client

Overview ¶

Package client provides a unified client abstraction for accessing muster resources both locally (filesystem) and in-cluster (Kubernetes API).

Overview ¶

The client package implements the unified access pattern described in Issues #30 and #36, providing seamless operation across different deployment environments:

- **Local Development**: Filesystem-based storage with YAML files - **In-Cluster**: Native Kubernetes API access using controller-runtime - **External Tools**: kubectl-compatible access patterns

Architecture ¶

The package implements a facade pattern with automatic environment detection:

┌─────────────────┐
│   MusterClient  │  ← Unified Interface
│   (Interface)   │
└─────────────────┘
         │
    ┌────┴────┐
    │ Factory │  ← Environment Detection
    └────┬────┘
         │
   ┌─────┴─────┐
   │           │
┌──▼──┐    ┌───▼──┐
│ K8s │    │ File │  ← Backend Implementations
│     │    │      │
└─────┘    └──────┘

Usage Examples ¶

## Basic Usage (Automatic Detection)

client, err := client.NewMusterClient()
if err != nil {
    log.Fatal(err)
}
defer client.Close()

servers, err := client.ListMCPServers(ctx, "default")
if err != nil {
    log.Fatal(err)
}

## Explicit Configuration

config := &client.MusterClientConfig{
    Namespace: "muster-system",
    ForceFilesystemMode: true,
}
client, err := client.NewMusterClientWithConfig(config)

Environment Detection ¶

The client automatically detects the execution environment:

1. **Kubernetes Detection**: Uses controller-runtime's standard config detection

• In-cluster service account credentials
• kubeconfig file (~/.kube/config)
• Environment variables (KUBECONFIG)

2. **Filesystem Fallback**: Used when Kubernetes is not available

• Local development environments
• Standalone deployment scenarios
• Testing and debugging

Interface Compatibility ¶

MusterClient extends controller-runtime's client.Client interface, ensuring compatibility with existing Kubernetes tooling while adding muster-specific convenience methods.

Future Extensibility ¶

The interface design supports future CRD implementations:

// Current (v1alpha1)
client.GetMCPServer(ctx, name, namespace)

// Future (as CRDs are implemented)
client.GetServiceClass(ctx, name, namespace)
client.ListWorkflows(ctx, namespace)
client.CreateService(ctx, service)

Error Handling ¶

The client provides consistent error handling across both backends:

server, err := client.GetMCPServer(ctx, "server-name", "default")
if err != nil {
    if errors.IsNotFound(err) {
        // Handle not found consistently across backends
    }
    // Handle other errors
}

Thread Safety ¶

All client implementations are thread-safe and can be used concurrently from multiple goroutines.