Voltgate

Features

• Reverse proxy supporting multiple services and domains
• Basic rate limiting with Redis
• Basic caching with Redis
• Hot reloading of endpoints and services
• Log publishing to Loki

Docker-compose example

services:
  proxy:
    image: d4rckh/voltgate:latest
    ports:
      - "80:80" # proxy port
      - "9999:9999" # management port
    volumes:
      - ./voltgate.yaml:/app/config.yaml

Minimal Configuration Example (config.yaml)

services:
  - name: service_name
    url: http://localhost:9090

endpoints:
  - host: domain.com
    service: service_name

Grafana Dashboard

Using the grafana.json file you can import the dashboard below in your instance!

All Configurations Example (config.yaml)

management:
  address: ":9999"
    # Default: ":9999"
proxy:
  address: ":80"
    # Default: ":80"

config:
  reload_interval: 10
    # Reloads monitoring, services, and endpoints every 10 seconds
    # Default: do not reload

storage:
  redis:
    address: localhost:6379
    password: my-password
    username: my-username
      # Configure Redis for use in rate limiting

rate_limit:
  storage: redis
    # Use Redis for rate limiting
    # Default: memory (Not recommended for production!)

cache:
  storage: redis
    # Use Redis for caching
    # Default: memory (Not recommended for production!)

monitoring:
  loki: http://localhost:3100/loki/api/v1/push
    # Publishes logs to Loki
    # Default: do not publish
  prometheus: true
    # Exposes /metrics on the management address
    # Default: false

services:
  - name: service_name
    url: http://localhost:9090

endpoints:
  - host: domain.com
    service: service_name
    cache:
      rules:
        - path: "^/myendpoint"
          ttl: 10 # seconds
          params: ["param1", "params2"] # Optional array of params to construct the cache key, by default it will use all params
            # Optional caching rules, will cache all GET requests that match the regex path, make sure to configure Redis for production 
    rate_limit:
      rules:
        - path: "^/api/some_action" # regex
          method: POST # must be defined
          window: 10 # seconds
          requests: 2
            # Optional rate limiting rules, make sure to configure Redis for production

Metrics Overview

Voltgate Proxy collects and exposes metrics to Prometheus for monitoring.

http_requests_total (Counter)

Counts the total number of HTTP requests received.

• Type: Counter
• Labels:
  • method: HTTP method (e.g., GET, POST)
  • host: Original requested host
  • target_service_name: Proxied service name
  • path: Request path
  • status: HTTP response status code

Query Example:

rate(http_requests_total{method="GET", status="200"}[5m])

(Displays the rate of successful GET requests over 5 minutes.)

http_blocked_requests_total (Counter)

Counts the total number of blocked HTTP requests.

• Type: Counter
• Labels:
  • method: HTTP method (e.g., GET, POST)
  • host: Original requested host
  • target_service_name: Proxied service name
  • path: Request path

Query Example:

rate(http_blocked_requests_total[5m])

(Displays the rate of successful blocked requests over 5 minutes.)

---

http_request_duration_seconds (Histogram)

Measures the duration of HTTP requests in seconds.

• Type: Histogram
• Buckets: Default Prometheus latency buckets (0.005s, 0.01s, 0.025s, ...)
• Labels:
  • method: HTTP method
  • host: Requested host
  • target_service_name: Proxied service name
  • path: Request path

Query Example:

histogram_quantile(0.95, rate(http_request_duration_seconds_bucket[5m]))

(Displays the 95th percentile of request durations over the last 5 minutes.)

---

http_response_size_bytes (Histogram)

Tracks the size of HTTP responses in bytes.

• Type: Histogram
• Buckets: Exponential buckets (starting at 100 bytes, scaling by a factor of 2, up to 10 steps)
• Labels:
  • method: HTTP method
  • host: Requested host
  • target_service_name: Proxied service name
  • path: Request path

Query Example:

histogram_quantile(0.5, rate(http_response_size_bytes_bucket[5m]))

(Displays the median response size over the last 5 minutes.)

Accessing Metrics

Prometheus metrics are available via an HTTP endpoint. Ensure the monitoring service is running and query the endpoint:

GET /metrics

Prometheus Configuration

Add the following to prometheus.yml to enable scraping of the proxy service:

scrape_configs:
  - job_name: "voltgate_proxy"
    static_configs:
      - targets: ["localhost:9999"] # Management address set in the configuration