/
capturer.go
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/
capturer.go
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package relationship
import (
v1 "k8s.io/api/core/v1"
discoveryV1 "k8s.io/api/discovery/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/types"
"sigs.k8s.io/controller-runtime/pkg/client"
gatewayv1 "sigs.k8s.io/gateway-api/apis/v1"
"github.com/nginxinc/nginx-gateway-fabric/internal/framework/controller/index"
"github.com/nginxinc/nginx-gateway-fabric/internal/mode/static/state/graph"
)
//go:generate go run github.com/maxbrunsfeld/counterfeiter/v6 . Capturer
// Capturer captures relationships between Kubernetes objects and can be queried for whether a relationship exists
// for a given object.
//
// The relationships between HTTPRoutes -> Services are many to 1,
// so these relationships are tracked using a counter.
// A Service relationship exists if at least one HTTPRoute references it.
// An EndpointSlice relationship exists if its Service owner is referenced by at least one HTTPRoute.
//
// A Namespace relationship exists if it has labels that match a Gateway listener's label selector.
type Capturer interface {
Capture(obj client.Object)
Remove(resourceType client.Object, nsname types.NamespacedName)
Exists(resourceType client.Object, nsname types.NamespacedName) bool
}
type (
// routeToServicesMap maps HTTPRoute names to the set of Services it references.
routeToServicesMap map[types.NamespacedName]map[types.NamespacedName]struct{}
// serviceRefCountMap maps Service names to the number of HTTPRoutes that reference it.
serviceRefCountMap map[types.NamespacedName]int
// gatewayLabelSelectorsMap maps Gateways to the label selectors that their listeners use for allowed routes
gatewayLabelSelectorsMap map[types.NamespacedName][]labels.Selector
// namespaceCfg holds information about a namespace
// - labels that it contains
// - gateways that reference it (if labels match)
namespaceCfg struct {
labelMap map[string]string
gateways map[types.NamespacedName]struct{}
}
// namespaces is a collection of namespaces in the system
namespaces map[types.NamespacedName]namespaceCfg
)
func (n namespaceCfg) match() bool {
return len(n.gateways) > 0
}
// CapturerImpl implements the Capturer interface.
type CapturerImpl struct {
routesToServices routeToServicesMap
serviceRefCount serviceRefCountMap
gatewayLabelSelectors gatewayLabelSelectorsMap
namespaces namespaces
endpointSliceOwners map[types.NamespacedName]types.NamespacedName
}
// NewCapturerImpl creates a new instance of CapturerImpl.
func NewCapturerImpl() *CapturerImpl {
return &CapturerImpl{
routesToServices: make(routeToServicesMap),
serviceRefCount: make(serviceRefCountMap),
gatewayLabelSelectors: make(gatewayLabelSelectorsMap),
namespaces: make(namespaces),
endpointSliceOwners: make(map[types.NamespacedName]types.NamespacedName),
}
}
// Capture captures relationships for the given object.
func (c *CapturerImpl) Capture(obj client.Object) {
switch o := obj.(type) {
case *gatewayv1.HTTPRoute:
c.upsertForRoute(o)
case *discoveryV1.EndpointSlice:
svcName := index.GetServiceNameFromEndpointSlice(o)
if svcName != "" {
c.endpointSliceOwners[client.ObjectKeyFromObject(o)] = types.NamespacedName{
Namespace: o.Namespace,
Name: svcName,
}
}
case *gatewayv1.Gateway:
var selectors []labels.Selector
for _, listener := range o.Spec.Listeners {
if selector := graph.GetAllowedRouteLabelSelector(listener); selector != nil {
convertedSelector, err := metav1.LabelSelectorAsSelector(selector)
if err == nil {
selectors = append(selectors, convertedSelector)
}
}
}
gatewayName := client.ObjectKeyFromObject(o)
if len(selectors) > 0 {
c.gatewayLabelSelectors[gatewayName] = selectors
for ns, cfg := range c.namespaces {
var gatewayMatches bool
for _, selector := range selectors {
if selector.Matches(labels.Set(cfg.labelMap)) {
gatewayMatches = true
cfg.gateways[gatewayName] = struct{}{}
break
}
}
if !gatewayMatches {
// if gateway was previously referenced by this namespace, clean it up
delete(cfg.gateways, gatewayName)
}
c.namespaces[ns] = cfg
}
} else if _, exists := c.gatewayLabelSelectors[gatewayName]; exists {
// label selectors existed previously for this gateway, so clean up any references to them
c.removeGatewayLabelSelector(gatewayName)
}
case *v1.Namespace:
nsLabels := o.GetLabels()
gateways := c.matchingGateways(nsLabels)
nsCfg := namespaceCfg{
labelMap: nsLabels,
gateways: gateways,
}
c.namespaces[client.ObjectKeyFromObject(o)] = nsCfg
}
}
// Remove removes the relationship for the given object from the CapturerImpl.
func (c *CapturerImpl) Remove(resourceType client.Object, nsname types.NamespacedName) {
switch resourceType.(type) {
case *gatewayv1.HTTPRoute:
c.deleteForRoute(nsname)
case *discoveryV1.EndpointSlice:
delete(c.endpointSliceOwners, nsname)
case *gatewayv1.Gateway:
c.removeGatewayLabelSelector(nsname)
case *v1.Namespace:
delete(c.namespaces, nsname)
}
}
// Exists returns true if the given object has a relationship with another object.
func (c *CapturerImpl) Exists(resourceType client.Object, nsname types.NamespacedName) bool {
switch resourceType.(type) {
case *v1.Service:
return c.serviceRefCount[nsname] > 0
case *discoveryV1.EndpointSlice:
svcOwner, exists := c.endpointSliceOwners[nsname]
return exists && c.serviceRefCount[svcOwner] > 0
case *v1.Namespace:
cfg, exists := c.namespaces[nsname]
return exists && cfg.match()
}
return false
}
// GetRefCountForService is used for unit testing purposes. It is not exposed through the Capturer interface.
func (c *CapturerImpl) GetRefCountForService(svcName types.NamespacedName) int {
return c.serviceRefCount[svcName]
}
func (c *CapturerImpl) upsertForRoute(route *gatewayv1.HTTPRoute) {
oldServices := c.routesToServices[client.ObjectKeyFromObject(route)]
newServices := getBackendServiceNamesFromRoute(route)
for svc := range oldServices {
if _, exist := newServices[svc]; !exist {
c.decrementRefCount(svc)
}
}
for svc := range newServices {
if _, exist := oldServices[svc]; !exist {
c.serviceRefCount[svc]++
}
}
c.routesToServices[client.ObjectKeyFromObject(route)] = newServices
}
func (c *CapturerImpl) deleteForRoute(routeName types.NamespacedName) {
services := c.routesToServices[routeName]
for svc := range services {
c.decrementRefCount(svc)
}
delete(c.routesToServices, routeName)
}
func (c *CapturerImpl) decrementRefCount(svcName types.NamespacedName) {
if count, exist := c.serviceRefCount[svcName]; exist {
if count == 1 {
delete(c.serviceRefCount, svcName)
return
}
c.serviceRefCount[svcName]--
}
}
func getBackendServiceNamesFromRoute(hr *gatewayv1.HTTPRoute) map[types.NamespacedName]struct{} {
svcNames := make(map[types.NamespacedName]struct{})
for _, rule := range hr.Spec.Rules {
for _, ref := range rule.BackendRefs {
if ref.Kind != nil && *ref.Kind != "Service" {
continue
}
ns := hr.Namespace
if ref.Namespace != nil {
ns = string(*ref.Namespace)
}
svcNames[types.NamespacedName{Namespace: ns, Name: string(ref.Name)}] = struct{}{}
}
}
return svcNames
}
// matchingGateways looks through all existing label selectors defined by listeners in a gateway,
// and if any matches are found, returns a map of those gateways
func (c *CapturerImpl) matchingGateways(labelMap map[string]string) map[types.NamespacedName]struct{} {
gateways := make(map[types.NamespacedName]struct{})
for gw, selectors := range c.gatewayLabelSelectors {
for _, selector := range selectors {
if selector.Matches(labels.Set(labelMap)) {
gateways[gw] = struct{}{}
break
}
}
}
return gateways
}
func (c *CapturerImpl) removeGatewayLabelSelector(gatewayName types.NamespacedName) {
delete(c.gatewayLabelSelectors, gatewayName)
for ns, cfg := range c.namespaces {
delete(cfg.gateways, gatewayName)
c.namespaces[ns] = cfg
}
}