mesh-sdk/go/catalogue/artifacts.go

package catalogue

import (
	"strings"
)

// ArtifactStoreScheme marks a reference to something in the mesh's artifact store, kept without
// the store's address.
const ArtifactStoreScheme = ArtifactStoreProvision + "://"

// Recorded is a reference as the mesh records it: the artifact store's address, if the builder wrote
// one, taken off.
//
// For a reference the builder announced — one it pushed to the store — which is the only kind
// this is called on. An image the builder named `<host>/<path>@sha256:…` is kept as its path; an
// archive it named `http://<host>/v2/<path>/blobs/<digest>` likewise. A reference with no address
// in it — an image id from a genesis build that had nowhere to publish, a package version — is
// what it was.
func Recorded(reference string) string {
	if strings.HasPrefix(reference, ArtifactStoreScheme) {
		return reference
	}
	if rest, isURL := strings.CutPrefix(reference, "http://"); isURL {
		if _, path, ok := strings.Cut(rest, "/v2/"); ok && strings.Contains(path, "/blobs/") {
			return ArtifactStoreScheme + path
		}
		return reference
	}
	host, path, ok := strings.Cut(reference, "/")
	if !ok || !isRegistryHost(host) || !strings.Contains(path, "@sha256:") {
		return reference
	}
	return ArtifactStoreScheme + path
}

// isRegistryHost is the runtime's own rule for reading the first component of a reference as a
// registry rather than as a namespace: it has a dot or a port in it, or it is localhost.
func isRegistryHost(component string) bool {
	return component == "localhost" || strings.ContainsAny(component, ".:")
}

// InArtifactStore reports whether a reference is a kept one, and what it names there.
func InArtifactStore(reference string) (path string, kept bool) {
	return strings.CutPrefix(reference, ArtifactStoreScheme)
}

// Routed is a kept reference as a machine fetches it, through the artifact store at `address`
// (host:port). A reference that is not a kept one is what it was.
func Routed(reference, address string) string {
	path, kept := InArtifactStore(reference)
	if !kept {
		return reference
	}
	if strings.Contains(path, "/blobs/") {
		return "http://" + address + "/v2/" + path
	}
	return address + "/" + path
}