Magnus Persson
Add the Hugging Face image adapter, billing-safe retries and try_image script
6494c95 | """Shared HTTP call for provider adapters: retries, deadline and typed errors (spec section 7). | |
| Retries only on 429, 500, 502, 503, 504 and network timeouts or drops: at most 2, with | |
| exponential backoff and jitter, and never beyond the total time budget. Nothing from a response | |
| body or a request (prompts, keys, image bytes) is logged or put into an exception. | |
| """ | |
| from __future__ import annotations | |
| import asyncio | |
| import logging | |
| import random | |
| import re | |
| import time | |
| from collections.abc import Awaitable, Callable | |
| from typing import Any, TypeVar | |
| import httpx | |
| from src.errors import ProviderError, ProviderTimeoutError, RateLimitedError | |
| logger = logging.getLogger(__name__) | |
| T = TypeVar("T") | |
| MAX_RETRIES = 2 | |
| RETRY_STATUSES = frozenset({429, 500, 502, 503, 504}) | |
| UNBILLED_RETRY_STATUSES = frozenset({429, 503}) # the provider has not started the work | |
| BACKOFF_BASE_SECONDS = 0.5 | |
| BACKOFF_CAP_SECONDS = 4.0 | |
| JITTER_SECONDS = 0.25 | |
| _CODE_SHAPE = re.compile(r"[a-z0-9_.-]{1,60}") | |
| def _backoff(attempt: int, retry_after: str | None, rand: Callable[[], float]) -> float: | |
| delay = min(BACKOFF_BASE_SECONDS * 2**attempt, BACKOFF_CAP_SECONDS) + rand() * JITTER_SECONDS | |
| if retry_after and retry_after.strip().isdigit(): | |
| delay = max(delay, min(float(retry_after), BACKOFF_CAP_SECONDS)) | |
| return delay | |
| class Retry(Exception): | |
| """Raised by one attempt to ask `run_with_retries` for another try.""" | |
| def __init__(self, failure: Exception, retry_after: str | None = None) -> None: | |
| super().__init__() | |
| self.failure = failure # what to raise if the retries run out | |
| self.retry_after = retry_after | |
| async def run_with_retries( | |
| attempt: Callable[[float], Awaitable[T]], | |
| *, | |
| total_timeout: float, | |
| sleep: Callable[[float], Awaitable[None]] = asyncio.sleep, | |
| rand: Callable[[], float] = random.random, | |
| ) -> T: | |
| """Call `attempt(seconds_left)` until it returns, raises a typed error, or the retries or the | |
| total budget run out. An attempt asks for a retry by raising `Retry`. | |
| At most MAX_RETRIES retries, exponential backoff with jitter, and never beyond the budget, | |
| which is enforced as a hard cap. | |
| """ | |
| try: | |
| async with asyncio.timeout(total_timeout): | |
| deadline = time.monotonic() + total_timeout | |
| failure: Exception = ProviderError() | |
| for tried in range(MAX_RETRIES + 1): | |
| remaining = deadline - time.monotonic() | |
| if remaining <= 0: | |
| raise ProviderTimeoutError | |
| try: | |
| return await attempt(remaining) | |
| except Retry as retry: | |
| failure = retry.failure | |
| if tried == MAX_RETRIES: | |
| break | |
| delay = _backoff(tried, retry.retry_after, rand) | |
| if time.monotonic() + delay >= deadline: | |
| break | |
| await sleep(delay) | |
| raise failure | |
| except TimeoutError as exc: | |
| raise ProviderTimeoutError from exc | |
| async def post_json( | |
| client: httpx.AsyncClient, | |
| url: str, | |
| *, | |
| headers: dict[str, str], | |
| payload: dict[str, Any], | |
| total_timeout: float, | |
| what: str, | |
| idempotent: bool = True, | |
| sleep: Callable[[float], Awaitable[None]] = asyncio.sleep, | |
| rand: Callable[[], float] = random.random, | |
| ) -> dict[str, Any]: | |
| """POST `payload` as JSON and return the parsed JSON object, or raise a typed error. | |
| `what` names the call in logs ("openai moderation"). `total_timeout` is the whole budget, | |
| retries and waits included. Set `idempotent=False` for a call that costs money: then only 429 | |
| and 503 are retried (the provider did not start the work), never timeouts or dropped | |
| connections, so a request that may already be billed is not sent twice. | |
| """ | |
| retry_statuses = RETRY_STATUSES if idempotent else UNBILLED_RETRY_STATUSES | |
| tries = 0 | |
| async def attempt(remaining: float) -> dict[str, Any]: | |
| nonlocal tries | |
| tries += 1 | |
| try: | |
| response = await client.post(url, headers=headers, json=payload, timeout=remaining) | |
| except httpx.TimeoutException: | |
| logger.warning("%s: timeout (attempt %d)", what, tries) | |
| raise ( | |
| Retry(ProviderTimeoutError()) if idempotent else ProviderTimeoutError() | |
| ) from None | |
| except httpx.TransportError as exc: | |
| logger.warning("%s: %s (attempt %d)", what, type(exc).__qualname__, tries) | |
| raise (Retry(ProviderError()) if idempotent else ProviderError()) from exc | |
| except httpx.HTTPError as exc: | |
| logger.error("%s: %s, not retried", what, type(exc).__qualname__) | |
| raise ProviderError from exc | |
| status = response.status_code | |
| if status < 400: | |
| return _json_object(response, what) | |
| if status not in retry_statuses: | |
| logger.error("%s: HTTP %d (%s), not retried", what, status, _error_code(response)) | |
| raise ProviderError | |
| logger.warning("%s: HTTP %d (%s) (attempt %d)", what, status, _error_code(response), tries) | |
| raise Retry( | |
| RateLimitedError() if status == 429 else ProviderError(), | |
| response.headers.get("retry-after"), | |
| ) | |
| return await run_with_retries(attempt, total_timeout=total_timeout, sleep=sleep, rand=rand) | |
| def _error_code(response: httpx.Response) -> str: | |
| """The provider's short machine code for an error (for example "invalid_api_key"), or "-". | |
| Only a code-shaped token is returned, never the message, which could echo request content. | |
| """ | |
| try: | |
| error = response.json().get("error") | |
| except (ValueError, AttributeError): | |
| return "-" | |
| if isinstance(error, dict): | |
| for key in ("code", "type"): | |
| value = error.get(key) | |
| if isinstance(value, str) and _CODE_SHAPE.fullmatch(value): | |
| return value | |
| return "-" | |
| def _json_object(response: httpx.Response, what: str) -> dict[str, Any]: | |
| try: | |
| data = response.json() | |
| except ValueError as exc: | |
| logger.error("%s: the reply was not JSON", what) | |
| raise ProviderError from exc | |
| if not isinstance(data, dict): | |
| logger.error("%s: the reply was not a JSON object", what) | |
| raise ProviderError | |
| return data | |