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clair/vendor/bitbucket.org/liamstask/goose/README.md

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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.
[![Build Status](https://drone.io/bitbucket.org/liamstask/goose/status.png)](https://drone.io/bitbucket.org/liamstask/goose/latest)
# Install
$ go get bitbucket.org/liamstask/goose/cmd/goose
This will install the `goose` binary to your `$GOPATH/bin` directory.
You can also build goose into your own applications by importing `bitbucket.org/liamstask/goose/lib/goose`. Documentation is available at [godoc.org](http://godoc.org/bitbucket.org/liamstask/goose/lib/goose).
NOTE: the API is still new, and may undergo some changes.
# Usage
goose provides several commands to help manage your database schema.
## create
Create a new Go migration.
$ goose create AddSomeColumns
$ goose: created db/migrations/20130106093224_AddSomeColumns.go
Edit the newly created script to define the behavior of your migration.
You can also create an SQL migration:
$ goose create AddSomeColumns sql
$ goose: created db/migrations/20130106093224_AddSomeColumns.sql
## 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
### option: pgschema
Use the `pgschema` flag with the `up` command specify a postgres schema.
$ goose -pgschema=my_schema_name 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
## redo
Roll back the most recently applied migration, then run it again.
$ goose redo
$ goose: migrating db environment 'development', current version: 3, target: 2
$ OK 003_and_again.go
$ goose: migrating db environment 'development', current version: 2, target: 3
$ 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
## dbversion
Print the current version of the database:
$ goose dbversion
$ goose: dbversion 002
`goose -h` provides more detailed info on each command.
# Migrations
goose supports migrations written in SQL or in Go - see the `goose create` command above for details on how to generate them.
## 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.
By default, SQL statements are delimited by semicolons - in fact, query statements must end with a semicolon to be properly recognized by goose.
More complex statements (PL/pgSQL) that have semicolons within them must be annotated with `-- +goose StatementBegin` and `-- +goose StatementEnd` to be properly recognized. For example:
```sql
-- +goose Up
-- +goose StatementBegin
CREATE OR REPLACE FUNCTION histories_partition_creation( DATE, DATE )
returns void AS $$
DECLARE
create_query text;
BEGIN
FOR create_query IN SELECT
'CREATE TABLE IF NOT EXISTS histories_'
|| TO_CHAR( d, 'YYYY_MM' )
|| ' ( CHECK( created_at >= timestamp '''
|| TO_CHAR( d, 'YYYY-MM-DD 00:00:00' )
|| ''' AND created_at < timestamp '''
|| TO_CHAR( d + INTERVAL '1 month', 'YYYY-MM-DD 00:00:00' )
|| ''' ) ) inherits ( histories );'
FROM generate_series( $1, $2, '1 month' ) AS d
LOOP
EXECUTE create_query;
END LOOP; -- LOOP END
END; -- FUNCTION END
$$
language plpgsql;
-- +goose StatementEnd
```
## Go Migrations
A sample Go migration looks like:
```go
package main
import (
"database/sql"
"fmt"
)
func Up_20130106222315(txn *sql.Tx) {
fmt.Println("Hello from migration 20130106222315 Up!")
}
func Down_20130106222315(txn *sql.Tx) {
fmt.Println("Hello from migration 20130106222315 Down!")
}
```
`Up_20130106222315()` will be executed as part of a forward migration, and `Down_20130106222315()` will be executed as part of a rollback.
The numeric portion of the function name (`20130106222315`) must be the leading portion of migration's filename, such as `20130106222315_descriptive_name.go`. `goose create` does this by default.
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
```yml
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`.
goose will expand environment variables in the `open` element. For an example, see the Heroku section below.
## Other Drivers
goose knows about some common SQL drivers, but it can still be used to run Go-based migrations with any driver supported by `database/sql`. An import path and known dialect are required.
Currently, available dialects are: "postgres", "mysql", or "sqlite3"
To run Go-based migrations with another driver, specify its import path and dialect, as shown below.
```yml
customdriver:
driver: custom
open: custom open string
import: github.com/custom/driver
dialect: mysql
```
NOTE: Because migrations written in SQL are executed directly by the goose binary, only drivers compiled into goose may be used for these migrations.
## Using goose with Heroku
These instructions assume that you're using [Keith Rarick's Heroku Go buildpack](https://github.com/kr/heroku-buildpack-go). First, add a file to your project called (e.g.) `install_goose.go` to trigger building of the goose executable during deployment, with these contents:
```go
// use build constraints to work around http://code.google.com/p/go/issues/detail?id=4210
// +build heroku
// note: need at least one blank line after build constraint
package main
import _ "bitbucket.org/liamstask/goose/cmd/goose"
```
[Set up your Heroku database(s) as usual.](https://devcenter.heroku.com/articles/heroku-postgresql)
Then make use of environment variable expansion in your `dbconf.yml`:
```yml
production:
driver: postgres
open: $DATABASE_URL
```
To run goose in production, use `heroku run`:
heroku run goose -env production up
# Contributors
Thank you!
* Josh Bleecher Snyder (josharian)
* Abigail Walthall (ghthor)
* Daniel Heath (danielrheath)
* Chris Baynes (chris_baynes)
* Michael Gerow (gerow)
* Vytautas Šaltenis (rtfb)
* James Cooper (coopernurse)
* Gyepi Sam (gyepisam)
* Matt Sherman (clipperhouse)
* runner_mei
* John Luebs (jkl1337)
* Luke Hutton (lukehutton)
* Kevin Gorjan (kevingorjan)
* Brendan Fosberry (Fozz)
* Nate Guerin (gusennan)