zero: resource bundle reconciler (#4445)

internal/zero/reconciler/reconciler.go

@@ -0,0 +1,34 @@
+package reconciler
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/pomerium/pomerium/pkg/grpc/databroker"
+)
+
+// Reconcile reconciles the target and current record sets with the databroker.
+func Reconcile(
+	ctx context.Context,
+	client databroker.DataBrokerServiceClient,
+	target, current RecordSetBundle[DatabrokerRecord],
+) error {
+	updates := NewDatabrokerChangeSet()
+
+	for _, rec := range current.GetRemoved(target).Flatten() {
+		updates.Remove(rec.GetType(), rec.GetID())
+	}
+	for _, rec := range current.GetModified(target).Flatten() {
+		updates.Upsert(rec.V)
+	}
+	for _, rec := range current.GetAdded(target).Flatten() {
+		updates.Upsert(rec.V)
+	}
+
+	err := ApplyChanges(ctx, client, updates)
+	if err != nil {
+		return fmt.Errorf("apply databroker changes: %w", err)
+	}
+
+	return nil
+}