Traefik Unleash Middleware

This Traefik middleware validates requests against an Unleash (feature flag) server and rewrites the path, headers and host of the request based on input parameters defined in the YAML configuration file.

Table of Contents

• Installation
• Configuration
  • Input Parameters
• Usage
• Example
• Contributing
• License

Installation

Follow the Traefik instructions for installing plugins.

Configuration

To configure this middleware, you need to define the parameters in the dynamic.yml file.

Input Parameters

Parameter	Type	Required	Description
url	string	Yes	URL of the Unleash server
app	string	Yes	Name of the application in Unleash
interval	int	No	Update interval in seconds
metrics.interval	int	No	Metrics reporting interval in seconds
toggles	list	Yes	List of feature flag toggles
toggles[].feature	string	Yes	Name of the feature flag
toggles[].pathRewrite.pathMatcher	string	No	Path to be validated
toggles[].pathRewrite.rewriteRule	string	No	Path to redirect to if the feature flag is active
toggles[].hostRewrite.hostMatcher	string	No	Host to be validated
toggles[].hostRewrite.rewriteRule	string	No	Host to redirect to if the feature flag is active
toggles[].headerModifers	list	No	List of headers to be added to the request or response
toggles[].headerModifiers[].headerName	string	Yes	Header key
toggles[].headerModifiers[].headerValue	string	Yes	Header value
toggles[].headerModifiers[].context	string	Yes	Context of the header (either "request" or "response")
offlineMode	boolean	No	The plugin is configured in local mode without external dependencies

Usage

1. Define the configuration in the dynamic.yml file:

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   unleash:
     url: "http://unleash:4242/api/"
     app: "test-app"
     interval: 10
     metrics:
       interval: 10
     toggles:
       - feature: "test-toggle-user-id"
         pathRewrite:
           pathMatcher: "/foo"
           rewriteRule: "/bar"
         hostRewrite:
           hostMatcher: "localhost"
           rewriteRule: "whoami2"
       - feature: "test-toggle"
         pathRewrite:
           pathMatcher: "/bar"
           rewriteRule: "/foo"
         hostRewrite:
           hostMatcher: "localhost"
           rewriteRule: "whoami2"
       - feature: "test-toggle-path"
         pathRewrite:
           pathMatcher: "/john"
           rewriteRule: "/doe"
       - feature: "test-toggle-host"
         hostRewrite:
           hostMatcher: "localhost"
           rewriteRule: "whoami1"

2. Apply the middleware to your routers in the Traefik configuration:

   Copy
   http:
     routers:
       my-router:
         rule: "Host(`example.com`)"
         service: "my-service"
         middlewares: 
           - "unleash"

Example

Here is a complete configuration example:

Copy
http:
  routers:
    my-router:
      rule: "Host(`example.com`)"
      service: "my-service"
      middlewares:
        - "unleash"

  middlewares:
    unleash:
      plugin:
        unleash:
          url: "http://unleash:4242/api/"
          app: "test-app"
          interval: 10
          metrics:
            interval: 10
          toggles:
            - feature: "test-toggle-user-id"
              pathRewrite:
                pathMatcher: "/foo"
                rewriteRule: "/bar"
              hostRewrite:
                hostMatcher: "localhost"
                rewriteRule: "whoami2"
              headerModifiers:
                - headerName: "X-Foo"
                  headerValue: "Bar"
                  context: "request"
                - headerName: "X-Served-By"
                  headerValue: "whoami2"
                  context: "response"
            - feature: "test-toggle"
              pathRewrite:
                pathMatcher: "/bar"
                rewriteRule: "/foo"
              hostRewrite:
                value: "localhost"
                rewrite: "whoami2"
            - feature: "test-toggle-path"
              pathRewrite:
                pathMatcher: "/john"
                rewriteRule: "/doe"
            - feature: "test-toggle-host"
              hostRewrite:
                hostMatcher: "localhost"
                rewriteRule: "whoami1"

Contributing

Contributions are welcome! If you want to contribute, please open an issue or a pull request in this repository.

License

This project is licensed under the MIT License.