Healthcheck moved to HTTP control server

internal/server/health.go

@@ -0,0 +1,27 @@
+package server
+
+import (
+	"fmt"
+	"net/http"
+)
+
+func (s *server) handleHealth(w http.ResponseWriter) {
+	// TODO option to disable
+	// TODO use mullvad API if current provider is Mullvad
+	ips, err := s.lookupIP("github.com")
+	var errorMessage string
+	switch {
+	case err != nil:
+		errorMessage = fmt.Sprintf("cannot resolve github.com (%s)", err)
+	case len(ips) == 0:
+		errorMessage = "resolved no IP addresses for github.com"
+	default: // success
+		w.WriteHeader(http.StatusOK)
+		return
+	}
+	s.logger.Warn(errorMessage)
+	w.WriteHeader(http.StatusInternalServerError)
+	if _, err := w.Write([]byte(errorMessage)); err != nil {
+		s.logger.Warn(err)
+	}
+}