better message formatting

api/notification/internal/server/notificationimp/mail/internal/builder/builder.go

@@ -42,7 +42,7 @@ func (mb *MessageBuilderImp) AddData(key, value string) mmail.MailBuilder {
 
 func (mb *MessageBuilderImp) Build() (mmail.Message, error) {
 	if len(mb.message.recipients) == 0 {
-		return nil, merrors.InvalidArgument("Recipient not set")
+		return nil, merrors.InvalidArgument("Recipient not set", "recipients")
 	}
 	return mb.message, nil
 }

api/notification/internal/server/notificationimp/mail/internal/mailimp.go

@@ -69,7 +69,7 @@ func (c *Client) Send(r mmail.MailBuilder) error {
 		c.logger.Warn("Malformed messge", zap.String("template_id", m.TemplateID()),
 			zap.String("locale", m.Locale()), zap.Strings("recipients", m.Recipients()),
 			zap.Int("body_size", len(body)))
-		return merrors.InvalidArgument("malformed message")
+		return merrors.InvalidArgument("malformed message", "message.body", "message.recipients")
 	}
 	subj, err := mailkey.Subject(c.l, m.Parameters(), m.TemplateID(), m.Locale())
 	if err != nil {

api/notification/internal/server/notificationimp/mail/mail.go

@@ -1,6 +1,7 @@
 package mail
 
 import (
+	"github.com/mitchellh/mapstructure"
 	"github.com/tech/sendico/notification/interface/api/localizer"
 	notification "github.com/tech/sendico/notification/interface/services/notification/config"
 	mi "github.com/tech/sendico/notification/internal/server/notificationimp/mail/internal"
@@ -9,7 +10,6 @@ import (
 	"github.com/tech/sendico/pkg/merrors"
 	"github.com/tech/sendico/pkg/messaging"
 	"github.com/tech/sendico/pkg/mlogger"
-	"github.com/mitchellh/mapstructure"
 	"go.uber.org/zap"
 )
 
@@ -22,7 +22,7 @@ type Config = notification.Config
 
 func createMailClient(logger mlogger.Logger, producer messaging.Producer, l localizer.Localizer, dp domainprovider.DomainProvider, config *Config) (Client, error) {
 	if len(config.Driver) == 0 {
-		return nil, merrors.InvalidArgument("Mail driver name must be provided")
+		return nil, merrors.InvalidArgument("Mail driver name must be provided", "config.driver")
 	}
 	logger.Info("Connecting mail client...", zap.String("driver", config.Driver))
 	if config.Driver == "dummy" {
@@ -45,7 +45,7 @@ func createMailClient(logger mlogger.Logger, producer messaging.Producer, l loca
 
 		return mi.NewClient(logger, l, dp, &gsmconfing), nil
 	}
-	return nil, merrors.InvalidArgument("Unkwnown mail driver: " + config.Driver)
+	return nil, merrors.InvalidArgument("Unkwnown mail driver: "+config.Driver, "config.driver")
 }
 
 func CreateMailClient(logger mlogger.Logger, sender string, producer messaging.Producer, l localizer.Localizer, dp domainprovider.DomainProvider, config *Config) (Client, error) {