txn

Documentation

Overview

Package txn provides functions for running transactions.

Index

• func AddPostCommitHook(ctx context.Context, hook MustFunc)
• func AddPostCompleteHook(ctx context.Context, hook MustFunc)
• func AddPostRollbackHook(ctx context.Context, hook MustFunc)
• func AddPreCommitHook(ctx context.Context, hook TxnFunc)
• func WithDatabase(ctx context.Context, p DatabaseProvider, fn TxnFunc) error
• func WithReadTxn(ctx context.Context, m Manager, fn TxnFunc) error
• func WithTxn(ctx context.Context, m Manager, fn TxnFunc) error
• type DatabaseProvider
• type Manager
• type MustFunc
• type Retryer
  • func (r Retryer) WithTxn(ctx context.Context, fn TxnFunc) error
• type TxnFunc

Functions

func AddPostCommitHook

func AddPostCommitHook(ctx context.Context, hook MustFunc)

func AddPostCompleteHook

func AddPostCompleteHook(ctx context.Context, hook MustFunc)

func AddPostRollbackHook

func AddPostRollbackHook(ctx context.Context, hook MustFunc)

func AddPreCommitHook

func AddPreCommitHook(ctx context.Context, hook TxnFunc)

func WithDatabase

func WithDatabase(ctx context.Context, p DatabaseProvider, fn TxnFunc) error

WithDatabase executes fn with the context provided by p.WithDatabase. It does not run inside a transaction, so all database operations will be executed in their own transaction.

func WithReadTxn

func WithReadTxn(ctx context.Context, m Manager, fn TxnFunc) error

WithReadTxn executes fn in a transaction. If fn returns an error then the transaction is rolled back. Otherwise it is committed. This function will call m.Begin with writable = false.

func WithTxn

func WithTxn(ctx context.Context, m Manager, fn TxnFunc) error

WithTxn executes fn in a transaction. If fn returns an error then the transaction is rolled back. Otherwise it is committed. This function will call m.Begin with writable = true. This function should be used for making changes to the database.

Types

type DatabaseProvider

type DatabaseProvider interface {
	WithDatabase(ctx context.Context) (context.Context, error)
}

type Manager

type Manager interface {
	Begin(ctx context.Context, writable bool) (context.Context, error)
	Commit(ctx context.Context) error
	Rollback(ctx context.Context) error

	IsLocked(err error) bool
}

type MustFunc

type MustFunc func(ctx context.Context)

MustFunc is a function that is used in transaction hooks. It does not return an error.

type Retryer

type Retryer struct {
	Manager Manager
	// use value < 0 to retry forever
	Retries int
	OnFail  func(ctx context.Context, err error, attempt int) error
}

Retryer is a provides WithTxn function that retries the transaction if it fails with a locked database error. Transactions are run in exclusive mode.

func (Retryer) WithTxn

func (r Retryer) WithTxn(ctx context.Context, fn TxnFunc) error

type TxnFunc

type TxnFunc func(ctx context.Context) error

TxnFunc is a function that is used in transaction hooks. It should return an error if something went wrong.