Console & Output Control

Logly gives you full control over where logs go. You can enable console output, disable it, route logs to files only, or combine multiple destinations.

Disabling Console Output

By default, Logly outputs to stderr. To disable console output and log to files only:

import sys
from logly import logger

# Remove the default stderr handler
logger.remove()

# Add file sinks only
logger.add("app.log", level="DEBUG")
logger.add("errors.log", level="ERROR")

logger.info("This goes to files only, not the console")

Disable Console Globally at Import

Set the LOGLY_AUTOINIT environment variable to false before importing:

import os

os.environ["LOGLY_AUTOINIT"] = "false"

from logly import logger

# No sinks are registered yet
logger.add("app.log", level="INFO")
logger.info("File only")

Or in your shell:

export LOGLY_AUTOINIT=false
python app.py

Enabling Console Output

Add a console sink at any time:

from logly import logger

# Remove defaults first
logger.remove()

# Add stderr
logger.add("stderr", level="INFO", colorize=True)

# Or add stdout
logger.add("stdout", level="DEBUG", colorize=True)

logger.info("Visible on console")

Stdout vs Stderr

Sink	Stream	Typical Use
"stderr" or sys.stderr	Standard error	Default, error messages
"stdout" or sys.stdout	Standard output	Application output

import sys
from logly import logger

logger.remove()

# Info and above to stdout
logger.add("stdout", level="INFO", colorize=True)

# Errors to stderr
logger.add("stderr", level="ERROR", colorize=True)

Colorize Control

The colorize parameter controls ANSI color output:

from logly import logger

logger.remove()

# Force colors on (for pipes, redirect)
logger.add("stderr", colorize=True)

# Force colors off (for files)
logger.add("app.log", colorize=False)

# Auto-detect (default for console sinks)
logger.add("stderr", colorize=None)

colorize	Behavior
None	Auto-detect via .isatty()
True	Always render ANSI colors
False	Strip all color tags

File-Only Logging

from logly import logger

# Remove all existing sinks
logger.remove()

# Application log
logger.add(
    "logs/app.log",
    level="DEBUG",
    rotation="daily",
    retention="30 days",
    compression="gzip",
)

# Error log
logger.add(
    "logs/errors.log",
    level="ERROR",
    rotation="daily",
    retention="90 days",
)

logger.info("This goes to files only")
logger.error("This goes to both files")

Multiple Destinations

from logly import logger

logger.remove()

# Console with colors
logger.add("stderr", level="INFO", colorize=True)

# File without colors
logger.add(
    "app.log",
    level="DEBUG",
    rotation="daily",
    retention="30 days",
)

# JSON to another file
logger.add(
    "app.json",
    level="INFO",
    serialize=True,
    rotation="daily",
)

logger.info("Goes to console, app.log, and app.json")

Disable/Enable Logger Names

Disable all log emission for a specific logger name:

from logly import logger

# Disable logging for "myapp" name
logger.disable("myapp")

# These are silently dropped
myapp = logger.bind(name="myapp")
myapp.info("This is never logged")  # Silently dropped

# Re-enable later
logger.enable("myapp")
myapp.info("This is logged again")

configure() for Bulk Control

from logly import logger

# Replace all sinks and enable/disable names
logger.configure(
    handlers=[
        {"sink": "stderr", "level": "INFO", "colorize": True},
        {"sink": "app.log", "level": "DEBUG", "rotation": "daily"},
    ],
    activation=[
        ("myapp", True),  # Enable myapp
        ("debug", False),  # Disable debug
    ],
)

Environment Variable Control

Variable	Effect
LOGLY_AUTOINIT=false	Disable default stderr sink at import
LOGLY_LEVEL=WARNING	Override minimum level
LOGLY_COLORIZE=NO	Disable colors globally
LOGLY_SERIALIZE=YES	Enable JSON output globally