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Prometheus Metrics

FDM Monster can expose Prometheus metrics for monitoring and troubleshooting performance issues. This is useful for tracking system health, diagnosing problems, and setting up monitoring dashboards.

Enabling Prometheus Metrics​

To enable Prometheus metrics, set the ENABLE_PROMETHEUS_METRICS environment variable to true.

Docker Compose:

services:
  fdm-monster:
    environment:
      - ENABLE_PROMETHEUS_METRICS=true

Docker:

docker run -d \
  -e ENABLE_PROMETHEUS_METRICS=true \
  fdmmonster/fdm-monster:2

For more configuration options, see the Environment Variables Guide.

Accessing Metrics​

Once enabled, Prometheus metrics are available at:

http://<your-server-ip>:<your-server-port>/metrics

For example: http://localhost:4000/metrics or http://monsterpi.local:4000/metrics

What Metrics Are Available?​

The metrics endpoint provides various system and application metrics including:

  • HTTP request durations and counts
  • Active connections
  • Memory usage
  • Process CPU usage
  • Node.js event loop metrics
  • Custom application metrics

Setting Up Prometheus​

To collect these metrics with Prometheus, add FDM Monster as a scrape target in your prometheus.yml:

scrape_configs:
  - job_name: 'fdm-monster'
    static_configs:
      - targets: ['<your-server-ip>:<your-server-port>']

Replace <your-server-ip> and <your-server-port> with your FDM Monster server's address.

Use Cases​

Prometheus metrics are useful for:

  • Performance monitoring - Track response times and resource usage over time
  • Troubleshooting - Identify bottlenecks and performance issues
  • Alerting - Set up alerts for high memory usage, slow responses, etc.
  • Capacity planning - Understand resource usage patterns to plan scaling