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Refactor cached discovery client

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This commit is contained in:
Dan Mace
2017-06-27 11:31:32 -04:00
parent 8e7db3a0d3
commit 2639b75d84
4 changed files with 63 additions and 54 deletions
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21
pkg/controller/garbagecollector/memcachediscovery/BUILD → staging/src/k8s.io/client-go/discovery/cached/BUILD
View File

@@ -10,7 +10,7 @@ load(
go_test(
name = "go_default_test",
srcs = ["client_test.go"],
srcs = ["memcache_test.go"],
library = ":go_default_library",
tags = ["automanaged"],
deps = [
@@ -21,29 +21,16 @@ go_test(
go_library(
name = "go_default_library",
srcs = ["client.go"],
srcs = ["memcache.go"],
tags = ["automanaged"],
deps = [
"//vendor/github.com/emicklei/go-restful-swagger12:go_default_library",
"//vendor/github.com/go-openapi/spec:go_default_library",
"//vendor/github.com/golang/glog:go_default_library",
"//vendor/github.com/googleapis/gnostic/OpenAPIv2:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/apis/meta/v1:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/runtime/schema:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/util/runtime:go_default_library",
"//vendor/k8s.io/apimachinery/pkg/version:go_default_library",
"//vendor/k8s.io/client-go/discovery:go_default_library",
"//vendor/k8s.io/client-go/rest:go_default_library",
],
)
filegroup(
name = "package-srcs",
srcs = glob(["**"]),
tags = ["automanaged"],
visibility = ["//visibility:private"],
)
filegroup(
name = "all-srcs",
srcs = [":package-srcs"],
tags = ["automanaged"],
)

86
pkg/controller/garbagecollector/memcachediscovery/client.go → staging/src/k8s.io/client-go/discovery/cached/memcache.go
View File

@@ -14,28 +14,30 @@ See the License for the specific language governing permissions and
limitations under the License.
*/
// Package memcachediscovery includes a Client which is a CachedDiscoveryInterface.
package memcachediscovery
package cached
import (
"errors"
"fmt"
"sync"
"github.com/emicklei/go-restful-swagger12"
"github.com/go-openapi/spec"
"github.com/golang/glog"
"github.com/googleapis/gnostic/OpenAPIv2"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime/schema"
utilruntime "k8s.io/apimachinery/pkg/util/runtime"
"k8s.io/apimachinery/pkg/version"
"k8s.io/client-go/discovery"
restclient "k8s.io/client-go/rest"
)
// Client can Refresh() to stay up-to-date with discovery information. Before
// this is moved some place where it's easier to call, it needs to switch to a
// watch interface. Right now it will poll anytime Refresh() is called.
type Client struct {
// memCacheClient can Invalidate() to stay up-to-date with discovery
// information.
//
// TODO: Switch to a watch interface. Right now it will poll anytime
// Invalidate() is called.
type memCacheClient struct {
delegate discovery.DiscoveryInterface
lock sync.RWMutex
@@ -45,24 +47,28 @@ type Client struct {
}
var (
ErrCacheEmpty = errors.New("the cache has not been filled yet")
ErrCacheEmpty = errors.New("the cache has not been filled yet")
ErrCacheNotFound = errors.New("not found")
)
var _ discovery.CachedDiscoveryInterface = &Client{}
var _ discovery.CachedDiscoveryInterface = &memCacheClient{}
// ServerResourcesForGroupVersion returns the supported resources for a group and version.
func (d *Client) ServerResourcesForGroupVersion(groupVersion string) (*metav1.APIResourceList, error) {
func (d *memCacheClient) ServerResourcesForGroupVersion(groupVersion string) (*metav1.APIResourceList, error) {
d.lock.RLock()
defer d.lock.RUnlock()
if !d.cacheValid {
return nil, ErrCacheEmpty
}
cachedVal, ok := d.groupToServerResources[groupVersion]
if !ok {
return nil, ErrCacheEmpty
return nil, ErrCacheNotFound
}
return cachedVal, nil
}
// ServerResources returns the supported resources for all groups and versions.
func (d *Client) ServerResources() ([]*metav1.APIResourceList, error) {
func (d *memCacheClient) ServerResources() ([]*metav1.APIResourceList, error) {
apiGroups, err := d.ServerGroups()
if err != nil {
return nil, err
@@ -79,7 +85,7 @@ func (d *Client) ServerResources() ([]*metav1.APIResourceList, error) {
return result, nil
}
func (d *Client) ServerGroups() (*metav1.APIGroupList, error) {
func (d *memCacheClient) ServerGroups() (*metav1.APIGroupList, error) {
d.lock.RLock()
defer d.lock.RUnlock()
if d.groupList == nil {
@@ -88,51 +94,60 @@ func (d *Client) ServerGroups() (*metav1.APIGroupList, error) {
return d.groupList, nil
}
func (d *Client) RESTClient() restclient.Interface {
func (d *memCacheClient) RESTClient() restclient.Interface {
return d.delegate.RESTClient()
}
func (d *Client) ServerPreferredResources() ([]*metav1.APIResourceList, error) {
// TODO: Should this also be cached? The results seem more likely to be
// inconsistent with ServerGroups and ServerResources given the requirement to
// actively Invalidate.
func (d *memCacheClient) ServerPreferredResources() ([]*metav1.APIResourceList, error) {
return d.delegate.ServerPreferredResources()
}
func (d *Client) ServerPreferredNamespacedResources() ([]*metav1.APIResourceList, error) {
// TODO: Should this also be cached? The results seem more likely to be
// inconsistent with ServerGroups and ServerResources given the requirement to
// actively Invalidate.
func (d *memCacheClient) ServerPreferredNamespacedResources() ([]*metav1.APIResourceList, error) {
return d.delegate.ServerPreferredNamespacedResources()
}
func (d *Client) ServerVersion() (*version.Info, error) {
func (d *memCacheClient) ServerVersion() (*version.Info, error) {
return d.delegate.ServerVersion()
}
func (d *Client) SwaggerSchema(version schema.GroupVersion) (*swagger.ApiDeclaration, error) {
func (d *memCacheClient) SwaggerSchema(version schema.GroupVersion) (*swagger.ApiDeclaration, error) {
return d.delegate.SwaggerSchema(version)
}
func (d *Client) OpenAPISchema() (*spec.Swagger, error) {
func (d *memCacheClient) OpenAPISchema() (*openapi_v2.Document, error) {
return d.delegate.OpenAPISchema()
}
func (d *Client) Fresh() bool {
func (d *memCacheClient) Fresh() bool {
d.lock.RLock()
defer d.lock.RUnlock()
// Fresh is supposed to tell the caller whether or not to retry if the
// cache fails to find something. The idea here is that Refresh and/or
// Invalidate will be called periodically and therefore we'll always be
// returning the latest data. (And in the future we can watch and stay
// even more up-to-date.) So we only return false if the cache has
// never been filled.
// Fresh is supposed to tell the caller whether or not to retry if the cache
// fails to find something. The idea here is that Invalidate will be called
// periodically and therefore we'll always be returning the latest data. (And
// in the future we can watch and stay even more up-to-date.) So we only
// return false if the cache has never been filled.
return d.cacheValid
}
// Invalidate refreshes the cache, blocking calls until the cache has been
// refreshed. It would be trivial to make a version that does this in the
// background while continuing to respond to requests if needed.
func (d *Client) Invalidate() {
func (d *memCacheClient) Invalidate() {
d.lock.Lock()
defer d.lock.Unlock()
// TODO: Could this multiplicative set of calls be replaced by a single call
// to ServerResources? If it's possible for more than one resulting
// APIResourceList to have the same GroupVersion, the lists would need merged.
gl, err := d.delegate.ServerGroups()
if err != nil || len(gl.Groups) == 0 {
glog.V(2).Infof("Error getting current server API group list, will keep using cached value. (%v)", err)
utilruntime.HandleError(fmt.Errorf("couldn't get current server API group list; will keep using cached value. (%v)", err))
return
}
@@ -141,7 +156,7 @@ func (d *Client) Invalidate() {
for _, v := range g.Versions {
r, err := d.delegate.ServerResourcesForGroupVersion(v.GroupVersion)
if err != nil || len(r.APIResources) == 0 {
glog.V(2).Infof("Error getting resource list for %v: %v", v.GroupVersion, err)
utilruntime.HandleError(fmt.Errorf("couldn't get resource list for %v: %v", v.GroupVersion, err))
if cur, ok := d.groupToServerResources[v.GroupVersion]; ok {
// retain the existing list, if we had it.
r = cur
@@ -157,10 +172,13 @@ func (d *Client) Invalidate() {
d.cacheValid = true
}
// NewClient creates a new Client which caches discovery information in memory
// and will stay up-to-date if Invalidate is called with regularity.
func NewClient(delegate discovery.DiscoveryInterface) *Client {
return &Client{
// NewMemCacheClient creates a new CachedDiscoveryInterface which caches
// discovery information in memory and will stay up-to-date if Invalidate is
// called with regularity.
//
// NOTE: The client will NOT resort to live lookups on cache misses.
func NewMemCacheClient(delegate discovery.DiscoveryInterface) discovery.CachedDiscoveryInterface {
return &memCacheClient{
delegate: delegate,
groupToServerResources: map[string]*metav1.APIResourceList{},
}

4
pkg/controller/garbagecollector/memcachediscovery/client_test.go → staging/src/k8s.io/client-go/discovery/cached/memcache_test.go
View File

@@ -14,7 +14,7 @@ See the License for the specific language governing permissions and
limitations under the License.
*/
package memcachediscovery
package cached
import (
"errors"
@@ -77,7 +77,7 @@ func TestClient(t *testing.T) {
},
}
c := NewClient(fake)
c := NewMemCacheClient(fake)
g, err := c.ServerGroups()
if err == nil {
t.Errorf("Unexpected non-error.")

6
staging/src/k8s.io/client-go/discovery/discovery_client.go
View File

@@ -55,7 +55,11 @@ type DiscoveryInterface interface {
// CachedDiscoveryInterface is a DiscoveryInterface with cache invalidation and freshness.
type CachedDiscoveryInterface interface {
DiscoveryInterface
// Fresh returns true if no cached data was used that had been retrieved before the instantiation.
// Fresh is supposed to tell the caller whether or not to retry if the cache
// fails to find something (false = retry, true = no need to retry).
//
// TODO: this needs to be revisited, this interface can't be locked properly
// and doesn't make a lot of sense.
Fresh() bool
// Invalidate enforces that no cached data is used in the future that is older than the current time.
Invalidate()