Source

dynamodb-mapper / README.rst

Dynamodb-mapper -- a DynamoDB object mapper, based on boto.

Presentation

DynamoDB is a minimalistic NoSQL engine provided by Amazon as a part of their AWS product.

DynamoDB allows you to stores documents composed of unicode strings or numbers as well as sets of unicode strings and numbers. Each tables must define a hash key and may define a range key. All other fields are optional.

Dynamodb-mapper brings a tiny abstraction layer over DynamoDB to overcome some of the limitations with no performance compromise. It is highly inspired by the mature MoongoKit project

Requirements

  • Boto = 2.6.0
  • AWS account

Highlights

  • Python <--> DynamoDB type mapping
  • Deep schema definition and validation with Onctuous (new in 1.8.0)
  • Multi-target transaction (new in 1.6.0)
  • Sub-transactions (new in 1.6.2)
  • Migration engine (new in 1.7.0)
  • Smart conflict detection (new in 1.7.0)
  • Full low-level chunking abstraction for scan, query and get_batch
  • Default values
  • Auto-inc hash_key
  • Framework agnostic

Example usage

We assume you've correctly set your Boto credentials or use ddbmock.

Quick install

$ pip install dynamodb-mapper

If you have not yet configured Boto, you may simply

$ export AWS_ACCESS_KEY_ID=<your id key here>
$ export AWS_SECRET_ACCESS_KEY=<your secret key here>

First Model

from dynamodb_mapper.model import DynamoDBModel


class DoomMap(DynamoDBModel):
    __table__ = u"doom_map"
    __hash_key__ = u"episode"
    __range_key__ = u"map"
    __schema__ = {
        u"episode": int,
        u"map": int,
        u"name": unicode,
        u"cheats": set,
    }
    __defaults__ = {
        "cheats": set([u"Konami"]),
    }

Initial Table creation

from dynamodb_mapper.model import ConnectionBorg

conn = ConnectionBorg()
conn.create_table(DoomMap, 10, 10, wait_for_active=True)

Model Usage

e1m1 = DoomMap()
e1m1.episode = 1
e1m1.map = 1
e1m1.name = u"Hangar"
e1m1.cheats = set([u"idkfa", u"iddqd", u"idclip"])
e1m1.save()


# Later on, retrieve that same object from the DB...
e1m1 = DoomMap.get(1, 1)

# query all maps of episode 1
e1_maps = DoomMap.query(hash_key=1)

# query all maps of episode 1 with 'map' hash_key > 5
from boto.dynamodb.condition import GT
e1_maps_after_5 = DoomMap.query(
    hash_key=1,
    range_key_condition=GT(5))

Contribute

Want to contribute, report a but of request a feature ? The development goes on at Ludia's BitBucket account:

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