Structlog processor

[apelsynca]

Short summary:

1: changed relative imports to absolute.

2:
added LogTideProcessor based on structlog, and tests for that. (and fixed tests)
does not requires structlog to be installed.

usage example:

from logtide_sdk.structlog import LogTideProcessor

# then somewhere in code:

structlog.configure_once(processors=[
    ...,
    ...,
    LogtideProcessor(client=logtide_client, service="service_name_string")
]

[Polliog]

@
Thanks for this! A few things before merge:

1. Blocker: middleware/__init__.py uses wrong absolute imports — logtide_sdk.flask should be logtide_sdk.middleware.flask (same for django/fastapi/starlette). Since they are in try/except ImportError: pass, all middleware silently fail to import (__all__ becomes []).

2. The pydantic quickfix does not fully work. Adding default=repr only fixes the size calc. _process_value leaves unknown objects untouched, and the actual send (_send_logs/_send_batch) posts with json=payload and no default=, so it still raises TypeError at flush time. I would prefer your other idea: do the repr/serialization inside LogTideProcessor so metadata is JSON-safe before it reaches the SDK. Let us drop the json.dumps(..., default=repr) change.

3. frozenset[str] annotation in structlog.py breaks Python 3.8 (PEP 585 needs 3.9+), and we declare requires-python = ">=3.8". Use typing.FrozenSet or from __future__ import annotations.

The structlog processor itself looks good 👍
@