graphene-pynamodb 2.3.0
Graphene PynamoDB integration
License: MIT
Keywords: api graphql protocol rest relay graphene pynamodb dynamodb

Graphene-PynamoDB |Build Status| |Coverage Status| |PyPI version|
=================================================================================

A `PynamoDB <http://pynamodb.readthedocs.io/>`__ integration for
`Graphene <http://graphene-python.org/>`__.

Installation
------------

For instaling graphene, just run this command in your shell

.. code:: bash

    pip install graphene-pynamodb

Examples
--------

Here is a simple PynamoDB model:

.. code:: python

    from uuid import uuid4
    from pynamodb.attributes import UnicodeAttribute
    from pynamodb.models import Model


    class User(Model):
        class Meta:
            table_name = "my_users"
            host = "http://localhost:8000"

        id = UnicodeAttribute(hash_key=True)
        name = UnicodeAttribute(null=False)


    if not User.exists():
        User.create_table(read_capacity_units=1, write_capacity_units=1, wait=True)
        User(id=str(uuid4()), name="John Snow").save()
        User(id=str(uuid4()), name="Daenerys Targaryen").save()

To create a GraphQL schema for it you simply have to write the
following:

.. code:: python

    import graphene
    from graphene_pynamodb import PynamoObjectType


    class UserNode(PynamoObjectType):
        class Meta:
            model = User
            interfaces = (graphene.Node,)


    class Query(graphene.ObjectType):
        users = graphene.List(UserNode)

        def resolve_users(self, args, context, info):
            return list(User.scan())


    schema = graphene.Schema(query=Query)

Then you can simply query the schema:

.. code:: python

    query = '''
        query {
          users {
            name
          }
        }
    '''
    result = schema.execute(query)

To learn more check out the following
`examples <https://github.com/yfilali/graphql-pynamodb/tree/master/examples/>`__:

-  **Full example**: `Flask PynamoDB
   example <https://github.com/yfilali/graphql-pynamodb/tree/master/examples/flask_pynamodb>`__

Limitations
-----------

graphene-pynamodb includes a basic implementation of relationships using
lists. OneToOne and OneToMany relationships are serialized as a List of
the ids and unserialized lazyly. The limit for an item's size in
DynamoDB is 400KB (see
http://docs.aws.amazon.com/amazondynamodb/latest/developerguide/Limits.html)
This means the total "row" size including the serialized relationship
needs to fit within 400KB so make sure to use this accordingly.

In addition, scan operations on DynamoDB are unsorted by design. This
means that there is no reliable way to get a paginated result (Cursor
support) on a root PynamoConnectionField.

This means that if you need to paginate items, it is best to have them
as a OneToMany relationship inside another Field (usually viewer or
node).

Contributing
------------

After cloning `this
repo <https://github.com/yfilali/graphql-pynamodb>`__, ensure
dependencies are installed by running:

.. code:: sh

    python setup.py install

After developing, the full test suite can be evaluated by running:

.. code:: sh

    python setup.py test # Use --pytest-args="-v -s" for verbose mode

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