registry

Overview ¶

Package registry implements the Epoch snapshot registry backed by an S3-compatible object store.

vk-cocoon Integration ¶

vk-cocoon imports this package to automatically pull snapshots before cloning VMs.

Setup in vk-cocoon's main.go or provider initialization:

import "github.com/cocoonstack/epoch/registry"

// Create puller — reads object store settings from a k8s ConfigMap.
puller, err := registry.NewPuller("/var/lib/cocoon", "prod", "agent-env")
if err != nil {
    log.WithFunc("main").Fatalf(ctx, err, "epoch puller: %v", err)
}

// Pre-warm known snapshots at startup (non-blocking).
puller.PreWarm(ctx, []string{"sre-agent-bot", "sre-agent-diagnosis"})

In the provider's CreatePod, before calling `cocoon vm clone`:

// Ensure snapshot is available locally before cloning.
if err := puller.EnsureSnapshot(ctx, image); err != nil {
    return fmt.Errorf("epoch ensure %s: %w", image, err)
}
// Now safe to: cocoon vm clone --cold <image>

The Puller is thread-safe, idempotent, and caches pull results. Subsequent calls for the same snapshot return immediately.

Package registry implements the Epoch snapshot registry backed by an S3-compatible object store.

It handles push/pull of Cocoon snapshots as content-addressable artifacts:

• Blobs are stored at epoch/blobs/sha256/{digest}
• Manifests at epoch/manifests/{name}/{tag}.json
• Catalog at epoch/catalog.json