dazl 7.5.2

high-level Ledger API client for DAML ledgers

dazl

Copyright (c) 2017-2021 Digital Asset (Switzerland) GmbH and/or its affiliates. All Rights Reserved. SPDX-License-Identifier: Apache-2.0

Rich Python bindings for accessing Ledger API-based applications.

Documentation

The user documentation is available online here.

Installation

If you just want to use the library, you can install it locally with pip:

pip install --user dazl

Requirements

• Python 3.6+
• Daml Connect
• Python gRPC libraries (1.32.0 or later) and Protobuf

WARNING: The next major version of dazl (v8.0.0) will require Python 3.7 or later.

Examples

All of the examples below assume you imported dazl, and are running a ledger with the default scenario generated with daml new.

Connect to the ledger and submit a single command:

import asyncio
import dazl

async def main():
    async with dazl.connect('http://localhost:6865', act_as='Alice') as client:
        contract = { 'issuer' : 'Alice', 'owner' : 'Alice', 'name' : 'hello world!' }
        await client.create('Main:Asset', contract)

# Python 3.7+
asyncio.run(main())

# Python 3.6+
loop = asyncio.get_event_loop()
loop.run_until_complete(main())

Connect to the ledger as a single party, print all contracts, and close:

import asyncio
import dazl
from dazl.ledgerutil import ACS

async def main():
    async with dazl.connect('http://localhost:6865', read_as='Alice') as conn:
        async with ACS(conn, {"*": {}}) as acs:
            snapshot = await acs.read()
            
    print(snapshot)

# Python 3.7+
asyncio.run(main())

# Python 3.6+
loop = asyncio.get_event_loop()
loop.run_until_complete(main())

Building locally

You will need additional dependencies to build locally:

• GNU Make
• Poetry for build/dependency management

Once you have these prerequisites in place:

make build

If you see errors about incompatible python versions, switch your environment to python3 using poetry env use python3, for instance.

Tests

Tests in dazl are written using pytest. You can run them by doing:

make test