65 lines
1.7 KiB
Python
65 lines
1.7 KiB
Python
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"""Retry and reconnect helpers for transient MT5 failures."""
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from __future__ import annotations
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import logging
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import time
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from typing import TYPE_CHECKING, TypeVar
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from .exceptions import is_recoverable_mt5_error
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if TYPE_CHECKING:
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from collections.abc import Callable
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T = TypeVar("T")
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logger = logging.getLogger(__name__)
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__all__ = [
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"retry_with_backoff",
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]
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def retry_with_backoff(
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fn: Callable[[], T],
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*,
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retry_count: int = 0,
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backoff_base: float = 2.0,
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operation: str = "MT5 operation",
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) -> T:
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"""Call ``fn`` with bounded exponential backoff on recoverable MT5 errors.
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Only ``pdmt5.Mt5RuntimeError`` and ``pdmt5.Mt5TradingError`` are retried.
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Other exceptions propagate immediately. The final failure is re-raised once
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retries are exhausted.
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Args:
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fn: Callable performing MT5 work.
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retry_count: Maximum number of retries after the first attempt. ``0``
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disables retries.
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backoff_base: Base for exponential backoff. The delay before retry
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attempt ``n`` (1-indexed) is ``backoff_base ** n`` seconds.
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operation: Label used in warning logs.
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Returns:
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Value returned by ``fn`` on success.
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"""
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attempts = max(retry_count, 0) + 1
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for attempt in range(attempts - 1):
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try:
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return fn()
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except Exception as exc:
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if not is_recoverable_mt5_error(exc):
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raise
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delay = backoff_base ** (attempt + 1)
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logger.warning(
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"%s failed (attempt %d/%d): %s; retrying in %.1fs",
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operation,
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attempt + 1,
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attempts,
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exc,
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delay,
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)
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time.sleep(delay)
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return fn()
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