Fixup pkg/cache with comments from #29

pkg/cache/cache.go

@@ -17,9 +17,8 @@ limitations under the License.
 package cache
 
 import (
-	"time"
-
 	"fmt"
+	"time"
 
 	"github.com/kubernetes-sigs/controller-runtime/pkg/cache/internal"
 	"github.com/kubernetes-sigs/controller-runtime/pkg/client"
@@ -35,9 +34,9 @@ import (
 
 var log = logf.KBLog.WithName("object-cache")
 
-// Cache implements Reader by reading objects from a cache populated by InformersMap
+// Cache implements CacheReader by reading objects from a cache populated by InformersMap
 type Cache interface {
-	// Cache implements the client Reader
+	// Cache implements the client CacheReader
 	client.Reader
 
 	// Cache implements InformersMap
@@ -82,13 +81,16 @@ type Options struct {
 	Resync *time.Duration
 }
 
-var _ Informers = &informerCache{}
-var _ client.Reader = &informerCache{}
-var _ Cache = &informerCache{}
+var defaultResyncTime = 10 * time.Hour
 
-// cache is a Kubernetes Object cache populated from InformersMap.  cache wraps a CacheProvider and InformersMap.
-type informerCache struct {
-	*internal.InformersMap
+// New initializes and returns a new Cache
+func New(config *rest.Config, opts Options) (Cache, error) {
+	opts, err := defaultOpts(config, opts)
+	if err != nil {
+		return nil, err
+	}
+	im := internal.NewInformersMap(config, opts.Scheme, opts.Mapper, *opts.Resync)
+	return &informerCache{InformersMap: im}, nil
 }
 
 func defaultOpts(config *rest.Config, opts Options) (Options, error) {
@@ -109,18 +111,7 @@ func defaultOpts(config *rest.Config, opts Options) (Options, error) {
 
 	// Default the resync period to 10 hours if unset
 	if opts.Resync == nil {
-		r := 10 * time.Hour
-		opts.Resync = &r
+		opts.Resync = &defaultResyncTime
 	}
 	return opts, nil
 }
-
-// New initializes and returns a new Cache
-func New(config *rest.Config, opts Options) (Cache, error) {
-	opts, err := defaultOpts(config, opts)
-	if err != nil {
-		return nil, err
-	}
-	im := internal.NewInformersMap(config, opts.Scheme, opts.Mapper, *opts.Resync)
-	return &informerCache{InformersMap: im}, nil
-}

pkg/cache/informers.go → pkg/cache/informer_cache.go

@@ -17,7 +17,9 @@ limitations under the License.
 package cache
 
 import (
+	"context"
 	"fmt"
+	"reflect"
 
 	"github.com/kubernetes-sigs/controller-runtime/pkg/cache/internal"
 	"github.com/kubernetes-sigs/controller-runtime/pkg/client"
@@ -28,6 +30,56 @@ import (
 	"k8s.io/client-go/tools/cache"
 )
 
+var _ Informers = &informerCache{}
+var _ client.Reader = &informerCache{}
+var _ Cache = &informerCache{}
+
+// informerCache is a Kubernetes Object cache populated from InformersMap.  cache wraps an InformersMap.
+type informerCache struct {
+	*internal.InformersMap
+}
+
+// Get implements Reader
+func (ip *informerCache) Get(ctx context.Context, key client.ObjectKey, out runtime.Object) error {
+	gvk, err := apiutil.GVKForObject(out, ip.Scheme)
+	if err != nil {
+		return err
+	}
+
+	cache, err := ip.InformersMap.Get(gvk, out)
+	if err != nil {
+		return err
+	}
+	return cache.Reader.Get(ctx, key, out)
+}
+
+// List implements Reader
+func (ip *informerCache) List(ctx context.Context, opts *client.ListOptions, out runtime.Object) error {
+	itemsPtr, err := apimeta.GetItemsPtr(out)
+	if err != nil {
+		return nil
+	}
+
+	// http://knowyourmeme.com/memes/this-is-fine
+	outType := reflect.Indirect(reflect.ValueOf(itemsPtr)).Type().Elem()
+	cacheType, ok := outType.(runtime.Object)
+	if !ok {
+		return fmt.Errorf("cannot get cache for %T, its element is not a runtime.Object", out)
+	}
+
+	gvk, err := apiutil.GVKForObject(out, ip.Scheme)
+	if err != nil {
+		return err
+	}
+
+	cache, err := ip.InformersMap.Get(gvk, cacheType)
+	if err != nil {
+		return err
+	}
+
+	return cache.Reader.List(ctx, opts, out)
+}
+
 // GetInformerForKind returns the informer for the GroupVersionKind
 func (ip *informerCache) GetInformerForKind(gvk schema.GroupVersionKind) (cache.SharedIndexInformer, error) {
 	// Map the gvk to an object

pkg/cache/internal/typed_reader.go → pkg/cache/internal/cache_reader.go

@@ -32,11 +32,11 @@ import (
 	"k8s.io/client-go/tools/cache"
 )
 
-// Reader is a Reader
-var _ client.Reader = &Reader{}
+// CacheReader is a CacheReader
+var _ client.Reader = &CacheReader{}
 
-// Reader wraps a cache.Index to implement the client.Reader interface for a single type
-type Reader struct {
+// CacheReader wraps a cache.Index to implement the client.CacheReader interface for a single type
+type CacheReader struct {
 	// indexer is the underlying indexer wrapped by this cache.
 	indexer cache.Indexer
 
@@ -45,7 +45,7 @@ type Reader struct {
 }
 
 // Get checks the indexer for the object and writes a copy of it if found
-func (c *Reader) Get(_ context.Context, key client.ObjectKey, out runtime.Object) error {
+func (c *CacheReader) Get(_ context.Context, key client.ObjectKey, out runtime.Object) error {
 	storeKey := objectKeyToStoreKey(key)
 
 	// Lookup the object from the indexer cache
@@ -86,7 +86,7 @@ func (c *Reader) Get(_ context.Context, key client.ObjectKey, out runtime.Object
 }
 
 // List lists items out of the indexer and writes them to out
-func (c *Reader) List(ctx context.Context, opts *client.ListOptions, out runtime.Object) error {
+func (c *CacheReader) List(ctx context.Context, opts *client.ListOptions, out runtime.Object) error {
 	var objs []interface{}
 	var err error
 
@@ -121,7 +121,7 @@ func (c *Reader) List(ctx context.Context, opts *client.ListOptions, out runtime
 	return apimeta.SetList(out, outItems)
 }
 
-func (c *Reader) getListItems(objs []interface{}, labelSel labels.Selector) ([]runtime.Object, error) {
+func (c *CacheReader) getListItems(objs []interface{}, labelSel labels.Selector) ([]runtime.Object, error) {
 	outItems := make([]runtime.Object, 0, len(objs))
 	for _, item := range objs {
 		obj, isObj := item.(runtime.Object)

pkg/cache/internal/factory.go → pkg/cache/internal/informers_map.go

@@ -54,8 +54,8 @@ type MapEntry struct {
 	// Informer is the cached informer
 	Informer cache.SharedIndexInformer
 
-	// Reader wraps Informer and implements the Reader interface for a single type
-	Reader Reader
+	// CacheReader wraps Informer and implements the CacheReader interface for a single type
+	Reader CacheReader
 }
 
 // InformersMap create and caches Informers for (runtime.Object, schema.GroupVersionKind) pairs.
@@ -122,7 +122,7 @@ func (ip *InformersMap) WaitForCacheSync(stop <-chan struct{}) bool {
 	return cache.WaitForCacheSync(stop, syncedFuncs...)
 }
 
-// Get will create a new Informer and added it to the map of InformersMap if none exists.  Returns
+// Get will create a new Informer and add it to the map of InformersMap if none exists.  Returns
 // the Informer from the map.
 func (ip *InformersMap) Get(gvk schema.GroupVersionKind, obj runtime.Object) (*MapEntry, error) {
 	// Return the informer if it is found
@@ -137,7 +137,7 @@ func (ip *InformersMap) Get(gvk schema.GroupVersionKind, obj runtime.Object) (*M
 	}
 
 	// Do the mutex part in its own function so we can use defer without blocking pieces that don't
-	// to be locked
+	// need to be locked
 	var sync bool
 	i, err := func() (*MapEntry, error) {
 		ip.mu.Lock()
@@ -161,7 +161,7 @@ func (ip *InformersMap) Get(gvk schema.GroupVersionKind, obj runtime.Object) (*M
 		ni := cache.NewSharedIndexInformer(lw, obj, ip.resync, cache.Indexers{})
 		i = &MapEntry{
 			Informer: ni,
-			Reader:   Reader{indexer: ni.GetIndexer(), groupVersionKind: gvk}}
+			Reader:   CacheReader{indexer: ni.GetIndexer(), groupVersionKind: gvk}}
 		ip.informersByGVK[gvk] = i
 
 		// Start the Informer if need by