read from yaml config file some struct item is null

[xiangxud]

type ConfYaml struct {
Logger logger.Config yaml:"logger"
Identity identity.IdentitySection yaml:"identity"
IP identity.IPSection yaml:"ip"
Stra stra.StraSection yaml:"stra"
Enable enableSection yaml:"enable"
Report reportSection yaml:"report"
Sys sys.SysSection yaml:"sys"
UI uiSection yaml:"ui"
Mqtt mqttSection yaml:"mqtt"
Screen screenSection yaml:"screen"
}
type screenSection struct {
BUsed bool yaml:"bused"
CaptureTimeDelay uint yaml:"capturetimedelay"
JpegFileLocalPath string yaml:"jpeglocalpath"
JpegFileURL string yaml:"jpegurl"
}

type mqttSection struct {
SUBTOPIC string yaml:"subtopic" //"topic1"
PUBTOPIC string yaml:"pubtopic"
QOS byte yaml:"qos" //1
SERVERADDRESS string yaml:"serveraddress" //= "tcp://mosquitto:1883"
CLIENTID string yaml:"clientid" //= "mqtt_subscriber"
WRITETOLOG bool yaml:"writelog" //= true // If true then received messages will be written to the console
WRITETODISK bool yaml:"writetodisk" //= false // If true then received messages will be written to the file below
OUTPUTFILE string yaml:"outputfile" //= "/binds/receivedMessages.txt"
// CommandLocalPath string yam:"commanlocalpath"
}
my yaml file
mqtt:
subtopic: "Control/#"
pubtopic: "bbt"
qos: 1
serveraddress: "tcp://10.0.23.123:1883"
clientid: "mqtt_subscriber"
writelog: true
writetodisk: true
outputfile: "./receivedMessages.txt"
screen:
bused: true
capturetimedelay: 600
jpeglocalpath: "jpg/" ??? why is null
jpegurl: "ftp://192.168.0.25/file" ??? why is null

i use like this:
err = viper.Unmarshal(&Config)
but
BUsed ok is true
CaptureTimeDelay ok is 600
JpegFileLocalPath string is "" must is "jpg/" why ？？？？
JpegFileURL is "" must is "ftp://192.168.0.25/file" why ???

WRITETOLOG is false must is true why ???

[sagikazarmark]

Take a look at https://github.com/spf13/viper#unmarshaling-doesnt-work

[xiangxud]

I change my struct maping(add mapstructure key words) like this:
UI uiSection yaml:"ui" mapstructure:"ui"
Mqtt mqttSection yaml:"mqtt" mapstructure:"mqtt"
Screen screenSection yaml:"screen" mapstructure:"screen"

but
come to the same thing
Maybe I misunderstand

[xiangxud]

thanks ，i add mapstructure key word in struct item ，it is ok