Extending Janus

Janus can be extended with plugins. Plugins add missing functionality to Janus. They are "plugged in" at compile-time. The plugins are attached to an API Definition and you can enable or disable them at any time.

Janus comes with a set of built in plugins that you can add to your API Definitions:

How can I create a plugin?

Even though there are different kinds of plugins, the process of creating one is roughly the same for all.

1. Create a package and register your plugin.

Start a new Go package with an init function and register your plugin with Janus:

import "github.com/hellofresh/janus/pkg/plugin"

func init() {
    // register a "generic" plugin, like a directive or middleware
    plugin.RegisterPlugin("name", myPlugin)
}

Every plugin must have a name and, when applicable, the name must be unique.

2. Plug in your plugin.

To plug your plugin into Janus, import it. This is usually done near the top of loader.go:

import _ "your/plugin/package/path/here"

3. Write Tests!

Write tests. Get good coverage where possible, and make sure your assertions test what you think they are testing! Use go vet and go test -race to ensure your plugin is as error-free as possible.

4. Maintain your plugin.

People will use plugins that are useful, clearly documented, easy to use, and maintained by their owner. And congratulations, you're a Janus plugin author!

Plugins