Going crazy on golang maps

[Chris Polderman]

Hello!

I am working on a home automation project in Go. 

One of the components is polling all the sensors in a HUE bridge (this is some LED lighting system with smart lamps and buttons).

I am wanting to make a map, keyed on int to "Sensor" objects. These objects are located in a sensors package (so: sensors.Sensor).

My noob feeling says to do it like this:

   var previousSensorInfo map[int]sensors.Sensor = make(map[int]sensors.Sensor)

but the compiler says:

src/github.com/cpo/events/bridges/hue/hue.go:91:40: sensors.Sensor undefined (type *sensors.Sensors has no field or method Sensor)

(this is the line indicated above)

This sensors.Sensor type is a simple struct:

type Sensor struct {
   ID               int    `json:"id,omitempty"`
   Name             string `json:"name"`
   State            State  `json:"state,omitempty"`
   Config           Config `json:"config,omitempty"`
   Type             string `json:"type,omitempty"`
   ModelID          string `json:"modelid,omitempty"`
   SWVersion        string `json:"swversion,omitempty"`
   ManufacturerName string `json:"manufacturername,omitempty"`
   UniqueID         string `json:"uniqueid,omitempty"`
}

The full code reads:

func (hue *HueBridge) pollSensors(sensors *sensors.Sensors) {
   var previousSensorInfo map[int]sensors.Sensor = make(map[int]sensors.Sensor)
   for true {
      logger.Printf("Polling sensors")
      sensorInfo, err := sensors.GetAllSensors()
      if err == nil {
         if previousSensorInfo == nil {
            // first call
            logger.Printf("Got %d sensors", len(sensorInfo))
            for _, sensor := range sensorInfo {
               previousSensorInfo[sensor.ID] = &sensor
            }
         } else {
            // diff the two
            for _, sensor := range sensorInfo {
               prevSensor, found := previousSensorInfo[sensor.ID]
               if found {
                  if hue.diffSensor(prevSensor, sensor) {
                     logger.Printf(" Previous: %s", prevSensor)
                     logger.Printf(" Now     : %s", sensor)
                  }
               } else {
                  logger.Printf("New sensor: %d", sensor.ID)
               }
               previousSensorInfo[sensor.ID] = sensor
            }
         }
      }
      time.Sleep(1 * time.Second)
   }
}

What is going on here?

Regards,

Chris

[Jan Mercl]

On Sat, Sep 23, 2017 at 4:37 PM Chris Polderman <chris.p...@gmail.com> wrote:

> The full code reads:

The full code is not full code. It lacks eg. the import declarations. Please provide a link to the really full code at a specific commit for others to reproduce.

--

-j

[Tamás Gulácsi]

   previousSensorInfo := make(map[int]*sensors.Sensor)

[Jakob Borg]

On 23 Sep 2017, at 15:27, Chris Polderman <chris.p...@gmail.com> wrote:
>
> func (hue *HueBridge) pollSensors(sensors *sensors.Sensors) {
> var previousSensorInfo map[int]sensors.Sensor = make(map[int]sensors.Sensor)

In your function declaration, you're declaring a parameter "sensors" of the type *sensors.Sensors. This shadows the *package* also called "sensors" inside the function.

//jb

[Chris Polderman]

YES We have a winner!

I really did not see that!

Regards,

Chris

Op zaterdag 23 september 2017 18:32:25 UTC+2 schreef Jakob Borg: