Migrate from Mailgun

email,domain,reason,expires_at
blocked@example.com,YOUR_SENDING_DOMAIN,Migrated unsubscribe,RFC3339_FUTURE_EXPIRY

import csv, hashlib, json, os, sys, time, urllib.error, urllib.request
from datetime import datetime, timezone
with open(sys.argv[1], newline="", encoding="utf-8-sig") as source:
    rows = list(csv.DictReader(source))
fields = ("email", "domain", "reason", "expires_at")
for number, row in enumerate(rows, 1):
    if any(not row.get(field, "").strip() for field in fields):
        raise SystemExit(f"Row {number}: fill every required column")
    expiry = datetime.fromisoformat(row["expires_at"].replace("Z", "+00:00"))
    if expiry.tzinfo is None or expiry <= datetime.now(timezone.utc):
        raise SystemExit(f"Row {number}: use a future expiry with a timezone")
url = f"https://api.ahasend.com/v2/accounts/{os.environ['AHASEND_ACCOUNT_ID']}/suppressions"
for number, row in enumerate(rows, 1):
    payload = {field: row[field].strip() for field in fields}
    encoded = json.dumps(payload, sort_keys=True).encode()
    request = urllib.request.Request(url, encoded, headers={
        "Authorization": f"Bearer {os.environ['AHASEND_IMPORT_KEY']}",
        "Content-Type": "application/json",
        "Idempotency-Key": "import-" + hashlib.sha256(encoded).hexdigest(),
    })
    try:
        with urllib.request.urlopen(request, timeout=15) as response:
            result = json.load(response)
            if response.status != 201 or not result.get("data"):
                raise ValueError("Unexpected import result")
    except (urllib.error.URLError, TimeoutError, ValueError):
        raise SystemExit(f"Stopped at row {number}; inspect it before retrying") from None
    print(f"Imported row {number}")
    time.sleep(0.05)