Varnish Cluster Purger

Tool to replicate a Purge request to all instances of Varnish in a cluster.

Supported Clusters

• Docker Compose
• Docker Swarm

Usage

Docker Compose

Add a new service to a Docker Compose:

  purger:
    image: ghcr.io/kitconcept/cluster-purger:latest
    ports:
      - "8000:80"
    environment:
      PURGER_MODE: "compose"
      PURGER_SERVICE_NAME: varnish
      PURGER_SERVICE_PORT: 80
      PURGER_PUBLIC_SITES: "['site.example.com', 'cms.example.com']"

This service exposes port 8000 on the local host (only for debugging purposes), and relies on the existence of another service called varnish.

To purge the /de path on Varnish, from another service in the same compose:

import httpx

response = httpx.request(method="PURGE", url="http://purger/de")

To purge the /de path on Varnish, from the host, use:

import httpx

response = httpx.request(method="PURGE", url="http://localhost:8000/de")

Environment Variables

Variable	Description	Example	Default
PURGER_MODE	Which type of cluster. Could be compose or swarm	swarm	swarm
PURGER_SERVICE_NAME	Varnish service name in the cluster	varnish
PURGER_SERVICE_PORT	Service port	8080	80
PURGER_PUBLIC_SITES	List of public hostnames to send in the Host header	"['site.example.com', 'cms.example.com']"

OpenTelemetry support

This tool has OpenTelemetry support built-in. To use it, set the following environment variables on your service definition.

Variable	Description	Example
OTEL_EXPORTER_OTLP_ENDPOINT	OpenTelemetry endpoint	http://192.168.1.1:4317
OTEL_RESOURCE_ATTRIBUTES	Set attributes for OpenTelemetry, i.e. service name	service.name=cluster-purger
OTEL_DEBUG	Dump OpenTelemetry traces to console instead of sending it to the server	True

Credits

License

The project is licensed under MIT License