File Logging

Basic File Sink

from logly import logger

# Simple file sink
logger.add("app.log", level="INFO")
logger.info("This goes to app.log")

TIP

By default, Logly creates the file if it doesn't exist and appends to it.

Custom Encoding

logger.add("app.log", encoding="utf-8")
logger.add("legacy.log", encoding="latin-1")

File Modes

# Append mode (default)
logger.add("app.log", mode="a")

# Write mode (truncate on open)
logger.add("app.log", mode="w")

Custom Opener

Use the opener parameter to customize how files are opened (e.g., for custom permissions):

import os

def custom_opener(path, mode):
    fd = os.open(path, os.O_WRONLY | os.O_CREAT, 0o644)
    return os.fdopen(fd, mode)

logger.add("app.log", opener=custom_opener)

Delay Opening

# Don't open the file until the first message is logged
logger.add("app.log", delay=True)

Combining with Rotation

logger.add(
    "app.log",
    level="INFO",
    rotation="100 MB",
    retention="30 days",
    compression="gzip",
    encoding="utf-8",
    mode="a",
)

Using root_dir

Set a default root directory so all file paths are relative to it:

logger.root_dir("/var/log/myapp")
logger.add("app.log")  # Creates /var/log/myapp/app.log
logger.add("errors.log", level="ERROR")  # Creates /var/log/myapp/errors.log

INFO

root_dir() creates the directory if it doesn't exist.