loguru-kit 0.6.0

Dead simple loguru setup

loguru-kit

Safe & extensible loguru setup with conflict-free isolation.

Language: 한국어 | English

Features

• Conflict-free: No logger.remove() - safe to use alongside other loguru users
• Isolated loggers: Each module gets its own context via logger.bind()
• Extensible: Handler, Formatter, ContextProvider protocols
• Async-safe: contextvars-based context propagation
• Integrations: FastAPI middleware, OpenTelemetry, stdlib intercept

Installation

pip install loguru-kit

Quick Start

from loguru_kit import setup, get_logger

# Initialize once at app startup
setup()

# Get isolated logger for your module
logger = get_logger(__name__)
logger.info("Hello, world!")

Configuration

Via Code

from loguru_kit import setup, ConsoleHandler, JsonFormatter

setup(
    level="DEBUG",
    handlers=[
        ConsoleHandler(level="INFO"),
    ],
    formatters=[
        JsonFormatter(),
    ],
)

Via Environment Variables

Variable	Default	Description
LOGURU_KIT_LEVEL	INFO	Log level
LOGURU_KIT_JSON	false	JSON output

Priority: code args > env vars > defaults

Extension System

Custom Handler

from loguru_kit import Handler, setup

class SlackHandler:
    """Send critical logs to Slack."""
    
    def __call__(self, message) -> None:
        if message.record["level"].name == "CRITICAL":
            send_to_slack(str(message))

setup(handlers=[SlackHandler()])

Custom Formatter

from loguru_kit import Formatter, setup

class CompactFormatter:
    """Minimal log format."""
    
    def __call__(self, record: dict) -> str:
        return "{level}: {message}\n"

setup(formatters=[CompactFormatter()])

Custom Context Provider

from loguru_kit import ContextProvider, setup

class UserProvider:
    """Inject current user into logs."""
    
    def __call__(self) -> dict:
        return {"user_id": get_current_user_id()}

setup(context_providers=[UserProvider()])

Integrations

FastAPI

pip install loguru-kit[fastapi]

from fastapi import FastAPI
from loguru_kit import setup, get_logger
from loguru_kit.integrations.fastapi import LoggingMiddleware

setup()
logger = get_logger(__name__)

app = FastAPI()
app.add_middleware(LoggingMiddleware)

@app.get("/")
async def root():
    logger.info("processing request")
    return {"status": "ok"}

Request ID is automatically injected into all logs within a request context.

OpenTelemetry

pip install loguru-kit[otel]

from loguru_kit import setup
from loguru_kit.integrations.otel import patch_loguru

setup()
patch_loguru()
# trace_id, span_id automatically injected into logs

stdlib Logging Intercept

Selectively intercept stdlib loggers (e.g., from third-party libraries):

from loguru_kit import setup
from loguru_kit.integrations.stdlib import intercept_stdlib

setup()
intercept_stdlib(loggers=["uvicorn", "sqlalchemy"])
# Only specified loggers are redirected to loguru

Migration from v1

Breaking Changes

v1	v2
from loguru_kit import logger	from loguru_kit import get_logger; logger = get_logger(__name__)
LOGURU_* env vars	LOGURU_KIT_* env vars
setup(intercept=True)	intercept_stdlib(loggers=[...]) (explicit)
setup(otel=True)	patch_loguru() (explicit)

Migration Steps

1. Replace logger import with get_logger(__name__)
2. Update environment variables from LOGURU_* to LOGURU_KIT_*
3. Use explicit intercept_stdlib() instead of intercept=True
4. Use explicit patch_loguru() instead of otel=True

Before (v1)

from loguru_kit import setup, logger

setup(level="DEBUG", intercept=True, otel=True)
logger.info("Hello!")

After (v2)

from loguru_kit import setup, get_logger
from loguru_kit.integrations.stdlib import intercept_stdlib
from loguru_kit.integrations.otel import patch_loguru

setup(level="DEBUG")
intercept_stdlib(loggers=["uvicorn"])
patch_loguru()

logger = get_logger(__name__)
logger.info("Hello!")

Why v2?

v1 had a critical flaw: calling logger.remove() which pollutes global loguru state. This caused conflicts when:

• Multiple packages use loguru-kit
• Other packages use raw loguru
• stdlib logging handlers get hijacked

v2 uses logger.bind() for isolation - your loguru-kit usage never affects other loguru users.

License

MIT License - See LICENSE for details.