Rate limits and retries

const sleep = (ms) => new Promise((r) => setTimeout(r, ms));

async function meliora(path, params = {}, maxAttempts = 6) {
  const url = new URL(`https://api.melioralab.io/v1${path}`);
  for (const [k, v] of Object.entries(params)) url.searchParams.set(k, v);
  for (let attempt = 1; ; attempt++) {
    let res;
    try {
      res = await fetch(url, {
        headers: { Authorization: `Bearer ${process.env.MELIORA_API_KEY}` },
        signal: AbortSignal.timeout(15_000),
      });
    } catch (networkError) {
      if (attempt >= maxAttempts) throw networkError;
      await sleep(Math.min(60, 2 ** attempt) * 1000);
      continue;
    }
    if (res.ok) return res.json();
    const problem = await res.json().catch(() => ({}));
    if ((res.status === 429 || res.status === 503) && attempt < maxAttempts) {
      const base = Number(res.headers.get('Retry-After')) || 5;
      const wait = Math.min(60, base * (res.status === 503 ? 2 ** (attempt - 1) : 1));
      await sleep((wait + Math.random() * Math.max(1, wait * 0.25)) * 1000);
      continue;
    }
    const error = new Error(`Meliora API ${res.status} ${problem.code ?? ''}`);
    Object.assign(error, { status: res.status, code: problem.code, requestId: res.headers.get('Request-Id') });
    throw error;
  }
}

import os
import random
import time

import requests

session = requests.Session()
session.headers["Authorization"] = f"Bearer {os.environ['MELIORA_API_KEY']}"


class MelioraError(Exception):
    def __init__(self, status, code, request_id):
        super().__init__(f"Meliora API {status} {code}")
        self.status, self.code, self.request_id = status, code, request_id


def meliora(path, params=None, max_attempts=6):
    for attempt in range(1, max_attempts + 1):
        try:
            resp = session.get(f"https://api.melioralab.io/v1{path}", params=params, timeout=15)
        except requests.RequestException:
            if attempt == max_attempts:
                raise
            time.sleep(min(60, 2 ** attempt))
            continue
        if resp.ok:
            return resp.json()
        if resp.status_code in (429, 503) and attempt < max_attempts:
            base = int(resp.headers.get("Retry-After", "5"))
            wait = min(60, base * (2 ** (attempt - 1) if resp.status_code == 503 else 1))
            time.sleep(wait + random.uniform(0, max(1, wait * 0.25)))
            continue
        try:
            code = resp.json().get("code")
        except ValueError:
            code = None
        raise MelioraError(resp.status_code, code, resp.headers.get("Request-Id"))
    raise RuntimeError("unreachable")