Make MQTT keepalive interval configurable. (#176)

Author: smaXtecStefan

Makefile

@@ -44,4 +44,4 @@ serve: build
 	./build/chirpstack-gateway-bridge
 
 run-compose-test:
-	docker-compose run --rm gatewaybridge make test
+	docker-compose run --rm chirpstack-gateway-bridge make test

cmd/chirpstack-gateway-bridge/cmd/configfile.go

@@ -224,6 +224,11 @@ marshaler="{{ .Integration.Marshaler }}"
   # Command topic template.
   command_topic_template="{{ .Integration.MQTT.CommandTopicTemplate }}"
 
+  # Keep alive will set the amount of time (in seconds) that the client should
+  # wait before sending a PING request to the broker. This will allow the client
+  # to know that a connection has not been lost with the server.
+  keep_alive="{{ .Integration.MQTT.KeepAlive }}"
+
   # Maximum interval that will be waited between reconnection attempts when connection is lost.
   # Valid units are 'ms', 's', 'm', 'h'. Note that these values can be combined, e.g. '24h30m15s'.
   max_reconnect_interval="{{ .Integration.MQTT.MaxReconnectInterval }}"

cmd/chirpstack-gateway-bridge/cmd/root.go

@@ -58,6 +58,7 @@ func init() {
 
 	viper.SetDefault("integration.mqtt.event_topic_template", "gateway/{{ .GatewayID }}/event/{{ .EventType }}")
 	viper.SetDefault("integration.mqtt.command_topic_template", "gateway/{{ .GatewayID }}/command/#")
+	viper.SetDefault("integration.mqtt.keep_alive", 30*time.Second)
 	viper.SetDefault("integration.mqtt.max_reconnect_interval", time.Minute)
 
 	viper.SetDefault("integration.mqtt.auth.generic.servers", []string{"tcp://127.0.0.1:1883"})

internal/config/config.go

@@ -58,6 +58,7 @@ type Config struct {
 		MQTT struct {
 			EventTopicTemplate      string        `mapstructure:"event_topic_template"`
 			CommandTopicTemplate    string        `mapstructure:"command_topic_template"`
+			KeepAlive               time.Duration `mapstructure:"keep_alive"`
 			MaxReconnectInterval    time.Duration `mapstructure:"max_reconnect_interval"`
 			TerminateOnConnectError bool          `mapstructure:"terminate_on_connect_error"`
 

internal/integration/mqtt/backend.go

@@ -128,6 +128,7 @@ func NewBackend(conf config.Config) (*Backend, error) {
 	b.clientOpts.SetAutoReconnect(true) // this is required for buffering messages in case offline!
 	b.clientOpts.SetOnConnectHandler(b.onConnected)
 	b.clientOpts.SetConnectionLostHandler(b.onConnectionLost)
+	b.clientOpts.SetKeepAlive(conf.Integration.MQTT.KeepAlive)
 	b.clientOpts.SetMaxReconnectInterval(conf.Integration.MQTT.MaxReconnectInterval)
 
 	if err = b.auth.Init(b.clientOpts); err != nil {