Implemented retry logic on all transactions

cmd/model/articles_tags.go

@@ -3,31 +3,47 @@ package model
 import (
 	"fmt"
 	"log"
+	"math"
+	"math/rand/v2"
+	"time"
 )
 
 func (db *DB) WriteArticleTags(articleID int64, tagIDs []int64) error {
-	tx, err := db.Begin()
+	for i := 0; i < TxMaxRetries; i++ {
-	if err != nil {
+		err := func() error {
-		return fmt.Errorf("error starting transaction: %v", err)
+			tx, err := db.Begin()
-	}
+			if err != nil {
-
+				return fmt.Errorf("error starting transaction: %v", err)
-	for _, tagID := range tagIDs {
-		query := `
-        INSERT INTO articles_tags (article_id, tag_id)
-        VALUES (?, ?)
-        `
-		if _, err := tx.Exec(query, articleID, tagID); err != nil {
-			if rollbackErr := tx.Rollback(); rollbackErr != nil {
-				log.Fatalf("error: transaction error: %v, rollback error: %v", err, rollbackErr)
 			}
-			return fmt.Errorf("error inserting into articles_tags: %v", err)
-		}
-	}
 
-	if err = tx.Commit(); err != nil {
+			for _, tagID := range tagIDs {
-		return fmt.Errorf("error committing transaction: %v", err)
+				query := `
+                INSERT INTO articles_tags (article_id, tag_id)
+                VALUES (?, ?)
+                `
+				if _, err := tx.Exec(query, articleID, tagID); err != nil {
+					if rollbackErr := tx.Rollback(); rollbackErr != nil {
+						log.Fatalf("error: transaction error: %v, rollback error: %v", err, rollbackErr)
+					}
+					return fmt.Errorf("error inserting into articles_tags: %v", err)
+				}
+			}
+
+			if err = tx.Commit(); err != nil {
+				return fmt.Errorf("error committing transaction: %v", err)
+			}
+			return nil
+		}()
+		if err == nil {
+			return nil
+		}
+
+		log.Println(err)
+		waitTime := time.Duration(math.Pow(2, float64(i))) * time.Second
+		jitter := time.Duration(rand.IntN(1000)) * time.Millisecond
+		time.Sleep(waitTime + jitter)
 	}
-	return nil
+	return fmt.Errorf("error: %v unsuccessful retries for DB operation, aborting", TxMaxRetries)
 }
 
 func (db *DB) GetArticleTags(articleID int64) ([]*Tag, error) {

cmd/model/db.go

@@ -18,20 +18,16 @@ import (
 
 var TxMaxRetries = 3
 
-type DB struct {
+type (
-	*sql.DB
+	DB        struct{ *sql.DB }
-}
+	Tx        struct{ *sql.Tx }
-
+	Attribute struct {
-type Tx struct {
+		Value   interface{}
-	*sql.Tx
+		Table   string
-}
+		AttName string
-
+		ID      int64
-type Attribute struct {
+	}
-	Value   interface{}
+)
-	Table   string
-	AttName string
-	ID      int64
-}
 
 func getUsername() (string, error) {
 	user := os.Getenv("DB_USER")
@@ -126,8 +122,8 @@ func (db *DB) UpdateAttributes(a ...*Attribute) error {
 		if err == nil {
 			return nil
 		}
-		log.Println(err)
 
+		log.Println(err)
 		waitTime := time.Duration(math.Pow(2, float64(i))) * time.Second
 		jitter := time.Duration(rand.IntN(1000)) * time.Millisecond
 		time.Sleep(waitTime + jitter)

cmd/model/users.go

@@ -3,6 +3,9 @@ package model
 import (
 	"fmt"
 	"log"
+	"math"
+	"math/rand/v2"
+	"time"
 
 	"golang.org/x/crypto/bcrypt"
 )
@@ -135,3 +138,61 @@ func (db *DB) GetUser(id int64) (*User, error) {
 
 	return user, nil
 }
+
+func (db *DB) UpdateUserAttributes(id int64, user, first, last, oldPass, newPass, newPass2 string) error {
+	passwordEmpty := true
+	if len(newPass) > 0 || len(newPass2) > 0 {
+		if newPass != newPass2 {
+			return fmt.Errorf("error: passwords do not match")
+		}
+		passwordEmpty = false
+	}
+
+	tx := new(Tx)
+	var err error
+
+	for i := 0; i < TxMaxRetries; i++ {
+		err := func() error {
+			tx.Tx, err = db.Begin()
+			if err != nil {
+				return fmt.Errorf("error starting transaction: %v", err)
+			}
+
+			if !passwordEmpty {
+				if err = tx.ChangePassword(id, oldPass, newPass); err != nil {
+					if rollbackErr := tx.Rollback(); rollbackErr != nil {
+						log.Fatalf("error: transaction error: %v, rollback error: %v", err, rollbackErr)
+					}
+					return fmt.Errorf("error changing password: %v", err)
+				}
+			}
+
+			if err = tx.UpdateAttributes(
+				&Attribute{Table: "users", ID: id, AttName: "username", Value: user},
+				&Attribute{Table: "users", ID: id, AttName: "first_name", Value: first},
+				&Attribute{Table: "users", ID: id, AttName: "last_name", Value: last},
+			); err != nil {
+				if rollbackErr := tx.Rollback(); rollbackErr != nil {
+					log.Fatalf("error: transaction error: %v, rollback error: %v", err, rollbackErr)
+				}
+				return fmt.Errorf("error updating attributes in DB: %v", err)
+			}
+
+			if err = tx.Commit(); err != nil {
+				return fmt.Errorf("error committing transaction: %v", err)
+			}
+
+			return nil
+		}()
+		if err == nil {
+			return nil
+		}
+
+		log.Println(err)
+		waitTime := time.Duration(math.Pow(2, float64(i))) * time.Second
+		jitter := time.Duration(rand.IntN(1000)) * time.Millisecond
+		time.Sleep(waitTime + jitter)
+	}
+
+	return fmt.Errorf("error: %v unsuccessful retries for DB operation, aborting", TxMaxRetries)
+}

cmd/view/users.go

@@ -192,47 +192,17 @@ func UpdateUser(db *model.DB, s *control.CookieStore) http.HandlerFunc {
 			}
 		}
 
-		tx, err := db.StartTransaction()
+		if err = db.UpdateUserAttributes(
-		if err != nil {
+			userData.ID,
-			log.Println(err)
+			userData.UserName,
-			http.Error(w, err.Error(), http.StatusInternalServerError)
+			userData.FirstName,
-			return
+			userData.LastName,
-		}
+			oldPass,
-
+			newPass,
-		if len(newPass) > 0 || len(newPass2) > 0 {
+			newPass2); err != nil {
-			if newPass != newPass2 {
+			userData.Msg = "Aktualisierung der Benutzerdaten fehlgeschlagen."
-				tx.RollbackTransaction()
+			tmpl, err := template.ParseFiles("web/templates/edit-user.html")
-				userData.Msg = "Die Passwörter stimmen nicht überein."
+			template.Must(tmpl, err).ExecuteTemplate(w, "page-content", userData)
-				tmpl, err := template.ParseFiles("web/templates/edit-user.html")
-				tmpl = template.Must(tmpl, err)
-				tmpl.ExecuteTemplate(w, "page-content", userData)
-				return
-			}
-
-			if err = tx.ChangePassword(userData.ID, oldPass, newPass); err != nil {
-				log.Println(err)
-				userData.Msg = "Das alte Passwort ist nicht korrekt."
-				tmpl, err := template.ParseFiles("web/templates/edit-user.html")
-				tmpl = template.Must(tmpl, err)
-				tmpl.ExecuteTemplate(w, "page-content", userData)
-				return
-			}
-		}
-
-		if err = tx.UpdateAttributes(
-			&model.Attribute{Table: "users", ID: userData.ID, AttName: "username", Value: userData.UserName},
-			&model.Attribute{Table: "users", ID: userData.ID, AttName: "first_name", Value: userData.FirstName},
-			&model.Attribute{Table: "users", ID: userData.ID, AttName: "last_name", Value: userData.LastName},
-		); err != nil {
-			log.Println(err)
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
-		}
-
-		if err = tx.Commit(); err != nil {
-			log.Println(err)
-			http.Error(w, err.Error(), http.StatusInternalServerError)
-			return
 		}
 
 		tmpl, err := template.ParseFiles("web/templates/hub.html")