overrides

Overrides Package

The overrides package provides functionality for extracting configuration overrides by comparing configured values against default values from Helm charts.

Overview

This package contains the core logic for identifying differences between configured values and default values, producing a minimal set of overrides that represent only the meaningful differences.

Usage

import "github.com/cloudzero/cloudzero-agent/app/functions/helmless/overrides"

// Create an extractor with optional exclude keys
extractor := overrides.NewExtractor("kubeStateMetrics", "excludedKey")

// Extract overrides
overrides := extractor.Extract(configuredValues, defaultValues)

Key Features

Extractor

The Extractor type handles the comparison logic and provides:

• Configurable exclusions: Specify keys to exclude from comparison
• Deep comparison: Recursively compares nested maps and arrays
• Significance filtering: Only includes values that are considered "significant"

Significance Rules

A value is considered significant if it is:

• A non-empty string
• Any number (including zero)
• Any boolean value (true or false)
• A non-empty map with at least one significant value
• A non-empty array with at least one significant value

Values that are not significant:

• Empty strings
• nil values
• Empty maps
• Empty arrays
• Maps/arrays containing only insignificant values

Example

configured := map[string]interface{}{
    "replicas": 5,
    "image": "nginx:latest",
    "config": map[string]interface{}{
        "database": map[string]interface{}{
            "host": "prod.db.com",
            "port": 5432,
        },
    },
    "kubeStateMetrics": map[string]interface{}{
        "enabled": true,
    },
}

defaults := map[string]interface{}{
    "replicas": 3,
    "image": "nginx:latest",
    "config": map[string]interface{}{
        "database": map[string]interface{}{
            "host": "localhost",
            "port": 5432,
        },
    },
    "kubeStateMetrics": map[string]interface{}{
        "enabled": false,
    },
}

// Exclude kubeStateMetrics from comparison
extractor := overrides.NewExtractor("kubeStateMetrics")
result := extractor.Extract(configured, defaults)

// Result will be:
// {
//   "replicas": 5,
//   "config": {
//     "database": {
//       "host": "prod.db.com"
//     }
//   }
// }

Testing

The package includes comprehensive tests covering:

• Basic extractor creation and configuration
• Simple and complex override scenarios
• Nested data structure handling
• Exclude key functionality
• Significance value determination
• Edge cases and type variations

Run tests with:

go test ./overrides