github.com/CloudCom/goose@v0.0.0-20151110184009-e03c3249c21b/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.

## Stability notice
This repo is a fork from https://bitbucket.org/liamstask/goose. There are many things that we plan to change, mostly to make the tool easier to use, and more standardized.

As such, until this notice goes away, vendoring is highly recommended.

# Install

    $ go get github.com/CloudCom/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 `github.com/CloudCom/goose/lib/goose`. Documentation is available at [godoc.org](http://godoc.org/github.com/CloudCom/goose/lib/goose).

NOTE: the API is still new, and may undergo some changes.

## Omitting drivers

The default goose binary includes support for all available drivers. Sometimes this results in a lengthy build process. Drivers may be omitted from the build by using build tags.

For example

    $ go get -tags nosqlite3 github.com/CloudCom/goose/cmd/goose

The available tags are:

  * `nomymysql`
  * `nomysql`
  * `nopq`
  * `nosqlite3`

# Usage

goose provides several commands to help manage your database schema.

## create

Create a new SQL migration.

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

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

You can also create a Go migration:

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

## 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.yaml` 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`.

The configuration may also be environment-less, with all fields at the top level. For example:

```yaml
driver: postgres
open: user=liam dbname=tester sslmode=disable
```

You can even use a mixture of both. If a field is not specified within an environment, goose will fall back to looking at the top level.

You may also include environment variables in any field of the config. Specify them as `$MY_ENV_VAR` or `${MY_ENV_VAR}`.

## Configless

Goose can also run without a config file, by pulling all parameters from environment variables. This mode operates exactly as if you passed the following config file:

```yaml
migrationsDir: $DB_MIGRATIONS_DIR
driver: $DB_DRIVER
import: $DB_DRIVER_IMPORT
dialect: $DB_DIALECT
open: $DB_DSN
```

## 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", "sqlite3", and "redshift"

To run Go-based migrations with another driver, specify its import path and dialect, as shown below.

```yml
myenv:
    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 _ "github.com/CloudCom/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)