kvm2: Create, Get, Delete and ListByTag with the contract tests

Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>

internal/provider/kvm2/list.go

@@ -0,0 +1,60 @@
+package kvm2
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/digitalocean/go-libvirt"
+
+	"gitea.home.hrajfrisbee.cz/kacerr/egress-proxies-operator/internal/provider"
+)
+
+// ListByTag is spec entry 12: every domain on every configured host, in
+// config order, filtered client-side on the kvm2 mark. A host that cannot
+// be reached or listed fails the whole call (fail-whole); a single domain
+// that cannot be read is skipped, unless ctx ended, which fails the call
+// rather than pass off an empty view as the truth.
+func (p *Provider) ListByTag(ctx context.Context) ([]provider.Instance, error) {
+	log := p.logger(ctx)
+	var out []provider.Instance
+	for _, host := range p.cfg.Hosts {
+		hlog := log.WithValues("host", host.Name)
+		be, err := p.hosts.get(ctx, host)
+		if err != nil {
+			logAPIError(hlog, "list", err)
+			return nil, p.wrapErr("list", "", err)
+		}
+		doms, _, err := be.ConnectListAllDomains(ctx, 1, libvirt.ConnectListDomainsActive|libvirt.ConnectListDomainsInactive)
+		if err != nil {
+			err = fmt.Errorf("listing domains on host %s: %w", host.Name, err)
+			logAPIError(hlog, "list", err)
+			return nil, p.wrapErr("list", "", err)
+		}
+		for _, dom := range doms {
+			dlog := hlog.WithValues("name", dom.Name)
+			meta, err := readMetadata(ctx, be, dom)
+			if err != nil {
+				if ctx.Err() != nil {
+					return nil, p.wrapErr("list", "", err)
+				}
+				dlog.V(1).Info("skipping domain with unreadable metadata", "error", err.Error())
+				continue
+			}
+			if !meta.managed() {
+				continue
+			}
+			inst, err := inspect(ctx, dlog, be, host.Name, dom, meta)
+			if err != nil {
+				if ctx.Err() != nil {
+					return nil, p.wrapErr("list", "", err)
+				}
+				dlog.V(1).Info("skipping domain that could not be inspected", "error", err.Error())
+				continue
+			}
+			dlog.V(2).Info("kvm2 listed instance", "id", inst.ID, "state", inst.State, "uid", inst.UID, "createdAt", inst.CreatedAt)
+			out = append(out, inst)
+		}
+	}
+	log.V(1).Info("kvm2 domains listed", "hosts", len(p.cfg.Hosts), "managed", len(out))
+	return out, nil
+}