Added ssl/tls support

.gitignore

@@ -2,4 +2,5 @@
 *.csv
 
 # binary file
-MQTTLogger 
+MQTTLogger 
+.vscode/launch.json

cmd/MQTTLogger/main.go

@@ -18,6 +18,7 @@ func main() {
 			NewLogger,
 			config.NewConfig,
 			mqtt.NewClient,
+			mqtt.NewTLSConfig,
 			csv.NewHelper,
 		),
 		fx.Invoke(

config/config.go

@@ -13,6 +13,7 @@ type Config struct {
 	Username string
 	Password string
 	Topics   []string
+	CACert   string
 }
 
 func NewConfig(logger *zap.Logger) *Config {
@@ -51,10 +52,16 @@ func NewConfig(logger *zap.Logger) *Config {
 		}
 	}
 
+	caCert := os.Getenv("MQTT_CACERT")
+	if caCert == "" {
+		logger.Warn("MQTT_CACERT is not set, not using TLS")
+	}
+
 	return &Config{
 		URI:      uri,
 		Username: username,
 		Password: password,
 		Topics:   topics,
+		CACert:   caCert,
 	}
 }

go.mod

@@ -3,13 +3,16 @@ module MQTTLogger
 go 1.25.1
 
 require (
-	github.com/eclipse/paho.mqtt.golang v1.5.1 // indirect
+	github.com/eclipse/paho.mqtt.golang v1.5.1
+	github.com/joho/godotenv v1.5.1
+	go.uber.org/fx v1.24.0
+	go.uber.org/zap v1.27.0
+)
+
+require (
 	github.com/gorilla/websocket v1.5.3 // indirect
-	github.com/joho/godotenv v1.5.1 // indirect
 	go.uber.org/dig v1.19.0 // indirect
-	go.uber.org/fx v1.24.0 // indirect
 	go.uber.org/multierr v1.11.0 // indirect
-	go.uber.org/zap v1.27.0 // indirect
 	golang.org/x/net v0.44.0 // indirect
 	golang.org/x/sync v0.17.0 // indirect
 	golang.org/x/sys v0.36.0 // indirect

go.sum

@@ -1,19 +1,23 @@
+github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
+github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/eclipse/paho.mqtt.golang v1.5.1 h1:/VSOv3oDLlpqR2Epjn1Q7b2bSTplJIeV2ISgCl2W7nE=
 github.com/eclipse/paho.mqtt.golang v1.5.1/go.mod h1:1/yJCneuyOoCOzKSsOTUc0AJfpsItBGWvYpBLimhArU=
 github.com/gorilla/websocket v1.5.3 h1:saDtZ6Pbx/0u+bgYQ3q96pZgCzfhKXGPqt7kZ72aNNg=
 github.com/gorilla/websocket v1.5.3/go.mod h1:YR8l580nyteQvAITg2hZ9XVh4b55+EU/adAjf1fMHhE=
 github.com/joho/godotenv v1.5.1 h1:7eLL/+HRGLY0ldzfGMeQkb7vMd0as4CfYvUVzLqw0N0=
 github.com/joho/godotenv v1.5.1/go.mod h1:f4LDr5Voq0i2e/R5DDNOoa2zzDfwtkZa6DnEwAbqwq4=
+github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
+github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/stretchr/testify v1.8.1 h1:w7B6lhMri9wdJUVmEZPGGhZzrYTPvgJArz7wNPgYKsk=
+github.com/stretchr/testify v1.8.1/go.mod h1:w2LPCIKwWwSfY2zedu0+kehJoqGctiVI29o6fzry7u4=
 go.uber.org/dig v1.19.0 h1:BACLhebsYdpQ7IROQ1AGPjrXcP5dF80U3gKoFzbaq/4=
 go.uber.org/dig v1.19.0/go.mod h1:Us0rSJiThwCv2GteUN0Q7OKvU7n5J4dxZ9JKUXozFdE=
 go.uber.org/fx v1.24.0 h1:wE8mruvpg2kiiL1Vqd0CC+tr0/24XIB10Iwp2lLWzkg=
 go.uber.org/fx v1.24.0/go.mod h1:AmDeGyS+ZARGKM4tlH4FY2Jr63VjbEDJHtqXTGP5hbo=
-go.uber.org/multierr v1.10.0 h1:S0h4aNzvfcFsC3dRF1jLoaov7oRaKqRGC/pUEJ2yvPQ=
+go.uber.org/goleak v1.3.0 h1:2K3zAYmnTNqV73imy9J1T3WC+gmCePx2hEGkimedGto=
-go.uber.org/multierr v1.10.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
+go.uber.org/goleak v1.3.0/go.mod h1:CoHD4mav9JJNrW/WLlf7HGZPjdw8EucARQHekz1X6bE=
 go.uber.org/multierr v1.11.0 h1:blXXJkSxSSfBVBlC76pxqeO+LN3aDfLQo+309xJstO0=
 go.uber.org/multierr v1.11.0/go.mod h1:20+QtiLqy0Nd6FdQB9TLXag12DsQkrbs3htMFfDN80Y=
-go.uber.org/zap v1.26.0 h1:sI7k6L95XOKS281NhVKOFCUNIvv9e0w4BF8N3u+tCRo=
-go.uber.org/zap v1.26.0/go.mod h1:dtElttAiwGvoJ/vj4IwHBS/gXsEu/pZ50mUIRWuG0so=
 go.uber.org/zap v1.27.0 h1:aJMhYGrd5QSmlpLMr2MftRKl7t8J8PTZPA732ud/XR8=
 go.uber.org/zap v1.27.0/go.mod h1:GB2qFLM7cTU87MWRP2mPIjqfIDnGu+VIO4V/SdhGo2E=
 golang.org/x/net v0.44.0 h1:evd8IRDyfNBMBTTY5XRF1vaZlD+EmWx6x8PkhR04H/I=
@@ -22,3 +26,5 @@ golang.org/x/sync v0.17.0 h1:l60nONMj9l5drqw6jlhIELNv9I0A4OFgRsG9k2oT9Ug=
 golang.org/x/sync v0.17.0/go.mod h1:9KTHXmSnoGruLpwFjVSX0lNNA75CykiMECbovNTZqGI=
 golang.org/x/sys v0.36.0 h1:KVRy2GtZBrk1cBYA7MKu5bEZFxQk4NIDV6RLVcC8o0k=
 golang.org/x/sys v0.36.0/go.mod h1:OgkHotnGiDImocRcuBABYBEXf8A9a87e/uXjp9XT3ks=
+gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
+gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

internal/mqtt/mqtt.go

@@ -1,27 +1,37 @@
 package mqtt
 
 import (
+	"fmt"
 	"MQTTLogger/config"
 	"MQTTLogger/internal/csv"
+	"crypto/tls"
+	"math/rand/v2"
 	"time"
 
 	mqtt "github.com/eclipse/paho.mqtt.golang"
 	"go.uber.org/zap"
 )
 
-func NewClient(logger *zap.Logger, config *config.Config, csvHelper *csv.Helper) mqtt.Client {
+func NewClient(logger *zap.Logger, config *config.Config, csvHelper *csv.Helper, tlsConfig *tls.Config) mqtt.Client {
+	
 	var f mqtt.MessageHandler = func(client mqtt.Client, msg mqtt.Message) {
 		csvHelper.AddEntry(time.Now().UTC().Format("2006-01-02 15:04:05"), msg.Topic(), string(msg.Payload()))
 	}
 
-	opts := mqtt.NewClientOptions().AddBroker(config.URI).SetClientID("mqtt-logger")
+	randomClientID := "mqtt-logger-" + fmt.Sprint(rand.Int())
+	logger.Info("Creating MQTT client", zap.String("clientID", randomClientID))
+	opts := mqtt.NewClientOptions().AddBroker(config.URI).SetClientID(randomClientID)
+	if tlsConfig != nil {
+		opts.SetTLSConfig(tlsConfig)
+	}
 	opts.SetKeepAlive(2 * time.Second)
 	opts.SetDefaultPublishHandler(f)
-	opts.SetPingTimeout(1 * time.Second)
+	opts.SetPingTimeout(1 * time.Second)	
 	opts.SetConnectionNotificationHandler(func(client mqtt.Client, notification mqtt.ConnectionNotification) {
 		switch n := notification.(type) {
 		case mqtt.ConnectionNotificationConnected:
 			logger.Info("Connected to MQTT broker")
+			// Re-susbcribe to topics on reconnect
 			StartListening(logger, config, client)
 		case mqtt.ConnectionNotificationConnecting:
 			logger.Info("connecting", zap.Bool("isReconnect", n.IsReconnect), zap.Int("attempt", n.Attempt))

internal/mqtt/tls.go

@@ -0,0 +1,34 @@
+package mqtt
+
+import (
+	"MQTTLogger/config"
+	"crypto/tls"
+	"crypto/x509"
+	"os"
+
+	"go.uber.org/zap"
+)
+
+func NewTLSConfig(logger *zap.Logger, config *config.Config) *tls.Config {
+
+	if config.CACert == "" {
+		return nil
+	}
+
+	certpool := x509.NewCertPool()
+	pemCerts, err := os.ReadFile(config.CACert)
+	if err == nil {
+		certpool.AppendCertsFromPEM(pemCerts)
+	} else {
+		logger.Fatal("error loading CA cert", zap.Error(err))
+	}
+
+	return &tls.Config{
+		RootCAs: certpool,
+		// We use the provided cert not the one server sends.
+		ClientAuth:         tls.NoClientCert,
+		ClientCAs:          nil,
+		InsecureSkipVerify: true, // I know
+		Certificates: nil,
+	}
+}