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goose

goose is a database migration tool.

You can manage your database's evolution by creating incremental SQL or Go scripts.

Install

$ go get bitbucket.org/liamstask/goose

This will install the goose binary to your $GOPATH/bin directory.

Usage

goose provides several commands to help manage your database schema.

create

Create a new migration script.

$ goose create AddSomeColumns
$ goose: created db/migrations/20130106093224_AddSomeColumns.go

Edit the newly created script to define the behavior of your migration.

up

Apply all available migrations.

$ goose up
$ goose: migrating db environment 'development', current version: 0, target: 3
$ OK    001_basics.sql
$ OK    002_next.sql
$ OK    003_and_again.go

down

Roll back a single migration from the current version.

$ goose down
$ goose: migrating db environment 'development', current version: 3, target: 2
$ OK    003_and_again.go

status

Print the status of all migrations:

$ goose status
$ goose: status for environment 'development'
$   Applied At                  Migration
$   =======================================
$   Sun Jan  6 11:25:03 2013 -- 001_basics.sql
$   Sun Jan  6 11:25:03 2013 -- 002_next.sql
$   Pending                  -- 003_and_again.go

goose -h provides more detailed info on each command.

Migrations

goose supports migrations written in SQL or in Go.

SQL Migrations

A sample SQL migration looks like:

:::sql
-- +goose Up
CREATE TABLE post (
    id int NOT NULL,
    title text,
    body text,
    PRIMARY KEY(id)
);

-- +goose Down
DROP TABLE post;

Notice the annotations in the comments. Any statements following -- +goose Up will be executed as part of a forward migration, and any statements following -- +goose Down will be executed as part of a rollback.

Go Migrations

A sample Go migration looks like:

:::go
package migration_003

import (
    "database/sql"
    "fmt"
)

func Up(txn *sql.Tx) {
    fmt.Println("Hello from migration_003 Up!")
}

func Down(txn *sql.Tx) {
    fmt.Println("Hello from migration_003 Down!")
}

Up() will be executed as part of a forward migration, and Down() will be executed as part of a rollback.

A transaction is provided, rather than the DB instance directly, since goose also needs to record the schema version within the same transaction. Each migration should run as a single transaction to ensure DB integrity, so it's good practice anyway.

Configuration

goose expects you to maintain a folder (typically called "db"), which contains the following:

a dbconf.yml file that describes the database configurations you'd like to use
a folder called "migrations" which contains .sql and/or .go scripts that implement your migrations

You may use the -path option to specify an alternate location for the folder containing your config and migrations.

A sample dbconf.yml looks like

development:
    driver: postgres
    open: user=liam dbname=tester sslmode=disable

Here, development specifies the name of the environment, and the driver and open elements are passed directly to database/sql to access the specified database.

You may include as many environments as you like, and you can use the -env command line option to specify which one to use. goose defaults to using an environment called development.

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