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Merge pull request #3113 from dmcgowan/upstream-redis-fixes

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Redis cache fixes and metrics
This commit is contained in:
Derek McGowan 2020-03-09 13:36:53 -07:00 committed by GitHub
commit 581be91482
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GPG key ID: 4AEE18F83AFDEB23
6 changed files with 238 additions and 139 deletions
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66
registry/storage/blobcachemetrics.go
View file

@ -1,66 +0,0 @@
package storage
import (
"context"
"expvar"
"sync/atomic"
dcontext "github.com/docker/distribution/context"
"github.com/docker/distribution/registry/storage/cache"
)
type blobStatCollector struct {
metrics cache.Metrics
}
func (bsc *blobStatCollector) Hit() {
atomic.AddUint64(&bsc.metrics.Requests, 1)
atomic.AddUint64(&bsc.metrics.Hits, 1)
}
func (bsc *blobStatCollector) Miss() {
atomic.AddUint64(&bsc.metrics.Requests, 1)
atomic.AddUint64(&bsc.metrics.Misses, 1)
}
func (bsc *blobStatCollector) Metrics() cache.Metrics {
return bsc.metrics
}
func (bsc *blobStatCollector) Logger(ctx context.Context) cache.Logger {
return dcontext.GetLogger(ctx)
}
// blobStatterCacheMetrics keeps track of cache metrics for blob descriptor
// cache requests. Note this is kept globally and made available via expvar.
// For more detailed metrics, its recommend to instrument a particular cache
// implementation.
var blobStatterCacheMetrics cache.MetricsTracker = &blobStatCollector{}
func init() {
registry := expvar.Get("registry")
if registry == nil {
registry = expvar.NewMap("registry")
}
cache := registry.(*expvar.Map).Get("cache")
if cache == nil {
cache = &expvar.Map{}
cache.(*expvar.Map).Init()
registry.(*expvar.Map).Set("cache", cache)
}
storage := cache.(*expvar.Map).Get("storage")
if storage == nil {
storage = &expvar.Map{}
storage.(*expvar.Map).Init()
cache.(*expvar.Map).Set("storage", storage)
}
storage.(*expvar.Map).Set("blobdescriptor", expvar.Func(func() interface{} {
// no need for synchronous access: the increments are atomic and
// during reading, we don't care if the data is up to date. The
// numbers will always *eventually* be reported correctly.
return blobStatterCacheMetrics
}))
}

131
registry/storage/cache/cache_test.go vendored Normal file
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@ -0,0 +1,131 @@
package cache
import (
"context"
"errors"
"testing"
"github.com/docker/distribution"
digest "github.com/opencontainers/go-digest"
)
func TestCacheSet(t *testing.T) {
cache := newTestStatter()
backend := newTestStatter()
st := NewCachedBlobStatter(cache, backend)
ctx := context.Background()
dgst := digest.Digest("dontvalidate")
_, err := st.Stat(ctx, dgst)
if err != distribution.ErrBlobUnknown {
t.Fatalf("Unexpected error %v, expected %v", err, distribution.ErrBlobUnknown)
}
desc := distribution.Descriptor{
Digest: dgst,
}
if err := backend.SetDescriptor(ctx, dgst, desc); err != nil {
t.Fatal(err)
}
actual, err := st.Stat(ctx, dgst)
if err != nil {
t.Fatal(err)
}
if actual.Digest != desc.Digest {
t.Fatalf("Unexpected descriptor %v, expected %v", actual, desc)
}
if len(cache.sets) != 1 || len(cache.sets[dgst]) == 0 {
t.Fatalf("Expected cache set")
}
if cache.sets[dgst][0].Digest != desc.Digest {
t.Fatalf("Unexpected descriptor %v, expected %v", cache.sets[dgst][0], desc)
}
desc2 := distribution.Descriptor{
Digest: digest.Digest("dontvalidate 2"),
}
cache.sets[dgst] = append(cache.sets[dgst], desc2)
actual, err = st.Stat(ctx, dgst)
if err != nil {
t.Fatal(err)
}
if actual.Digest != desc2.Digest {
t.Fatalf("Unexpected descriptor %v, expected %v", actual, desc)
}
}
func TestCacheError(t *testing.T) {
cache := newErrTestStatter(errors.New("cache error"))
backend := newTestStatter()
st := NewCachedBlobStatter(cache, backend)
ctx := context.Background()
dgst := digest.Digest("dontvalidate")
_, err := st.Stat(ctx, dgst)
if err != distribution.ErrBlobUnknown {
t.Fatalf("Unexpected error %v, expected %v", err, distribution.ErrBlobUnknown)
}
desc := distribution.Descriptor{
Digest: dgst,
}
if err := backend.SetDescriptor(ctx, dgst, desc); err != nil {
t.Fatal(err)
}
actual, err := st.Stat(ctx, dgst)
if err != nil {
t.Fatal(err)
}
if actual.Digest != desc.Digest {
t.Fatalf("Unexpected descriptor %v, expected %v", actual, desc)
}
if len(cache.sets) > 0 {
t.Fatalf("Set should not be called after stat error")
}
}
func newTestStatter() *testStatter {
return &testStatter{
stats: []digest.Digest{},
sets: map[digest.Digest][]distribution.Descriptor{},
}
}
func newErrTestStatter(err error) *testStatter {
return &testStatter{
sets: map[digest.Digest][]distribution.Descriptor{},
err: err,
}
}
type testStatter struct {
stats []digest.Digest
sets map[digest.Digest][]distribution.Descriptor
err error
}
func (s *testStatter) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
if s.err != nil {
return distribution.Descriptor{}, s.err
}
if set := s.sets[dgst]; len(set) > 0 {
return set[len(set)-1], nil
}
return distribution.Descriptor{}, distribution.ErrBlobUnknown
}
func (s *testStatter) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
s.sets[dgst] = append(s.sets[dgst], desc)
return s.err
}
func (s *testStatter) Clear(ctx context.Context, dgst digest.Digest) error {
return s.err
}

4
registry/storage/cache/cachecheck/suite.go vendored
View file

@ -54,6 +54,10 @@ func checkBlobDescriptorCacheEmptyRepository(ctx context.Context, t *testing.T,
t.Fatalf("expected error checking for cache item with empty digest: %v", err)
}
if _, err := cache.Stat(ctx, "sha384:cba111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111"); err != distribution.ErrBlobUnknown {
t.Fatalf("expected unknown blob error with uncached repo: %v", err)
}
if _, err := cache.Stat(ctx, "sha384:abc111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111"); err != distribution.ErrBlobUnknown {
t.Fatalf("expected unknown blob error with empty repo: %v", err)
}

86
registry/storage/cache/cachedblobdescriptorstore.go vendored
View file

@ -4,39 +4,14 @@ import (
"context"
"github.com/docker/distribution"
dcontext "github.com/docker/distribution/context"
prometheus "github.com/docker/distribution/metrics"
"github.com/opencontainers/go-digest"
)
// Metrics is used to hold metric counters
// related to the number of times a cache was
// hit or missed.
type Metrics struct {
Requests uint64
Hits uint64
Misses uint64
}
// Logger can be provided on the MetricsTracker to log errors.
//
// Usually, this is just a proxy to dcontext.GetLogger.
type Logger interface {
Errorf(format string, args ...interface{})
}
// MetricsTracker represents a metric tracker
// which simply counts the number of hits and misses.
type MetricsTracker interface {
Hit()
Miss()
Metrics() Metrics
Logger(context.Context) Logger
}
type cachedBlobStatter struct {
cache distribution.BlobDescriptorService
backend distribution.BlobDescriptorService
tracker MetricsTracker
}
var (
@ -53,47 +28,36 @@ func NewCachedBlobStatter(cache distribution.BlobDescriptorService, backend dist
}
}
// NewCachedBlobStatterWithMetrics creates a new statter which prefers a cache and
// falls back to a backend. Hits and misses will send to the tracker.
func NewCachedBlobStatterWithMetrics(cache distribution.BlobDescriptorService, backend distribution.BlobDescriptorService, tracker MetricsTracker) distribution.BlobStatter {
return &cachedBlobStatter{
cache: cache,
backend: backend,
tracker: tracker,
}
}
func (cbds *cachedBlobStatter) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
cacheCount.WithValues("Request").Inc(1)
desc, err := cbds.cache.Stat(ctx, dgst)
if err != nil {
if err != distribution.ErrBlobUnknown {
logErrorf(ctx, cbds.tracker, "error retrieving descriptor from cache: %v", err)
}
goto fallback
}
// try getting from cache
desc, cacheErr := cbds.cache.Stat(ctx, dgst)
if cacheErr == nil {
cacheCount.WithValues("Hit").Inc(1)
if cbds.tracker != nil {
cbds.tracker.Hit()
}
return desc, nil
fallback:
cacheCount.WithValues("Miss").Inc(1)
if cbds.tracker != nil {
cbds.tracker.Miss()
}
desc, err = cbds.backend.Stat(ctx, dgst)
// couldn't get from cache; get from backend
desc, err := cbds.backend.Stat(ctx, dgst)
if err != nil {
return desc, err
}
if cacheErr == distribution.ErrBlobUnknown {
// cache doesn't have info. update it with info got from backend
cacheCount.WithValues("Miss").Inc(1)
if err := cbds.cache.SetDescriptor(ctx, dgst, desc); err != nil {
logErrorf(ctx, cbds.tracker, "error adding descriptor %v to cache: %v", desc.Digest, err)
dcontext.GetLoggerWithField(ctx, "blob", dgst).WithError(err).Error("error from cache setting desc")
}
// we don't need to return cache error upstream if any. continue returning value from backend
} else {
// unknown error from cache. just log and error. do not store cache as it may be trigger many set calls
dcontext.GetLoggerWithField(ctx, "blob", dgst).WithError(cacheErr).Error("error from cache stat(ing) blob")
cacheCount.WithValues("Error").Inc(1)
}
return desc, err
return desc, nil
}
func (cbds *cachedBlobStatter) Clear(ctx context.Context, dgst digest.Digest) error {
@ -111,19 +75,7 @@ func (cbds *cachedBlobStatter) Clear(ctx context.Context, dgst digest.Digest) er
func (cbds *cachedBlobStatter) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
if err := cbds.cache.SetDescriptor(ctx, dgst, desc); err != nil {
logErrorf(ctx, cbds.tracker, "error adding descriptor %v to cache: %v", desc.Digest, err)
dcontext.GetLoggerWithField(ctx, "blob", dgst).WithError(err).Error("error from cache setting desc")
}
return nil
}
func logErrorf(ctx context.Context, tracker MetricsTracker, format string, args ...interface{}) {
if tracker == nil {
return
}
logger := tracker.Logger(ctx)
if logger == nil {
return
}
logger.Errorf(format, args...)
}

69
registry/storage/cache/metrics/prom.go vendored Normal file
View file

@ -0,0 +1,69 @@
package metrics
import (
"context"
"time"
"github.com/docker/distribution"
prometheus "github.com/docker/distribution/metrics"
"github.com/docker/distribution/registry/storage/cache"
"github.com/docker/go-metrics"
"github.com/opencontainers/go-digest"
)
type prometheusCacheProvider struct {
cache.BlobDescriptorCacheProvider
latencyTimer metrics.LabeledTimer
}
func NewPrometheusCacheProvider(wrap cache.BlobDescriptorCacheProvider, name, help string) cache.BlobDescriptorCacheProvider {
return &prometheusCacheProvider{
wrap,
// TODO: May want to have fine grained buckets since redis calls are generally <1ms and the default minimum bucket is 5ms.
prometheus.StorageNamespace.NewLabeledTimer(name, help, "operation"),
}
}
func (p *prometheusCacheProvider) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
start := time.Now()
d, e := p.BlobDescriptorCacheProvider.Stat(ctx, dgst)
p.latencyTimer.WithValues("Stat").UpdateSince(start)
return d, e
}
func (p *prometheusCacheProvider) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
start := time.Now()
e := p.BlobDescriptorCacheProvider.SetDescriptor(ctx, dgst, desc)
p.latencyTimer.WithValues("SetDescriptor").UpdateSince(start)
return e
}
type prometheusRepoCacheProvider struct {
distribution.BlobDescriptorService
latencyTimer metrics.LabeledTimer
}
func (p *prometheusRepoCacheProvider) Stat(ctx context.Context, dgst digest.Digest) (distribution.Descriptor, error) {
start := time.Now()
d, e := p.BlobDescriptorService.Stat(ctx, dgst)
p.latencyTimer.WithValues("RepoStat").UpdateSince(start)
return d, e
}
func (p *prometheusRepoCacheProvider) SetDescriptor(ctx context.Context, dgst digest.Digest, desc distribution.Descriptor) error {
start := time.Now()
e := p.BlobDescriptorService.SetDescriptor(ctx, dgst, desc)
p.latencyTimer.WithValues("RepoSetDescriptor").UpdateSince(start)
return e
}
func (p *prometheusCacheProvider) RepositoryScoped(repo string) (distribution.BlobDescriptorService, error) {
s, err := p.BlobDescriptorCacheProvider.RepositoryScoped(repo)
if err != nil {
return nil, err
}
return &prometheusRepoCacheProvider{
s,
p.latencyTimer,
}, nil
}

13
registry/storage/cache/redis/redis.go vendored
View file

@ -7,6 +7,7 @@ import (
"github.com/docker/distribution"
"github.com/docker/distribution/reference"
"github.com/docker/distribution/registry/storage/cache"
"github.com/docker/distribution/registry/storage/cache/metrics"
"github.com/garyburd/redigo/redis"
"github.com/opencontainers/go-digest"
)
@ -34,9 +35,13 @@ type redisBlobDescriptorService struct {
// NewRedisBlobDescriptorCacheProvider returns a new redis-based
// BlobDescriptorCacheProvider using the provided redis connection pool.
func NewRedisBlobDescriptorCacheProvider(pool *redis.Pool) cache.BlobDescriptorCacheProvider {
return &redisBlobDescriptorService{
return metrics.NewPrometheusCacheProvider(
&redisBlobDescriptorService{
pool: pool,
}
},
"cache_redis",
"Number of seconds taken by redis",
)
}
// RepositoryScoped returns the scoped cache.
@ -181,6 +186,10 @@ func (rsrbds *repositoryScopedRedisBlobDescriptorService) Stat(ctx context.Conte
// We allow a per repository mediatype, let's look it up here.
mediatype, err := redis.String(conn.Do("HGET", rsrbds.blobDescriptorHashKey(dgst), "mediatype"))
if err != nil {
if err == redis.ErrNil {
return distribution.Descriptor{}, distribution.ErrBlobUnknown
}
return distribution.Descriptor{}, err
}