Fix InternalLogger to properly register with logging hierarchy

[jkebinger]

Problem

InternalLogger instances were not being registered with Python's logging manager, causing several issues:

• No parent logger: InternalLogger instances had parent = None
• No handler propagation: logging.basicConfig() and parent logger handlers had no effect
• Invisible internal logs: Users couldn't see Prefab's internal logs (config loading, checkpoint updates, etc.) without manual workarounds

Example of the issue:

import logging
logging.basicConfig(level=logging.DEBUG)

from prefab_cloud_python._internal_logging import InternalLogger
logger = InternalLogger('prefab_cloud_python.config_client')
logger.info('This message was invisible')  # Would not appear

Solution

This PR fixes the issue by properly integrating InternalLogger with Python's logging system:

1. Register with logging manager (lines 72-94)

• Registers each InternalLogger instance with logging.Logger.manager.loggerDict
• Sets up parent loggers in the hierarchy (adapted from Python's _fixupParents)
• Ensures proper handler propagation through the logger tree

2. Fix prefab_internal attribute injection (lines 96-126)

• Changed from overriding log() to overriding _log()
• This is necessary because info(), debug(), etc. call _log() directly, not log()
• Properly adds prefab_internal=True to the extra dict on all log records

Compatibility

✅ Standard logging: Works with basicConfig() and manual handler configuration
✅ Structlog: Works when structlog is configured to use stdlib logging
✅ Maintains prefab_internal attribute: Still adds the extra attribute to identify Prefab's internal logs

Testing

Tested with both standard logging and structlog:

import logging
logging.basicConfig(level=logging.DEBUG)

from prefab_cloud_python._internal_logging import InternalLogger
logger = InternalLogger('prefab_cloud_python.config_client')
logger.info('This message now appears correctly')
# Output: INFO:prefab_cloud_python.config_client:This message now appears correctly

Impact

This fix allows users to see important Prefab internal logs such as:

• Config version updates (highwater marks)
• Checkpoint synchronization
• SSE stream connections
• Configuration initialization

Previously, these logs were invisible unless users manually configured handlers for Prefab's loggers.

🤖 Generated with Claude Code

[jdwyah]

thanks