[DRAFT] Improved Schema Definition Cache

go.mod

@@ -12,6 +12,7 @@ replace (
 require (
 	github.com/adrg/xdg v0.4.0
 	github.com/golang/mock v1.6.0
+	github.com/google/gnostic v0.5.7-v3refs
 	github.com/gorilla/mux v1.8.0
 	github.com/gorilla/websocket v1.5.0
 	github.com/pborman/uuid v1.2.1
@@ -28,6 +29,7 @@ require (
 	github.com/urfave/cli v1.22.14
 	github.com/urfave/cli/v2 v2.25.7
 	golang.org/x/sync v0.3.0
+	gopkg.in/yaml.v3 v3.0.1
 	k8s.io/api v0.27.4
 	k8s.io/apiextensions-apiserver v0.27.4
 	k8s.io/apimachinery v0.27.4
@@ -56,7 +58,6 @@ require (
 	github.com/go-openapi/swag v0.22.3 // indirect
 	github.com/gogo/protobuf v1.3.2 // indirect
 	github.com/golang/protobuf v1.5.3 // indirect
-	github.com/google/gnostic v0.5.7-v3refs // indirect
 	github.com/google/go-cmp v0.5.9 // indirect
 	github.com/google/gofuzz v1.2.0 // indirect
 	github.com/google/uuid v1.3.0 // indirect
@@ -100,7 +101,6 @@ require (
 	google.golang.org/protobuf v1.31.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/yaml.v2 v2.4.0 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/component-base v0.27.4 // indirect
 	k8s.io/klog/v2 v2.100.1 // indirect
 	k8s.io/utils v0.0.0-20230209194617-a36077c30491 // indirect

pkg/debounce/refresher.go

@@ -0,0 +1,51 @@
+package debounce
+
+import (
+	"context"
+	"sync"
+	"time"
+
+	"github.com/sirupsen/logrus"
+)
+
+// Refreshable represents an object which can be refreshed. This should be protected by a mutex for concurrent operation.
+type Refreshable interface {
+	Refresh() error
+}
+
+// DebouncableRefresher is used to debounce multiple attempts to refresh a refreshable type.
+type DebouncableRefresher struct {
+	sync.Mutex
+	// Refreshable is any type that can be refreshed. The refresh method should by protected by a mutex internally.
+	Refreshable Refreshable
+	current     context.CancelFunc
+}
+
+// RefreshAfter requests a refresh after a certain time has passed. Subsequent calls to this method will
+// delay the requested refresh by the new duration. Note that this is a total override of the previous calls - calling
+// RefreshAfter(time.Second * 2) and then immediatley calling RefreshAfter(time.Microsecond * 1) will run a refresh
+// in one microsecond
+func (d *DebouncableRefresher) RefreshAfter(duration time.Duration) {
+	d.Lock()
+	defer d.Unlock()
+	ctx := context.Background()
+	ctx, cancel := context.WithCancel(ctx)
+	if d.current != nil {
+		d.current()
+	}
+	d.current = cancel
+	go func() {
+		timer := time.NewTimer(duration)
+		defer timer.Stop()
+		select {
+		case <-ctx.Done():
+			// this indicates that the context was cancelled. Do nothing.
+		case <-timer.C:
+			// note this can cause multiple refreshes to happen concurrently
+			err := d.Refreshable.Refresh()
+			if err != nil {
+				logrus.Errorf("failed to refresh with error: %v", err)
+			}
+		}
+	}()
+}

pkg/debounce/refresher_test.go

@@ -0,0 +1,44 @@
+package debounce
+
+import (
+	"fmt"
+	"sync/atomic"
+	"testing"
+	"time"
+
+	"github.com/stretchr/testify/require"
+)
+
+type refreshable struct {
+	wasRefreshed atomic.Bool
+	retErr       error
+}
+
+func (r *refreshable) Refresh() error {
+	r.wasRefreshed.Store(true)
+	return r.retErr
+}
+
+func TestRefreshAfter(t *testing.T) {
+	ref := refreshable{}
+	debounce := DebouncableRefresher{
+		Refreshable: &ref,
+	}
+	debounce.RefreshAfter(time.Millisecond * 2)
+	debounce.RefreshAfter(time.Microsecond * 2)
+	time.Sleep(time.Millisecond * 1)
+	require.True(t, ref.wasRefreshed.Load())
+	ref.wasRefreshed.Store(false)
+	time.Sleep(time.Millisecond * 2)
+	require.False(t, ref.wasRefreshed.Load())
+
+	ref = refreshable{
+		retErr: fmt.Errorf("Some error"),
+	}
+	debounce = DebouncableRefresher{
+		Refreshable: &ref,
+	}
+	debounce.RefreshAfter(time.Microsecond * 2)
+	time.Sleep(time.Millisecond * 1)
+	require.True(t, ref.wasRefreshed.Load())
+}

pkg/resources/schema.go

@@ -16,7 +16,6 @@ import (
 	"github.com/rancher/steve/pkg/resources/formatters"
 	"github.com/rancher/steve/pkg/resources/userpreferences"
 	"github.com/rancher/steve/pkg/schema"
-	steveschema "github.com/rancher/steve/pkg/schema"
 	"github.com/rancher/steve/pkg/stores/proxy"
 	"github.com/rancher/steve/pkg/summarycache"
 	corecontrollers "github.com/rancher/wrangler/pkg/generated/controllers/core/v1"
@@ -25,7 +24,7 @@ import (
 )
 
 func DefaultSchemas(ctx context.Context, baseSchema *types.APISchemas, ccache clustercache.ClusterCache,
-	cg proxy.ClientGetter, schemaFactory steveschema.Factory, serverVersion string) error {
+	cg proxy.ClientGetter, schemaFactory schema.Factory, serverVersion string) error {
 	counts.Register(baseSchema, ccache)
 	subscribe.Register(baseSchema, func(apiOp *types.APIRequest) *types.APISchemas {
 		user, ok := request.UserFrom(apiOp.Context())

pkg/schema/converter/crd.go

@@ -27,7 +27,9 @@ var (
 	}
 )
 
-func AddCustomResources(crd apiextv1.CustomResourceDefinitionClient, schemas map[string]*types.APISchema) error {
+// addCustomResources uses the openAPISchema defined on CRDs to provide field definitions to previously discovered schemas.
+// Note that this function does not create new schemas - it only adds details to resources already present in the schemas map.
+func addCustomResources(crd apiextv1.CustomResourceDefinitionClient, schemas map[string]*types.APISchema) error {
 	crds, err := crd.List(metav1.ListOptions{})
 	if err != nil {
 		return nil
@@ -41,14 +43,14 @@ func AddCustomResources(crd apiextv1.CustomResourceDefinitionClient, schemas map
 		group, kind := crd.Spec.Group, crd.Status.AcceptedNames.Kind
 
 		for _, version := range crd.Spec.Versions {
-			forVersion(&crd, group, kind, version, schemas)
+			forVersion(group, kind, version, schemas)
 		}
 	}
 
 	return nil
 }
 
-func forVersion(crd *v1.CustomResourceDefinition, group, kind string, version v1.CustomResourceDefinitionVersion, schemasMap map[string]*types.APISchema) {
+func forVersion(group, kind string, version v1.CustomResourceDefinitionVersion, schemasMap map[string]*types.APISchema) {
 	var versionColumns []table.Column
 	for _, col := range version.AdditionalPrinterColumns {
 		versionColumns = append(versionColumns, table.Column{
@@ -73,18 +75,6 @@ func forVersion(crd *v1.CustomResourceDefinition, group, kind string, version v1
 		attributes.SetColumns(schema, versionColumns)
 	}
 	if version.Schema != nil && version.Schema.OpenAPIV3Schema != nil {
-		if fieldsSchema := modelV3ToSchema(id, crd.Spec.Versions[0].Schema.OpenAPIV3Schema, schemasMap); fieldsSchema != nil {
-			for k, v := range staticFields {
-				fieldsSchema.ResourceFields[k] = v
-			}
-			for k, v := range fieldsSchema.ResourceFields {
-				if schema.ResourceFields == nil {
-					schema.ResourceFields = map[string]schemas.Field{}
-				}
-				if _, ok := schema.ResourceFields[k]; !ok {
-					schema.ResourceFields[k] = v
-				}
-			}
-		}
+		schema.Description = version.Schema.OpenAPIV3Schema.Description
 	}
 }