Adds bundle data snapshotting for resolution

We now snapshot bundle data in the client for the duration of single resolution.

This reduces reads (from network or cache) and unmarshalling
since data in memory. And it also ensures that different variable sources
involved in the resolution process have the same view of catalogs and bundles.

Signed-off-by: Mikalai Radchuk <mradchuk@redhat.com>

cmd/manager/main.go

@@ -112,9 +112,11 @@ func main() {
 	if err = (&controllers.OperatorReconciler{
 		Client: cl,
 		Scheme: mgr.GetScheme(),
-		Resolver: solver.NewDeppySolver(
-			controllers.NewVariableSource(cl, catalogClient),
-		),
+		NewSolver: func() *solver.DeppySolver {
+			return solver.NewDeppySolver(
+				controllers.NewVariableSource(cl, catalogclient.NewSnapshotClient(catalogClient)),
+			)
+		},
 	}).SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create controller", "controller", "Operator")
 		os.Exit(1)

internal/catalogmetadata/client/client.go

@@ -100,6 +100,34 @@ func (c *Client) Bundles(ctx context.Context) ([]*catalogmetadata.Bundle, error)
 	return allBundles, nil
 }
 
+func NewSnapshotClient(catalogClient *Client) *SnapshotClient {
+	return &SnapshotClient{
+		Client: catalogClient,
+	}
+}
+
+// SnapshotClient fetches data from catalogs and caches them for the lifetime of the
+// SnapshotClient instance. Meaning that if new catalog or new bundles get created
+// in between calls to the same instance of the client they will not appear in the result.
+// This is convenient for bundle resolution process where we want all components
+// to have the same view of catalogs.
+type SnapshotClient struct {
+	*Client
+	bundlesSnapshot []*catalogmetadata.Bundle
+}
+
+func (c *SnapshotClient) Bundles(ctx context.Context) ([]*catalogmetadata.Bundle, error) {
+	if c.bundlesSnapshot == nil {
+		allBundles, err := c.Client.Bundles(ctx)
+		if err != nil {
+			return nil, err
+		}
+		c.bundlesSnapshot = allBundles
+	}
+
+	return c.bundlesSnapshot, nil
+}
+
 func PopulateExtraFields(catalogName string, channels []*catalogmetadata.Channel, bundles []*catalogmetadata.Bundle) ([]*catalogmetadata.Bundle, error) {
 	bundlesMap := map[string]*catalogmetadata.Bundle{}
 	for i := range bundles {

internal/controllers/operator_controller.go

@@ -49,11 +49,18 @@ import (
 	olmvariables "github.com/operator-framework/operator-controller/internal/resolution/variables"
 )
 
+// BundleProvider provides the Bundles method through which we can retrieve
+// a list of Bundles from any source, generally from a catalog client of
+// some kind.
+type BundleProvider interface {
+	Bundles(ctx context.Context) ([]*catalogmetadata.Bundle, error)
+}
+
 // OperatorReconciler reconciles a Operator object
 type OperatorReconciler struct {
 	client.Client
-	Scheme   *runtime.Scheme
-	Resolver *solver.DeppySolver
+	Scheme    *runtime.Scheme
+	NewSolver func() *solver.DeppySolver
 }
 
 //+kubebuilder:rbac:groups=operators.operatorframework.io,resources=operators,verbs=get;list;watch
@@ -130,7 +137,7 @@ func (r *OperatorReconciler) reconcile(ctx context.Context, op *operatorsv1alpha
 		return ctrl.Result{}, nil
 	}
 	// run resolution
-	solution, err := r.Resolver.Solve(ctx)
+	solution, err := r.NewSolver().Solve(ctx)
 	if err != nil {
 		op.Status.InstalledBundleResource = ""
 		setInstalledStatusConditionUnknown(&op.Status.Conditions, "installation has not been attempted as resolution failed", op.GetGeneration())

internal/controllers/operator_controller_test.go

@@ -37,9 +37,13 @@ var _ = Describe("Operator Controller Test", func() {
 		ctx = context.Background()
 		fakeCatalogClient = testutil.NewFakeCatalogClient(testBundleList)
 		reconciler = &controllers.OperatorReconciler{
-			Client:   cl,
-			Scheme:   sch,
-			Resolver: solver.NewDeppySolver(controllers.NewVariableSource(cl, &fakeCatalogClient)),
+			Client: cl,
+			Scheme: sch,
+			NewSolver: func() *solver.DeppySolver {
+				return solver.NewDeppySolver(
+					controllers.NewVariableSource(cl, &fakeCatalogClient),
+				)
+			},
 		}
 	})
 	When("the operator does not exist", func() {