Filesystem Exporter

A lightweight Go-based metrics collection service for Prometheus that monitors filesystem and directory sizes.

Image: ghcr.io/d0ugal/filesystem-exporter:latest

Metrics

Filesystem Metrics

• filesystem_exporter_volume_size_bytes: Total size of filesystem in bytes
• filesystem_exporter_volume_available_bytes: Available space on filesystem in bytes
• filesystem_exporter_volume_used_ratio: Ratio of used space (0.0 to 1.0)

Directory Metrics

• filesystem_exporter_directory_size_bytes: Size of directory in bytes

Collection Metrics

• filesystem_exporter_collection_duration_seconds: Duration of collection in seconds
• filesystem_exporter_collection_success_total: Total number of successful collections
• filesystem_exporter_collection_failed_total: Total number of failed collections

Endpoints

• GET /: HTML dashboard with service status and metrics information
• GET /metrics: Prometheus metrics endpoint
• GET /health: Health check endpoint

Quick Start

Docker Compose

version: '3.8'
services:
  filesystem-exporter:
    image: ghcr.io/d0ugal/filesystem-exporter:latest
    ports:
      - "8080:8080"
    volumes:
      - /:/host:ro
      - ./config.yaml:/root/config.yaml:ro
    restart: unless-stopped

1. Create a config.yaml file (see Configuration section)
2. Run: docker-compose up -d
3. Access metrics: curl http://localhost:8080/metrics

Configuration

Create a config.yaml file to configure filesystems and directories to monitor:

server:
  host: "0.0.0.0"
  port: 8080

logging:
  level: "info"
  format: "json"

metrics:
  collection:
    default_interval: "5m"

filesystems:
  - name: "root"
    mount_point: "/"
    device: "sda1"
    interval: "1m"

directories:
  home:
    path: "/home"
    subdirectory_levels: 1

Deployment

Docker Compose (Environment Variables)

version: '3.8'
services:
  filesystem-exporter:
    image: ghcr.io/d0ugal/filesystem-exporter:latest
    ports:
      - "8080:8080"
    volumes:
      - /:/host:ro
    environment:
      - FILESYSTEM_EXPORTER_CONFIG_FROM_ENV=true
      - FILESYSTEM_EXPORTER_FILESYSTEMS=root:/host:sda1:1m
      - FILESYSTEM_EXPORTER_DIRECTORIES=home:/host/home:1:10m,logs:/host/var/log:0:5m
    restart: unless-stopped

Kubernetes

apiVersion: apps/v1
kind: Deployment
metadata:
  name: filesystem-exporter
spec:
  replicas: 1
  selector:
    matchLabels:
      app: filesystem-exporter
  template:
    metadata:
      labels:
        app: filesystem-exporter
    spec:
      containers:
      - name: filesystem-exporter
        image: ghcr.io/d0ugal/filesystem-exporter:latest
        ports:
        - containerPort: 8080
        env:
        - name: FILESYSTEM_EXPORTER_CONFIG_FROM_ENV
          value: "true"
        - name: FILESYSTEM_EXPORTER_FILESYSTEMS
          value: "root:/host:sda1:1m"
        - name: FILESYSTEM_EXPORTER_DIRECTORIES
          value: "home:/host/home:1:10m,logs:/host/var/log:0:5m"
        volumeMounts:
        - name: host-root
          mountPath: /host
          readOnly: true
      volumes:
      - name: host-root
        hostPath:
          path: /
          type: Directory

Development

Prerequisites

• Go 1.21 or later
• Docker (optional)

Local Development

1. Install dependencies:

   make deps

2. Run tests:

   make test

3. Build the application:

   make build

4. Run the application:

   make run

Docker Development

1. Build the Docker image:

   make docker-build

2. Run the container:

   make docker-run

Or build and run in one command:

make docker

Testing

Run all tests:

make test

Run tests with coverage:

make test-coverage

Code Quality

Format code:

make fmt

Lint code:

make lint

Prometheus Integration

Add to your prometheus.yml:

scrape_configs:
  - job_name: 'filesystem-exporter'
    static_configs:
      - targets: ['filesystem-exporter:8080']

Troubleshooting

Common Issues

1. Permission Denied: Ensure the container has read access to the mounted volumes
2. Command Not Found: The application requires df and du commands to be available
3. Configuration Errors: Check the YAML syntax in config.yaml
4. High Memory Usage: Large directories with many subdirectories can consume significant memory

Logs

The application uses structured logging with JSON format. Log levels can be configured in the YAML configuration.

Debug Mode

Enable debug logging to troubleshoot issues:

logging:
  level: "debug"
  format: "json"

Contributing

1. Fork the repository
2. Create a feature branch
3. Make your changes
4. Add tests for new functionality
5. Run the test suite
6. Submit a pull request

License

This project is licensed under the MIT License.