How to write a new plugin?

If you want to add a custom plugin in SkyWalking Satellite, the following contents would guide you. Let’s use memory-queue as an example of how to write a plugin.

1. Choose the plugin category. As the memory-queue is a queue, the plugin should be written in the skywalking-satellite/plugins/queue directory. So we create a new directory called memory as the plugin codes space.

2. Implement the interface in the skywalking-satellite/plugins/queue/api. Each plugin has 3 common methods, which are Name(), Description(), DefaultConfig().

   • Name() returns the unique name in the plugin category.
   • Description() returns the description of the plugin, which would be used to generate the plugin documentation.
   • DefaultConfig() returns the default plugin config with yaml pattern, which would be used as the default value in the plugin struct and to generate the plugin documentation.

   type Queue struct {
   	config.CommonFields
   	// config
   	EventBufferSize int `mapstructure:"event_buffer_size"` // The maximum buffer event size.
   
   	// components
   	buffer *goconcurrentqueue.FixedFIFO
   }
   
   func (q *Queue) Name() string {
   	return Name
   }
   
   func (q *Queue) Description() string {
   	return "this is a memory queue to buffer the input event."
   }
   
   func (q *Queue) DefaultConfig() string {
   	return `
   # The maximum buffer event size.
   event_buffer_size: 5000
   

3. Add unit test.

4. Generate the plugin docs.

make gen-docs