Implement health check for deploy. Make version endpoint to return revision if not set

internal/api/version/version_handler.go

@@ -0,0 +1,59 @@
+package version
+
+import (
+	"io"
+	"net/http"
+	"runtime/debug"
+
+	"go.uber.org/fx"
+
+	// import embedded version
+	"payouts/internal/version"
+)
+
+// Route version route
+const Route = "/version"
+
+// Module is a fx module
+var Module = fx.Options(
+	fx.Provide(New),
+)
+
+// New constructs a new config Handler.
+func New() (Handler, error) {
+
+	return &handler{
+		version.Version,
+	}, nil
+}
+
+// Handler config handler interface
+type Handler interface {
+	VersionHandler(http.ResponseWriter, *http.Request)
+}
+
+type handler struct {
+	version string
+}
+
+// VersionHandler handles the version requests
+func (h *handler) VersionHandler(w http.ResponseWriter, r *http.Request) {
+	defer r.Body.Close()
+
+	ver := h.version
+	if ver == "unknown" {
+		buildInfo, ok := debug.ReadBuildInfo()
+		if ok {
+			for _, setting := range buildInfo.Settings {
+				if setting.Key == "vcs.revision" {
+					ver = ver + "-" + setting.Value
+					break
+				}
+			}
+		}
+	}
+
+	w.Header().Set("Content-Type", "text/plain")
+	w.WriteHeader(http.StatusOK)
+	io.WriteString(w, ver+"\n")
+}