refactor(cli): improve performance for seed_users

Author: pan93412

cli/seed_users.go

@@ -10,36 +10,53 @@ import (
 	"github.com/database-playground/backend-v2/ent/group"
 	"github.com/database-playground/backend-v2/ent/user"
 	"github.com/database-playground/backend-v2/internal/useraccount"
+	"github.com/samber/lo"
 )
 
+// SeedUsers creates users from the provided seed records.
+//
+// Each record must contain a valid email and an optional group slug.
+// If the referenced group does not exist, an error is returned.
+// If a user with the same email already exists, it is skipped without error.
+//
+// SeedUsers returns an error if validation, group lookup, or user creation fails.
 func (c *Context) SeedUsers(ctx context.Context, userSeedRecords []UserSeedRecord) error {
 	// validate records
+	if len(userSeedRecords) == 0 {
+		return nil
+	}
+
 	for i, record := range userSeedRecords {
 		if err := record.Validate(); err != nil {
 			return fmt.Errorf("user seed record #%d: %w", i, err)
 		}
 	}
 
-	// query groups for the records
-	groups := make(map[string]*ent.Group)
-	for _, record := range userSeedRecords {
-		group, err := c.entClient.Group.Query().Where(group.NameEQ(record.GetGroup())).Only(ctx)
-		if err != nil {
-			if ent.IsNotFound(err) {
-				return fmt.Errorf("group %q not found", record.GetGroup())
-			}
+	// collect unique group names
+	uniqueGroupName := lo.Uniq(lo.Map(userSeedRecords, func(record UserSeedRecord, _ int) string {
+		return record.GetGroup()
+	}))
 
-			return fmt.Errorf("query group %q: %w", record.GetGroup(), err)
-		}
-		groups[record.GetGroup()] = group
+	// query all required groups in a single batch
+	entGroups, err := c.entClient.Group.Query().Where(group.NameIn(uniqueGroupName...)).All(ctx)
+	if err != nil {
+		return fmt.Errorf("query groups: %w", err)
 	}
 
+	groups := make(map[string]*ent.Group, len(entGroups))
+	for _, g := range entGroups {
+		groups[g.Name] = g
+	}
+
+	// ensure all requested groups were found
+	for _, name := range uniqueGroupName {
+		if _, ok := groups[name]; !ok {
+			return fmt.Errorf("group %q not found", name)
+		}
+	}
 	// create users
 	for _, record := range userSeedRecords {
-		group, ok := groups[record.GetGroup()]
-		if !ok {
-			return fmt.Errorf("user record %q: group %q not found", record.GetEmail(), record.GetGroup())
-		}
+		group := groups[record.GetGroup()]
 
 		// check if user already exists
 		user, err := c.entClient.User.Query().Where(user.EmailEQ(record.Email)).First(ctx)
@@ -63,15 +80,19 @@ func (c *Context) SeedUsers(ctx context.Context, userSeedRecords []UserSeedRecor
 	return nil
 }
 
+// UserSeedRecord represents a user seed record.
 type UserSeedRecord struct {
 	Email string `json:"email"`
 	Group string `json:"group"`
 }
 
+// GetEmail returns the email of the user seed record.
 func (r UserSeedRecord) GetEmail() string {
 	return r.Email
 }
 
+// GetGroup returns the group of the user seed record.
+// If the group slug is omitted, the user will be added to the `student` group.
 func (r UserSeedRecord) GetGroup() string {
 	if r.Group == "" {
 		return useraccount.StudentGroupSlug
@@ -80,6 +101,7 @@ func (r UserSeedRecord) GetGroup() string {
 	return r.Group
 }
 
+// Validate validates the user seed record.
 func (r UserSeedRecord) Validate() error {
 	if r.Email == "" {
 		return errors.New("email is required")