Integrate gpsd connection management with managment interface.

Disabling GPS on the management interface will close the gpsd connection.

Add internal function for disconnecting.

main/gen_gdl90.go

@@ -984,6 +984,7 @@ type settings struct {
 	ES_Enabled           bool
 	Ping_Enabled         bool
 	GPS_Enabled          bool
+	GpsdAddress          string
 	NetworkOutputs       []networkConnection
 	SerialOutputs        map[string]serialConnection
 	AHRS_Enabled         bool
@@ -1046,6 +1047,7 @@ func defaultSettings() {
 	globalSettings.UAT_Enabled = true
 	globalSettings.ES_Enabled = true
 	globalSettings.GPS_Enabled = true
+	globalSettings.GpsdAddress = "localhost:2947"
 	//FIXME: Need to change format below.
 	globalSettings.NetworkOutputs = []networkConnection{
 		{Conn: nil, Ip: "", Port: 4000, Capability: NETWORK_GDL90_STANDARD | NETWORK_AHRS_GDL90},

main/gpsd.go

@@ -10,7 +10,7 @@ import (
 )
 
 // Channel to disconnect current gpsd connection
-var disconnectGpsd chan struct{}
+var killGpsd chan struct{}
 var gps *gpsd.Session
 
 // Determine type of satellite based on PRN number.
@@ -201,16 +201,24 @@ func initGpsd() {
 	satelliteMutex = &sync.Mutex{}
 	Satellites = make(map[string]SatelliteInfo)
 
-	disconnectGpsd = make(chan struct{})
+	killGpsd = make(chan struct{})
 
-	setGpsdHost(gpsd.DefaultAddress)
+	if globalSettings.GPS_Enabled {
+		connectGpsd(globalSettings.GpsdAddress)
+	}
 }
 
-func setGpsdHost(address string) {
+// Main interface for enabling and changing the gpsd connection
+// Calling will block until previous connection disconnects
+// If address is zero value, it connects to gpsd on the local machine
+func connectGpsd(address string) {
 	// kill existing monitor goroutine if it exists
 	if gps != nil {
-		log.Printf("Stopping previous gpsd session")
-		disconnectGpsd <- struct{}{}
+		disconnectGpsd()
+	}
+
+	if address == "" {
+		address = gpsd.DefaultAddress
 	}
 
 	go func() {
@@ -232,9 +240,10 @@ func setGpsdHost(address string) {
 			reconnect := gps.Watch()
 
 			select {
-			case <-disconnectGpsd:
+			case <-killGpsd:
 				log.Printf("Gpsd %s disconnecting", address)
 				gps.Close()
+				gps = nil
 				return
 			case <-reconnect:
 				log.Printf("Gpsd %s disconnected. Reconnecting..", address)
@@ -243,3 +252,10 @@ func setGpsdHost(address string) {
 		}
 	}()
 }
+
+// Disconnect from gpsd
+// Blocks until connection is disconnected and all goroutines are stopped
+func disconnectGpsd() {
+	log.Printf("Stopping gpsd session")
+	killGpsd <- struct{}{}
+}

main/managementinterface.go

@@ -218,6 +218,12 @@ func handleSettingsSetRequest(w http.ResponseWriter, r *http.Request) {
 					case "Ping_Enabled":
 						globalSettings.Ping_Enabled = val.(bool)
 					case "GPS_Enabled":
+						switch {
+						case val.(bool) == true && globalSettings.GPS_Enabled == false:
+							connectGpsd(globalSettings.GpsdAddress)
+						case val.(bool) == false && globalSettings.GPS_Enabled == true:
+							disconnectGpsd()
+						}
 						globalSettings.GPS_Enabled = val.(bool)
 					case "AHRS_Enabled":
 						globalSettings.AHRS_Enabled = val.(bool)