package scripting import ( "git.kirsle.net/apps/doodle/pkg/log" "github.com/dop251/goja" ) // Message holds data being published from one script VM with information sent // to the linked VMs. type Message struct { Name string SenderID string Args []goja.Value } /* RegisterPublishHooks adds the pub/sub hooks to a JavaScript VM. This adds the global methods `Message.Subscribe(name, func)` and `Message.Publish(name, args)` to the JavaScript VM's scope. */ func RegisterPublishHooks(s *Supervisor, vm *VM) { // Goroutine to watch the VM's inbound channel and invoke Subscribe handlers // for any matching messages received. go func() { // Catch any exceptions raised by the JavaScript VM. defer func() { if err := recover(); err != nil { // TODO EXCEPTIONS log.Error("RegisterPublishHooks(%s): %s", vm.Name, err) } }() // Watch the Inbound channel for PubSub messages and the stop channel for Teardown. for { select { case <-vm.stop: log.Info("JavaScript VM %s stopping PubSub goroutine", vm.Name) return case msg := <-vm.Inbound: vm.muSubscribe.Lock() if _, ok := vm.subscribe[msg.Name]; ok { for _, callback := range vm.subscribe[msg.Name] { log.Debug("PubSub: %s receives from %s: %s", vm.Name, msg.SenderID, msg.Name) if function, ok := goja.AssertFunction(callback); ok { function(goja.Undefined(), msg.Args...) } } } vm.muSubscribe.Unlock() } } }() // Register the Message.Subscribe and Message.Publish functions. vm.vm.Set("Message", map[string]interface{}{ "Subscribe": func(name string, callback goja.Value) { vm.muSubscribe.Lock() defer vm.muSubscribe.Unlock() if _, ok := goja.AssertFunction(callback); !ok { log.Error("SUBSCRIBE(%s): callback is not a function", name) return } if _, ok := vm.subscribe[name]; !ok { vm.subscribe[name] = []goja.Value{} } vm.subscribe[name] = append(vm.subscribe[name], callback) }, "Publish": func(name string, v ...goja.Value) { for _, channel := range vm.Outbound { channel <- Message{ Name: name, SenderID: vm.Name, Args: v, } } }, "Broadcast": func(name string, v ...goja.Value) { // Send the message to all actor VMs. for _, toVM := range s.scripts { if toVM == nil { continue } if vm.Name == toVM.Name { log.Debug("Broadcast(%s): skip to vm '%s' cuz it is the sender", name, toVM.Name) continue } toVM.Inbound <- Message{ Name: name, SenderID: vm.Name, Args: v, } } }, }) }