access-log-exporter

README

access-log-exporter

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A Prometheus exporter that receives web server access logs via syslog and converts them into metrics.

access-log-exporter processes logs from multiple web servers and has undergone testing with Nginx and Apache HTTP Server 2.4. It supports flexible metric configuration through presets and provides comprehensive monitoring capabilities for web traffic analysis.

Features

• Multi-server support: Works with Nginx and Apache HTTP Server,
• Syslog protocol: Receives logs via UDP/TCP syslog for real-time processing,
• Flexible configuration: Customizable presets for different monitoring needs,
• Built-in presets: Ready-to-use configurations for common scenarios,
• Upstream metrics: Support for Nginx upstream server monitoring,
• Label transformation: Regex-based label value normalization,
• Mathematical operations: Unit conversion for proper Prometheus base units,
• High performance: Configurable buffering and worker threads.

Quick Start

Installation

Using package managers:

# Debian/Ubuntu
curl -L https://raw.githubusercontent.com/jkroepke/access-log-exporter/refs/heads/main/packaging/apt/access-log-exporter.sources | sudo tee /etc/apt/sources.list.d/access-log-exporter.sources
sudo apt update && sudo apt install access-log-exporter

# Manual download
# Download the latest release from GitHub releases page

Using Docker:

docker run -p 4040:4040 -p 8514:8514/udp ghcr.io/jkroepke/access-log-exporter:latest

Basic Configuration

1. Configure your web server to send logs via syslog:

For Nginx, add to your configuration:

log_format accesslog_exporter '$http_host\t$request_method\t$status\t$request_time\t$request_length\t$bytes_sent';
access_log syslog:server=127.0.0.1:8514 accesslog_exporter,nohostname;

For Apache2, add to your configuration:

LogFormat "%v\t%m\t%>s\t%{ms}T\t%I\t%O" accesslog_exporter
CustomLog "|/usr/bin/logger --rfc3164 --server 127.0.0.1 --port 8514 --udp" accesslog_exporter

2. Start access-log-exporter:

access-log-exporter --preset simple

3. Access metrics:

curl http://localhost:4040/metrics

Available Presets

• simple: Basic HTTP metrics (requests, response times, sizes) - compatible with both Nginx and Apache
• simple_upstream: Includes upstream server metrics - Nginx only
• all: Comprehensive metrics including user agent parsing, SSL info, and upstream details - Nginx only

Configuration

access-log-exporter supports configuration via:

• Command-line flags
• Environment variables
• YAML configuration files

Example command-line usage:

# Use different preset
access-log-exporter --preset simple_upstream

# Custom syslog port
access-log-exporter --syslog.listen-address udp://0.0.0.0:9514

# Custom metrics port
access-log-exporter --web.listen-address :9090

Example configuration file:

preset: "simple"
syslog:
  listenAddress: "udp://[::]:8514"
web:
  listenAddress: ":4040"
bufferSize: 1000
workerCount: 4

Metrics Examples

With the simple preset, you get metrics like:

# HELP http_requests_total The total number of client requests
# TYPE http_requests_total counter
http_requests_total{host="example.com",method="GET",status="200"} 1234

# HELP http_response_duration_seconds The time spent on receiving and response the response to the client
# TYPE http_response_duration_seconds histogram
http_response_duration_seconds_bucket{host="example.com",method="GET",status="200",le="0.005"} 123
http_response_duration_seconds_bucket{host="example.com",method="GET",status="200",le="0.01"} 234

Documentation

For detailed documentation, please refer to:

• Installation Guide: Package installation, manual builds, Kubernetes deployment
• Configuration Guide: Complete configuration reference and custom presets
• Webserver Setup: Nginx and Apache configuration examples
• Wiki: Additional guides and examples

Requirements

• Go 1.21+ (for building from source)
• Web server with syslog support (Nginx, Apache)
• Network connectivity between web server and access-log-exporter

Contributing

Contributions welcome! Please read our Code of Conduct and submit pull requests to help improve the project.

Related Projects

• martin-helmich/prometheus-nginxlog-exporter.
• ozonru/accesslog-exporter

Copyright and license

© 2025 Jan-Otto Kröpke (jkroepke)

Licensed under the Apache License, Version 2.0.

Open Source Sponsors

Thanks to all sponsors!

Acknowledgements

Thanks to JetBrains IDEs for their support.

JetBrains IDEs