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dendrite/common/sql.go
2019-05-21 21:56:55 +01:00

76 lines
2.2 KiB
Go

// Copyright 2017 Vector Creations Ltd
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package common
import (
"database/sql"
"github.com/lib/pq"
)
// A Transaction is something that can be committed or rolledback.
type Transaction interface {
// Commit the transaction
Commit() error
// Rollback the transaction.
Rollback() error
}
// EndTransaction ends a transaction.
// If the transaction succeeded then it is committed, otherwise it is rolledback.
func EndTransaction(txn Transaction, succeeded *bool) {
if *succeeded {
txn.Commit() // nolint: errcheck
} else {
txn.Rollback() // nolint: errcheck
}
}
// WithTransaction runs a block of code passing in an SQL transaction
// If the code returns an error or panics then the transactions is rolledback
// Otherwise the transaction is committed.
func WithTransaction(db *sql.DB, fn func(txn *sql.Tx) error) (err error) {
txn, err := db.Begin()
if err != nil {
return
}
succeeded := false
defer EndTransaction(txn, &succeeded)
err = fn(txn)
if err != nil {
return
}
succeeded = true
return
}
// TxStmt wraps an SQL stmt inside an optional transaction.
// If the transaction is nil then it returns the original statement that will
// run outside of a transaction.
// Otherwise returns a copy of the statement that will run inside the transaction.
func TxStmt(transaction *sql.Tx, statement *sql.Stmt) *sql.Stmt {
if transaction != nil {
statement = transaction.Stmt(statement)
}
return statement
}
// IsUniqueConstraintViolationErr returns true if the error is a postgresql unique_violation error
func IsUniqueConstraintViolationErr(err error) bool {
pqErr, ok := err.(*pq.Error)
return ok && pqErr.Code == "23505"
}