istio

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// Copyright Istio Authors
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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//     http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package ingress
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import (
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	"errors"
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	"fmt"
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	"sort"
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	"strconv"
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	"strings"
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	"github.com/hashicorp/go-multierror"
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	corev1 "k8s.io/api/core/v1"
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	knetworking "k8s.io/api/networking/v1"
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	"istio.io/api/annotation"
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	meshconfig "istio.io/api/mesh/v1alpha1"
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	networking "istio.io/api/networking/v1alpha3"
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	"istio.io/istio/pkg/config"
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	"istio.io/istio/pkg/config/constants"
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	"istio.io/istio/pkg/config/labels"
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	"istio.io/istio/pkg/config/protocol"
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	"istio.io/istio/pkg/config/schema/gvk"
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	"istio.io/istio/pkg/kube/kclient"
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	"istio.io/istio/pkg/log"
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)
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const (
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	IstioIngressController = "istio.io/ingress-controller"
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)
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var errNotFound = errors.New("item not found")
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// EncodeIngressRuleName encodes an ingress rule name for a given ingress resource name,
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// as well as the position of the rule and path specified within it, counting from 1.
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// ruleNum == pathNum == 0 indicates the default backend specified for an ingress.
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func EncodeIngressRuleName(ingressName string, ruleNum, pathNum int) string {
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	return fmt.Sprintf("%s-%d-%d", ingressName, ruleNum, pathNum)
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}
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// decodeIngressRuleName decodes an ingress rule name previously encoded with EncodeIngressRuleName.
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func decodeIngressRuleName(name string) (ingressName string, ruleNum, pathNum int, err error) {
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	parts := strings.Split(name, "-")
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	if len(parts) < 3 {
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		err = fmt.Errorf("could not decode string into ingress rule name: %s", name)
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		return
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	}
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	ingressName = strings.Join(parts[0:len(parts)-2], "-")
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	ruleNum, ruleErr := strconv.Atoi(parts[len(parts)-2])
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	pathNum, pathErr := strconv.Atoi(parts[len(parts)-1])
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	if pathErr != nil || ruleErr != nil {
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		err = multierror.Append(
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			fmt.Errorf("could not decode string into ingress rule name: %s", name),
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			pathErr, ruleErr)
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		return
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	}
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	return
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}
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// ConvertIngressV1alpha3 converts from ingress spec to Istio Gateway
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func ConvertIngressV1alpha3(ingress knetworking.Ingress, mesh *meshconfig.MeshConfig, domainSuffix string) config.Config {
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	gateway := &networking.Gateway{}
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	gateway.Selector = getIngressGatewaySelector(mesh.IngressSelector, mesh.IngressService)
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	for i, tls := range ingress.Spec.TLS {
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		if tls.SecretName == "" {
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			log.Infof("invalid ingress rule %s:%s for hosts %q, no secretName defined", ingress.Namespace, ingress.Name, tls.Hosts)
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			continue
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		}
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		// TODO validation when multiple wildcard tls secrets are given
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		if len(tls.Hosts) == 0 {
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			tls.Hosts = []string{"*"}
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		}
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		gateway.Servers = append(gateway.Servers, &networking.Server{
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			Port: &networking.Port{
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				Number:   443,
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				Protocol: string(protocol.HTTPS),
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				Name:     fmt.Sprintf("https-443-ingress-%s-%s-%d", ingress.Name, ingress.Namespace, i),
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			},
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			Hosts: tls.Hosts,
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			Tls: &networking.ServerTLSSettings{
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				HttpsRedirect:  false,
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				Mode:           networking.ServerTLSSettings_SIMPLE,
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				CredentialName: tls.SecretName,
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			},
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		})
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	}
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	gateway.Servers = append(gateway.Servers, &networking.Server{
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		Port: &networking.Port{
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			Number:   80,
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			Protocol: string(protocol.HTTP),
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			Name:     fmt.Sprintf("http-80-ingress-%s-%s", ingress.Name, ingress.Namespace),
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		},
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		Hosts: []string{"*"},
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	})
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	gatewayConfig := config.Config{
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		Meta: config.Meta{
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			GroupVersionKind: gvk.Gateway,
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			Name:             ingress.Name + "-" + constants.IstioIngressGatewayName + "-" + ingress.Namespace,
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			Namespace:        IngressNamespace,
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			Domain:           domainSuffix,
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		},
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		Spec: gateway,
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	}
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	return gatewayConfig
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}
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// ConvertIngressVirtualService converts from ingress spec to Istio VirtualServices
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func ConvertIngressVirtualService(ingress knetworking.Ingress, domainSuffix string,
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	ingressByHost map[string]*config.Config, services kclient.Client[*corev1.Service],
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) {
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	// Ingress allows a single host - if missing '*' is assumed
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	// We need to merge all rules with a particular host across
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	// all ingresses, and return a separate VirtualService for each
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	// host.
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	for _, rule := range ingress.Spec.Rules {
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		if rule.HTTP == nil {
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			log.Infof("invalid ingress rule %s:%s for host %q, no paths defined", ingress.Namespace, ingress.Name, rule.Host)
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			continue
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		}
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		host := rule.Host
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		namePrefix := strings.Replace(host, ".", "-", -1)
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		if host == "" {
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			host = "*"
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		}
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		virtualService := &networking.VirtualService{
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			Hosts:    []string{host},
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			Gateways: []string{fmt.Sprintf("%s/%s-%s-%s", IngressNamespace, ingress.Name, constants.IstioIngressGatewayName, ingress.Namespace)},
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		}
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		httpRoutes := make([]*networking.HTTPRoute, 0, len(rule.HTTP.Paths))
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		for _, httpPath := range rule.HTTP.Paths {
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			httpMatch := &networking.HTTPMatchRequest{}
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			if httpPath.PathType != nil {
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				switch *httpPath.PathType {
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				case knetworking.PathTypeExact:
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					httpMatch.Uri = &networking.StringMatch{
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						MatchType: &networking.StringMatch_Exact{Exact: httpPath.Path},
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					}
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				case knetworking.PathTypePrefix:
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					// Optimize common case of / to not needed regex
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					httpMatch.Uri = &networking.StringMatch{
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						MatchType: &networking.StringMatch_Prefix{Prefix: httpPath.Path},
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					}
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				default:
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					// Fallback to the legacy string matching
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					// If the httpPath.Path is a wildcard path, Uri will be nil
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					httpMatch.Uri = createFallbackStringMatch(httpPath.Path)
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				}
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			} else {
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				httpMatch.Uri = createFallbackStringMatch(httpPath.Path)
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			}
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			httpRoute := ingressBackendToHTTPRoute(&httpPath.Backend, ingress.Namespace, domainSuffix, services)
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			if httpRoute == nil {
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				log.Infof("invalid ingress rule %s:%s for host %q, no backend defined for path", ingress.Namespace, ingress.Name, rule.Host)
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				continue
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			}
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			// Only create a match if Uri is not nil. HttpMatchRequest cannot be empty
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			if httpMatch.Uri != nil {
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				httpRoute.Match = []*networking.HTTPMatchRequest{httpMatch}
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			}
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			httpRoutes = append(httpRoutes, httpRoute)
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		}
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		virtualService.Http = httpRoutes
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		virtualServiceConfig := config.Config{
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			Meta: config.Meta{
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				GroupVersionKind: gvk.VirtualService,
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				Name:             namePrefix + "-" + ingress.Name + "-" + constants.IstioIngressGatewayName,
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				Namespace:        ingress.Namespace,
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				Domain:           domainSuffix,
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				Annotations:      map[string]string{constants.InternalRouteSemantics: constants.RouteSemanticsIngress},
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			},
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			Spec: virtualService,
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		}
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		old, f := ingressByHost[host]
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		if f {
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			vs := old.Spec.(*networking.VirtualService)
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			vs.Http = append(vs.Http, httpRoutes...)
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		} else {
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			ingressByHost[host] = &virtualServiceConfig
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		}
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		// sort routes to meet ingress route precedence requirements
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		// see https://kubernetes.io/docs/concepts/services-networking/ingress/#multiple-matches
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		vs := ingressByHost[host].Spec.(*networking.VirtualService)
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		sort.SliceStable(vs.Http, func(i, j int) bool {
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			var r1Len, r2Len int
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			var r1Ex, r2Ex bool
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			if vs.Http[i].Match != nil || len(vs.Http[i].Match) != 0 {
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				r1Len, r1Ex = getMatchURILength(vs.Http[i].Match[0])
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			}
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			if vs.Http[j].Match != nil || len(vs.Http[j].Match) != 0 {
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				r2Len, r2Ex = getMatchURILength(vs.Http[j].Match[0])
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			}
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			// TODO: default at the end
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			if r1Len == r2Len {
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				return r1Ex && !r2Ex
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			}
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			return r1Len > r2Len
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		})
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	}
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	// Matches * and "/". Currently not supported - would conflict
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	// with any other explicit VirtualService.
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	if ingress.Spec.DefaultBackend != nil {
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		log.Infof("Ignore default wildcard ingress, use VirtualService %s:%s",
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			ingress.Namespace, ingress.Name)
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	}
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}
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// getMatchURILength returns the length of matching path, and whether the match type is EXACT
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func getMatchURILength(match *networking.HTTPMatchRequest) (length int, exact bool) {
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	uri := match.GetUri()
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	switch uri.GetMatchType().(type) {
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	case *networking.StringMatch_Exact:
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		return len(uri.GetExact()), true
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	case *networking.StringMatch_Prefix:
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		return len(uri.GetPrefix()), false
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	}
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	// should not happen
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	return -1, false
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}
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func ingressBackendToHTTPRoute(backend *knetworking.IngressBackend, namespace string,
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	domainSuffix string, services kclient.Client[*corev1.Service],
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) *networking.HTTPRoute {
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	if backend == nil {
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		return nil
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	}
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	port := &networking.PortSelector{}
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	if backend.Service == nil {
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		log.Infof("backend service must be specified")
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		return nil
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	}
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	if backend.Service.Port.Number > 0 {
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		port.Number = uint32(backend.Service.Port.Number)
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	} else {
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		resolvedPort, err := resolveNamedPort(backend, namespace, services)
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		if err != nil {
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			log.Infof("failed to resolve named port %s, error: %v", backend.Service.Port.Name, err)
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			return nil
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		}
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		port.Number = uint32(resolvedPort)
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	}
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	return &networking.HTTPRoute{
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		Route: []*networking.HTTPRouteDestination{
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			{
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				Destination: &networking.Destination{
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					Host: fmt.Sprintf("%s.%s.svc.%s", backend.Service.Name, namespace, domainSuffix),
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					Port: port,
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				},
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				Weight: 100,
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			},
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		},
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	}
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}
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func resolveNamedPort(backend *knetworking.IngressBackend, namespace string, services kclient.Client[*corev1.Service]) (int32, error) {
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	svc := services.Get(backend.Service.Name, namespace)
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	if svc == nil {
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		return 0, errNotFound
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	}
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	for _, port := range svc.Spec.Ports {
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		if port.Name == backend.Service.Port.Name {
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			return port.Port, nil
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		}
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	}
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	return 0, errNotFound
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}
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// shouldProcessIngress determines whether the given knetworking resource should be processed
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// by the controller, based on its knetworking class annotation or, in more recent versions of
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// kubernetes (v1.18+), based on the Ingress's specified IngressClass
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// See https://kubernetes.io/docs/concepts/services-networking/ingress/#ingress-class
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func shouldProcessIngressWithClass(mesh *meshconfig.MeshConfig, ingress *knetworking.Ingress, ingressClass *knetworking.IngressClass) bool {
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	if class, exists := ingress.Annotations[annotation.IoKubernetesIngressClass.Name]; exists {
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		switch mesh.IngressControllerMode {
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		case meshconfig.MeshConfig_OFF:
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			return false
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		case meshconfig.MeshConfig_STRICT:
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			return class == mesh.IngressClass
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		case meshconfig.MeshConfig_DEFAULT:
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			return class == mesh.IngressClass
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		default:
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			log.Warnf("invalid ingress synchronization mode: %v", mesh.IngressControllerMode)
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			return false
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		}
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	} else if ingressClass != nil {
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		return ingressClass.Spec.Controller == IstioIngressController
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	} else {
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		switch mesh.IngressControllerMode {
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		case meshconfig.MeshConfig_OFF:
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			return false
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		case meshconfig.MeshConfig_STRICT:
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			return false
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		case meshconfig.MeshConfig_DEFAULT:
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			return true
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		default:
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			log.Warnf("invalid ingress synchronization mode: %v", mesh.IngressControllerMode)
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			return false
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		}
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	}
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}
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func createFallbackStringMatch(s string) *networking.StringMatch {
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	// If the string is empty or a wildcard, return nil
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	if s == "" || s == "*" || s == "/*" || s == ".*" {
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		return nil
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	}
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	// Note that this implementation only converts prefix and exact matches, not regexps.
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	// Replace e.g. "foo.*" with prefix match
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	if strings.HasSuffix(s, ".*") {
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		return &networking.StringMatch{
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			MatchType: &networking.StringMatch_Prefix{Prefix: strings.TrimSuffix(s, ".*")},
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		}
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	}
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	if strings.HasSuffix(s, "/*") {
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		return &networking.StringMatch{
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			MatchType: &networking.StringMatch_Prefix{Prefix: strings.TrimSuffix(s, "/*")},
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		}
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	}
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	// Replace e.g. "foo" with a exact match
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	return &networking.StringMatch{
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		MatchType: &networking.StringMatch_Exact{Exact: s},
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	}
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}
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func getIngressGatewaySelector(ingressSelector, ingressService string) map[string]string {
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	// Setup the selector for the gateway
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	if ingressSelector != "" {
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		// If explicitly defined, use this one
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		return labels.Instance{constants.IstioLabel: ingressSelector}
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	} else if ingressService != "istio-ingressgateway" && ingressService != "" {
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		// Otherwise, we will use the ingress service as the default. It is common for the selector and service
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		// to be the same, so this removes the need for two configurations
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		// However, if its istio-ingressgateway we need to use the old values for backwards compatibility
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		return labels.Instance{constants.IstioLabel: ingressService}
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	}
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	// If we have neither an explicitly defined ingressSelector or ingressService then use a selector
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	// pointing to the ingressgateway from the default installation
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	return labels.Instance{constants.IstioLabel: constants.IstioIngressLabelValue}
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}
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