fix: use a single translator for middleware (#10633)

# Which Problems Are Solved

Comparing the v3 and v4 deployments we noticed an increase in memory
usage. A first analysis revealed that it might be related to the
(multiple) initialization of the `i18n.Translator`, partially related

# How the Problems Are Solved

Initialize the tranlator once (apart from the translator interceptor,
which uses context / request specific information) and pass it to all
necessary middleware.

# Additional Changes

Removed unnecessary error return parameter from the translator
initialization.

# Additional Context

- noticed internally
- backport to v4.x

(cherry picked from commit a0c3ccecf7)

internal/api/grpc/server/middleware/instance_interceptor.go

@@ -7,7 +7,6 @@ import (
 	"strings"
 
 	"github.com/zitadel/logging"
-	"golang.org/x/text/language"
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/codes"
 	"google.golang.org/grpc/status"
@@ -24,9 +23,7 @@ const (
 	HTTP1Host = "x-zitadel-http1-host"
 )
 
-func InstanceInterceptor(verifier authz.InstanceVerifier, externalDomain string, explicitInstanceIdServices ...string) grpc.UnaryServerInterceptor {
-	translator, err := i18n.NewZitadelTranslator(language.English)
-	logging.OnError(err).Panic("unable to get translator")
+func InstanceInterceptor(verifier authz.InstanceVerifier, externalDomain string, translator *i18n.Translator, explicitInstanceIdServices ...string) grpc.UnaryServerInterceptor {
 	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
 		return setInstance(ctx, req, info, handler, verifier, externalDomain, translator, explicitInstanceIdServices...)
 	}

internal/api/grpc/server/middleware/translation_interceptor.go

@@ -3,7 +3,6 @@ package middleware
 import (
 	"context"
 
-	"github.com/zitadel/logging"
 	"google.golang.org/grpc"
 
 	"github.com/zitadel/zitadel/internal/api/authz"
@@ -19,27 +18,17 @@ func TranslationHandler() func(ctx context.Context, req interface{}, info *grpc.
 		defer func() { span.EndWithError(err) }()
 
 		if loc, ok := resp.(localizers); ok && resp != nil {
-			translator, translatorError := getTranslator(ctx)
-			if translatorError != nil {
-				return resp, err
-			}
+			translator := getTranslator(ctx)
 			translateFields(ctx, loc, translator)
 		}
 		if err != nil {
-			translator, translatorError := getTranslator(ctx)
-			if translatorError != nil {
-				return resp, err
-			}
+			translator := getTranslator(ctx)
 			err = translateError(ctx, err, translator)
 		}
 		return resp, err
 	}
 }
 
-func getTranslator(ctx context.Context) (*i18n.Translator, error) {
-	translator, err := i18n.NewZitadelTranslator(authz.GetInstance(ctx).DefaultLanguage())
-	if err != nil {
-		logging.New().WithError(err).Error("could not load translator")
-	}
-	return translator, err
+func getTranslator(ctx context.Context) *i18n.Translator {
+	return i18n.NewZitadelTranslator(authz.GetInstance(ctx).DefaultLanguage())
 }