fix: Handle kubernetes API conflicts properly for signing keys

Signed-off-by: m.nabokikh <maksim.nabokikh@flant.com>

storage/kubernetes/storage.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"errors"
 	"fmt"
+	"net/http"
 	"strings"
 	"time"
 
@@ -512,6 +513,7 @@ func (cli *client) UpdateKeys(updater func(old storage.Keys) (storage.Keys, erro
 		}
 		firstUpdate = true
 	}
+
 	var oldKeys storage.Keys
 	if !firstUpdate {
 		oldKeys = toStorageKeys(keys)
@@ -521,12 +523,32 @@ func (cli *client) UpdateKeys(updater func(old storage.Keys) (storage.Keys, erro
 	if err != nil {
 		return err
 	}
+
 	newKeys := cli.fromStorageKeys(updated)
 	if firstUpdate {
-		return cli.post(resourceKeys, newKeys)
+		err = cli.post(resourceKeys, newKeys)
+		if err != nil && errors.Is(err, storage.ErrAlreadyExists) {
+			// We need to tolerate conflicts here in case of HA mode.
+			cli.logger.Debugf("Keys creation failed: %v. It is possible that keys have already been created by another dex instance.", err)
+			return errors.New("keys already created by another server instance")
+		}
+
+		return err
 	}
+
 	newKeys.ObjectMeta = keys.ObjectMeta
-	return cli.put(resourceKeys, keysName, newKeys)
+
+	err = cli.put(resourceKeys, keysName, newKeys)
+	if httpErr, ok := err.(httpError); ok {
+		// We need to tolerate conflicts here in case of HA mode.
+		// Dex instances run keys rotation at the same time because they use SigningKey.nextRotation CR field as a trigger.
+		if httpErr.StatusCode() == http.StatusConflict {
+			cli.logger.Debugf("Keys rotation failed: %v. It is possible that keys have already been rotated by another dex instance.", err)
+			return errors.New("keys already rotated by another server instance")
+		}
+	}
+
+	return err
 }
 
 func (cli *client) UpdateAuthRequest(id string, updater func(a storage.AuthRequest) (storage.AuthRequest, error)) error {

storage/kubernetes/storage_test.go

@@ -1,7 +1,12 @@
 package kubernetes
 
 import (
+	"crypto/tls"
+	"errors"
+	"fmt"
 	"io/ioutil"
+	"net/http"
+	"net/http/httptest"
 	"os"
 	"strings"
 	"testing"
@@ -150,3 +155,120 @@ func TestURLFor(t *testing.T) {
 		}
 	}
 }
+
+func TestUpdateKeys(t *testing.T) {
+	fakeUpdater := func(old storage.Keys) (storage.Keys, error) { return storage.Keys{}, nil }
+
+	tests := []struct {
+		name               string
+		updater            func(old storage.Keys) (storage.Keys, error)
+		getResponseCode    int
+		actionResponseCode int
+		wantErr            bool
+		exactErr           error
+	}{
+		{
+			"Create OK test",
+			fakeUpdater,
+			404,
+			201,
+			false,
+			nil,
+		},
+		{
+			"Update should be OK",
+			fakeUpdater,
+			200,
+			200,
+			false,
+			nil,
+		},
+		{
+			"Create conflict should be OK",
+			fakeUpdater,
+			404,
+			409,
+			true,
+			errors.New("keys already created by another server instance"),
+		},
+		{
+			"Update conflict should be OK",
+			fakeUpdater,
+			200,
+			409,
+			true,
+			errors.New("keys already rotated by another server instance"),
+		},
+		{
+			"Client error is error",
+			fakeUpdater,
+			404,
+			500,
+			true,
+			nil,
+		},
+		{
+			"Client error during update is error",
+			fakeUpdater,
+			200,
+			500,
+			true,
+			nil,
+		},
+		{
+			"Get error is error",
+			fakeUpdater,
+			500,
+			200,
+			true,
+			nil,
+		},
+		{
+			"Updater error is error",
+			func(old storage.Keys) (storage.Keys, error) { return storage.Keys{}, fmt.Errorf("test") },
+			200,
+			201,
+			true,
+			nil,
+		},
+	}
+
+	for _, test := range tests {
+		client := newStatusCodesResponseTestClient(test.getResponseCode, test.actionResponseCode)
+
+		err := client.UpdateKeys(test.updater)
+		if err != nil {
+			if !test.wantErr {
+				t.Fatalf("Test %q: %v", test.name, err)
+			}
+
+			if test.exactErr != nil && test.exactErr.Error() != err.Error() {
+				t.Fatalf("Test %q: %v, wanted: %v", test.name, err, test.exactErr)
+			}
+		}
+	}
+}
+
+func newStatusCodesResponseTestClient(getResponseCode, actionResponseCode int) *client {
+	s := httptest.NewTLSServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		if r.Method == http.MethodGet {
+			w.WriteHeader(getResponseCode)
+		} else {
+			w.WriteHeader(actionResponseCode)
+		}
+		w.Write([]byte(`{}`)) // Empty json is enough, we will test only response codes here
+	}))
+
+	tr := &http.Transport{
+		TLSClientConfig: &tls.Config{InsecureSkipVerify: true},
+	}
+	return &client{
+		client:  &http.Client{Transport: tr},
+		baseURL: s.URL,
+		logger: &logrus.Logger{
+			Out:       os.Stderr,
+			Formatter: &logrus.TextFormatter{DisableColors: true},
+			Level:     logrus.DebugLevel,
+		},
+	}
+}