A Rust-powered, high-performance logging library for Python.
A Rust-powered, high-performance logging library for Python with structured sinks, custom levels, rotation, compression, and telemetry integrations.
Note
This project is under active development. If you encounter any issues, bugs, or have feature requests, please open an issue on GitHub. Contributions are welcome!
If you love logly, make sure to give it a star!
Table of Contents (click to expand)
Features of Logly (click to expand)
| Feature | Description | Documentation |
|---|---|---|
| Rust-native engine | High-performance logging via PyO3 with zero unsafe Rust | Docs |
| 10 built-in levels | TRACE, DEBUG, INFO, NOTICE, SUCCESS, WARNING, ERROR, FAIL, CRITICAL, FATAL | Docs |
| Custom levels | Define your own levels with custom priorities and colors | Docs |
| Multiple sinks | Console, file, callable, and network outputs simultaneously | Docs |
| File rotation | Size-based, time-based, clock-based, and weekday rotation | Docs |
| Compression | gzip, zip, bz2, xz, zstd with tar-compatible aliases | Docs |
| JSON logging | Structured JSON output for storage and analysis | Docs |
| Context binding | Attach persistent key-value pairs to logs | Docs |
| Exception catching | catch() decorator and context manager |
Docs |
| Background workers | Non-blocking writes with enqueue=True |
Docs |
| 40+ integrations | FastAPI, Django, Flask, Rich, Redis, Kafka, and more | Docs |
| Thread-safe | Safe concurrent logging from multiple threads | Docs |
| Source location | Optional clickable file:line output |
Docs |
| Network logging | HTTP, TCP, UDP, Syslog sinks | Docs |
| Color themes | Custom ANSI color themes per level | Docs |
| Independent loggers | Separate sink sets per logger instance | Docs |
| Requirement | Version | Notes |
|---|---|---|
| Python | 3.10+ | Download from python.org |
| Rust | Latest stable | Only needed for building from source |
| Operating System | Linux, macOS, Windows | Cross-platform support |
pip install logly
# or
uv add loglyTip
Install with optional extras for integrations: pip install "logly[rich,fastapi]"
All Optional Extras (42 integrations)
# Core
pip install logly # core only (no optional deps)
# Frameworks & Libraries
pip install "logly[rich]" # Rich console output
pip install "logly[fastapi]" # FastAPI middleware
pip install "logly[starlette]" # Starlette middleware
pip install "logly[django]" # Django handler + middleware
pip install "logly[flask]" # Flask handler
pip install "logly[gunicorn]" # Gunicorn worker hooks
pip install "logly[uvicorn]" # Uvicorn log config
pip install "logly[sqlalchemy]" # SQLAlchemy query logging
pip install "logly[structlog]" # Structlog processor
pip install "logly[celery]" # Celery task logging
pip install "logly[click]" # Click CLI output
pip install "logly[typer]" # Typer CLI output
pip install "logly[apscheduler]" # APScheduler job logging
pip install "logly[rq]" # RQ worker logging
pip install "logly[pydantic]" # Pydantic log handler
pip install "logly[tqdm]" # tqdm progress bar sink
# Monitoring & Observability
pip install "logly[opentelemetry]" # OpenTelemetry export
pip install "logly[prometheus]" # Prometheus metrics
pip install "logly[elasticsearch]" # Elasticsearch indexing
pip install "logly[sentry]" # Sentry error tracking
pip install "logly[datadog]" # Datadog Logs API (stdlib)
pip install "logly[newrelic]" # New Relic agent
pip install "logly[seq]" # Seq structured logs (stdlib)
pip install "logly[telemetry]" # Generic telemetry (stdlib)
# Cloud Providers
pip install "logly[aws]" # AWS CloudWatch Logs
pip install "logly[gcloud]" # Google Cloud Logging
pip install "logly[azure]" # Azure Monitor
# Data Stores
pip install "logly[redis]" # Redis lists/streams
pip install "logly[kafka]" # Kafka topics (requires librdkafka)
pip install "logly[mongodb]" # MongoDB collections
pip install "logly[postgresql]" # PostgreSQL tables
pip install "logly[rabbitmq]" # RabbitMQ queues
# Log Aggregation
pip install "logly[logstash]" # Logstash TCP/UDP (stdlib)
pip install "logly[graylog]" # Graylog GELF (stdlib)
pip install "logly[loki]" # Grafana Loki
# Notifications
pip install "logly[discord]" # Discord webhooks (stdlib)
pip install "logly[slack]" # Slack webhooks (stdlib)
pip install "logly[email]" # Email via SMTP (stdlib)
pip install "logly[http]" # HTTP endpoint (stdlib)
# Utilities
pip install "logly[compression]" # Zstandard compression
# Everything
pip install "logly[all]" # all of the above[!NOTE] Several integrations (
datadog,seq,logstash,graylog,discord,slack,http,telemetry) use only Python stdlib and require no extra dependencies.
[!WARNING] The
kafkaextra requireslibrdkafkato be installed on your system. See Kafka integration docs for details.
uv Install Commands
# Core
uv add logly
# Frameworks & Libraries
uv add "logly[rich]"
uv add "logly[fastapi]"
uv add "logly[starlette]"
uv add "logly[django]"
uv add "logly[flask]"
uv add "logly[gunicorn]"
uv add "logly[uvicorn]"
uv add "logly[sqlalchemy]"
uv add "logly[structlog]"
uv add "logly[celery]"
uv add "logly[click]"
uv add "logly[typer]"
uv add "logly[apscheduler]"
uv add "logly[rq]"
uv add "logly[pydantic]"
uv add "logly[tqdm]"
# Monitoring & Observability
uv add "logly[opentelemetry]"
uv add "logly[prometheus]"
uv add "logly[elasticsearch]"
uv add "logly[sentry]"
uv add "logly[datadog]"
uv add "logly[newrelic]"
uv add "logly[seq]"
uv add "logly[telemetry]"
# Cloud Providers
uv add "logly[aws]"
uv add "logly[gcloud]"
uv add "logly[azure]"
# Data Stores
uv add "logly[redis]"
uv add "logly[kafka]"
uv add "logly[mongodb]"
uv add "logly[postgresql]"
uv add "logly[rabbitmq]"
# Log Aggregation
uv add "logly[logstash]"
uv add "logly[graylog]"
uv add "logly[loki]"
# Notifications
uv add "logly[discord]"
uv add "logly[slack]"
uv add "logly[email]"
uv add "logly[http]"
# Utilities
uv add "logly[compression]"
# Everything
uv add "logly[all]"git clone https://github.com/muhammad-fiaz/logly.git
cd logly
uv sync
uv run maturin developfrom logly import logger
logger.trace("Detailed trace")
logger.debug("Debug info")
logger.info("Application started")
logger.notice("Notice message")
logger.success("Operation completed!")
logger.warning("Warning message")
logger.error("Error occurred")
logger.fail("Operation failed")
logger.critical("Critical system error!")
logger.fatal("Fatal system failure!")
logger.complete()from logly import logger
# Register a custom level with icon and color
logger.level("HTTP", no=21, color="blue", icon=">")
logger.level("DATABASE", no=22, color="magenta", icon="*")
logger.level("SECURITY", no=35, color="red", icon="!")
# Log with custom levels
logger.log("HTTP", "GET /api/users")
logger.log("DATABASE", "Connected to PostgreSQL")
logger.log("SECURITY", "Authentication failed")
# Use icon in format strings
sink_id = logger.add(
lambda msg: print(msg, end=""),
format="{level_icon} {level} | {message}",
level="TRACE",
)
logger.log("HTTP", "GET /api/users")
logger.remove(sink_id)
# Output: > HTTP | GET /api/usersfrom logly import logger
logger.add(
"logs/app.log",
level="INFO",
rotation="daily",
retention="30 days",
compression="gzip",
)
logger.info("Application started")
logger.complete()from logly import logger
user_logger = logger.bind(user_id="12345", request_id="abc-789")
user_logger.info("User logged in")
# Output includes: user_id=12345 request_id=abc-789from logly import logger
with logger.catch():
risky_operation()
# With options
with logger.catch(exclude=ValueError, onerror=lambda e: print(f"Failed: {e}")):
dangerous_call()from logly import logger
logger.add("app.log", level="DEBUG", rotation="daily")
logger.add("errors.log", level="ERROR", retention="90 days")
logger.add("stdout", level="INFO", colorize=True)
logger.info("All three sinks receive this")Use Logger() when a subsystem needs a separate set of sinks that does not
write to the global logger.
from logly import Logger
api_logger = Logger()
worker_logger = Logger()
api_logger.add("api.log", level="INFO")
worker_logger.add("worker.log", level="DEBUG")
api_logger.info("request accepted")
worker_logger.debug("job claimed")from logly import logger
logger.opt(lazy=True).debug("Result: {}", lambda: expensive_computation())For more examples, see the documentation.
| Level | Priority | Method | Use Case |
|---|---|---|---|
| TRACE | 5 | logger.trace() |
Very detailed debugging |
| DEBUG | 10 | logger.debug() |
Debugging information |
| INFO | 20 | logger.info() |
General information |
| NOTICE | 25 | logger.notice() |
Notice messages |
| SUCCESS | 30 | logger.success() |
Successful operations |
| WARNING | 40 | logger.warning() |
Warning messages |
| ERROR | 50 | logger.error() |
Error conditions |
| FAIL | 55 | logger.fail() |
Operation failures |
| CRITICAL | 60 | logger.critical() |
Critical system errors |
| FATAL | 70 | logger.fatal() |
Fatal system errors |
Logly is built as a modular Rust workspace with a thin PyO3 binding:
| Crate | Purpose |
|---|---|
error |
Error types and conversions |
config |
Configuration data structures |
levels |
Log level definitions and registry |
record |
Log record builder |
color |
ANSI color engine and themes |
format |
Template, JSON, and custom formatters |
filter |
Level, prefix, extra, and chain filters |
rotate |
File rotation policies and execution |
compress |
Compression codecs (gzip, zip, bz2, xz, zstd) |
concurrency |
Background workers and thread pool |
schedule |
Scheduled tasks and scheduler |
context |
Bound context, scoped context, patchers |
sink |
Sink trait and built-in implementations |
core |
Logger engine dispatch |
network |
HTTP, TCP, UDP, Syslog sinks |
source |
Caller frame inspection |
| Tool | Version | Purpose |
|---|---|---|
| Rust | Latest stable | Compile the native engine |
| Python | 3.10+ | Runtime and build scripts |
| uv | Latest | Package manager (recommended) |
| Maturin | 1.x | Build backend for PyO3 wheels |
# Install uv (if not already installed)
pip install uv
# Build the extension in development mode
uv run maturin develop
# Run Python tests
uv run pytest
# Run Rust tests
cargo test --workspace
# Lint
uv run ruff check .
cargo clippy --workspace --all-targets -- -D warningsFull documentation is available at: https://muhammad-fiaz.github.io/logly
Contributions are welcome! Please feel free to submit a Pull Request.
Logly's Python API syntax and ergonomics are inspired by Loguru. The underlying engine is an independent, from-scratch Rust implementation.
This project is licensed under the MIT License.
- Documentation: https://muhammad-fiaz.github.io/logly
- PyPI: https://pypi.org/project/logly/
- Repository: https://github.com/muhammad-fiaz/logly
- Issues: https://github.com/muhammad-fiaz/logly/issues
