Adds new catalogmetadata package (#393)

* Adds new `catalogmetadata` package

At the moment it contains:
* Types which embed `declcfg.Package`, `declcfg.Channel` and `declcfg.Bundle`.
  Later we will be adding more methods to them (for unmarshalling properties, for example)
* A function to fetch metadata by scheme & catalog name
* `Filter` function which can filter all these 3 types using a given predicate
* `And`, `Or` and `Not` composite predicates to be used with `Filter`

Later we might expand/change this package to be more convinient in use with variable sources.

Signed-off-by: Mikalai Radchuk <[email protected]>

* Adds predicates and tests for them

Signed-off-by: Mikalai Radchuk <[email protected]>
Signed-off-by: dtfranz <[email protected]>

* Moves filter and predicates into a sub package

Signed-off-by: Mikalai Radchuk <[email protected]>

* Adds client to fetch bundles

Signed-off-by: Mikalai Radchuk <[email protected]>

* Adds sort subpackage to catalogmetadata

Signed-off-by: Mikalai Radchuk <[email protected]>

---------

Signed-off-by: Mikalai Radchuk <[email protected]>
Signed-off-by: dtfranz <[email protected]>

Author: m1kola

internal/catalogmetadata/client/client.go

@@ -0,0 +1,92 @@
+package client
+
+import (
+	"context"
+	"fmt"
+
+	"sigs.k8s.io/controller-runtime/pkg/client"
+
+	catalogd "github.com/operator-framework/catalogd/api/core/v1alpha1"
+	"github.com/operator-framework/operator-registry/alpha/declcfg"
+
+	"github.com/operator-framework/operator-controller/internal/catalogmetadata"
+)
+
+func NewClient(cl client.Client) *Client {
+	return &Client{cl: cl}
+}
+
+// Client is reading catalog metadata
+type Client struct {
+	// Note that eventually we will be reading from catalogd http API
+	// instead of kube API server. We will need to swap this implementation.
+	cl client.Client
+}
+
+func (c *Client) Bundles(ctx context.Context) ([]*catalogmetadata.Bundle, error) {
+	var allBundles []*catalogmetadata.Bundle
+
+	var catalogList catalogd.CatalogList
+	if err := c.cl.List(ctx, &catalogList); err != nil {
+		return nil, err
+	}
+	for _, catalog := range catalogList.Items {
+		channels, err := fetchCatalogMetadata[catalogmetadata.Channel](ctx, c.cl, catalog.Name, declcfg.SchemaChannel)
+		if err != nil {
+			return nil, err
+		}
+
+		bundles, err := fetchCatalogMetadata[catalogmetadata.Bundle](ctx, c.cl, catalog.Name, declcfg.SchemaBundle)
+		if err != nil {
+			return nil, err
+		}
+
+		bundles, err = populateExtraFields(catalog.Name, channels, bundles)
+		if err != nil {
+			return nil, err
+		}
+
+		allBundles = append(allBundles, bundles...)
+	}
+
+	return allBundles, nil
+}
+
+func fetchCatalogMetadata[T catalogmetadata.Schemas](ctx context.Context, cl client.Client, catalogName, schema string) ([]*T, error) {
+	var cmList catalogd.CatalogMetadataList
+	err := cl.List(ctx, &cmList, client.MatchingLabels{"catalog": catalogName, "schema": schema})
+	if err != nil {
+		return nil, err
+	}
+
+	content, err := catalogmetadata.Unmarshal[T](cmList.Items)
+	if err != nil {
+		return nil, fmt.Errorf("error unmarshalling catalog metadata: %s", err)
+	}
+
+	return content, nil
+}
+
+func populateExtraFields(catalogName string, channels []*catalogmetadata.Channel, bundles []*catalogmetadata.Bundle) ([]*catalogmetadata.Bundle, error) {
+	bundlesMap := map[string]*catalogmetadata.Bundle{}
+	for i := range bundles {
+		bundleKey := fmt.Sprintf("%s-%s", bundles[i].Package, bundles[i].Name)
+		bundlesMap[bundleKey] = bundles[i]
+
+		bundles[i].CatalogName = catalogName
+	}
+
+	for _, ch := range channels {
+		for _, chEntry := range ch.Entries {
+			bundleKey := fmt.Sprintf("%s-%s", ch.Package, chEntry.Name)
+			bundle, ok := bundlesMap[bundleKey]
+			if !ok {
+				return nil, fmt.Errorf("bundle %q not found in catalog %q (package %q, channel %q)", chEntry.Name, catalogName, ch.Package, ch.Name)
+			}
+
+			bundle.InChannels = append(bundle.InChannels, ch)
+		}
+	}
+
+	return bundles, nil
+}