Sample telegram bot

telegram.go

package main

import (
        "log"
        "gopkg.in/telegram-bot-api.v4"
        "fmt"
        "database/sql"
        _ "github.com/lib/pq"
)

const (
        DB_USER = "USER"
        DB_PASSWORD = "PASS"
        DB_NAME = "DBNAME"
        TOKEN = "THETOKEN"
)

func getLastTemp(db* sql.DB) (result string) {
        query := `SELECT value_int FROM data_sample_raw WHERE hostname like '%board%' AND data_item LIKE '%temperature' ORDER BY time_stamp DESC LIMIT 1`
        res := db.QueryRow(query)

        var temp int


        if err := res.Scan(&temp); err != nil {
                result = fmt.Sprintf("Error scanning : %s", err)
        }

        result = fmt.Sprintf("Temp=%d", temp)
        return
}

func getLastLight(db* sql.DB) (result string) {
        query := "SELECT value_int FROM data_sample_raw WHERE hostname like '%board%' AND data_item LIKE '%light' ORDER BY time_stamp DESC LIMIT 1"
        res := db.QueryRow(query)

        var light int

        if err := res.Scan(&light); err != nil {
                result = fmt.Sprintf("Error scanning : %s", err)
        }

        result = fmt.Sprintf("Light=%d", light)
        return
}

func getLastDistance(db* sql.DB) (result string) {
        query := "SELECT value_real FROM data_sample_raw WHERE hostname like '%board%' AND data_item LIKE '%distance' ORDER BY time_stamp DESC LIMIT 1"
        res := db.QueryRow(query)

        var distance float64

        if err := res.Scan(&distance); err != nil {
                result = fmt.Sprintf("Error scanning : %s", err)
        }
        result = fmt.Sprintf("Dist=%f", distance)
        return
}

func getDataFromDB() (result string) {
        dbconnect := fmt.Sprintf("user=%s password=%s dbname=%s sslmode=disable", 
                DB_USER, DB_PASSWORD, DB_NAME)  
        db, err := sql.Open("postgres", dbconnect)
        defer db.Close()

        if err != nil {
                result = fmt.Sprintf("Error in database : %s", err)
                return
        }


        temp := getLastTemp(db)
        light := getLastLight(db)
        dist := getLastDistance(db)
        
        result = fmt.Sprintf("%s\n%s\n%s\n", light, temp, dist)
        return
}

func main() {
        bot, err := tgbotapi.NewBotAPI(TOKEN)
        if err != nil {
                panic(err)
        }

        bot.Debug = false

        log.Printf("Authorized on account %s", bot.Self.UserName)

        u := tgbotapi.NewUpdate(0)
        u.Timeout = 60

        updates, err := bot.GetUpdatesChan(u)

        for update := range updates {
                if update.Message == nil {
                        continue
                }

                var tmp_msg string

                if update.Message.Text == `/getlastmetric` {
                        tmp_msg = getDataFromDB()
                } else {
                        tmp_msg = "Command not implemented"
                }

                msg := tgbotapi.NewMessage(update.Message.Chat.ID, tmp_msg)

                bot.Send(msg)
        }
}