GODT-35: Finish all details and make tests pass

pkg/pmapi/response.go

@@ -1,12 +1,35 @@
+// Copyright (c) 2021 Proton Technologies AG
+//
+// This file is part of ProtonMail Bridge.
+//
+// ProtonMail Bridge is free software: you can redistribute it and/or modify
+// it under the terms of the GNU General Public License as published by
+// the Free Software Foundation, either version 3 of the License, or
+// (at your option) any later version.
+//
+// ProtonMail Bridge is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+// GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License
+// along with ProtonMail Bridge.  If not, see <https://www.gnu.org/licenses/>.
+
 package pmapi
 
 import (
+	"math/rand"
 	"net/http"
 	"strconv"
 	"time"
 
 	"github.com/go-resty/resty/v2"
 	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+)
+
+const (
+	errCodeUpgradeApplication = 5003
 )
 
 type Error struct {
@@ -18,26 +41,34 @@ func (err Error) Error() string {
 	return err.Message
 }
 
-func catchAPIError(_ *resty.Client, res *resty.Response) error {
+func (m *manager) catchAPIError(_ *resty.Client, res *resty.Response) error {
 	if !res.IsError() {
 		return nil
 	}
 
+	if res.StatusCode() == http.StatusUnauthorized {
+		return ErrUnauthorized
+	}
+
 	var err error
 
 	if apiErr, ok := res.Error().(*Error); ok {
-		err = apiErr
+		switch {
+		case apiErr.Code == errCodeUpgradeApplication:
+			err = ErrUpgradeApplication
+			if m.cfg.UpgradeApplicationHandler != nil {
+				m.cfg.UpgradeApplicationHandler()
+			}
+		case res.StatusCode() == http.StatusUnprocessableEntity:
+			err = ErrUnprocessableEntity{apiErr}
+		default:
+			err = apiErr
+		}
 	} else {
 		err = errors.New(res.Status())
 	}
 
-	switch res.StatusCode() {
-	case http.StatusUnauthorized:
-		return errors.Wrap(ErrUnauthorized, err.Error())
-
-	default:
-		return errors.Wrap(ErrAPIFailure, err.Error())
-	}
+	return err
 }
 
 func catchRetryAfter(_ *resty.Client, res *resty.Response) (time.Duration, error) {
@@ -45,38 +76,47 @@ func catchRetryAfter(_ *resty.Client, res *resty.Response) (time.Duration, error
 		if after := res.Header().Get("Retry-After"); after != "" {
 			seconds, err := strconv.Atoi(after)
 			if err != nil {
-				return 0, err
+				log.WithError(err).Warning("Cannot convert Retry-After to number")
+				seconds = 10
 			}
 
+			// To avoid spikes when all clients retry at the same time, we add some random wait.
+			seconds += rand.Intn(10) //nolint[gosec] It is OK to use weak random number generator here.
+
+			log.Warningf("Retrying %s after %ds induced by http code %d", res.Request.URL, seconds, res.StatusCode())
 			return time.Duration(seconds) * time.Second, nil
 		}
 	}
 
+	// 0 and no error means default behaviour which is exponential backoff with jitter.
 	return 0, nil
 }
 
-func catchTooManyRequests(res *resty.Response, _ error) bool {
+func shouldRetry(res *resty.Response, err error) bool {
+	if isRetryDisabled(res.Request.Context()) {
+		return false
+	}
+	return isTooManyRequest(res) || isNoResponse(res, err)
+}
+
+func isTooManyRequest(res *resty.Response) bool {
 	return res.StatusCode() == http.StatusTooManyRequests
 }
 
-func catchNoResponse(res *resty.Response, err error) bool {
+func isNoResponse(res *resty.Response, err error) bool {
 	return res.RawResponse == nil && err != nil
 }
 
-func catchProxyAvailable(res *resty.Response, err error) bool {
-	/*
-		if res.Request.Attempt < ... {
-			return false
-		}
+func wrapNoConnection(res *resty.Response, err error) (*resty.Response, error) {
+	if err, ok := err.(*resty.ResponseError); ok {
+		return res, err
+	}
 
-		if response is not empty {
-			return false
-		}
+	if res.RawResponse != nil {
+		return res, err
+	}
 
-		if proxy is available {
-			return true
-		}
-	*/
-
-	return false
+	// Log useful information and return back nicer and clear error message.
+	logrus.WithError(err).WithField("url", res.Request.URL).Warn("No internet connection")
+	return res, ErrNoConnection
 }