Community SDKs - Cadence

Introduction

In addition to the official Go and Java SDKs, the Cadence community has developed client libraries for other popular programming languages. These SDKs are maintained by community members and provide varying levels of feature support.

Community SDKs may have limited features compared to official SDKs and may not be production-ready. Evaluate carefully before using in critical applications.

Available Community SDKs

Python SDK

cadence-python

Community-maintained Python client for Cadence workflows

Overview

The Python SDK provides a Pythonic interface for building Cadence workflows and activities. It’s suitable for prototyping, internal tools, and non-critical workflows.

Installation

pip install cadence-client

Quick Example

from cadence.workflow import workflow_method, Workflow
from cadence.activity_method import activity_method

@activity_method(task_list="python-tasks", schedule_to_close_timeout_seconds=300)
async def greet(name: str) -> str:
    return f"Hello, {name}!"

class HelloWorkflow:
    @workflow_method(execution_start_to_close_timeout_seconds=600, task_list="python-tasks")
    async def say_hello(self, name: str) -> str:
        return await greet(name)

Features

Supported Features

Basic workflow and activity definitions
Workflow execution and completion
Signal and query support
Child workflows
Timer operations
Basic error handling

Limitations

Limited production testing
Fewer built-in retry mechanisms
Less comprehensive documentation
May lag behind official SDK features
Community support only

Use Cases

Internal automation tools
Data processing pipelines
Prototyping and experimentation
Integration with Python data science libraries
Lightweight orchestration tasks

Ruby SDK

cadence-ruby

Community-maintained Ruby client developed by Coinbase

Overview

The Ruby SDK was developed by Coinbase for their internal use. It provides a Ruby-native interface for Cadence workflows and has been battle-tested in Coinbase’s production environment.

Installation

Add to your Gemfile:

Gemfile

gem 'cadence-ruby'

Then install:

bundle install

Quick Example

require 'cadence/workflow'
require 'cadence/activity'

class GreetingActivity < Cadence::Activity
  def execute(name)
    "Hello, #{name}!"
  end
end

class HelloWorkflow < Cadence::Workflow
  def execute(name)
    workflow.execute_activity(
      GreetingActivity,
      name,
      options: {
        start_to_close_timeout: 60,
        retry_policy: {
          initial_interval: 1,
          maximum_attempts: 3
        }
      }
    )
  end
end

Features

Supported Features

Workflow and activity execution
Signals and queries
Child workflows
Activity retries with exponential backoff
Rails integration helpers
Production-tested at Coinbase

Production Usage

Actively used at Coinbase
Battle-tested in financial services
Good documentation and examples
Active maintenance (though not official)

Use Cases

Ruby on Rails applications
Background job orchestration
Complex business process automation
Financial transaction workflows
Integration with existing Ruby services

Other Community Projects

iWF Framework

iWF

Domain-specific language (DSL) framework built on top of Cadence

Developed by Indeed, iWF provides a simplified interface for building workflows with Cadence. It offers:

Simplified workflow definition syntax
Multi-language support through HTTP API
State machine-based workflow modeling
Built-in best practices and patterns
Reduced boilerplate code

Example

from iwf import workflow, state

@workflow
class OrderWorkflow:
    @state(start=True)
    def submit_order(self, context):
        # Submit order logic
        return "process_payment"
    
    @state
    def process_payment(self, context):
        # Payment processing
        return "fulfill_order"
    
    @state(end=True)
    def fulfill_order(self, context):
        # Order fulfillment
        return "completed"

TypeScript/JavaScript

While there’s no official TypeScript/JavaScript SDK for Cadence, developers looking for TypeScript support may consider:

Temporal
REST API

Temporal (a fork of Cadence) has excellent TypeScript support:

import { proxyActivities } from '@temporalio/workflow';

const { greet } = proxyActivities({
  startToCloseTimeout: '1 minute',
});

export async function helloWorkflow(name: string): Promise<string> {
  return await greet(name);
}

Note: Temporal and Cadence are not wire-compatible.

Use Cadence’s REST API directly:

import axios from 'axios';

async function startWorkflow() {
  const response = await axios.post(
    'http://localhost:8088/api/domains/my-domain/workflows',
    {
      workflowType: 'HelloWorkflow',
      taskList: 'my-tasks',
      input: { name: 'World' },
      executionStartToCloseTimeout: '600s'
    }
  );
  return response.data;
}

Comparing Community vs Official SDKs

Official SDKs (Go, Java)
Community SDKs

Advantages:

Full feature support
Regular updates and bug fixes
Comprehensive documentation
Official support channels
Production-ready guarantees
Performance optimizations
Extensive testing

Best for:

Production applications
Mission-critical workflows
Long-term maintenance
Enterprise deployments

Contributing to Community SDKs

How to Contribute

Choose a Project

Select a community SDK that aligns with your skills and interests.

Understand the SDK

Review the existing codebase, documentation, and open issues.

Start Small

Begin with documentation improvements or bug fixes before major features.

Follow Guidelines

Adhere to the project’s contributing guidelines and code style.

Engage with Maintainers

Communicate with maintainers before starting significant work.

Building a New SDK

Interested in creating an SDK for a new language?

Prerequisites

Deep understanding of Cadence concepts
Familiarity with the target language
Understanding of RPC frameworks (Thrift/gRPC)
Knowledge of async/concurrent programming
Access to Cadence IDL definitions

Core Components to Implement

Service Client: Connection to Cadence server
Workflow Runtime: Deterministic execution engine
Activity Runtime: Non-deterministic task execution
Worker: Task polling and execution
State Management: Workflow state persistence
Retry Logic: Configurable retry policies
Testing Framework: Unit testing support

Best Practices

Study official SDK implementations
Start with core features (workflow, activity, worker)
Ensure deterministic execution
Implement comprehensive tests
Document all public APIs
Provide working examples
Engage with Cadence community

Community Resources

Slack

Join #cadence-users on CNCF Slack for discussions

GitHub Discussions

Ask questions and share ideas

Stack Overflow

Find answers to common questions

Contributing Guide

Learn how to contribute to Cadence

Migration Paths

From Community SDK to Official SDK

If you start with a community SDK and later need to migrate to an official SDK:

Audit Existing Workflows

Document all workflows, activities, and their dependencies.

Map Features

Identify equivalent features in the target official SDK.

Incremental Migration

Migrate one workflow at a time, starting with the simplest.

Parallel Deployment

Run both SDK workers simultaneously during transition.

Testing

Thoroughly test migrated workflows before decommissioning old workers.

Monitor

Track metrics and errors during and after migration.

Next Steps

Go SDK

Explore the official Go client SDK

Java SDK

Learn about the official Java client SDK

Core Concepts

Understand Cadence fundamentals

CLI

Manage workflows with Cadence CLI

Get Started

Core Concepts

Architecture

Deployment

Operations

Client SDKs

​Introduction

​Available Community SDKs

​Python SDK

cadence-python

​Overview

​Installation

​Quick Example

​Features

​Use Cases

​Ruby SDK

cadence-ruby

​Overview

​Installation

​Quick Example

​Features

​Use Cases

​Other Community Projects

​iWF Framework

iWF

​Example

​TypeScript/JavaScript

​Comparing Community vs Official SDKs

​Contributing to Community SDKs

​How to Contribute

​Building a New SDK

​Community Resources

Slack

GitHub Discussions

Stack Overflow

Contributing Guide

​Migration Paths

​From Community SDK to Official SDK

​Next Steps

Go SDK

Java SDK

Core Concepts

CLI

Build docs developers (and LLMs) love

Introduction

Available Community SDKs

Python SDK

Overview

Installation

Quick Example

Features

Use Cases

Ruby SDK

Overview

Installation

Quick Example

Features

Use Cases

Other Community Projects

iWF Framework

Example

TypeScript/JavaScript

Comparing Community vs Official SDKs

Contributing to Community SDKs

How to Contribute

Building a New SDK

Community Resources

Migration Paths

From Community SDK to Official SDK

Next Steps