Add support for external sender

This commit allows using an external unix exporter to send the messages
instead of directly sending the messages to Telegram

.gitignore

@@ -16,7 +16,7 @@
 *.out
 
 # build directory
-tracker/build
+**/build
 
 # Dependency directories (remove the comment below to include it)
 # vendor/

Dockerfile

@@ -10,7 +10,7 @@ FROM --platform=$TARGETPLATFORM alpine:latest
 WORKDIR /root
 COPY --from=builder go/src/git.faercol.me/public-ip-tracker/build/tracker ./
 
-VOLUME [ "/config" ]
+VOLUME [ "/config", "/output" ]
 
 ENTRYPOINT [ "./tracker" ]
 CMD [ "-config", "/config/config.json" ]

README.md

@@ -44,6 +44,9 @@ For now, the program is configured through a JSON configuration file. Here is a
     "polling_frequency": 5,
     "log": {
         "level": "info"
+    },
+    "export": {
+        "mode": "native
     }
 }
 ```

examples/docker-compose-unix.yml

@@ -0,0 +1,17 @@
+services:
+  telegram_exporter:
+    container_name: telegram_exporter
+    image: git.faercol.me/notification/telegram-notifier:latest
+    environment:
+      - SOCK_PATH=/input/telegram.sock
+    volumes:
+      - './build/config/exporter:/config'
+      - './build/run:/input'
+
+  ip_tracker:
+    container_name: ip_tracker
+    image: git.faercol.me/faercol/public-ip-tracker:latest
+    # Volumes store your data between container upgrades
+    volumes:
+      - './build/config/tracker:/config'
+      - './build/run:/output'

tracker/bot/bot.go

@@ -10,6 +10,8 @@ import (
 	"git.faercol.me/faercol/public-ip-tracker/tracker/config"
 	"git.faercol.me/faercol/public-ip-tracker/tracker/ip"
 	"git.faercol.me/faercol/public-ip-tracker/tracker/logger"
+	"git.faercol.me/faercol/public-ip-tracker/tracker/messager"
+	"git.faercol.me/faercol/public-ip-tracker/tracker/unixsender"
 	"github.com/ahugues/go-telegram-api/bot"
 	"github.com/ahugues/go-telegram-api/notifier"
 	"github.com/ahugues/go-telegram-api/structs"
@@ -41,10 +43,22 @@ type Notifier struct {
 	currentIP  net.IP
 	frequency  time.Duration
 	errChan    chan error
-	changesChan chan net.IP
 	exitChan   chan struct{}
 	logger     logrus.Logger
 	hostname   string
+	sendMode   config.ExportMode
+	sender     messager.Sender
+}
+
+func (n *Notifier) sendMessage(msg string) error {
+	switch n.sendMode {
+	case config.ExportNative:
+		return n.tgBot.SendMessage(n.ctx, n.tgChatID, msg, structs.FormattingMarkdownV2)
+	case config.ExportUnix:
+		return n.sender.SendMessage(msg)
+	default:
+		return fmt.Errorf("invalid sending mode %v", n.sendMode)
+	}
 }
 
 func (n *Notifier) SendInitMessage() error {
@@ -59,7 +73,8 @@ func (n *Notifier) SendInitMessage() error {
 	currentTime := n.timeGetter()
 
 	n.logger.Debug("Sending init message to Telegram")
-	if err := n.tgBot.SendMessage(n.ctx, n.tgChatID, formatInitMsg(currentTime, publicIP, n.hostname), structs.FormattingMarkdownV2); err != nil {
+	initMsg := formatInitMsg(currentTime, publicIP, n.hostname)
+	if err := n.sendMessage(initMsg); err != nil {
 		return fmt.Errorf("failed to send initialization message: %w", err)
 	}
 	n.logger.Debug("Message sent")
@@ -67,7 +82,8 @@ func (n *Notifier) SendInitMessage() error {
 }
 
 func (n *Notifier) sendUpdatedIPMsg() error {
-	if err := n.tgBot.SendMessage(n.ctx, n.tgChatID, formatUpdate(n.timeGetter(), n.currentIP, n.hostname), structs.FormattingMarkdownV2); err != nil {
+	updateMsg := formatUpdate(n.timeGetter(), n.currentIP, n.hostname)
+	if err := n.sendMessage(updateMsg); err != nil {
 		return fmt.Errorf("failed to send update message: %w", err)
 	}
 	return nil
@@ -75,7 +91,7 @@ func (n *Notifier) sendUpdatedIPMsg() error {
 
 func (n *Notifier) sendCurrentIP() error {
 	statusMsg := fmt.Sprintf("Current public IP is %s", n.currentIP)
-	if err := n.tgBot.SendMessage(n.ctx, n.tgChatID, statusMsg, structs.FormattingMarkdownV2); err != nil {
+	if err := n.sendMessage(statusMsg); err != nil {
 		return fmt.Errorf("failed to send message: %w", err)
 	}
 	return nil
@@ -140,10 +156,26 @@ func (n *Notifier) Exit() <-chan struct{} {
 	return n.exitChan
 }
 
-func New(ctx context.Context, config *config.Config) *Notifier {
+func buildSender(ctx context.Context, conf *config.Config) (messager.Sender, error) {
+	switch conf.Export.Mode {
+	case config.ExportUnix:
+		logger.L.Infof("Building notifier in Unix mode")
+		return unixsender.New(ctx, conf)
+	default:
+		return nil, nil
+	}
+}
+
+func New(ctx context.Context, config *config.Config) (*Notifier, error) {
 	subCtx, cancel := context.WithCancel(ctx)
 	tgBot := bot.New(config.Telegram.Token)
 
+	sender, err := buildSender(subCtx, config)
+	if err != nil {
+		cancel()
+		return nil, fmt.Errorf("failed to build message sender: %w", err)
+	}
+
 	return &Notifier{
 		ctx:        subCtx,
 		cancel:     cancel,
@@ -157,5 +189,7 @@ func New(ctx context.Context, config *config.Config) *Notifier {
 		tgWatcher:  notifier.New(config.Telegram.Token),
 		logger:     logger.L,
 		hostname:   config.Hostname,
-	}
+		sendMode:   config.Export.Mode,
+		sender:     sender,
+	}, nil
 }

tracker/config/config.go

@@ -9,6 +9,24 @@ import (
 	"github.com/sirupsen/logrus"
 )
 
+type ExportMode int64
+
+const (
+	ExportNative = iota
+	ExportUnix
+)
+
+func exportModeFromStr(val string) ExportMode {
+	switch val {
+	case "native":
+		return ExportNative
+	case "unix":
+		return ExportUnix
+	default:
+		return ExportNative
+	}
+}
+
 type TelegramConfig struct {
 	ChannelID int64  `json:"channel_id"`
 	Token     string `json:"token"`
@@ -22,18 +40,30 @@ type jsonLogConfig struct {
 	Level string `json:"level"`
 }
 
+type ExportConfig struct {
+	Mode     ExportMode
+	UnixSock string
+}
+
+type jsonExportConfig struct {
+	Mode     string `json:"mode"`
+	UnixSock string `json:"sock_path"`
+}
+
 type Config struct {
 	Telegram         *TelegramConfig
 	PollingFrequency time.Duration
 	Hostname         string
-	Log              *LogConfig
+	Log              LogConfig
+	Export           ExportConfig
 }
 
 type jsonConfig struct {
 	Telegram         *TelegramConfig  `json:"telegram"`
 	PollingFrequency int64            `json:"polling_frequency"`
 	Hostname         string           `json:"hostname"`
-	Log              *jsonLogConfig  `json:"log"`
+	Log              jsonLogConfig    `json:"log"`
+	Export           jsonExportConfig `json:"export"`
 }
 
 func parseLevel(lvlStr string) logrus.Level {
@@ -54,12 +84,17 @@ func New(filepath string) (*Config, error) {
 	if err := json.Unmarshal(content, &jsonConf); err != nil {
 		return nil, fmt.Errorf("failed to parse config file: %w", err)
 	}
+
 	return &Config{
 		Telegram:         jsonConf.Telegram,
 		PollingFrequency: time.Duration(jsonConf.PollingFrequency) * time.Second,
 		Hostname:         jsonConf.Hostname,
-		Log: &LogConfig{
+		Log: LogConfig{
 			Level: parseLevel(jsonConf.Log.Level),
 		},
+		Export: ExportConfig{
+			UnixSock: jsonConf.Export.UnixSock,
+			Mode:     exportModeFromStr(jsonConf.Export.Mode),
+		},
 	}, nil
 }

tracker/main.go

@@ -48,7 +48,10 @@ func main() {
 	}
 
 	logger.L.Debug("Initializing notification bot")
-	notifBot := bot.New(mainCtx, conf)
+	notifBot, err := bot.New(mainCtx, conf)
+	if err != nil {
+		logger.L.Fatalf("Failed to create notification bot: %s", err.Error())
+	}
 
 	logger.L.Debug("Sending initialization message to Telegram")
 	if err := notifBot.SendInitMessage(); err != nil {

tracker/messager/messager.go

@@ -0,0 +1,26 @@
+package messager
+
+import (
+	"fmt"
+	"net"
+	"strings"
+	"time"
+)
+
+type Sender interface {
+	SendMessage(message string) error
+}
+
+func FormatInitMsg(currentTime time.Time, publicIP net.IP, hostname string) string {
+	formattedHostname := fmt.Sprintf("`%s`", hostname)
+	formattedIP := strings.ReplaceAll(publicIP.String(), ".", "\\.")
+	return fmt.Sprintf(`\[Host %s\] %s
+Public IP tracker initialized\. Current IP is %s`, formattedHostname, currentTime.Format(time.RFC1123), formattedIP)
+}
+
+func FormatUpdate(currentTime time.Time, publicIP net.IP, hostname string) string {
+	formattedHostname := fmt.Sprintf("`%s`", hostname)
+	formattedIP := strings.ReplaceAll(publicIP.String(), ".", "\\.")
+	return fmt.Sprintf(`\[Host %s\] %s
+Public IP has changed, new IP is %s`, formattedHostname, currentTime.Format(time.RFC1123), formattedIP)
+}

tracker/unixsender/unixsender.go

@@ -0,0 +1,66 @@
+package unixsender
+
+import (
+	"bytes"
+	"context"
+	"fmt"
+	"net"
+	"net/http"
+
+	"git.faercol.me/faercol/public-ip-tracker/tracker/config"
+	"git.faercol.me/faercol/public-ip-tracker/tracker/logger"
+	"github.com/sirupsen/logrus"
+)
+
+const method = http.MethodPost
+const baseURL = "http://unix/"
+
+type UnixSender struct {
+	logger  *logrus.Logger
+	ctx     context.Context
+	cancel  context.CancelFunc
+	httpClt *http.Client
+}
+
+func (s *UnixSender) SendMessage(message string) error {
+	s.logger.Debug("Sending message to unix sock")
+
+	body := bytes.NewBufferString(message)
+
+	req, err := http.NewRequestWithContext(s.ctx, method, baseURL, body)
+	if err != nil {
+		return fmt.Errorf("failed to prepare request: %w", err)
+	}
+
+	resp, err := s.httpClt.Do(req)
+	if err != nil {
+		return fmt.Errorf("failed to run query: %w", err)
+	}
+	if resp.StatusCode != http.StatusOK {
+		return fmt.Errorf("invalid returncode %d", resp.StatusCode)
+	}
+
+	return nil
+}
+
+func New(ctx context.Context, config *config.Config) (*UnixSender, error) {
+	subCtx, cancel := context.WithCancel(ctx)
+
+	logger.L.Infof("Creating Unix exporter to sock %q", config.Export.UnixSock)
+
+	httpClt := http.Client{
+		Transport: &http.Transport{
+			DialContext: func(ctx context.Context, network, addr string) (net.Conn, error) {
+				dialer := net.Dialer{}
+				return dialer.DialContext(ctx, "unix", config.Export.UnixSock)
+			},
+		},
+	}
+
+	return &UnixSender{
+		ctx:     subCtx,
+		cancel:  cancel,
+		httpClt: &httpClt,
+		logger:  &logger.L,
+	}, nil
+}