migration

README

migration

The migration package provides a way to generate, list, and apply PostgreSQL database migrations. The package can be imported like so:

import (
	"code.soquee.net/migration"
)

License

The package may be used under the terms of the BSD 2-Clause License a copy of which may be found in the LICENSE file.

Unless you explicitly state otherwise, any contribution submitted for inclusion in the work by you shall be licensed as above, without any additional terms or conditions.

Documentation

Overview

Package migration contains functions for generating and finding PostgreSQL database migrations.

Index

• func Generator(basePath string) func(name string) error
• func LastRun(ctx context.Context, migrationsTable string, vfs fs.FS, tx *sql.Tx) (ident, name string, err error)
• func Setup(ctx context.Context, migrationsTable string, tx *sql.Tx) error
• type RunStatus
• type WalkFunc
• type Walker
  • func NewWalker(ctx context.Context, migrationsTable string, tx *sql.Tx) (Walker, error)

Functions

func Generator

func Generator(basePath string) func(name string) error

Generator returns a function that creates migration files at the given base path.

func LastRun

func LastRun(ctx context.Context, migrationsTable string, vfs fs.FS, tx *sql.Tx) (ident, name string, err error)

LastRun returns the last migration directory by lexical order that exists in the database and on disk.

func Setup

func Setup(ctx context.Context, migrationsTable string, tx *sql.Tx) error

Setup creates a migrations table with the given name.

Types

type RunStatus

type RunStatus int

RunStatus is a type that indicates if a migration has been run, not run, or if we can't determine the status.

const (
	StatusUnknown RunStatus = iota
	StatusNotRun
	StatusRun
)

Valid RunStatus values. For more information see RunStatus.

type WalkFunc

type WalkFunc func(name string, info fs.DirEntry, status RunStatus) error

WalkFunc is the type of the function called for each file or directory visited by a Walker.

type Walker

type Walker func(vfs fs.FS, f WalkFunc) error

Walker is a function that can be used to walk a filesystem and calls WalkFunc for each migration.

func NewWalker

func NewWalker(ctx context.Context, migrationsTable string, tx *sql.Tx) (Walker, error)

NewWalker queries the database for migration status information and returns a function that walks the migrations it finds on the filesystem in lexical order (mostly, keep reading) and calls a function for each discovered migration, passing in its name, status, and file information.

If a migration exists in the database but not on the filesystem, info will be nil and f will be called for it after the migrations that exist on the filesystem. No particular order is guaranteed for calls to f for migrations that do not exist on the filesystem.

If NewWalker returns an error and a non-nil function, the function may still be used to walk the migrations on the filesystem but the status information may be wrong since the DB may not have been queried successfully.