Migrate

Migrating from dazl v5 from v4

Library Initialization

Old API:

# original dazl API
with create_client(participant_url='http://localhost:7600', parties=['Alice', 'Bob']) as manager:
    alice_client = manager.client('Alice')
    bob_client = manager.client('Bob')
    # register some event handlers for Alice and Bob
    manager.run_forever()

New API:

# asyncio-based API
network = Network()
network.set_config(url='http://localhost:7600')

alice_client = network.aio_party('Alice')
bob_client = network.aio_party('Bob')

# run
alice_client.run_forever()

Initialization Event Listeners

Arguments to event listeners have changed in order to provide more information about events and for consistency across event handlers.

Initialization has been collapsed into a single event, where formerly, there were two events (on_init and on_init_metadata):

Old API:

# original dazl API
client = manager.client('Some Party')
client.on_init(lambda: print('Ledger initialization is happening')
client.on_init_metadata(lambda store: print(f'Ledger package store: {store}'))

New API:

# asyncio-based API
client.add_ledger_init(lambda event: print(f'Ledger initialization with package store: {event.store}'))

Ready Event Listeners

Old API:

# original dazl API
client = manager.client('Some Party')
client.on_ready(lambda party_name, client\_: print(f'Party {party_name} is ready'))

New API:

# asyncio-based API
client = network.aio_party('Some Party')
client.add_ledger_ready(lambda event: print(f'Party {event.party} is ready'))

Create/Archive Event Listeners

Create and archive events now take a single parameter, called event by convention, that contain the contract ID, contract data, and additional metadata about the event, such as the time of execution, ledger ID, and access to the active contract set.

Old API:

# original dazl API
client = manager.client('Some Party')
client.on_created('Some.Asset', lambda cid, cdata: print(cid, cdata))
client.on_archived('Some.Asset', lambda cid: print(cid))

New API:

# asyncio-based API
client = network.aio_party('Some Party')
client.add_ledger_created('Some.Asset', lambda event: print(event.cid, event.cdata))
client.add_ledger_archived('Some.Asset', lambda event: print(event.cid))