Fix a race condition in pull through cache population by removing the functionality

of readers joining current downloads.  Concurrent requests for the same blob
will not block, but only the first instance will be comitted locally.

Signed-off-by: Richard Scothern <richard.scothern@gmail.com>
This commit is contained in:
Richard Scothern 2015-09-18 16:11:35 -07:00
parent 4946d0d035
commit 515b9596e7
3 changed files with 260 additions and 175 deletions

View file

@ -1,10 +1,13 @@
package proxy
import (
"fmt"
"io/ioutil"
"math/rand"
"net/http"
"net/http/httptest"
"sync"
"testing"
"time"
"github.com/docker/distribution"
"github.com/docker/distribution/context"
@ -12,75 +15,119 @@ import (
"github.com/docker/distribution/registry/proxy/scheduler"
"github.com/docker/distribution/registry/storage"
"github.com/docker/distribution/registry/storage/cache/memory"
"github.com/docker/distribution/registry/storage/driver/filesystem"
"github.com/docker/distribution/registry/storage/driver/inmemory"
)
var sbsMu sync.Mutex
type statsBlobStore struct {
stats map[string]int
blobs distribution.BlobStore
}
func (sbs statsBlobStore) Put(ctx context.Context, mediaType string, p []byte) (distribution.Descriptor, error) {
sbsMu.Lock()
sbs.stats["put"]++
sbsMu.Unlock()
return sbs.blobs.Put(ctx, mediaType, p)
}
func (sbs statsBlobStore) Get(ctx context.Context, dgst digest.Digest) ([]byte, error) {
sbsMu.Lock()
sbs.stats["get"]++
sbsMu.Unlock()
return sbs.blobs.Get(ctx, dgst)
}
func (sbs statsBlobStore) Create(ctx context.Context) (distribution.BlobWriter, error) {
sbsMu.Lock()
sbs.stats["create"]++
sbsMu.Unlock()
return sbs.blobs.Create(ctx)
}
func (sbs statsBlobStore) Resume(ctx context.Context, id string) (distribution.BlobWriter, error) {
sbsMu.Lock()
sbs.stats["resume"]++
sbsMu.Unlock()
return sbs.blobs.Resume(ctx, id)
}
func (sbs statsBlobStore) Open(ctx context.Context, dgst digest.Digest) (distribution.ReadSeekCloser, error) {
sbsMu.Lock()
sbs.stats["open"]++
sbsMu.Unlock()
return sbs.blobs.Open(ctx, dgst)
}
func (sbs statsBlobStore) ServeBlob(ctx context.Context, w http.ResponseWriter, r *http.Request, dgst digest.Digest) error {
sbsMu.Lock()
sbs.stats["serveblob"]++
sbsMu.Unlock()
return sbs.blobs.ServeBlob(ctx, w, r, dgst)
}
func (sbs statsBlobStore) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
sbsMu.Lock()
sbs.stats["stat"]++
sbsMu.Unlock()
return sbs.blobs.Stat(ctx, dgst)
}
func (sbs statsBlobStore) Delete(ctx context.Context, dgst digest.Digest) error {
sbsMu.Lock()
sbs.stats["delete"]++
sbsMu.Unlock()
return sbs.blobs.Delete(ctx, dgst)
}
type testEnv struct {
inRemote []distribution.Descriptor
store proxyBlobStore
ctx context.Context
numUnique int
inRemote []distribution.Descriptor
store proxyBlobStore
ctx context.Context
}
func (te testEnv) LocalStats() *map[string]int {
func (te *testEnv) LocalStats() *map[string]int {
sbsMu.Lock()
ls := te.store.localStore.(statsBlobStore).stats
sbsMu.Unlock()
return &ls
}
func (te testEnv) RemoteStats() *map[string]int {
func (te *testEnv) RemoteStats() *map[string]int {
sbsMu.Lock()
rs := te.store.remoteStore.(statsBlobStore).stats
sbsMu.Unlock()
return &rs
}
// Populate remote store and record the digests
func makeTestEnv(t *testing.T, name string) testEnv {
func makeTestEnv(t *testing.T, name string) *testEnv {
ctx := context.Background()
localRegistry, err := storage.NewRegistry(ctx, inmemory.New(), storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()), storage.EnableRedirect, storage.DisableDigestResumption)
truthDir, err := ioutil.TempDir("", "truth")
if err != nil {
t.Fatalf("unable to create tempdir: %s", err)
}
cacheDir, err := ioutil.TempDir("", "cache")
if err != nil {
t.Fatalf("unable to create tempdir: %s", err)
}
// todo: create a tempfile area here
localRegistry, err := storage.NewRegistry(ctx, filesystem.New(truthDir), storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()), storage.EnableRedirect, storage.DisableDigestResumption)
if err != nil {
t.Fatalf("error creating registry: %v", err)
}
@ -89,7 +136,7 @@ func makeTestEnv(t *testing.T, name string) testEnv {
t.Fatalf("unexpected error getting repo: %v", err)
}
truthRegistry, err := storage.NewRegistry(ctx, inmemory.New(), storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()))
truthRegistry, err := storage.NewRegistry(ctx, filesystem.New(cacheDir), storage.BlobDescriptorCacheProvider(memory.NewInMemoryBlobDescriptorCacheProvider()))
if err != nil {
t.Fatalf("error creating registry: %v", err)
}
@ -116,33 +163,59 @@ func makeTestEnv(t *testing.T, name string) testEnv {
scheduler: s,
}
te := testEnv{
te := &testEnv{
store: proxyBlobStore,
ctx: ctx,
}
return te
}
func populate(t *testing.T, te *testEnv, blobCount int) {
var inRemote []distribution.Descriptor
for i := 0; i < blobCount; i++ {
bytes := []byte(fmt.Sprintf("blob%d", i))
func makeBlob(size int) []byte {
blob := make([]byte, size, size)
for i := 0; i < size; i++ {
blob[i] = byte('A' + rand.Int()%48)
}
return blob
}
desc, err := te.store.remoteStore.Put(te.ctx, "", bytes)
if err != nil {
t.Errorf("Put in store")
func init() {
rand.Seed(42)
}
func perm(m []distribution.Descriptor) []distribution.Descriptor {
for i := 0; i < len(m); i++ {
j := rand.Intn(i + 1)
tmp := m[i]
m[i] = m[j]
m[j] = tmp
}
return m
}
func populate(t *testing.T, te *testEnv, blobCount, size, numUnique int) {
var inRemote []distribution.Descriptor
for i := 0; i < numUnique; i++ {
bytes := makeBlob(size)
for j := 0; j < blobCount/numUnique; j++ {
desc, err := te.store.remoteStore.Put(te.ctx, "", bytes)
if err != nil {
t.Fatalf("Put in store")
}
inRemote = append(inRemote, desc)
}
inRemote = append(inRemote, desc)
}
te.inRemote = inRemote
te.numUnique = numUnique
}
func TestProxyStoreStat(t *testing.T) {
te := makeTestEnv(t, "foo/bar")
remoteBlobCount := 1
populate(t, &te, remoteBlobCount)
populate(t, te, remoteBlobCount, 10, 1)
localStats := te.LocalStats()
remoteStats := te.RemoteStats()
@ -164,43 +237,91 @@ func TestProxyStoreStat(t *testing.T) {
}
}
func TestProxyStoreServe(t *testing.T) {
func TestProxyStoreServeHighConcurrency(t *testing.T) {
te := makeTestEnv(t, "foo/bar")
remoteBlobCount := 1
populate(t, &te, remoteBlobCount)
blobSize := 200
blobCount := 10
numUnique := 1
populate(t, te, blobCount, blobSize, numUnique)
numClients := 16
testProxyStoreServe(t, te, numClients)
}
func TestProxyStoreServeMany(t *testing.T) {
te := makeTestEnv(t, "foo/bar")
blobSize := 200
blobCount := 10
numUnique := 4
populate(t, te, blobCount, blobSize, numUnique)
numClients := 4
testProxyStoreServe(t, te, numClients)
}
// todo(richardscothern): blobCount must be smaller than num clients
func TestProxyStoreServeBig(t *testing.T) {
te := makeTestEnv(t, "foo/bar")
blobSize := 2 << 20
blobCount := 4
numUnique := 2
populate(t, te, blobCount, blobSize, numUnique)
numClients := 4
testProxyStoreServe(t, te, numClients)
}
// testProxyStoreServe will create clients to consume all blobs
// populated in the truth store
func testProxyStoreServe(t *testing.T, te *testEnv, numClients int) {
localStats := te.LocalStats()
remoteStats := te.RemoteStats()
// Serveblob - pulls through blobs
for _, dr := range te.inRemote {
w := httptest.NewRecorder()
r, err := http.NewRequest("GET", "", nil)
if err != nil {
t.Fatal(err)
}
var wg sync.WaitGroup
err = te.store.ServeBlob(te.ctx, w, r, dr.Digest)
if err != nil {
t.Fatalf(err.Error())
}
for i := 0; i < numClients; i++ {
// Serveblob - pulls through blobs
wg.Add(1)
go func() {
defer wg.Done()
for _, remoteBlob := range te.inRemote {
w := httptest.NewRecorder()
r, err := http.NewRequest("GET", "", nil)
if err != nil {
t.Fatal(err)
}
dl, err := digest.FromBytes(w.Body.Bytes())
if err != nil {
t.Fatalf("Error making digest from blob")
}
if dl != dr.Digest {
t.Errorf("Mismatching blob fetch from proxy")
}
err = te.store.ServeBlob(te.ctx, w, r, remoteBlob.Digest)
if err != nil {
t.Fatalf(err.Error())
}
bodyBytes := w.Body.Bytes()
localDigest, err := digest.FromBytes(bodyBytes)
if err != nil {
t.Fatalf("Error making digest from blob")
}
if localDigest != remoteBlob.Digest {
t.Fatalf("Mismatching blob fetch from proxy")
}
}
}()
}
if (*localStats)["stat"] != remoteBlobCount && (*localStats)["create"] != remoteBlobCount {
t.Fatalf("unexpected local stats")
}
if (*remoteStats)["stat"] != remoteBlobCount && (*remoteStats)["open"] != remoteBlobCount {
t.Fatalf("unexpected local stats")
wg.Wait()
remoteBlobCount := len(te.inRemote)
if (*localStats)["stat"] != remoteBlobCount*numClients && (*localStats)["create"] != te.numUnique {
t.Fatal("Expected: stat:", remoteBlobCount*numClients, "create:", remoteBlobCount)
}
// Wait for any async storage goroutines to finish
time.Sleep(3 * time.Second)
remoteStatCount := (*remoteStats)["stat"]
remoteOpenCount := (*remoteStats)["open"]
// Serveblob - blobs come from local
for _, dr := range te.inRemote {
w := httptest.NewRecorder()
@ -223,15 +344,11 @@ func TestProxyStoreServe(t *testing.T) {
}
}
// Stat to find local, but no new blobs were created
if (*localStats)["stat"] != remoteBlobCount*2 && (*localStats)["create"] != remoteBlobCount*2 {
t.Fatalf("unexpected local stats")
}
localStats = te.LocalStats()
remoteStats = te.RemoteStats()
// Remote unchanged
if (*remoteStats)["stat"] != remoteBlobCount && (*remoteStats)["open"] != remoteBlobCount {
fmt.Printf("\tlocal=%#v, \n\tremote=%#v\n", localStats, remoteStats)
t.Fatalf("unexpected local stats")
// Ensure remote unchanged
if (*remoteStats)["stat"] != remoteStatCount && (*remoteStats)["open"] != remoteOpenCount {
t.Fatalf("unexpected remote stats: %#v", remoteStats)
}
}