Patch Package

Patch Package Documentation

The patch package implements a powerful JSONPath-based declarative patching system for Kubernetes resources. It allows you to modify resources while preserving YAML structure, comments, and formatting.

Documentation

Patch File Format Specification

Complete specification of the .kpatch file format, including:

• Syntax and structure
• Scope selection
• Operation types
• Examples and best practices

Patch Engine Design

Technical design documentation covering:

• Architecture overview
• Processing pipeline
• Implementation details
• Performance considerations

Path Resolution

Detailed explanation of how paths are resolved:

• JSONPath syntax support
• Array indexing and wildcards
• Complex path expressions
• Resolution algorithm

Error Handling

Comprehensive error handling guide:

• Error types and categories
• Error recovery strategies
• Debugging patch issues
• Common problems and solutions

Quick Example

[Deployment.my-app]
set.spec.replicas = 5
set.metadata.labels.environment = "production"
add.spec.template.spec.containers[name=app].env = [
  { name = "LOG_LEVEL", value = "info" }
]

Features

• Declarative: Define what you want, not how to get there
• Type-safe: Operations are validated against resource schemas
• Preserves formatting: Maintains YAML comments and structure
• Powerful selection: Target resources by kind, name, labels, and more
• Flexible operations: Set, add, replace values with JSONPath precision

Getting Started

1. Start with the Patch File Format Specification
2. Review examples to see patches in action
3. Understand path resolution for complex selections
4. Learn about error handling for debugging