mongoengine-migrate 0.0.1a1.dev2

Migrations for MongoEngine ODM inspired by Django

Mongoengine-migrate

Work in progress

Schema migrations for Mongoengine ODM. Inspired by Django migrations system.

How it works

Let's suppose that we already have the following Document declaration:

from mongoengine import Document, fields
    
class Books(Document):
    name = fields.StringField()
    year = fields.StringField(max_length=4)
    isbn = fields.StringField()

Then we changed couple of things:

# Add Author Document
class Author(Document):
    name = fields.StringField(required=True)

class Books(Document):
    caption = fields.StringField(required=True)  # Make required and rename
    year = fields.fields.IntField()  # Change type to IntField
    # Removed field isbn
    author = fields.ReferenceField(Author)  # Add field

Such changes should be reflected in database during upgrading. To detect changes run the command:

mongoengine-migrate makemigrations -m myproject.db 

New migration file will be created:

from mongoengine_migrate.actions import *


dependencies = [
    'my_migration'
]

forward = [
    CreateDocument('Author', collection='author'),
    CreateField('Author', 'name', choices=None, db_field='name', default=None, max_length=None,
        min_length=None, null=False, primary_key=False, regex=None, required=True,
        sparse=False, type_key='StringField', unique=False, unique_with=None),
    RenameField('Books', 'name', new_name='caption'),
    AlterField('Books', 'caption', required=True, db_field='caption'),
    AlterField('Books', 'year', type_key='IntField', min_value=None, max_value=None),
    DropField('Books', 'isbn'),
    CreateField('Books', 'author', choices=None, db_field='author', dbref=False, default=None,
        target_doctype='Author', null=False, primary_key=False, required=False, sparse=False,
        type_key='ReferenceField', unique=False, unique_with=None),
]

Now in order to migrate database to the last migration, just run the command:

mongoengine-migrate migrate

Or to migrate to the certain migration:

mongoengine-migrate migrate my_migration

...to be continued

Roadmap

• Migrations graph utilities and core code
• Basic collection actions
• Basic field actions
• User-defined code action
• Basic data type fields support (string, integer, float, etc.)
• Dictionary, list fields support
• Reference fields support
• Embedded documents support + actions
• Geo fields support
• GridFS fields support
• Altering fields in embedded documents
• Document inheritance support
• Dynamic documents support
• Index support
• Generic* fields support
• Interactive mode
• Schema repair tools
• Alpha release

Author

Igor Derkach, [e-mail]