Retries og backoff

import os
import random
import time

import requests

PROEV_IGEN_STATUS = {429, 502, 503, 504}
ALDRIG_KODER = {"quota_exceeded", "rate_limit_exceeded"}


def fejlkode(r: requests.Response) -> str | None:
    try:
        body = r.json()
    except ValueError:
        return None
    return body.get("code") or (body.get("error") or {}).get("code")


def hent_med_retry(session, url, params=None, forsoeg=5, base=0.5, loft=30.0):
    for n in range(forsoeg):
        sidste = n == forsoeg - 1
        try:
            r = session.get(url, params=params, timeout=10)
        except (requests.ConnectionError, requests.Timeout):
            if sidste:
                raise
            time.sleep(random.uniform(0, min(loft, base * 2 ** n)))
            continue
        if r.status_code not in PROEV_IGEN_STATUS or fejlkode(r) in ALDRIG_KODER or sidste:
            r.raise_for_status()
            return r
        vent = random.uniform(0, min(loft, base * 2 ** n))
        retry_after = r.headers.get("Retry-After", "")
        if retry_after.isdigit():
            vent = max(vent, float(retry_after))
        time.sleep(min(vent, loft))
    raise RuntimeError("ikke nået")


session = requests.Session()
session.headers["X-Api-Key"] = os.environ["DANADRESSE_API_KEY"]
r = hent_med_retry(session, "https://api.danadresse.dk/autocomplete",
                   params={"q": "Rådhuspladsen 1", "per_side": 1})
print(r.json()[0]["forslagstekst"])

const PROEV_IGEN_STATUS = new Set([429, 502, 503, 504]);
const ALDRIG_KODER = new Set(["quota_exceeded", "rate_limit_exceeded"]);
const sov = (ms) => new Promise((r) => setTimeout(r, ms));

async function fejlkode(res) {
  try {
    const body = await res.clone().json();
    return body.code ?? body.error?.code ?? null;
  } catch {
    return null;
  }
}

export async function hentMedRetry(url, init = {}, { forsoeg = 5, base = 500, loft = 30000 } = {}) {
  for (let n = 0; n < forsoeg; n++) {
    const sidste = n === forsoeg - 1;
    let res;
    try {
      res = await fetch(url, { ...init, signal: AbortSignal.timeout(10000) });
    } catch (err) {
      if (sidste) throw err;
      await sov(Math.random() * Math.min(loft, base * 2 ** n));
      continue;
    }
    if (!PROEV_IGEN_STATUS.has(res.status) || ALDRIG_KODER.has(await fejlkode(res)) || sidste) {
      if (!res.ok) throw new Error(`HTTP ${res.status}: ${await res.text()}`);
      return res;
    }
    let vent = Math.random() * Math.min(loft, base * 2 ** n);
    const retryAfter = Number(res.headers.get("retry-after"));
    if (retryAfter > 0) vent = Math.max(vent, retryAfter * 1000);
    await sov(Math.min(vent, loft));
  }
  throw new Error("ikke nået");
}

const url = new URL("https://api.danadresse.dk/autocomplete");
url.search = new URLSearchParams({ q: "Rådhuspladsen 1", per_side: "1" });
const res = await hentMedRetry(url, { headers: { "X-Api-Key": process.env.DANADRESSE_API_KEY } });
console.log((await res.json())[0].forslagstekst);

<?php
function hentMedRetry(string $url, string $apiKey, int $forsoeg = 5, float $base = 0.5, float $loft = 30.0): array
{
    for ($n = 0; $n < $forsoeg; $n++) {
        $sidste = $n === $forsoeg - 1;
        $retryAfter = null;
        $ch = curl_init($url);
        curl_setopt_array($ch, [
            CURLOPT_RETURNTRANSFER => true,
            CURLOPT_TIMEOUT => 10,
            CURLOPT_HTTPHEADER => ["X-Api-Key: $apiKey"],
            CURLOPT_HEADERFUNCTION => function ($ch, $linje) use (&$retryAfter) {
                if (stripos($linje, 'Retry-After:') === 0) {
                    $retryAfter = (int) trim(substr($linje, 12));
                }
                return strlen($linje);
            },
        ]);
        $body = curl_exec($ch);
        $status = curl_getinfo($ch, CURLINFO_RESPONSE_CODE);
        $netfejl = curl_errno($ch) !== 0;
        curl_close($ch);

        $jitter = mt_rand() / mt_getrandmax() * min($loft, $base * 2 ** $n);
        if ($netfejl) {
            if ($sidste) {
                throw new RuntimeException('Netværksfejl');
            }
            usleep((int) ($jitter * 1e6));
            continue;
        }
        $data = json_decode($body, true) ?? [];
        $kode = $data['code'] ?? ($data['error']['code'] ?? null);
        $proevIgen = in_array($status, [429, 502, 503, 504], true)
            && !in_array($kode, ['quota_exceeded', 'rate_limit_exceeded'], true);
        if (!$proevIgen || $sidste) {
            if ($status >= 400) {
                throw new RuntimeException("HTTP $status: $body");
            }
            return $data;
        }
        $vent = max($jitter, (float) ($retryAfter ?? 0));
        usleep((int) (min($vent, $loft) * 1e6));
    }
    throw new RuntimeException('ikke nået');
}

$data = hentMedRetry(
    'https://api.danadresse.dk/autocomplete?q=' . rawurlencode('Rådhuspladsen 1') . '&per_side=1',
    getenv('DANADRESSE_API_KEY')
);
echo $data[0]['forslagstekst'], PHP_EOL;