npm package: @shoutem/migrate-mongodb
Description: Abstract migration framework for node
Author: shoutem
Latest version: 1.0.2

# migrate

  Abstract migration framework for node

## Installation

    $ npm install migrate

## Usage

```
Usage: migrate [options] [command]

Options:

   -c, --chdir <path>      change the working directory
   --state-file <path>     set path to state file (migrations/.migrate)
   --state-mongo <format>  name of env variable containing the mongo connection string for state storage (MONGO_CONNECTION_STRING)
   --template-file <path>  set path to template file to use for new migrations
   --date-format <format>  set a date format to use for new migration filenames

NOTE: if both --state-mongo and --state-file options are specified while migrations collection is empty, the state file is migrated to the migrations collection before migration is initiated. If migrations collection contains migration state, state-file is ignored.
This behaviour can be used for seamless switching from https://github.com/tj/node-migrate (which at the time of this fork did not support persisting of state file to mongo collection).

Commands:

   down   [name]    migrate down till given migration
   up     [name]    migrate up till given migration (the default command)
   create [title]   create a new migration file with optional [title]

```

## Programmatic usage

```javascript
var migrate = require('migrate');
var set = migrate.load('migration/.migrate', 'migration');

set.up(function (err) {
  if (err) throw err;

  console.log('Migration completed');
});
```

## Creating Migrations

To create a migration, execute `migrate create` with an optional title. `node-migrate` will create a node module within `./migrations/` which contains the following two exports:

    exports.up = function(next){
      next();
    };

    exports.down = function(next){
      next();
    };

All you have to do is populate these, invoking `next()` when complete, and you are ready to migrate!

For example:

    $ migrate create add-pets
    $ migrate create add-owners

The first call creates `./migrations/{timestamp in milliseconds}-add-pets.js`, which we can populate:

      var db = require('./db');

      exports.up = function(next){
        db.rpush('pets', 'tobi');
        db.rpush('pets', 'loki');
        db.rpush('pets', 'jane', next);
      };

      exports.down = function(next){
        db.rpop('pets');
        db.rpop('pets');
        db.rpop('pets', next);
      };

The second creates `./migrations/{timestamp in milliseconds}-add-owners.js`, which we can populate:

      var db = require('./db');

      exports.up = function(next){
        db.rpush('owners', 'taylor');
        db.rpush('owners', 'tj', next);
      };

      exports.down = function(next){
        db.rpop('owners');
        db.rpop('owners', next);
      };

## Running Migrations

When first running the migrations, all will be executed in sequence.

    $ migrate
    up : migrations/1316027432511-add-pets.js
    up : migrations/1316027432512-add-jane.js
    up : migrations/1316027432575-add-owners.js
    up : migrations/1316027433425-coolest-pet.js
    migration : complete

Subsequent attempts will simply output "complete", as they have already been executed in this machine. `node-migrate` knows this because it stores the current state in `./migrations/.migrate` which is typically a file that SCMs like GIT should ignore.

    $ migrate
    migration : complete

If we were to create another migration using `migrate create`, and then execute migrations again, we would execute only those not previously executed:

    $ migrate
    up : migrates/1316027433455-coolest-owner.js

You can also run migrations incrementally by specifying a migration.

    $ migrate up 1316027433425-coolest-pet.js
    up : migrations/1316027432511-add-pets.js
    up : migrations/1316027432512-add-jane.js
    up : migrations/1316027432575-add-owners.js
    up : migrations/1316027433425-coolest-pet.js
    migration : complete

This will run up-migrations upto (and including) `1316027433425-coolest-pet.js`. Similarly you can run down-migrations upto (and including) a specific migration, instead of migrating all the way down.

    $ migrate down 1316027432512-add-jane.js
    down : migrations/1316027432575-add-owners.js
    down : migrations/1316027432512-add-jane.js
    migration : complete

## API

### `migrate.load(stateFile, migrationsDirectory)`

Returns a `Set` populated with migration scripts from the `migrationsDirectory`
and state loaded from `stateFile`.

### `Set.up([migration, ]cb)`

Migrates up to the specified `migration` or, if none is specified, to the latest
migration. Calls the callback `cb`, possibly with an error `err`, when done.

### `Set.down([migration, ]cb)`

Migrates down to the specified `migration` or, if none is specified, to the
first migration. Calls the callback `cb`, possibly with an error `err`, when
done.

## License

(The MIT License)

Copyright (c) 2011 TJ Holowaychuk &lt;tj@vision-media.ca&gt;

Permission is hereby granted, free of charge, to any person obtaining
a copy of this software and associated documentation files (the
'Software'), to deal in the Software without restriction, including
without limitation the rights to use, copy, modify, merge, publish,
distribute, sublicense, and/or sell copies of the Software, and to
permit persons to whom the Software is furnished to do so, subject to
the following conditions:

The above copyright notice and this permission notice shall be
included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED 'AS IS', WITHOUT WARRANTY OF ANY KIND,
EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.