Python framework for Cadence

Cadence is a distributed, scalable, durable, and highly available orchestration engine we developed at Uber Engineering to execute asynchronous long-running business logic in a scalable and resilient way.

If you'd like to propose a new feature, first join the CNCF Slack workspace in the #cadence-users channel to start a discussion.

cadence-python-client is the Python framework for authoring workflows and activities.

Disclaimer

This SDK is currently an early work-in-progress (WIP) and is NOT ready for production use.

• This project is still in active development
• It has not been published to any package repository (PyPI, etc.)
• APIs and interfaces are subject to change without notice

Installation

git clone https://github.com/cadence-workflow/cadence-python-client.git
cd cadence-python-client

Development

Setup

1. Install protobuf (required):

   # macOS
   brew install protobuf@29
   
   # Linux/Other
   # Install protobuf 29.x via your package manager

2. Install uv (recommended):

   # macOS
   brew install uv
   
   # Linux/Other
   curl -LsSf https://astral.sh/uv/install.sh | sh
   source $HOME/.local/bin/env  # Add to your shell profile for persistence

3. Create virtual environment and install dependencies:

   uv venv
   uv pip install -e ".[dev]"

   Or if you prefer traditional pip:

   python3.11 -m venv venv
   source venv/bin/activate  # Windows: venv\Scripts\activate
   pip install -e ".[dev]"

Generate Protobuf and gRPC Files

Run the generation script:

# Using uv (recommended)
uv sync --extra dev
uv run python scripts/generate_proto.py

# Or using traditional Python
python scripts/generate_proto.py

This will:

• Download protoc 29.1 binary
• Install grpcio-tools if needed
• Generate Python protobuf files in cadence/api/v1/
• Generate gRPC service files in cadence/api/v1/
• Create proper package structure with both protobuf and gRPC imports

Test

Verify the generated files work:

# Using uv (recommended)
uv run python cadence/sample/simple_usage_example.py
uv run python cadence/sample/grpc_usage_example.py

# Or using traditional Python
python cadence/sample/simple_usage_example.py
python test_grpc_with_examples.py

Development Script

The project includes a development script that provides convenient commands for common tasks:

# Generate protobuf files
uv run python scripts/dev.py protobuf

# Run tests
uv run python scripts/dev.py test

# Run tests with coverage
uv run python scripts/dev.py test-cov

# Run linting
uv run python scripts/dev.py lint

# Format code
uv run python scripts/dev.py format

# Install in development mode
uv run python scripts/dev.py install

# Install with dev dependencies
uv run python scripts/dev.py install-dev

# Build package
uv run python scripts/dev.py build

# Clean build artifacts
uv run python scripts/dev.py clean

# Run all checks (lint + test)
uv run python scripts/dev.py check

License

Apache 2.0 License, please see LICENSE for details.