caravan/troupe

package internal

import (
    "github.com/caravan/troupe/actor"
    "github.com/caravan/troupe/actor/report"
    "github.com/caravan/troupe/actor/system"
)

// System is the internal implementation of system.System
type System struct {
    *Context
    system.Config
}

var devNull = actor.Singleton(func(c actor.Context) {
    for range c.Receive() {
        // do nothing with it
    }
})

// MakeSystem instantiates a new System
func MakeSystem(cfg system.Config) *System {
    sys := &System{
        Context: MakeContext(nil),
        Config:  cfg,
    }
    go sys.start()
    return sys
}

// Shutdown instructs the System to stop processing Messages and to destroy all
// of its actor.Actor children
func (s *System) Shutdown() {
    s.Close()
}

func (s *System) start() {
    deadLetters := s.spawnOrDevNull(s.DeadLetters)
    errors := s.spawnOrDevNull(s.Errors)

    for msg := range s.Receive() {
        switch msg := msg.(type) {
        case report.DeadLetter:
            deadLetters.Send() <- msg
        case report.Error:
            errors.Send() <- msg
        }
    }
}

func (s *System) spawnOrDevNull(f actor.Factory) actor.Address {
    if f != nil {
        return s.Spawn(f)
    }
    return s.Spawn(devNull)
}