stdlogging

Redirect stdout/stderr (or any stream) to a Python logger using an adapter class.

The stdlogging module provides a StreamToLogger adapter class and an initStream convenience function for redirecting any stream-like object (typically sys.stderr or sys.stdout) to a Python logging.Logger.

Capturing stdout can be fragile. Use with care and test thoroughly in your environment.

StreamToLogger

Adapter class that wraps a stream-like object and forwards each written line to a logging.Logger.

import sys
import logging
from alexber.utils.stdlogging import StreamToLogger

logging.basicConfig()
logger = logging.getLogger('stdout')

sl = StreamToLogger(logger=logger, stream=sys.stdout, log_level=logging.INFO)
sys.stdout = sl

print('This goes to the logger now')

It is recommended to use initStream() rather than instantiating StreamToLogger directly.

__init__

logger · logging.Logger · required

Standard Python Logger or any logger-compatible object. Cannot be None.

stream · IO · required

The original stream being wrapped (e.g. sys.stderr, sys.stdout). Cannot be None. Used by flush() to delegate flush calls.

log_level · int | str

Log level for emitted messages. Accepts an int constant (e.g. logging.DEBUG) or a level-name string (e.g. 'INFO'). Defaults to logging.DEBUG. The alias logger_level is also accepted.

write(lines)

Writes one or more lines to the logger. Each non-empty line is logged individually at the configured level.

lines · str · required

String content to log. Empty strings are silently ignored.

flush()

Delegates flush() to the underlying stream. Keeps the adapter compatible with the stream protocol.

---

initStream

Preferred API. Wraps a stream with StreamToLogger (or a custom adapter) and redirects it to a logger.

import logging
from alexber.utils.stdlogging import initStream

logging.basicConfig()

# Redirect sys.stderr to a logger named 'stderr' at ERROR level (defaults)
initStream()

# Redirect sys.stdout to a custom logger at INFO level
import sys
initStream(
    logger=logging.getLogger('stdout'),
    logger_level=logging.INFO,
    stream_getter=lambda: sys.stdout,
    stream_setter=lambda s: setattr(sys, 'stdout', s),
)

logger · logging.Logger

Logger to route stream output to. If not supplied, logging.getLogger('stderr') is used.

logger_level · int | str

Log level for emitted messages. Accepts an int constant or a level-name string. Defaults to logging.ERROR.

stream_getter · Callable[[], IO]

Zero-argument callable that returns the stream to wrap. If not supplied, defaults to lambda: sys.stderr.

stream_setter · Callable[[IO], None]

One-argument callable that installs the wrapped adapter in place of the original stream. If not supplied, defaults to lambda s: setattr(sys, 'stderr', s).

adapter_cls · type | str

Adapter class to instantiate. Can be a class or a fully-qualified dotted string resolved via importer. Defaults to StreamToLogger.

Returns: None.