inject build info into main during build process

Signed-off-by: Mikolaj Pawlikowski <mikolaj@pawlikowski.pl>

build/build.sh

@@ -37,5 +37,6 @@ export CGO_ENABLED=0
 export GOARCH="${ARCH}"
 
 go build \
-   -o ./bin/${BIN} \
-   ./cmd/${BIN}
+    -ldflags "-X 'main.Version=${VERSION}' -X 'main.Build=`date`'" \
+    -o ./bin/${BIN} \
+    ./cmd/${BIN}

cmd/goldpinger/main.go

@@ -29,7 +29,15 @@ import (
 	flags "github.com/jessevdk/go-flags"
 )
 
+// these will be injected during build in build.sh script to allow printing
+var (
+	Version, Build string
+)
+
 func main() {
+
+	log.Println("Goldpinger version:", Version, "build:", Build)
+
 	// load embedded swagger file
 	swaggerSpec, err := loads.Analyzed(restapi.SwaggerJSON, "")
 	if err != nil {