Kure Patch Module Examples (TOML Format)

This directory demonstrates the new TOML-style patch system with cert-manager as an example.

Files

• cert-manager-simple.yaml - Base cert-manager resources (simplified)
• resources.kpatch - Resource limits using TOML container selectors
• ingress.kpatch - Service configuration with port selectors
• security.kpatch - Security contexts with deployment targeting
• advanced.kpatch - Complex selectors and variable substitution

Running the Demo

go run ./cmd/demo -patches

TOML Patch Format

The patch files now use TOML-style headers for precise resource targeting:

# Basic resource targeting
[deployment.app]
spec.replicas: 3
metadata.labels.env: production

# Container-specific patches
[deployment.app.containers.name=main]
resources.requests.cpu: 100m
resources.limits.memory: 512Mi

# Service port configuration
[service.app.ports.name=https]
port: 443
nodePort: 30443

# Array index targeting
[ingress.web.rules.0.paths.0]
path: /api
pathType: Prefix

Header Grammar

The TOML header format follows this grammar:

[kind.name[.section[.subsection[.selector]]]]

Selector Types

1. Key-value selectors: containers.name=main
2. Index selectors: ports.0, rules.1
3. Bracketed selectors: containers[image=nginx]

Kubernetes Path Mapping

The system intelligently maps TOML sections to Kubernetes paths:

Variable Substitution

Support for dynamic values using variable substitution:

[deployment.app.containers.name=main]
image.tag: "${values.version}"
resources.requests.cpu: "${values.cpu_request}"
debug.enabled: "${features.enable_debug}"

Variable context:

&patch.VariableContext{
    Values: map[string]interface{}{
        "version": "1.20",
        "cpu_request": "100m",
    },
    Features: map[string]bool{
        "enable_debug": true,
    },
}

Examples by Complexity

Basic Resource Targeting

[deployment.cert-manager]
spec.replicas: 3
metadata.labels.environment: production

Container-Specific Configuration

[deployment.cert-manager.containers.name=cert-manager-controller]
resources.requests.cpu: 100m
resources.limits.memory: 512Mi
securityContext.readOnlyRootFilesystem: true

Service Configuration

[service.cert-manager-webhook.ports.name=https]
port: 9443
nodePort: 30443

Complex Array Manipulation

# Add new environment variable
[deployment.app.containers.name=main.env[+]]
name: DEBUG_MODE
value: "true"

# Add new volume mount
[deployment.app.containers.name=main.volumeMounts[+]]
name: config
mountPath: /etc/config
readOnly: true

Key Features

1. Intelligent Path Resolution - Automatic mapping based on resource kind
2. Precise Targeting - Container-specific, port-specific, rule-specific patches
3. Variable Substitution - Dynamic values with ${values.key} syntax
4. Complex Selectors - Multiple ways to target list items
5. Backward Compatibility - Still supports legacy YAML format
6. Context Awareness - Different behavior for different resource types

Migration from YAML

Old YAML format:

- target: cert-manager
  patch:
    spec.template.spec.containers[0].resources.requests.cpu: "100m"

New TOML format:

[deployment.cert-manager.containers.0]
resources.requests.cpu: 100m

Or with semantic selector:

[deployment.cert-manager.containers.name=cert-manager-controller]
resources.requests.cpu: 100m

The TOML format provides better readability, more precise targeting, and eliminates the need for long JSONPath expressions.