Kickoff go application

.gitignore

@@ -0,0 +1 @@
+/smartbridge

Makefile

@@ -0,0 +1,5 @@
+default: all
+all: smartbridge
+
+smartbridge: cmd/smartbridge/*.go
+	go build -o $@ $^

cmd/smartbridge/config.go

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+package main
+
+type Config struct {
+	Remote string // Remote IP address of the Smartbridge
+	Mqtt   string // mqtt server
+}
+
+var cf Config
+
+func (cf *Config) SetDefaults() {
+	cf.Remote = "192.168.242.199"
+	cf.Mqtt = "192.168.0.42"
+}

cmd/smartbridge/main.go

@@ -0,0 +1,49 @@
+package main
+
+import (
+	"fmt"
+	"os"
+	"time"
+)
+
+var mqtt_c Mqtt
+
+func establishMqtt() error {
+	var err error
+	n := 5
+
+	for i := 0; i < n; i++ {
+		mqtt_c, err = ConnectMqtt(cf.Mqtt, 1883)
+		if err == nil {
+			return nil
+		}
+		fmt.Fprintf(os.Stderr, "mqtt error: %s (attempt %d/%d)\n", err, i+1, n)
+		time.Sleep(time.Second * time.Duration(i))
+	}
+	return fmt.Errorf("connection failed")
+}
+
+func main() {
+
+	cf.SetDefaults()
+
+	if err := establishMqtt(); err != nil {
+		fmt.Fprintf(os.Stderr, "mqtt: %s\n", err)
+		os.Exit(1)
+	}
+
+	fmt.Println("smartbridge reader operational")
+	for true {
+		reading, err := ReadSmartbridge(cf.Remote)
+		if err != nil {
+			fmt.Fprintf(os.Stderr, "%s\n", err)
+		}
+		if reading.Status != "ok" {
+			fmt.Fprintf(os.Stderr, "status: %s\n", reading.Status)
+		} else {
+			data := fmt.Sprintf("{\"power\":%d,\"unit\":\"W\",\"timestamp\":%d}", reading.Electricity.Power.Current.Value, time.Now().Unix())
+			mqtt_c.Publish("home/power", data)
+		}
+		time.Sleep(5 * time.Second)
+	}
+}

cmd/smartbridge/mqtt.go

@@ -0,0 +1,34 @@
+package main
+
+import (
+	"fmt"
+
+	mqtt "github.com/eclipse/paho.mqtt.golang"
+)
+
+type Mqtt struct {
+	client mqtt.Client
+}
+
+func ConnectMqtt(broker string, port int) (Mqtt, error) {
+	var ret Mqtt
+	opts := mqtt.NewClientOptions()
+	opts.AddBroker(fmt.Sprintf("tcp://%s:%d", broker, port))
+	opts.SetClientID("smartbridge")
+	//opts.SetUsername("emqx")
+	//opts.SetPassword("public")
+	//opts.SetDefaultPublishHandler(messagePubHandler)
+	//opts.OnConnect = connectHandler
+	//opts.OnConnectionLost = connectLostHandler
+	opts.AutoReconnect = true
+	ret.client = mqtt.NewClient(opts)
+	token := ret.client.Connect()
+	token.Wait()
+	return ret, token.Error()
+}
+
+func (m *Mqtt) Publish(topic string, message string) error {
+	tok := m.client.Publish(topic, 0, false, message)
+	tok.Wait()
+	return tok.Error()
+}

cmd/smartbridge/smartbridge.go

@@ -0,0 +1,50 @@
+package main
+
+import (
+	"encoding/json"
+	"fmt"
+	"io"
+	"net/http"
+)
+
+type Reading struct {
+	Status      string      `json:"status"`
+	Electricity Electricity `json:"elec"`
+}
+
+type Electricity struct {
+	Power  Power `json:"power"`
+	Import Power `json:"import"`
+	Export Power `json:"export"`
+}
+
+type Power struct {
+	Current Value `json:"now"`
+	Minimun Value `json:"min"`
+	Maximum Value `json:"max"`
+}
+
+type Value struct {
+	Value     int    `json:"value"`
+	Unit      string `json:"unit"`
+	Timestamp int64  `json:"time"`
+}
+
+func ReadSmartbridge(remote string) (Reading, error) {
+	var reading Reading
+	uri := fmt.Sprintf("http://%s/meter/now", remote)
+	resp, err := http.Get(uri)
+	if err != nil {
+		return reading, err
+	}
+	if resp.StatusCode != 200 {
+		return reading, fmt.Errorf("http status code %d returned", resp.StatusCode)
+	}
+	defer resp.Body.Close()
+	buf, err := io.ReadAll(resp.Body)
+	if err != nil {
+		return reading, err
+	}
+	err = json.Unmarshal(buf, &reading)
+	return reading, err
+}

go.mod

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+module feldspaten.org/smartbridge/v2
+
+go 1.20
+
+require github.com/eclipse/paho.mqtt.golang v1.4.2
+
+require (
+	github.com/gorilla/websocket v1.4.2 // indirect
+	golang.org/x/net v0.0.0-20200425230154-ff2c4b7c35a0 // indirect
+	golang.org/x/sync v0.0.0-20210220032951-036812b2e83c // indirect
+)

go.sum

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+github.com/eclipse/paho.mqtt.golang v1.4.2 h1:66wOzfUHSSI1zamx7jR6yMEI5EuHnT1G6rNA5PM12m4=
+github.com/eclipse/paho.mqtt.golang v1.4.2/go.mod h1:JGt0RsEwEX+Xa/agj90YJ9d9DH2b7upDZMK9HRbFvCA=
+github.com/gorilla/websocket v1.4.2 h1:+/TMaTYc4QFitKJxsQ7Yye35DkWvkdLcvGKqM+x0Ufc=
+github.com/gorilla/websocket v1.4.2/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20200425230154-ff2c4b7c35a0 h1:Jcxah/M+oLZ/R4/z5RzfPzGbPXnVDPkEDtf2JnuxN+U=
+golang.org/x/net v0.0.0-20200425230154-ff2c4b7c35a0/go.mod h1:qpuaurCH72eLCgpAm/N6yyVIVM9cpaDIP3A8BGJEC5A=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c h1:5KslGYwFpkhGh+Q16bwMP3cOontH8FOep7tGV86Y7SQ=
+golang.org/x/sync v0.0.0-20210220032951-036812b2e83c/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/sys v0.0.0-20200323222414-85ca7c5b95cd/go.mod h1:h1NjWce9XRLGQEsW7wpKNCjG9DtNlClVuFLEZdDNbEs=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=

smartbridge.py

@@ -1,41 +0,0 @@
-#!/usr/bin/env python3
-# -*- coding: utf-8 -*-
-
-import requests
-import os
-import time
-import paho.mqtt.client as mqtt
-import json
-
-SOURCE = "http://192.168.242.199/meter/now"
-MQTT_SERVER = "192.168.0.42"
-MQTT_TOPIC = "home/power"
-DELAY = 5
-
-def obtain_data() :
-    req = requests.get(SOURCE)
-    req.raise_for_status()
-    return req.json()
-
-if __name__ == "__main__" :
-    # MQTT client
-    client = mqtt.Client()
-    client.connect(MQTT_SERVER, 1883, 60)
-
-    while True :
-        data = obtain_data()
-        if data['status'] != 'ok' :
-            print("status: %s" % data['status'])
-            os.Exit(1)
-
-        # Get Power readings
-        power = data['elec']['power']['now']['value']    # Current power readings in Watt
-
-        # MQTT publish
-        tsp = int(time.time())
-        data = {"power": power, "timestamp": tsp}
-        msg = json.dumps(data)
-        print(msg)
-        result = client.publish(MQTT_TOPIC, msg)
-        time.sleep(DELAY)
-