graphvent/listener.go

52 lines
1.3 KiB
Go

package graphvent
import (
"reflect"
"encoding/json"
)
// A Listener extension provides a channel that can receive signals on a different thread
type ListenerExt struct {
Buffer int `gv:"buffer"`
Chan chan Signal
}
func (ext *ListenerExt) PostDeserialize(ctx *Context) error {
ext.Chan = make(chan Signal, ext.Buffer)
return nil
}
// Create a new listener extension with a given buffer size
func NewListenerExt(buffer int) *ListenerExt {
return &ListenerExt{
Buffer: buffer,
Chan: make(chan Signal, buffer),
}
}
// Simple load function, unmarshal the buffer int from json
func (ext *ListenerExt) DeserializeListenerExt(ctx *Context, data []byte) error {
err := json.Unmarshal(data, &ext.Buffer)
ext.Chan = make(chan Signal, ext.Buffer)
return err
}
func (listener *ListenerExt) Type() ExtType {
return ListenerExtType
}
// Send the signal to the channel, logging an overflow if it occurs
func (ext *ListenerExt) Process(ctx *Context, node *Node, source NodeID, signal Signal) Messages {
ctx.Log.Logf("listener", "LISTENER_PROCESS: %s - %+v", node.ID, reflect.TypeOf(signal))
select {
case ext.Chan <- signal:
default:
ctx.Log.Logf("listener", "LISTENER_OVERFLOW: %s", node.ID)
}
return nil
}
func (ext *ListenerExt) MarshalBinary() ([]byte, error) {
return json.Marshal(ext.Buffer)
}