Code maintenance: HTTP proxy loop reworked

- Blocking method calls on loop
- Restart proxy when settings change
- Detect server crash error and restart it

internal/httpproxy/server.go

@@ -10,7 +10,7 @@ import (
 )
 
 type Server interface {
-	Run(ctx context.Context, wg *sync.WaitGroup)
+	Run(ctx context.Context, wg *sync.WaitGroup, errorCh chan<- error)
 }
 
 type server struct {
@@ -31,13 +31,13 @@ func New(ctx context.Context, address string, logger logging.Logger,
 	}
 }
 
-func (s *server) Run(ctx context.Context, wg *sync.WaitGroup) {
+func (s *server) Run(ctx context.Context, wg *sync.WaitGroup, errorCh chan<- error) {
 	defer wg.Done()
 	server := http.Server{Addr: s.address, Handler: s.handler}
 	go func() {
 		<-ctx.Done()
-		s.logger.Warn("context canceled: exiting loop")
-		defer s.logger.Warn("loop exited")
+		s.logger.Warn("shutting down server")
+		defer s.logger.Warn("server shut down")
 		const shutdownGraceDuration = 2 * time.Second
 		shutdownCtx, cancel := context.WithTimeout(context.Background(), shutdownGraceDuration)
 		defer cancel()
@@ -47,8 +47,8 @@ func (s *server) Run(ctx context.Context, wg *sync.WaitGroup) {
 	}()
 	s.logger.Info("listening on %s", s.address)
 	err := server.ListenAndServe()
-	if err != nil && ctx.Err() != context.Canceled {
-		s.logger.Error(err)
+	if err != nil && ctx.Err() == nil {
+		errorCh <- err
 	}
 	s.internalWG.Wait()
 }