Initial v1.0.0 commit

vendor/sigs.k8s.io/controller-runtime/pkg/client/split.go

@@ -0,0 +1,132 @@
+/*
+Copyright 2018 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package client
+
+import (
+	"context"
+	"strings"
+
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/apimachinery/pkg/runtime/schema"
+	"sigs.k8s.io/controller-runtime/pkg/client/apiutil"
+)
+
+// NewDelegatingClientInput encapsulates the input parameters to create a new delegating client.
+type NewDelegatingClientInput struct {
+	CacheReader     Reader
+	Client          Client
+	UncachedObjects []Object
+}
+
+// NewDelegatingClient creates a new delegating client.
+//
+// A delegating client forms a Client by composing separate reader, writer and
+// statusclient interfaces.  This way, you can have an Client that reads from a
+// cache and writes to the API server.
+func NewDelegatingClient(in NewDelegatingClientInput) (Client, error) {
+	uncachedGVKs := map[schema.GroupVersionKind]struct{}{}
+	for _, obj := range in.UncachedObjects {
+		gvk, err := apiutil.GVKForObject(obj, in.Client.Scheme())
+		if err != nil {
+			return nil, err
+		}
+		uncachedGVKs[gvk] = struct{}{}
+	}
+
+	return &delegatingClient{
+		scheme: in.Client.Scheme(),
+		mapper: in.Client.RESTMapper(),
+		Reader: &delegatingReader{
+			CacheReader:  in.CacheReader,
+			ClientReader: in.Client,
+			scheme:       in.Client.Scheme(),
+			uncachedGVKs: uncachedGVKs,
+		},
+		Writer:       in.Client,
+		StatusClient: in.Client,
+	}, nil
+}
+
+type delegatingClient struct {
+	Reader
+	Writer
+	StatusClient
+
+	scheme *runtime.Scheme
+	mapper meta.RESTMapper
+}
+
+// Scheme returns the scheme this client is using.
+func (d *delegatingClient) Scheme() *runtime.Scheme {
+	return d.scheme
+}
+
+// RESTMapper returns the rest mapper this client is using.
+func (d *delegatingClient) RESTMapper() meta.RESTMapper {
+	return d.mapper
+}
+
+// delegatingReader forms a Reader that will cause Get and List requests for
+// unstructured types to use the ClientReader while requests for any other type
+// of object with use the CacheReader.  This avoids accidentally caching the
+// entire cluster in the common case of loading arbitrary unstructured objects
+// (e.g. from OwnerReferences).
+type delegatingReader struct {
+	CacheReader  Reader
+	ClientReader Reader
+
+	uncachedGVKs map[schema.GroupVersionKind]struct{}
+	scheme       *runtime.Scheme
+}
+
+func (d *delegatingReader) shouldBypassCache(obj runtime.Object) (bool, error) {
+	gvk, err := apiutil.GVKForObject(obj, d.scheme)
+	if err != nil {
+		return false, err
+	}
+	// TODO: this is producing unsafe guesses that don't actually work,
+	// but it matches ~99% of the cases out there.
+	if meta.IsListType(obj) {
+		gvk.Kind = strings.TrimSuffix(gvk.Kind, "List")
+	}
+	_, isUncached := d.uncachedGVKs[gvk]
+	_, isUnstructured := obj.(*unstructured.Unstructured)
+	_, isUnstructuredList := obj.(*unstructured.UnstructuredList)
+	return isUncached || isUnstructured || isUnstructuredList, nil
+}
+
+// Get retrieves an obj for a given object key from the Kubernetes Cluster.
+func (d *delegatingReader) Get(ctx context.Context, key ObjectKey, obj Object) error {
+	if isUncached, err := d.shouldBypassCache(obj); err != nil {
+		return err
+	} else if isUncached {
+		return d.ClientReader.Get(ctx, key, obj)
+	}
+	return d.CacheReader.Get(ctx, key, obj)
+}
+
+// List retrieves list of objects for a given namespace and list options.
+func (d *delegatingReader) List(ctx context.Context, list ObjectList, opts ...ListOption) error {
+	if isUncached, err := d.shouldBypassCache(list); err != nil {
+		return err
+	} else if isUncached {
+		return d.ClientReader.List(ctx, list, opts...)
+	}
+	return d.CacheReader.List(ctx, list, opts...)
+}