                print(f"Network error. Retry {attempt+1}/{max_retries} in {delay:.1f}s")
                time.sleep(delay)
                delay *= 2
            else:
                return {"status": "error", "error_type": "network",
                        "error": f"Failed after {max_retries} retries: {str(e)}"}

    return {"status": "error", "error_type": "max_retries",
            "error": f"Gave up after {max_retries} retries"}

# Test
result = api_call_with_retry(
    "https://api.example.com/data",
    headers={"Authorization": "Bearer test-key"}
)
print(result["status"])