add version string to metrics

Dockerfile

@@ -112,7 +112,7 @@ ENV CGO_LDFLAGS="-L/usr/local/lib -lssl -lcrypto -lreadline -largon2 -lcurl -lon
 RUN echo $CGO_LDFLAGS
 
 WORKDIR /go/src/app/caddy/frankenphp
-RUN GOBIN=/usr/local/bin go install -tags 'nobadger,nomysql,nopgx' -ldflags "-w -s -X 'github.com/caddyserver/caddy/v2.CustomVersion=FrankenPHP $FRANKENPHP_VERSION PHP $PHP_VERSION Caddy'" && \
+RUN GOBIN=/usr/local/bin go install -tags 'nobadger,nomysql,nopgx' -ldflags "-w -s -X 'github.com/dunglas/frankenphp/versionString=$FRANKENPHP_VERSION' -X 'github.com/caddyserver/caddy/v2.CustomVersion=FrankenPHP $FRANKENPHP_VERSION PHP $PHP_VERSION Caddy'" && \
 	setcap cap_net_bind_service=+ep /usr/local/bin/frankenphp && \
 	cp Caddyfile /etc/caddy/Caddyfile && \
 	frankenphp version

alpine.Dockerfile

@@ -131,7 +131,7 @@ ENV CGO_CPPFLAGS=$PHP_CPPFLAGS
 ENV CGO_LDFLAGS="-lssl -lcrypto -lreadline -largon2 -lcurl -lonig -lz $PHP_LDFLAGS"
 
 WORKDIR /go/src/app/caddy/frankenphp
-RUN GOBIN=/usr/local/bin go install -tags 'nobadger,nomysql,nopgx' -ldflags "-w -s -extldflags '-Wl,-z,stack-size=0x80000' -X 'github.com/caddyserver/caddy/v2.CustomVersion=FrankenPHP $FRANKENPHP_VERSION PHP $PHP_VERSION Caddy'" && \
+RUN GOBIN=/usr/local/bin go install -tags 'nobadger,nomysql,nopgx' -ldflags "-w -s -extldflags '-Wl,-z,stack-size=0x80000' -X 'github.com/dunglas/frankenphp/versionString=$FRANKENPHP_VERSION' -X 'github.com/caddyserver/caddy/v2.CustomVersion=FrankenPHP $FRANKENPHP_VERSION PHP $PHP_VERSION Caddy'" && \
 	setcap cap_net_bind_service=+ep /usr/local/bin/frankenphp && \
 	([ -z "${NO_COMPRESS}" ] && upx --best /usr/local/bin/frankenphp || true) && \
 	frankenphp version

build-static.sh

@@ -271,7 +271,7 @@ fi
 
 cd caddy/frankenphp/
 go env
-go build -buildmode=pie -tags "cgo,netgo,osusergo,static_build,nobadger,nomysql,nopgx" -ldflags "-linkmode=external -extldflags '-static-pie ${extraExtldflags}' ${extraLdflags} -X 'github.com/caddyserver/caddy/v2.CustomVersion=FrankenPHP ${FRANKENPHP_VERSION} PHP ${LIBPHP_VERSION} Caddy'" -o "../../dist/${bin}"
+go build -buildmode=pie -tags "cgo,netgo,osusergo,static_build,nobadger,nomysql,nopgx" -ldflags "-linkmode=external -extldflags '-static-pie ${extraExtldflags}' ${extraLdflags} -X 'github.com/dunglas/frankenphp/versionString=${FRANKENPHP_VERSION}' -X 'github.com/caddyserver/caddy/v2.CustomVersion=FrankenPHP ${FRANKENPHP_VERSION} PHP ${LIBPHP_VERSION} Caddy'" -o "../../dist/${bin}"
 cd ../..
 
 if [ -d "${EMBED}" ]; then

metrics.go

@@ -11,6 +11,7 @@ import (
 
 var metricsNameRegex = regexp.MustCompile(`\W+`)
 var metricsNameFixRegex = regexp.MustCompile(`^_+|_+$`)
+var versionString = "dev"
 
 const (
 	StopReasonCrash = iota
@@ -85,6 +86,7 @@ type PrometheusMetrics struct {
 	workerRestarts     map[string]prometheus.Counter
 	workerRequestTime  map[string]prometheus.Counter
 	workerRequestCount map[string]prometheus.Counter
+	version            *prometheus.GaugeVec
 	mu                 sync.Mutex
 }
 
@@ -292,6 +294,8 @@ func (m *PrometheusMetrics) Shutdown() {
 	m.workerCrashes = map[string]prometheus.Counter{}
 	m.readyWorkers = map[string]prometheus.Gauge{}
 
+	// version does not change while running/restarting/stopping
+
 	m.registry.MustRegister(m.totalThreads)
 	m.registry.MustRegister(m.busyThreads)
 }
@@ -325,8 +329,15 @@ func NewPrometheusMetrics(registry prometheus.Registerer) *PrometheusMetrics {
 		workerRestarts:     map[string]prometheus.Counter{},
 		workerCrashes:      map[string]prometheus.Counter{},
 		readyWorkers:       map[string]prometheus.Gauge{},
+		version: prometheus.NewGaugeVec(prometheus.GaugeOpts{
+			Name: "frankenphp_version",
+			Help: "Current version of FrankenPHP",
+		}, []string{"version", "php_version"}),
 	}
 
+	m.registry.MustRegister(m.version)
+	m.version.WithLabelValues(versionString, Version().Version).Set(1)
+
 	m.registry.MustRegister(m.totalThreads)
 	m.registry.MustRegister(m.busyThreads)