Organize backend into product executable and shared Go modules

backend/product/auth/client/client.go

@@ -0,0 +1,29 @@
+package client
+
+import (
+	"context"
+	"errors"
+	sessionmodel "git.sendico.io/tech/sxchnge/product/sessions/model"
+	"strings"
+
+	"git.sendico.io/tech/sxchnge/product/sessions/store"
+	"git.sendico.io/tech/sxchnge/shared/errors"
+)
+
+var ErrUnknownClientID = merrors.Define("unknown client id")
+
+func Resolve(ctx context.Context, rtdb refreshtokens.DB, clientID string) (*sessionmodel.Client, error) {
+	clientID = strings.TrimSpace(clientID)
+	if clientID == "" {
+		return nil, ErrUnknownClientID
+	}
+
+	client, err := rtdb.GetClient(ctx, clientID)
+	if errors.Is(err, merrors.ErrNoData) || client == nil {
+		return nil, ErrUnknownClientID
+	}
+	if err != nil {
+		return nil, err
+	}
+	return client, nil
+}