eliminating duplicate communications. this caused problems with linkerd

and helm

cmd/policygen/generator.go

@@ -3,6 +3,7 @@ package main
 import (
 	"io"
 	"os"
+	"slices"
 )
 
 type Generator interface {
@@ -15,13 +16,15 @@ type Generator interface {
 type ApplicationPeer struct {
 	Application *Application
 	Ports       []Port
-	Rule        string
+	// used as convenience for template rendering.
+	Rule string
 }
 
 type NetworkPeer struct {
 	Network *Network
 	Ports   []Port
-	Rule    string
+	// Used as convenience for template rendering.
+	Rule string
 }
 
 type Peer struct {
@@ -32,13 +35,23 @@ type Peer struct {
 
 func (p *Peer) append(app *ApplicationPeer, network *NetworkPeer, predefined string) {
 	if app != nil {
-		p.Applications = append(p.Applications, app)
+		if !slices.ContainsFunc(p.Applications, func(a *ApplicationPeer) bool {
+			return a.Application.Name == app.Application.Name && slices.Equal(a.Ports, app.Ports)
+		}) {
+			p.Applications = append(p.Applications, app)
+		}
 	}
 	if network != nil {
-		p.Networks = append(p.Networks, network)
+		if !slices.ContainsFunc(p.Networks, func(n *NetworkPeer) bool {
+			return n.Network.Name == network.Network.Name && slices.Equal(n.Network.Ports, network.Network.Ports)
+		}) {
+			p.Networks = append(p.Networks, network)
+		}
 	}
 	if predefined != "" {
-		p.Predefined = append(p.Predefined, predefined)
+		if !slices.Contains(p.Predefined, predefined) {
+			p.Predefined = append(p.Predefined, predefined)
+		}
 	}
 }
 

cmd/policygen/linkerd_generator.go

@@ -7,7 +7,6 @@ import (
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"os"
 	"slices"
-	"strconv"
 	"strings"
 )
 
@@ -15,6 +14,7 @@ type LinkerdPolicyGenerator struct {
 	config          *Config
 	policyTemplates *PolicyTemplates
 
+	apps     map[string]*Application
 	networks map[string]*Network
 }
 
@@ -22,6 +22,7 @@ func NewLinkerdPolicyGenerator(config *Config, templates *PolicyTemplates) *Link
 	return &LinkerdPolicyGenerator{
 		config:          config,
 		policyTemplates: templates,
+		apps:            make(map[string]*Application),
 		networks:        make(map[string]*Network),
 	}
 }
@@ -53,83 +54,37 @@ func (g *LinkerdPolicyGenerator) GenerateCommunicationRule(
 		return err
 	}
 
-	if len(ingress.Applications)+
-		len(ingress.Networks) > 0 {
-		ports := make(map[int]bool)
-		//
-		clientApplications := make(map[int][]*ApplicationPeer)
-		for _, ingress := range ingress.Applications {
-			for _, port := range ingress.Ports {
-				if port.Protocol == "TCP" {
-					portno, err := strconv.Atoi(port.Port)
-					if err != nil {
-						return fmt.Errorf("Error convert port '%s' of ingress '%s' of app '%s': %w",
-							port.Port, ingress.Application.Name, app.Name, err)
-					}
-					ports[portno] = true
-					clientApplications[portno] = append(clientApplications[portno], ingress)
-				}
+	for _, ingress := range ingress.Applications {
+		for _, port := range ingress.Ports {
+			if port.Protocol != "TCP" {
+				continue
 			}
-		}
-
-		clientNetworks := make(map[int][]*NetworkPeer)
-		for _, ingress := range ingress.Networks {
-			for _, port := range ingress.Ports {
-				if port.Protocol == "TCP" {
-					portno, err := strconv.Atoi(port.Port)
-					if err != nil {
-						return fmt.Errorf("Error convert port '%s' of ingress '%s' of app '%s': %w",
-							port.Port, ingress.Network.Name, app.Name, err)
-					}
-					ports[portno] = true
-					clientNetworks[portno] = append(clientNetworks[portno], ingress)
-				}
-			}
-		}
-
-		for port, _ := range ports {
-			fmt.Fprintf(os.Stderr, "Generating authorization policy: %v %v -> %v : %v\n",
-				Map(clientApplications[port], func(peer *ApplicationPeer) string {
-					return peer.Application.Name
-				}),
-				Map(clientNetworks[port], func(peer *NetworkPeer) string {
-					return peer.Network.Name
-				}),
-				app.Name,
-				port)
-			// Optimization: keep track of the references clientApps and
-			// client Networks and only generate authentications for those instead of for
-			// all apps and networks.
-			for _, clientNetwork := range clientNetworks[port] {
-				g.networks[clientNetwork.Network.Name] = clientNetwork.Network
-			}
-
-			// linkerd rules
-			// 1. an authpolicy may contain only one meshtlsauthentication rule
-			// 2. an authpolicy may contain only one service account .
-			// 3. an authpolicy may contain only one networkauthentication
-			//
-			// Should generate here a methtlsautheorization for every port
-			// and pass in a list of service accounts instead of a list of apps.
-			serviceAccounts := g.serviceAccounts(clientApplications[port])
-			if len(serviceAccounts) > 0 {
-				err = g.policyTemplates.Execute("linkerd", "meshtlsauthentication",
-					writer,
-					map[string]any{
-						"app":             app,
-						"port":            port,
-						"serviceAccounts": serviceAccounts,
-					})
-				if err != nil {
-					return err
-				}
-			}
-			err = g.policyTemplates.Execute("linkerd", "authorizationpolicy",
+			g.apps[ingress.Application.Name] = ingress.Application
+			err = g.policyTemplates.Execute("linkerd", "authorizationpolicy-app",
 				writer,
 				map[string]any{
-					"app":            app,
-					"port":           port,
-					"clientNetworks": clientNetworks[port],
+					"app":    app,
+					"port":   port.Port,
+					"client": ingress.Application,
+				})
+			if err != nil {
+				return err
+			}
+		}
+	}
+
+	for _, ingress := range ingress.Networks {
+		for _, port := range ingress.Ports {
+			if port.Protocol != "TCP" {
+				continue
+			}
+			g.networks[ingress.Network.Name] = ingress.Network
+			err = g.policyTemplates.Execute("linkerd", "authorizationpolicy-net",
+				writer,
+				map[string]any{
+					"app":    app,
+					"port":   port.Port,
+					"client": ingress.Network,
 				})
 			if err != nil {
 				return err
@@ -160,6 +115,15 @@ func (g *LinkerdPolicyGenerator) serviceAccounts(peers []*ApplicationPeer) []v1.
 }
 
 func (g *LinkerdPolicyGenerator) Finalize(writer io.Writer) error {
+	for _, app := range g.apps {
+		fmt.Fprintf(os.Stderr, "MeshTLSAuthentication %s/%s %v\n",
+			app.Namespace.Name, app.Name, app.ServiceAccounts)
+		err := g.policyTemplates.Execute("linkerd", "meshtlsauthentication",
+			writer, app)
+		if err != nil {
+			return err
+		}
+	}
 	for _, network := range g.networks {
 		fmt.Fprintf(os.Stderr, "NetworkAuthentication default/%s\n", network.Name)
 		err := g.policyTemplates.Execute("linkerd", "networkauthentication", writer, network)

cmd/policygen/templates/linkerd/application/authorizationpolicy-app.yaml

@@ -0,0 +1,16 @@
+---
+apiVersion: policy.linkerd.io/v1alpha1
+kind: AuthorizationPolicy
+metadata:
+  name: app-{{ .client.Name }}-to-{{ .app.Name }}-p{{ .port }}
+  namespace: {{ .app.Namespace.Name}}
+spec:
+  targetRef:
+    group: policy.linkerd.io
+    kind: Server
+    name: {{ .app.Name }}-p{{ .port }}
+  requiredAuthenticationRefs:
+    - name: {{ .client.Name }}
+      namespace: {{ .client.Namespace.Name }}
+      kind: MeshTLSAuthentication
+      group: policy.linkerd.io

cmd/policygen/templates/linkerd/application/authorizationpolicy-net.yaml

@@ -2,7 +2,7 @@
 apiVersion: policy.linkerd.io/v1alpha1
 kind: AuthorizationPolicy
 metadata:
-  name: {{ .app.Name }}-p{{ .port }}
+  name: net-{{ .client.Name }}-to-{{ .app.Name }}-p{{ .port }}
   namespace: {{ .app.Namespace.Name}}
 spec:
   targetRef:
@@ -10,13 +10,7 @@ spec:
     kind: Server
     name: {{ .app.Name }}-p{{ .port }}
   requiredAuthenticationRefs:
-    - name: {{ .app.Name }}-p{{ .port }}
-      namespace: {{ .app.Namespace.Name }}
-      kind: MeshTLSAuthentication
-      group: policy.linkerd.io
-  {{- range $net := .clientNetworks }}
-    - name: {{ $net.Network.Name }}
+    - name: {{ .client.Name }}
       namespace: default
       kind: NetworkAuthentication
       group: policy.linkerd.io
-  {{- end }}

cmd/policygen/templates/linkerd/application/meshtlsauthentication.yaml

@@ -2,13 +2,16 @@
 apiVersion: policy.linkerd.io/v1alpha1
 kind: MeshTLSAuthentication
 metadata:
-  name: {{ .app.Name }}-p{{.port}}
-  namespace: {{ .app.Namespace.Name }}
+  name: {{ .Name }}
+  namespace: {{ .Namespace.Name }}
 spec:
+  {{- if .ServiceAccounts }}
   identityRefs:
-  {{- range $sa := .serviceAccounts }}
+  {{- range $sa := .ServiceAccounts }}
     - kind: ServiceAccount
-      name: {{ $sa.Name }}
-      namespace: {{ $sa.Namespace }}
+      name: {{ $sa }}
   {{- end }}
+  {{- else }}
+    fail (printf "no service accounts defined for app %s" .Name )
+  {{- end}}