Prometheus

PrometheusLogSink exposes log metrics via Prometheus client. Counts messages by level and tracks message sizes.

Installation

This integration requires the prometheus-client package.

uv

uv add logly[prometheus]

pip

pip install "logly[prometheus]"

uv (without extras)

uv add prometheus-client

pip (without extras)

pip install prometheus-client

Missing Dependency

If prometheus_client is not installed, you'll see:

ModuleNotFoundError: No module named 'prometheus_client'

Usage

from logly import logger
from logly.integrations.prometheus import PrometheusLogSink
from prometheus_client import start_http_server

logger.add(PrometheusLogSink(), level="INFO")
start_http_server(8000)

Metrics

Metric	Type	Description
logly_log_total	Counter	Total log messages by level
logly_log_message_size_bytes	Histogram	Message size distribution
logly_current_log_level	Gauge	Numeric level of last message

Full Example

from logly import logger
from logly.integrations.prometheus import PrometheusLogSink
from prometheus_client import start_http_server

logger.add(PrometheusLogSink(namespace="myapp"), level="INFO")

# Start Prometheus metrics endpoint
start_http_server(8000)

logger.info("Application started")
logger.warning("High memory usage")
logger.error("Request failed")