Handling errors

# Errors are application/problem+json; -i shows the Request-Id and Retry-After headers too.
curl -sS -i -G https://api.alura.io/v1/research/products \
  -H "Authorization: Bearer $ALURA_API_KEY" \
  --data-urlencode "q=mug" \
  --data-urlencode "sort_by=price"

interface Problem {
  code: string;
  detail: string;
  suggestion: string;
  retryable: boolean;
  request_id: string;
}

/** GET an Alura path, retrying errors marked `retryable` (up to 3 attempts). */
async function alura(path: string, attempts = 3): Promise<Response> {
  for (let attempt = 1; ; attempt++) {
    const res = await fetch(`https://api.alura.io${path}`, { headers: { Authorization: `Bearer ${process.env.ALURA_API_KEY}` } });
    if (res.ok || attempt >= attempts) return res;
    const problem = (await res.clone().json()) as Problem;
    if (!problem.retryable) return res;
    // Retry-After is in seconds; without it, back off 2, 4, 8... seconds.
    const wait = Number(res.headers.get('Retry-After') ?? 2 ** attempt);
    await new Promise((resolve) => setTimeout(resolve, wait * 1000));
  }
}

const res = await alura('/v1/research/products?q=mug&sort_by=price');
if (!res.ok) {
  const problem = (await res.json()) as Problem;
  console.log(`${res.status} ${problem.code}: ${problem.suggestion}`);
}

import json
import os
import time
import urllib.error
import urllib.request


def alura(path, attempts=3):
    """GET an Alura path, retrying errors marked `retryable` (up to 3 attempts). Returns (status, body)."""
    for attempt in range(1, attempts + 1):
        request = urllib.request.Request(
            f"https://api.alura.io{path}",
            headers={"Authorization": f"Bearer {os.environ['ALURA_API_KEY']}"},
        )
        try:
            with urllib.request.urlopen(request) as response:
                return response.status, json.load(response)
        except urllib.error.HTTPError as error:
            problem = json.load(error)
            if not problem["retryable"] or attempt == attempts:
                return error.code, problem
            # Retry-After is in seconds; without it, back off 2, 4, 8... seconds.
            time.sleep(int(error.headers.get("Retry-After") or 2**attempt))


status, body = alura("/v1/research/products?q=mug&sort_by=price")
if status >= 400:
    print(f"{status} {body['code']}: {body['suggestion']}")