txaioetcd 18.10.2

Installation

The implementation is pure Python code compatible with both Python 2 and 3 and runs perfect on PyPy. On the server-side, etcd version 3.1 or higher is required. To install txaioetcd

pip install txaioetcd

Getting Started

Get the complete example source code for the getting started below from here.

To start with txaioetcd using the high-level, remote persistent map API, define at least one class for data to be persisted, eg a User class:

class User(object):

    def marshal(self):
        """
        Marshal the object into a generic host language object.
        """

    @staticmethod
    def unmarshal(obj):
        """
        Parse a generic host language object into a native object of this class.
        """

Then define a table for a slot to be used with key-value stores:

from txaioetcd import pmap

# users table schema (a table with UUID keys and CBOR values holding User objects)
tab_users = pmap.MapUuidCbor(1, marshal=lambda user: user.marshal(), unmarshal=User.unmarshal)

Above will define a table slot (with index 1) that has UUIDs for keys, and CBOR serialized objects of User class for values.

The available types for keys and values of persistant maps include:

• String (UTF8), eg MapUuidString, MapStringString, MapStringUuid, ..

• Binary, eg MapUuidBinary, MapStringBinary, ..

• OID (uint64), eg MapUuidOid, MapOidCbor, ..

• UUID (uint128), eg MapUuidCbor, MapUuidUuid, ..

• JSON, eg MapUuidJson, MapOidJson, MapStringJson, ..

• CBOR, eg MapOidCbor, MapUuidCbor, MapStringCbor, ..

• Pickle (Python), eg MapStringPickle, ..

• Flatbuffers, eg MapUuidFlatbuffers, ..

For example, the following is another valid slot definition:

# users table schema (a table with OID keys and Python Pickle values holding User objects)
tab_users = pmap.MapOidPickle(2, marshal=lambda user: user.marshal(), unmarshal=User.parse)

Above will define a table slot (with index 2) that has OIDs for keys, and Python Pickle serialized objects of User class for values.

from txaioetcd import Client, Database

etcd = Client(reactor, url='http://localhost:2379')
db = Database(etcd)

revision = await db.status()
print('connected to etcd: revision', revision)

user = User()
user.name = 'foobar'
user.oid = uuid.uuid4()

# create an async writable transaction to modify etcd data
async with db.begin(write=True) as txn:
    tab_users[txn, user.oid] = user

# data is committed when transaction leaves scope .. here
print('user stored: {}'.format(user))

# create an async read-only transaction when only accessing data in etcd
async with db.begin() as txn:
    user = await tab_users[txn, user.oid]
    print('user loaded: {}'.format(user))

import txaio
txaio.use_twisted()

from twisted.internet.task import react
from twisted.internet.defer import ensureDeferred

from txaioetcd import Client, Database

async def main(reactor):
    etcd = Client(reactor, url='http://localhost:2379')
    db = Database()
    revision = await db.status()
    print('connected to etcd: revision', revision)

    # INSERT YOUR CODE HERE

def _main():
    return react(
        lambda reactor: ensureDeferred(
            main(reactor)
        )
    )

if __name__ == '__main__':
    txaio.start_logging(level='info')
    _main()