Flux Engine

Flux Engine - FluxCD Workflow Implementation

The fluxcd package implements the stack.Workflow interface for FluxCD, providing complete Flux resource generation from domain model definitions.

Overview

The Flux engine transforms Kure’s hierarchical domain model (Cluster, Node, Bundle, Application) into FluxCD resources (Kustomizations, source references) organized in a GitOps-ready directory structure.

The engine is composed of three specialized components:

Quick Start

import "github.com/go-kure/kure/pkg/stack/fluxcd"

// Create engine with defaults
engine := fluxcd.Engine()

// Generate all Flux resources for a cluster
objects, err := engine.GenerateFromCluster(cluster)

// Or with custom configuration
engine = fluxcd.EngineWithConfig(
    layout.KustomizationExplicit,
    layout.FluxSeparate,
)

Engine Construction

// Default engine
engine := fluxcd.Engine()

// Engine with specific kustomization mode
engine := fluxcd.EngineWithMode(layout.KustomizationExplicit)

// Engine with full configuration
engine := fluxcd.EngineWithConfig(mode, placement)

// Engine with custom components
engine := fluxcd.NewWorkflowEngine()

Resource Generation

Generate Flux resources at different hierarchy levels:

// From entire cluster
objects, err := engine.GenerateFromCluster(cluster)

// From a single node
objects, err := engine.GenerateFromNode(node)

// From a single bundle
objects, err := engine.GenerateFromBundle(bundle)

Each bundle produces a Flux Kustomization resource with:

• Path matching the layout directory structure
• Source reference from the node’s package ref
• Dependency ordering from Bundle.DependsOn
• Interval and pruning configuration

Layout Integration

Combine resource generation with directory structure:

// Create layout with Flux resources integrated
ml, err := engine.CreateLayoutWithResources(cluster, rules)

// Write to disk
err = layout.WriteManifest(ml, "./clusters")

Bootstrap Generation

Generate Flux system bootstrap manifests:

bootstrapConfig := &stack.BootstrapConfig{
    Enabled:     true,
    FluxMode:    "install",
    FluxVersion: "v2.6.4",
    SourceRef:   sourceRef,
}

objects, err := engine.GenerateBootstrap(bootstrapConfig, rootNode)

Configuration

Kustomization Mode

Controls how kustomization.yaml files reference resources:

• KustomizationExplicit - Lists all manifest files explicitly
• KustomizationRecursive - References subdirectories only

Flux Placement

Controls where Flux Kustomization resources are placed:

• FluxSeparate - Flux resources in a separate directory tree
• FluxIntegrated - Flux resources alongside application manifests

Related Packages

• stack - Core domain model
• stack/layout - Manifest directory organization
• kubernetes/fluxcd - Low-level Flux resource builders