wip: managed content cache

Signed-off-by: everettraven <everettraven@gmail.com>

internal/contentmanager/contentmanager.go

@@ -0,0 +1,104 @@
+package contentmanager
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/operator-framework/operator-controller/api/v1alpha1"
+	"k8s.io/apimachinery/pkg/api/meta"
+	"k8s.io/apimachinery/pkg/runtime"
+	"k8s.io/client-go/rest"
+	"sigs.k8s.io/controller-runtime/pkg/cache"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/controller"
+	"sigs.k8s.io/controller-runtime/pkg/handler"
+	"sigs.k8s.io/controller-runtime/pkg/source"
+)
+
+type ContentManager interface {
+	// ManageContent will:
+	// 1. Create a new controller-runtime cache.Cache belonging to the provided ClusterExtension
+	// 2. For each object provided:
+	//   A. Use the provided controller.Controller to establish a watch for the resource
+	ManageContent(context.Context, controller.Controller, *v1alpha1.ClusterExtension, []client.Object) error
+	// RemoveManagedContent will:
+	// 1. Remove/stop cache and any sources/informers for the provided ClusterExtension
+	RemoveManagedContent(*v1alpha1.ClusterExtension) error
+}
+
+type RestConfigMapper func(context.Context, client.Object, *rest.Config) (*rest.Config, error)
+
+type instance struct {
+	rcm             RestConfigMapper
+	baseCfg         *rest.Config
+	extensionCaches map[string]cache.Cache
+	scheme          *runtime.Scheme
+	mapper          meta.RESTMapper
+}
+
+func New(rcm RestConfigMapper, cfg *rest.Config, scheme *runtime.Scheme, mapper meta.RESTMapper) ContentManager {
+	return &instance{
+		rcm:             rcm,
+		baseCfg:         cfg,
+		extensionCaches: make(map[string]cache.Cache),
+		scheme:          scheme,
+		mapper:          mapper,
+	}
+}
+
+func (i *instance) ManageContent(ctx context.Context, ctrl controller.Controller, ce *v1alpha1.ClusterExtension, objs []client.Object) error {
+	cfg, err := i.rcm(ctx, ce, i.baseCfg)
+	if err != nil {
+		return fmt.Errorf("getting rest.Config for ClusterExtension %q: %w", ce.Name, err)
+	}
+
+	// TODO: add a http.RoundTripper to the config to ensure it is always using an up
+	// to date authentication token for the ServiceAccount token provided in the ClusterExtension.
+	// Maybe this should be handled by the RestConfigMapper?
+
+	c, err := cache.New(cfg, cache.Options{
+		// TODO: explore how we can dynamically build this scheme based on the provided
+		// resources to be managed. Using a top level scheme will not be sufficient as
+		// that means it will have to know of every type that could be watched on startup
+		Scheme: i.scheme,
+	})
+	if err != nil {
+		return fmt.Errorf("creating cache for ClusterExtension %q: %w", ce.Name, err)
+	}
+
+	for _, obj := range objs {
+		// TODO: Make sure we are sufficiently filtering
+		// the watches to cache the minimum amount of information necessary.
+		// This will likely result in some default label selection option being placed
+		// in the cache configuration.
+		err = ctrl.Watch(
+			source.Kind(
+				c,
+				obj,
+				handler.TypedEnqueueRequestForOwner[client.Object](
+					i.scheme,
+					i.mapper,
+					ce,
+				),
+				nil,
+			),
+		)
+		if err != nil {
+			return fmt.Errorf("creating watch for ClusterExtension %q managed resource %s: %w", ce.Name, obj.GetObjectKind().GroupVersionKind(), err)
+		}
+	}
+
+	go c.Start(ctx)
+	// TODO: If a cache already exists, we should ensure that we are removing informers
+	// for any resources that no longer need to be watched. Ideally we would not always create
+	// a new cache, but it could be acceptable to do so and leave optimization as a follow up item.
+	// if we continue to create a new cache every time, we should ensure that we are appropriately stopping
+	// the cache and configured sources _before_ replacing it in the mapping.
+	i.extensionCaches[ce.Name] = c
+
+	return nil
+}
+
+func (i *instance) RemoveManagedContent(ce *v1alpha1.ClusterExtension) error {
+	panic("Not implemented!")
+}