Open Cluster Management SDK for Go

A Go SDK providing libraries and utilities for building applications that integrate with Open Cluster Management (OCM). This SDK enables developers to build controllers, agents, and other components that work with OCM's multi-cluster management capabilities.

Overview

The OCM SDK for Go provides essential building blocks for:

• Building controllers and agents for multi-cluster management
• Implementing event-based communication using CloudEvents
• Managing ManifestWork resources across clusters
• Certificate management and rotation
• Resource patching and manipulation
• Testing OCM-related components

Main Components

CloudEvents Clients

The SDK includes comprehensive CloudEvents-based clients for implementing event-driven communication between hub clusters and managed clusters. This supports the Event Based ManifestWork architecture.

Supported Protocols:

• MQTT Protocol/Driver
• gRPC Protocol/Driver
• Kafka Protocol/Driver

Key Features:

• Generic CloudEvents clients for custom resources
• Specialized ManifestWork clients
• Source and agent client implementations
• Automatic reconnection handling
• Resource synchronization capabilities

Base Controller Utilities

Foundation components for building Kubernetes controllers that integrate with OCM:

• Controller factories and base implementations
• Event handling utilities
• Common controller patterns

API Definitions

Go types and clients for OCM APIs:

• Cluster management APIs
• WorkV1 APIs for ManifestWork resources
• Typed clients for OCM resources

Helper Utilities

Common utilities for OCM development:

• Resource application helpers
• Client utilities
• Certificate Signing Request (CSR) utilities

Additional Components

• Certificate Rotation: Automated certificate lifecycle management
• Resource Patchers: Utilities for modifying Kubernetes resources
• Testing Utilities: Helper functions and mocks for testing OCM components
• Serving Certificates: Certificate management for webhooks and APIs

Getting Started

Installation

go get open-cluster-management.io/sdk-go

Basic Usage

CloudEvents Client Example

import (
    "open-cluster-management.io/sdk-go/pkg/cloudevents/generic"
    "open-cluster-management.io/sdk-go/pkg/cloudevents/generic/options/mqtt"
)

// Create a CloudEvents source client
client, err := generic.NewCloudEventSourceClient[*YourResource](
    ctx,
    mqtt.NewSourceOptions(mqttConfig, "client-id", "source-id"),
    resourceLister,
    statusHashGetter,
    resourceCodec,
)

// Subscribe to receive events
client.Subscribe(ctx, resourceHandler)

ManifestWork Client Example

import (
    "open-cluster-management.io/sdk-go/pkg/cloudevents/work"
    "open-cluster-management.io/sdk-go/pkg/cloudevents/work/codec"
)

// Build a ManifestWork client
clientHolder, err := work.NewClientHolderBuilder(config).
    WithClientID("controller-client").
    WithSourceID("controller").
    WithCodec(codec.NewManifestBundleCodec()).
    NewSourceClientHolder(ctx)

manifestWorkClient := clientHolder.ManifestWorks(namespace)

Documentation

• CloudEvents: See pkg/cloudevents/README.md for detailed CloudEvents client documentation
• API Reference: Go package documentation available via go doc
• Examples: Check the test directories for usage examples

Development

Prerequisites

• Go 1.24.0 or later
• Access to a Kubernetes cluster (for testing)

Building

make build

Testing

make test

Contributing

We welcome contributions! Please see:

• CONTRIBUTING.md for contribution guidelines
• CODE_OF_CONDUCT.md for community standards
• DCO for sign-off requirements

Development Certificate of Origin

All commits must be signed off to indicate agreement with the Developer Certificate of Origin:

git commit --signoff

License

This project is licensed under the Apache License 2.0. See LICENSE for details.

Community

Open Cluster Management is a CNCF project. For more information:

• OCM Website
• OCM GitHub Organization
• Community Meetings and Resources

Related Projects

• OCM Core - Core OCM components
• OCM API - OCM API definitions
• Addon Framework - Framework for building OCM addons