Loops and HTTP control server rework (#308)

- CRUD REST HTTP server
- `/v1` HTTP server prefix
- Retrocompatible with older routes (redirects to v1 or handles the requests directly)
- DNS, Updater and Openvpn refactored to have a REST-like state with new methods to change their states synchronously
- Openvpn, Unbound and Updater status, see #287

internal/server/handlerv0.go

@@ -0,0 +1,69 @@
+package server
+
+import (
+	"net/http"
+
+	"github.com/qdm12/gluetun/internal/constants"
+	"github.com/qdm12/gluetun/internal/dns"
+	"github.com/qdm12/gluetun/internal/openvpn"
+	"github.com/qdm12/gluetun/internal/updater"
+	"github.com/qdm12/golibs/logging"
+)
+
+func newHandlerV0(logger logging.Logger,
+	openvpn openvpn.Looper, dns dns.Looper, updater updater.Looper) http.Handler {
+	return &handlerV0{
+		logger:  logger,
+		openvpn: openvpn,
+		dns:     dns,
+		updater: updater,
+	}
+}
+
+type handlerV0 struct {
+	logger  logging.Logger
+	openvpn openvpn.Looper
+	dns     dns.Looper
+	updater updater.Looper
+}
+
+func (h *handlerV0) ServeHTTP(w http.ResponseWriter, r *http.Request) {
+	if r.Method != http.MethodGet {
+		http.Error(w, "unversioned API: only supports GET method", http.StatusNotFound)
+		return
+	}
+	switch r.RequestURI {
+	case "/version":
+		http.Redirect(w, r, "/v1/version", http.StatusPermanentRedirect)
+	case "/openvpn/actions/restart":
+		outcome, _ := h.openvpn.SetStatus(constants.Stopped)
+		h.logger.Info("openvpn: %s", outcome)
+		outcome, _ = h.openvpn.SetStatus(constants.Running)
+		h.logger.Info("openvpn: %s", outcome)
+		if _, err := w.Write([]byte("openvpn restarted, please consider using the /v1/ API in the future.")); err != nil {
+			h.logger.Warn(err)
+		}
+	case "/unbound/actions/restart":
+		outcome, _ := h.dns.SetStatus(constants.Stopped)
+		h.logger.Info("dns: %s", outcome)
+		outcome, _ = h.dns.SetStatus(constants.Running)
+		h.logger.Info("dns: %s", outcome)
+		if _, err := w.Write([]byte("dns restarted, please consider using the /v1/ API in the future.")); err != nil {
+			h.logger.Warn(err)
+		}
+	case "/openvpn/portforwarded":
+		http.Redirect(w, r, "/v1/openvpn/portforwarded", http.StatusPermanentRedirect)
+	case "/openvpn/settings":
+		http.Redirect(w, r, "/v1/openvpn/settings", http.StatusPermanentRedirect)
+	case "/updater/restart":
+		outcome, _ := h.updater.SetStatus(constants.Stopped)
+		h.logger.Info("updater: %s", outcome)
+		outcome, _ = h.updater.SetStatus(constants.Running)
+		h.logger.Info("updater: %s", outcome)
+		if _, err := w.Write([]byte("updater restarted, please consider using the /v1/ API in the future.")); err != nil {
+			h.logger.Warn(err)
+		}
+	default:
+		http.Error(w, "unversioned API: requested URI not found", http.StatusNotFound)
+	}
+}