88 lines
1.9 KiB
Go
88 lines
1.9 KiB
Go
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package nats
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import (
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// stdlib
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"log"
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"sync"
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// local
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"github.com/pztrn/ffmpeger/config"
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// other
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"github.com/nats-io/nats.go"
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)
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const (
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Topic = "ffmpeger.v1"
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)
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var (
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natsConn *nats.Conn
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natsSubscription *nats.Subscription
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// Handlers.
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handlers []*Handler
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handlersMutex sync.Mutex
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)
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// AddHandler adds handler for received NATS messages.
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func AddHandler(hndl *Handler) {
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handlersMutex.Lock()
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handlers = append(handlers, hndl)
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handlersMutex.Unlock()
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}
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// Initialize initializes package.
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func Initialize() {
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log.Println("Initializing NATS handler...")
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handlers = make([]*Handler, 0, 8)
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}
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// Handler for NATS messages.
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func messageHandler(msg *nats.Msg) {
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log.Println("Received message:", string(msg.Data))
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handlersMutex.Lock()
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for _, hndl := range handlers {
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hndl.Func(msg.Data)
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}
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handlersMutex.Unlock()
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}
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// Shutdown unsubscribes from topic and disconnects from NATS.
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func Shutdown() {
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log.Println("Unsuscribing from NATS topic...")
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err := natsSubscription.Unsubscribe()
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if err != nil {
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log.Println("ERROR unsubscribing", Topic, "topic:", err.Error())
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}
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if natsConn != nil {
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log.Println("Closing connection to NATS...")
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natsConn.Close()
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} else {
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log.Println("Connection to NATS wasn't established")
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}
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}
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// StartListening connects to NATS and starts to listen for messages.
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func StartListening() {
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nc, err := nats.Connect(config.Cfg.NATS.ConnectionString)
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if err != nil {
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log.Fatalln("Failed to connect to NATS:", err.Error())
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}
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natsConn = nc
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log.Println("NATS connection established")
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// Beware - if ffmpeger will be launched more than once and subscribed
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// to same topic (which is hardcoded here) then ALL instances of
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// ffmpeger will receive this message!
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sub, err1 := nc.Subscribe(Topic, messageHandler)
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if err1 != nil {
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log.Fatalln("Failed to subscribe to", Topic, "topic:", err1.Error())
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}
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natsSubscription = sub
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}
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