A database transaction is an operation context that provides a consistent view of data while applying reads or writes. BoltDB supplies read-only and read-write transactions through callback-based View and Update operations. section 11.9
A persistent task store uses transactions to:
- Count tasks by opening a read-only transaction, selecting the tasks bucket, and iterating over its keys. section 11.9
- Read individual tasks or list all tasks inside read-only transactions, decoding stored JSON values. section 11.9
- Create buckets and store task values inside read-write transactions. section 11.9
Counting tasks
Count calls Db.View with a transaction callback, obtains the tasks bucket, increments a counter for each key, checks the returned error, and returns the count. section 11.9
func (t *TaskStore) Count() (int, error) {
taskCount := 0
err := t.Db.View(func(tx *bolt.Tx) error { #1
b := tx.Bucket([]byte("tasks")) #2
b.ForEach(func(k, v []byte) error { #3
taskCount++ #4
return nil
})
return nil
})
if err != nil { #5
return -1, err
}
return taskCount, nil #6
}
Inspect the minimal read-only transaction used to count records in a persistent bucket. section 11.9
