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