Traefik Ondemand Plugin

Traefik middleware to start containers on demand.

• Traefik Ondemand Plugin
  • Features
  • Usage
    • Plugin configuration
      • Strategies
      • Custom loading/error pages
    • Traefik-Ondemand-Service
  • Examples
  • Development
  • Authors

Features

• Support for Docker containers
• Support for Docker swarm mode, scale services
• Support for Kubernetes Deployments and Statefulsets
• Start your container/service on the first request
• Automatic scale to zero after configured timeout upon last request the service received
• Dynamic loading page (cloudflare or grafana cloud style)
• Customize dynamic and loading pages

Usage

Plugin configuration

Strategies

Dynamic Strategy (default)

Serve an HTML page that self reload.

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testData:
  serviceUrl: http://ondemand:10000
  name: TRAEFIK_HACKATHON_whoami
  timeout: 1m
  waitui: true

Blocking Strategy

Blocking strategy is enabled by setting waitui to false.

Instead of displaying a self refreshing page, the request hangs until the service is ready to receive the request.

The timeout is set by blockdelay.

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testData:
  serviceUrl: http://ondemand:10000
  name: TRAEFIK_HACKATHON_whoami
  timeout: 1m
  waitui: false
  blockdelay: 1m

Typical use case: an API calling another API

Custom loading/error pages

The loadingpage and errorpage keys in the plugin configuration can be used to override the default loading and error pages.

The value should be a path where a template that can be parsed by Go's html/template package can be found in the Traefik container.

An example of both a loading page and an error page template can be found in the pkg/pages/ directory in loading.html and error.html respectively.

The plugin will default to the built-in loading and error pages if these fields are omitted.

You must include <meta http-equiv="refresh" content="5" /> inside your html page to get auto refresh.

Example Configuration

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testData:
  serviceUrl: http://ondemand:10000
  name: TRAEFIK_HACKATHON_whoami
  timeout: 1m
  waitui: false
  blockdelay: 1m
  loadingpage: /etc/traefik/plugins/traefik-ondemand-plugin/custompages/loading.html
  errorpage: /etc/traefik/plugins/traefik-ondemand-plugin/custompages/error.html

Parameter	Type	Default	Required	Example	Description
serviceUrl	string	empty	yes	http://ondemand:10000	The docker container name, or the swarm service name
name	string	empty	yes (except if names is set)	TRAEFIK_HACKATHON_whoami	The container/service/kubernetes resource to be stopped (docker ps docker service ls)
names	[]string	[]	yes (except if name is set)	[TRAEFIK_HACKATHON_whoami-1, TRAEFIK_HACKATHON_whoami-2]	The containers/services to be stopped (docker ps docker service ls)
timeout	time.Duration	1m	no	1m30s	The duration after which the container/service will be scaled down to 0
waitui	bool	true	no	true	Serves a self-refreshing html page when the service is scaled down to 0
displayname	string	the middleware name	no	My App	Serves a self-refreshing html page when the service is scaled down to 0
blockdelay	time.Duration	1m	no	1m30s	When waitui is false, wait for the service to be scaled up before blockdelay
loadingpage	string	empty	no	/etc/traefik/plugins/traefik-ondemand-plugin/custompages/loading.html	The path in the traefik container for the loading page template
errorpage	string	empty	no	/etc/traefik/plugins/traefik-ondemand-plugin/custompages/error.html	The path in the traefik container for the error page template

Traefik-Ondemand-Service

The traefik-ondemand-service must be used to bypass Yaegi limitations.

Yaegi is the interpreter used by Traefik to load plugin and run them at runtime.

The docker library that interacts with the docker deamon uses unsafe which must be specified when instanciating Yaegi. Traefik doesn't, and probably never will by default.

Examples

• Docker Classic
• Docker Swarm
• Multiple Containers
• Kubernetes

Development

export TRAEFIK_PILOT_TOKEN=xxxxxxxx-xxxx-xxxx-xxxx-xxxxxxxxxxxx docker stack deploy -c docker-compose.yml TRAEFIK_HACKATHON

Authors

Alexis Couvreur (left) Alexandre Hiltcher (middle) Matthias Schneider (right)