Errors

import requests

resp = requests.post(
    "https://api-sandbox.ledgersyncappv2.com/v3/clients/cli_01HXYZ/connections",
    headers={"Authorization": "Bearer sk_test_..."},
    json={"institution_id": "ins_3c97c5da90335a04"},
)

trace_id = resp.headers.get("X-LS-Trace-Id")

if resp.ok:
    operation = resp.json()
else:
    err = resp.json()["error"]
    log.warning("LedgerSync code=%s status=%s trace=%s",
                err["code"], resp.status_code, trace_id)

    code = err["code"]
    if code in ("credentials_invalid", "mfa_required", "mfa_expired",
                "reauthorization_required", "agreement_required"):
        send_user_back_through_widget(...)      # re-auth
    elif code in ("institution_unavailable", "source_rate_limited",
                  "source_internal_error", "upstream_unavailable"):
        retry_with_backoff(...)                 # credentials are fine
    elif code == "not_found":
        ...                                     # fix the id
    elif resp.status_code == 401:
        ...                                     # bad key — don't retry
    elif resp.status_code == 429:
        backoff_and_retry(...)                  # see Rate limiting

const resp = await fetch(
  "https://api-sandbox.ledgersyncappv2.com/v3/clients/cli_01HXYZ/connections",
  {
    method: "POST",
    headers: {
      Authorization: "Bearer sk_test_...",
      "Content-Type": "application/json",
    },
    body: JSON.stringify({ institution_id: "ins_3c97c5da90335a04" }),
  }
);

const traceId = resp.headers.get("X-LS-Trace-Id");

if (!resp.ok) {
  const { error } = await resp.json();
  console.warn(`LedgerSync code=${error.code} status=${resp.status} trace=${traceId}`);

  const reauth = ["credentials_invalid", "mfa_required", "mfa_expired",
                  "reauthorization_required", "agreement_required"];
  const retry = ["institution_unavailable", "source_rate_limited",
                 "source_internal_error", "upstream_unavailable"];

  if (reauth.includes(error.code)) sendUserBackThroughWidget();
  else if (retry.includes(error.code)) retryWithBackoff();
  else if (error.code === "not_found") { /* fix the id */ }
  else if (resp.status === 401) { /* bad key — don't retry */ }
  else if (resp.status === 429) backoffAndRetry();
}

import time, random

def call_with_backoff(do_request, max_attempts=5):
    for attempt in range(max_attempts):
        resp = do_request()
        if resp.status_code != 429:
            return resp
        wait = float(resp.headers.get("Retry-After", (2 ** attempt))) + random.random()
        time.sleep(wait)
    return resp  # give up; log the trace id and escalate

async function callWithBackoff(doRequest, maxAttempts = 5) {
  let resp;
  for (let attempt = 0; attempt < maxAttempts; attempt++) {
    resp = await doRequest();
    if (resp.status !== 429) return resp;
    const retryAfter = Number(resp.headers.get("Retry-After")) || 2 ** attempt;
    await new Promise((r) => setTimeout(r, retryAfter * 1000 + Math.random() * 1000));
  }
  return resp; // give up; log the trace id and escalate
}