Add KVM provider image cache: fetch base images into host pools on first use

resolveImage maps placement.image to a configured key or URL; imageCache streams the download through StorageVolUpload with a sha256 tee, writes a marker volume when the upload is verified, and re-fetches when the marker is missing or the configured checksum changed. Errors carry taxonomy sentinels that classify now honours. Adds the in-memory fake libvirt API used from here on. Step 3b of docs/plans/2026-09-04-1404-kvm-provider.md. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
2026-09-05 03:32:39 +00:00
parent d171c0426e
commit 7d177b4817
6 changed files with 1087 additions and 8 deletions
@@ -0,0 +1,408 @@
+package kvm
+
+import (
+	"bytes"
+	"encoding/xml"
+	"fmt"
+	"io"
+	"slices"
+	"sync"
+
+	libvirt "github.com/digitalocean/go-libvirt"
+)
+
+// fakeAPI is an in-memory libvirtAPI: pools of volumes and a set of
+// domains, with per-method error injection. It models just enough libvirt
+// semantics for the provider's decisions to be observable — ErrStorageVolExist
+// on duplicate create, ErrNoDomain/ErrNoStorageVol on missing lookups,
+// ErrOperationInvalid on destroying a stopped domain, and so on.
+type fakeAPI struct {
+	mu       sync.Mutex
+	poolPath string
+	pools    map[string]map[string]*fakeVol
+	domains  map[string]*fakeDomain
+	calls    []string
+	fail     map[string]error
+	failOnce map[string]error
+	// uploadHook, when set, sees every StorageVolUpload before the fake
+	// reads the stream; it can return an error to simulate a broken upload.
+	uploadHook func(vol string, r io.Reader) error
+}
+
+type fakeVol struct {
+	name     string
+	format   string
+	capacity int64
+	backing  string
+	data     []byte
+}
+
+type fakeDomain struct {
+	name     string
+	xml      string
+	metadata string
+	running  bool
+	// addrs is what DomainInterfaceAddresses returns per source.
+	addrs map[uint32][]libvirt.DomainInterface
+}
+
+func newFakeAPI(pools ...string) *fakeAPI {
+	f := &fakeAPI{
+		poolPath: "/var/lib/libvirt/images",
+		pools:    map[string]map[string]*fakeVol{},
+		domains:  map[string]*fakeDomain{},
+		fail:     map[string]error{},
+		failOnce: map[string]error{},
+	}
+	for _, p := range pools {
+		f.pools[p] = map[string]*fakeVol{}
+	}
+	return f
+}
+
+// enter records the call and returns any injected error for method.
+func (f *fakeAPI) enter(method string) error {
+	f.calls = append(f.calls, method)
+	if err, ok := f.failOnce[method]; ok {
+		delete(f.failOnce, method)
+		return err
+	}
+	return f.fail[method]
+}
+
+func (f *fakeAPI) callCount(method string) int {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	n := 0
+	for _, c := range f.calls {
+		if c == method {
+			n++
+		}
+	}
+	return n
+}
+
+func (f *fakeAPI) hasCall(method string) bool { return f.callCount(method) > 0 }
+
+func (f *fakeAPI) vol(pool, name string) *fakeVol {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return f.pools[pool][name]
+}
+
+func (f *fakeAPI) putVol(pool, name, format string, data []byte) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.pools[pool][name] = &fakeVol{name: name, format: format, capacity: int64(len(data)), data: data}
+}
+
+func (f *fakeAPI) volNames(pool string) []string {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	var out []string
+	for n := range f.pools[pool] {
+		out = append(out, n)
+	}
+	slices.Sort(out)
+	return out
+}
+
+func (f *fakeAPI) domain(name string) *fakeDomain {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	return f.domains[name]
+}
+
+func (f *fakeAPI) putDomain(d *fakeDomain) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	f.domains[d.name] = d
+}
+
+func lvError(code libvirt.ErrorNumber, format string, args ...any) error {
+	return libvirt.Error{Code: uint32(code), Message: fmt.Sprintf(format, args...)}
+}
+
+// --- domains ---
+
+func (f *fakeAPI) DomainLookupByName(name string) (libvirt.Domain, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainLookupByName"); err != nil {
+		return libvirt.Domain{}, err
+	}
+	if _, ok := f.domains[name]; !ok {
+		return libvirt.Domain{}, lvError(libvirt.ErrNoDomain, "Domain not found: no domain with matching name '%s'", name)
+	}
+	return libvirt.Domain{Name: name}, nil
+}
+
+func (f *fakeAPI) DomainDefineXML(raw string) (libvirt.Domain, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainDefineXML"); err != nil {
+		return libvirt.Domain{}, err
+	}
+	var d domainXML
+	if err := xml.Unmarshal([]byte(raw), &d); err != nil {
+		return libvirt.Domain{}, lvError(libvirt.ErrXMLError, "%v", err)
+	}
+	meta, err := xml.Marshal(d.Metadata.Instance)
+	if err != nil {
+		return libvirt.Domain{}, lvError(libvirt.ErrXMLError, "%v", err)
+	}
+	existing := f.domains[d.Name]
+	nd := &fakeDomain{name: d.Name, xml: raw, metadata: string(meta)}
+	if existing != nil {
+		nd.running = existing.running
+		nd.addrs = existing.addrs
+	}
+	f.domains[d.Name] = nd
+	return libvirt.Domain{Name: d.Name}, nil
+}
+
+func (f *fakeAPI) DomainCreate(d libvirt.Domain) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainCreate"); err != nil {
+		return err
+	}
+	dom, ok := f.domains[d.Name]
+	if !ok {
+		return lvError(libvirt.ErrNoDomain, "no domain %s", d.Name)
+	}
+	if dom.running {
+		return lvError(libvirt.ErrOperationInvalid, "domain is already running")
+	}
+	dom.running = true
+	return nil
+}
+
+func (f *fakeAPI) DomainDestroy(d libvirt.Domain) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainDestroy"); err != nil {
+		return err
+	}
+	dom, ok := f.domains[d.Name]
+	if !ok {
+		return lvError(libvirt.ErrNoDomain, "no domain %s", d.Name)
+	}
+	if !dom.running {
+		return lvError(libvirt.ErrOperationInvalid, "domain is not running")
+	}
+	dom.running = false
+	return nil
+}
+
+func (f *fakeAPI) DomainUndefineFlags(d libvirt.Domain, _ libvirt.DomainUndefineFlagsValues) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainUndefineFlags"); err != nil {
+		return err
+	}
+	if _, ok := f.domains[d.Name]; !ok {
+		return lvError(libvirt.ErrNoDomain, "no domain %s", d.Name)
+	}
+	delete(f.domains, d.Name)
+	return nil
+}
+
+func (f *fakeAPI) DomainGetState(d libvirt.Domain, _ uint32) (int32, int32, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainGetState"); err != nil {
+		return 0, 0, err
+	}
+	dom, ok := f.domains[d.Name]
+	if !ok {
+		return 0, 0, lvError(libvirt.ErrNoDomain, "no domain %s", d.Name)
+	}
+	if dom.running {
+		return int32(libvirt.DomainRunning), 0, nil
+	}
+	return int32(libvirt.DomainShutoff), 0, nil
+}
+
+func (f *fakeAPI) DomainGetMetadata(d libvirt.Domain, typ int32, uri libvirt.OptString, _ libvirt.DomainModificationImpact) (string, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainGetMetadata"); err != nil {
+		return "", err
+	}
+	dom, ok := f.domains[d.Name]
+	if !ok {
+		return "", lvError(libvirt.ErrNoDomain, "no domain %s", d.Name)
+	}
+	if typ != int32(libvirt.DomainMetadataElement) || len(uri) != 1 || uri[0] != metadataURI || dom.metadata == "" {
+		return "", lvError(libvirt.ErrNoDomainMetadata, "Requested metadata element is not present")
+	}
+	return dom.metadata, nil
+}
+
+func (f *fakeAPI) DomainInterfaceAddresses(d libvirt.Domain, source uint32, _ uint32) ([]libvirt.DomainInterface, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("DomainInterfaceAddresses"); err != nil {
+		return nil, err
+	}
+	dom, ok := f.domains[d.Name]
+	if !ok {
+		return nil, lvError(libvirt.ErrNoDomain, "no domain %s", d.Name)
+	}
+	if !dom.running {
+		return nil, lvError(libvirt.ErrOperationInvalid, "domain is not running")
+	}
+	if source == uint32(libvirt.DomainInterfaceAddressesSrcAgent) && dom.addrs[source] == nil {
+		return nil, lvError(libvirt.ErrAgentUnresponsive, "Guest agent is not responding")
+	}
+	return dom.addrs[source], nil
+}
+
+func (f *fakeAPI) ConnectListAllDomains(_ int32, _ libvirt.ConnectListAllDomainsFlags) ([]libvirt.Domain, uint32, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("ConnectListAllDomains"); err != nil {
+		return nil, 0, err
+	}
+	names := make([]string, 0, len(f.domains))
+	for n := range f.domains {
+		names = append(names, n)
+	}
+	slices.Sort(names)
+	out := make([]libvirt.Domain, 0, len(names))
+	for _, n := range names {
+		out = append(out, libvirt.Domain{Name: n})
+	}
+	return out, uint32(len(out)), nil
+}
+
+// --- storage ---
+
+func (f *fakeAPI) StoragePoolLookupByName(name string) (libvirt.StoragePool, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StoragePoolLookupByName"); err != nil {
+		return libvirt.StoragePool{}, err
+	}
+	if _, ok := f.pools[name]; !ok {
+		return libvirt.StoragePool{}, lvError(libvirt.ErrNoStoragePool, "Storage pool not found: no storage pool with matching name '%s'", name)
+	}
+	return libvirt.StoragePool{Name: name}, nil
+}
+
+func (f *fakeAPI) StoragePoolRefresh(pool libvirt.StoragePool, _ uint32) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StoragePoolRefresh"); err != nil {
+		return err
+	}
+	if _, ok := f.pools[pool.Name]; !ok {
+		return lvError(libvirt.ErrNoStoragePool, "no pool %s", pool.Name)
+	}
+	return nil
+}
+
+func (f *fakeAPI) StorageVolLookupByName(pool libvirt.StoragePool, name string) (libvirt.StorageVol, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StorageVolLookupByName"); err != nil {
+		return libvirt.StorageVol{}, err
+	}
+	if _, ok := f.pools[pool.Name][name]; !ok {
+		return libvirt.StorageVol{}, lvError(libvirt.ErrNoStorageVol, "Storage volume not found: no storage vol with matching name '%s'", name)
+	}
+	return libvirt.StorageVol{Pool: pool.Name, Name: name, Key: f.poolPath + "/" + name}, nil
+}
+
+func (f *fakeAPI) StorageVolGetPath(vol libvirt.StorageVol) (string, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StorageVolGetPath"); err != nil {
+		return "", err
+	}
+	if _, ok := f.pools[vol.Pool][vol.Name]; !ok {
+		return "", lvError(libvirt.ErrNoStorageVol, "no vol %s", vol.Name)
+	}
+	return f.poolPath + "/" + vol.Name, nil
+}
+
+func (f *fakeAPI) StorageVolCreateXML(pool libvirt.StoragePool, raw string, _ libvirt.StorageVolCreateFlags) (libvirt.StorageVol, error) {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StorageVolCreateXML"); err != nil {
+		return libvirt.StorageVol{}, err
+	}
+	vols, ok := f.pools[pool.Name]
+	if !ok {
+		return libvirt.StorageVol{}, lvError(libvirt.ErrNoStoragePool, "no pool %s", pool.Name)
+	}
+	var v volumeXML
+	if err := xml.Unmarshal([]byte(raw), &v); err != nil {
+		return libvirt.StorageVol{}, lvError(libvirt.ErrXMLError, "%v", err)
+	}
+	if _, exists := vols[v.Name]; exists {
+		return libvirt.StorageVol{}, lvError(libvirt.ErrStorageVolExist, "storage volume '%s' exists already", v.Name)
+	}
+	fv := &fakeVol{name: v.Name, format: v.Target.Format.Type, capacity: v.Capacity.Value}
+	if v.BackingStore != nil {
+		fv.backing = v.BackingStore.Path
+	}
+	vols[v.Name] = fv
+	return libvirt.StorageVol{Pool: pool.Name, Name: v.Name, Key: f.poolPath + "/" + v.Name}, nil
+}
+
+func (f *fakeAPI) StorageVolUpload(vol libvirt.StorageVol, r io.Reader, _, _ uint64, _ libvirt.StorageVolUploadFlags) error {
+	f.mu.Lock()
+	if err := f.enter("StorageVolUpload"); err != nil {
+		f.mu.Unlock()
+		return err
+	}
+	fv, ok := f.pools[vol.Pool][vol.Name]
+	hook := f.uploadHook
+	f.mu.Unlock()
+	if !ok {
+		return lvError(libvirt.ErrNoStorageVol, "no vol %s", vol.Name)
+	}
+	if hook != nil {
+		if err := hook(vol.Name, r); err != nil {
+			return err
+		}
+	}
+	// Read outside the lock: the stream may be a slow HTTP body.
+	data, err := io.ReadAll(r)
+	if err != nil {
+		return fmt.Errorf("reading upload stream: %w", err)
+	}
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	fv.data = data
+	return nil
+}
+
+func (f *fakeAPI) StorageVolDownload(vol libvirt.StorageVol, w io.Writer, _, _ uint64, _ libvirt.StorageVolDownloadFlags) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StorageVolDownload"); err != nil {
+		return err
+	}
+	fv, ok := f.pools[vol.Pool][vol.Name]
+	if !ok {
+		return lvError(libvirt.ErrNoStorageVol, "no vol %s", vol.Name)
+	}
+	_, err := io.Copy(w, bytes.NewReader(fv.data))
+	return err
+}
+
+func (f *fakeAPI) StorageVolDelete(vol libvirt.StorageVol, _ libvirt.StorageVolDeleteFlags) error {
+	f.mu.Lock()
+	defer f.mu.Unlock()
+	if err := f.enter("StorageVolDelete"); err != nil {
+		return err
+	}
+	if _, ok := f.pools[vol.Pool][vol.Name]; !ok {
+		return lvError(libvirt.ErrNoStorageVol, "no vol %s", vol.Name)
+	}
+	delete(f.pools[vol.Pool], vol.Name)
+	return nil
+}