miflorad: add version

Makefile

@@ -1,6 +1,7 @@
 .POSIX:
 
 MIFLORA_ADDR?=00:00:00:00:00:00
+MIFLORAD_VERSION?=master
 
 RUN_COMMAND=miflorad
 RUN_OPTIONS=$(MIFLORA_ADDR)
@@ -34,7 +35,7 @@ remote-run: clean
 
 .PHONY: cmd/munin-miflora/miflorad
 cmd/munin-miflora/miflorad:
-	cd cmd/miflorad && CGO_ENABLED=0 go build && cd ../..
+	cd cmd/miflorad && CGO_ENABLED=0 go build -ldflags "-X main.version=$(MIFLORAD_VERSION)" && cd ../..
 
 .PHONY: cmd/munin-miflora/munin-miflora
 cmd/munin-miflora/munin-miflora:

cmd/miflorad/main.go

@@ -19,6 +19,9 @@ import (
 	"github.com/pkg/errors"
 )
 
+// program version, will be populated on build
+var version string
+
 var (
 	scanTimeout = flag.Duration("scantimeout", 10*time.Second, "timeout after that a scan per peripheral will be aborted")
 	interval    = flag.Duration("interval", 25*time.Second, "metrics collection interval")
@@ -49,6 +52,14 @@ func checkTooShortInterval() error {
 	return nil
 }
 
+func getVersion() string {
+	if version == "" {
+		return "dev"
+	} else {
+		return version
+	}
+}
+
 func readData(peripheral *peripheral, client ble.Client) error {
 	// re-request meta data (for battery level) if last check more than 24 hours ago
 	// Source: https://github.com/open-homeautomation/miflora/blob/ffd95c3e616df8843cc8bff99c9b60765b124092/miflora/miflora_poller.py#L92
@@ -181,6 +192,8 @@ func main() {
 		os.Exit(1)
 	}
 
+	fmt.Fprintf(os.Stderr, "miflorad version %s\n", getVersion())
+
 	device, err := dev.NewDevice("default")
 	if err != nil {
 		fmt.Fprintf(os.Stderr, "Failed to open device, err: %s\n", err)