Add version flag

And print version at startup.

.build.yml

@@ -11,6 +11,7 @@ sources:
 tasks:
     - test: |
           cd ntfy-alertmanager
+          go generate ./...
           go test -v ./...
     - lint: |
           cd ntfy-alertmanager

.gitignore

@@ -1 +1,2 @@
 /ntfy-alertmanager
+version.txt

docker/Dockerfile-dev

@@ -2,7 +2,8 @@ FROM golang:alpine as build
 WORKDIR /app
 
 COPY . .
-RUN go build -o /app/ntfy-alertmanager
+RUN apk add --no-cache git
+RUN go generate ./... && go build -o /app/ntfy-alertmanager
 
 
 FROM alpine:latest

main.go

@@ -4,11 +4,13 @@ package main
 import (
 	"crypto/sha512"
 	"crypto/subtle"
+	_ "embed"
 	"encoding/base64"
 	"encoding/json"
 	"flag"
 	"fmt"
 	"net/http"
+	"os"
 	"strings"
 	"time"
 
@@ -17,6 +19,10 @@ import (
 	"golang.org/x/text/language"
 )
 
+//go:generate sh -c "git describe --long > version.txt"
+//go:embed version.txt
+var version string
+
 type receiver struct {
 	cfg    *config
 	logger *log.Logger
@@ -205,8 +211,15 @@ func (rcv *receiver) basicAuthMiddleware(handler http.HandlerFunc) http.HandlerF
 func main() {
 	var configPath string
 	flag.StringVar(&configPath, "config", "/etc/ntfy-alertmanager/config", "config file path")
+	var showVersion bool
+	flag.BoolVar(&showVersion, "version", false, "Show version and exit")
 	flag.Parse()
 
+	if showVersion {
+		fmt.Println(version)
+		os.Exit(0)
+	}
+
 	logger := log.NewDefaultLogger()
 
 	cfg, err := readConfig(configPath)
@@ -220,7 +233,7 @@ func main() {
 
 	receiver := &receiver{cfg: cfg, logger: logger}
 
-	logger.Infof("Listening on %s", cfg.HTTPAddress)
+	logger.Infof("Listening on %s, ntfy-alertmanager %s", cfg.HTTPAddress, version)
 
 	if cfg.User != "" && cfg.Password != "" {
 		logger.Info("Enabling HTTP Basic Authentication")