DataOps-platform/app/core/events/consumer.py

from __future__ import annotations

import re
from dataclasses import dataclass
from datetime import datetime, timedelta, timezone
from typing import Any, Callable


@dataclass(frozen=True)
class ClaimedEvent:
    event_id: str
    event_type: str
    payload: dict[str, Any]
    attempts: int


@dataclass(frozen=True)
class DispatchResult:
    status: str
    attempts: int
    available_at: datetime | None = None
    last_error: str | None = None
    record_consumption: bool = False


def retry_delay(
    attempts: int,
    *,
    base_seconds: int = 2,
    maximum_seconds: int = 300,
) -> timedelta:
    seconds = min(maximum_seconds, base_seconds * (2 ** max(0, attempts - 1)))
    return timedelta(seconds=seconds)


def _redact_error(error: Exception) -> str:
    message = str(error)
    message = re.sub(
        r"(?i)(secret[-_ ]?token|api[-_ ]?key|authorization|bearer)(?:[=: ]+\S+)?",
        "[redacted]",
        message,
    )
    return message[:1000]


def dispatch_event(
    event: ClaimedEvent,
    handler: Callable[[dict[str, Any]], None],
    *,
    already_processed: bool = False,
    max_attempts: int = 5,
    now: datetime | None = None,
) -> DispatchResult:
    if already_processed:
        return DispatchResult(status="published", attempts=event.attempts)

    now = now or datetime.now(timezone.utc)
    try:
        handler(event.payload)
    except Exception as exc:
        attempts = event.attempts + 1
        if attempts >= max_attempts:
            return DispatchResult(
                status="dead_letter",
                attempts=attempts,
                last_error=_redact_error(exc),
            )
        return DispatchResult(
            status="pending",
            attempts=attempts,
            available_at=now + retry_delay(attempts),
            last_error=_redact_error(exc),
        )

    return DispatchResult(
        status="published",
        attempts=event.attempts + 1,
        record_consumption=True,
    )