kataras/iris · info

key not found

Error message

key not found

What it means

ErrKeyNotFound ('key not found') signals that a redis key for a session ID does not exist. Producers wrap it with fmt.Errorf to include the missing key name, so callers must check with errors.Is rather than string equality. It lets the session manager treat a missing session as an expired/invalid session instead of a hard failure.

Source

Thrown at sessions/sessiondb/redis/database.go:316

// Close terminates the redis connection.
func (db *Database) Close() error {
	return closeDB(db)
}

func closeDB(db *Database) error {
	return db.c.Driver.CloseConnection()
}

var (
	// ErrRedisClosed an error with message 'redis: already closed'
	ErrRedisClosed = errors.New("redis: already closed")
	// ErrKeyNotFound a type of error of non-existing redis keys.
	// The producers(the library) of this error will dynamically wrap this error(fmt.Errorf) with the key name.
	// Usage:
	// if err != nil && errors.Is(err, ErrKeyNotFound) {
	// [...]
	// }
	ErrKeyNotFound = errors.New("key not found")
)

View on GitHub (pinned to 7bedaf55a0)

Solutions

1. Treat it as 'session expired': regenerate a new session and re-authenticate the user
2. Check errors.Is(err, redisdb.ErrKeyNotFound) before generic error handling so expiry is not logged as a failure
3. Enable redis persistence (AOF/RDB) or sticky sessions if losing sessions across restarts is unacceptable

Example fix

// before
if err := db.Acquire(sid); err != nil { return err }
// after
if err := db.Acquire(sid); err != nil {
    if errors.Is(err, redisdb.ErrKeyNotFound) {
        sid, _ = db.Acquire("") // new session
    } else { return err }
}

// cannot pre-check remote existence cheaply; optionally:
exists, _ := store.Exists(sid)
if !exists { sid = "" } // force new session

func isKeyNotFound(err error) bool { return errors.Is(err, redisdb.ErrKeyNotFound) }

if err := db.Acquire(sid); err != nil {
    if errors.Is(err, redisdb.ErrKeyNotFound) {
        sid, err = db.Acquire("") // regenerate session
    }
    return sid, err
}

When it happens

Trigger: Database.Acquire called with a session ID that no longer exists in redis (expired TTL, flushed DB, or never-created ID); Decode called with data/key absent from the store.

Common situations: Users returning after redis TTL expiry or a redis restart (no persistence); a load balancer routing to a different instance whose redis lacks the session; clients replaying stale session cookies after a cache flush.

Related errors

• redis: already closed
• unknown value type of %T
• not implemented yet
• session not found
• directoryPath is empty

AI-assisted analysis of kataras/iris@7bedaf55a0 (2026-08-30). Data as JSON: /api/errors/3e574ca89b922ad4. Report an issue: GitHub.