feat: add support for additional CLI arg/env var extensions + add azure/kubelogin based example

go.mod

@@ -5,6 +5,7 @@ go 1.24.0
 require (
 	github.com/onsi/ginkgo v1.16.5
 	github.com/onsi/gomega v1.36.1
+	gopkg.in/yaml.v3 v3.0.1
 	k8s.io/api v0.33.0
 	k8s.io/apimachinery v0.33.0
 	k8s.io/client-go v0.33.0
@@ -53,7 +54,6 @@ require (
 	gopkg.in/evanphx/json-patch.v4 v4.12.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
 	gopkg.in/tomb.v1 v1.0.0-20141024135613-dd632973f1e7 // indirect
-	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/apiextensions-apiserver v0.32.1 // indirect
 	k8s.io/gengo/v2 v2.0.0-20240911193312-2b36238f13e9 // indirect
 	k8s.io/kube-openapi v0.0.0-20250318190949-c8a335a9a2ff // indirect

pkg/credentials/config.go

@@ -8,22 +8,40 @@ import (
 	"net/url"
 	"os"
 
+	"gopkg.in/yaml.v3"
 	"k8s.io/client-go/rest"
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 	clientcmdlatest "k8s.io/client-go/tools/clientcmd/api/latest"
 	"k8s.io/klog/v2"
 	"sigs.k8s.io/cluster-inventory-api/apis/v1alpha1"
 )
 
-// client.authentication.k8s.io/exec is a reserved extension key defined by the Kubernetes
-// client authentication API (SIG Auth), not by the ClusterProfile API.
-// Reference:
-// https://kubernetes.io/docs/reference/config-api/client-authentication.v1beta1/#client-authentication-k8s-io-v1beta1-Cluster
-const clusterExtensionKey = "client.authentication.k8s.io/exec"
+const (
+	// client.authentication.k8s.io/exec is a reserved extension key defined by the Kubernetes
+	// client authentication API (SIG Auth), not by the ClusterProfile API.
+	// Reference:
+	// https://kubernetes.io/docs/reference/config-api/client-authentication.v1beta1/#client-authentication-k8s-io-v1beta1-Cluster
+	clusterExecExtensionKey = "client.authentication.k8s.io/exec"
+
+	// additionalCLIArgsExtensionKey and additionalEnvVarsExtensionKey are
+	// two reserved extensions defined in KEP 5339, which allows users to pass in (usually cluster-specific)
+	// additional command-line arguments and environment variables to the exec plugin from
+	// the ClusterProfile API side.
+	additionalCLIArgsExtensionKey = "multicluster.x-k8s.io/clusterprofiles/auth/exec/additional-args"
+	additionalEnvVarsExtensionKey = "multicluster.x-k8s.io/clusterprofiles/auth/exec/additional-envs"
+)
+
+type AdditionalCLIArgEnvVarExtensionFlag int
+
+const (
+	AdditionalCLIArgEnvVarExtensionFlagIgnore AdditionalCLIArgEnvVarExtensionFlag = iota
+	AdditionalCLIArgEnvVarExtensionFlagAllow
+)
 
 type Provider struct {
-	Name       string                   `json:"name"`
-	ExecConfig *clientcmdapi.ExecConfig `json:"execConfig"`
+	Name                                string                              `json:"name"`
+	ExecConfig                          *clientcmdapi.ExecConfig            `json:"execConfig"`
+	AdditionalCLIArgEnvVarExtensionFlag AdditionalCLIArgEnvVarExtensionFlag `json:"additionalCLIArgEnvVarExtensionFlag,omitempty"`
 }
 
 type CredentialsProvider struct {
@@ -68,11 +86,47 @@ func (cp *CredentialsProvider) BuildConfigFromCP(clusterprofile *v1alpha1.Cluste
 	}
 
 	// 2. Get Exec Config
-	execConfig := cp.getExecConfigFromConfig(clusterAccessor.Name)
+	execConfig, additionalCLIArgEnvVarsExtFlag := cp.getExecConfigAndFlagsFromConfig(clusterAccessor.Name)
 	if execConfig == nil {
 		return nil, fmt.Errorf("no exec credentials found for provider %q", clusterAccessor.Name)
 	}
 
+	// 3. Add additional CLI arguments and environment variables from cluster extensions if allowed.
+	for idx := range clusterAccessor.Cluster.Extensions {
+		ext := &clusterAccessor.Cluster.Extensions[idx]
+
+		switch {
+		case additionalCLIArgEnvVarsExtFlag == AdditionalCLIArgEnvVarExtensionFlagAllow && ext.Name == additionalCLIArgsExtensionKey:
+			var additionalArgs []string
+			if err := yaml.Unmarshal(ext.Extension.Raw, &additionalArgs); err != nil {
+				return nil, fmt.Errorf("failed to unmarshal additional CLI args extension: %w", err)
+			}
+			execConfig.Args = append(execConfig.Args, additionalArgs...)
+		case additionalCLIArgEnvVarsExtFlag == AdditionalCLIArgEnvVarExtensionFlagAllow && ext.Name == additionalEnvVarsExtensionKey:
+			var additionalEnvs map[string]string
+			if err := yaml.Unmarshal(ext.Extension.Raw, &additionalEnvs); err != nil {
+				return nil, fmt.Errorf("failed to unmarshal additional env vars extension: %w", err)
+			}
+
+			// Update the value of existing env vars.
+			for idx := range execConfig.Env {
+				env := &execConfig.Env[idx]
+				if _, exists := additionalEnvs[env.Name]; exists {
+					env.Value = additionalEnvs[env.Name]
+					delete(additionalEnvs, env.Name)
+				}
+			}
+
+			// Add new env vars.
+			for name, value := range additionalEnvs {
+				execConfig.Env = append(execConfig.Env, clientcmdapi.ExecEnvVar{
+					Name:  name,
+					Value: value,
+				})
+			}
+		}
+	}
+
 	// 3. build resulting rest.Config
 	config := &rest.Config{
 		Host: clusterAccessor.Cluster.Server,
@@ -94,25 +148,28 @@ func (cp *CredentialsProvider) BuildConfigFromCP(clusterprofile *v1alpha1.Cluste
 		Env:                execConfig.Env,
 		InteractiveMode:    "Never",
 		ProvideClusterInfo: execConfig.ProvideClusterInfo,
+		Config:             execConfig.Config,
 	}
 
 	// Propagate reserved extension into ExecCredential.Spec.Cluster.Config if present
 	internalCluster := clientcmdapi.NewCluster()
 	if err := clientcmdlatest.Scheme.Convert(&clusterAccessor.Cluster, internalCluster, nil); err != nil {
 		return nil, fmt.Errorf("failed to convert v1 Cluster to internal: %w", err)
 	}
-	config.ExecProvider.Config = internalCluster.Extensions[clusterExtensionKey]
+	if extData, ok := internalCluster.Extensions[clusterExecExtensionKey]; ok {
+		config.ExecProvider.Config = extData
+	}
 
 	return config, nil
 }
 
-func (cp *CredentialsProvider) getExecConfigFromConfig(providerName string) *clientcmdapi.ExecConfig {
+func (cp *CredentialsProvider) getExecConfigAndFlagsFromConfig(providerName string) (*clientcmdapi.ExecConfig, AdditionalCLIArgEnvVarExtensionFlag) {
 	for _, provider := range cp.Providers {
 		if provider.Name == providerName {
-			return provider.ExecConfig
+			return provider.ExecConfig, provider.AdditionalCLIArgEnvVarExtensionFlag
 		}
 	}
-	return nil
+	return nil, AdditionalCLIArgEnvVarExtensionFlagIgnore
 }
 
 // getClusterAccessorFromClusterProfile returns the first AccessProvider from the ClusterProfile

pkg/credentials/config_test.go

@@ -25,7 +25,9 @@ import (
 
 	"github.com/onsi/ginkgo"
 	"github.com/onsi/gomega"
+	"gopkg.in/yaml.v3"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
 	clientauthenticationv1 "k8s.io/client-go/pkg/apis/clientauthentication/v1"
 	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 	clientcmdv1 "k8s.io/client-go/tools/clientcmd/api/v1"
@@ -65,6 +67,7 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 					Args:       []string{"arg3"},
 					APIVersion: "client.authentication.k8s.io/v1beta1",
 				},
+				AdditionalCLIArgEnvVarExtensionFlag: AdditionalCLIArgEnvVarExtensionFlagAllow,
 			},
 		}
 		credentialsProvider = New(testProviders)
@@ -132,6 +135,7 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 							Command:            "gke-gcloud-auth-plugin",
 							ProvideClusterInfo: true,
 						},
+						AdditionalCLIArgEnvVarExtensionFlag: AdditionalCLIArgEnvVarExtensionFlagIgnore,
 					},
 				},
 			}
@@ -150,6 +154,7 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 			gomega.Expect(cp.Providers).To(gomega.HaveLen(1))
 			gomega.Expect(cp.Providers[0].Name).To(gomega.Equal("gkeFleet"))
 			gomega.Expect(cp.Providers[0].ExecConfig.Command).To(gomega.Equal("gke-gcloud-auth-plugin"))
+			gomega.Expect(cp.Providers[0].AdditionalCLIArgEnvVarExtensionFlag).To(gomega.Equal(AdditionalCLIArgEnvVarExtensionFlagIgnore))
 		})
 
 		ginkgo.It("should return an error when file does not exist", func() {
@@ -185,26 +190,38 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 
 	ginkgo.Describe("getExecConfigFromConfig", func() {
 		ginkgo.It("should return the correct ExecConfig for existing provider", func() {
-			execConfig := credentialsProvider.getExecConfigFromConfig("test-provider-1")
+			execConfig, additionalCLIArgEnvVarsExtFlag := credentialsProvider.getExecConfigAndFlagsFromConfig("test-provider-1")
 			gomega.Expect(execConfig).NotTo(gomega.BeNil())
 			gomega.Expect(execConfig.Command).To(gomega.Equal("test-command-1"))
 			gomega.Expect(execConfig.Args).To(gomega.Equal([]string{"arg1", "arg2"}))
+			gomega.Expect(additionalCLIArgEnvVarsExtFlag).To(gomega.Equal(AdditionalCLIArgEnvVarExtensionFlagIgnore))
+		})
+
+		ginkgo.It("should return the correct ExecConfig for another existing provider", func() {
+			execConfig, additionalCLIArgEnvVarsExtFlag := credentialsProvider.getExecConfigAndFlagsFromConfig("test-provider-2")
+			gomega.Expect(execConfig).NotTo(gomega.BeNil())
+			gomega.Expect(execConfig.Command).To(gomega.Equal("test-command-2"))
+			gomega.Expect(execConfig.Args).To(gomega.Equal([]string{"arg3"}))
+			gomega.Expect(additionalCLIArgEnvVarsExtFlag).To(gomega.Equal(AdditionalCLIArgEnvVarExtensionFlagAllow))
 		})
 
 		ginkgo.It("should return nil for non-existing provider", func() {
-			execConfig := credentialsProvider.getExecConfigFromConfig("non-existent-provider")
+			execConfig, additionalCLIArgEnvVarsExtFlag := credentialsProvider.getExecConfigAndFlagsFromConfig("non-existent-provider")
 			gomega.Expect(execConfig).To(gomega.BeNil())
+			gomega.Expect(additionalCLIArgEnvVarsExtFlag).To(gomega.Equal(AdditionalCLIArgEnvVarExtensionFlagIgnore))
 		})
 
 		ginkgo.It("should return nil for empty provider name", func() {
-			execConfig := credentialsProvider.getExecConfigFromConfig("")
+			execConfig, additionalCLIArgEnvVarsExtFlag := credentialsProvider.getExecConfigAndFlagsFromConfig("")
 			gomega.Expect(execConfig).To(gomega.BeNil())
+			gomega.Expect(additionalCLIArgEnvVarsExtFlag).To(gomega.Equal(AdditionalCLIArgEnvVarExtensionFlagIgnore))
 		})
 
 		ginkgo.It("should handle CredentialsProvider with no providers", func() {
 			emptyCP := New([]Provider{})
-			execConfig := emptyCP.getExecConfigFromConfig("any-provider")
+			execConfig, additionalCLIArgEnvVarsExtFlag := emptyCP.getExecConfigAndFlagsFromConfig("any-provider")
 			gomega.Expect(execConfig).To(gomega.BeNil())
+			gomega.Expect(additionalCLIArgEnvVarsExtFlag).To(gomega.Equal(AdditionalCLIArgEnvVarExtensionFlagIgnore))
 		})
 	})
 
@@ -285,6 +302,8 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 	ginkgo.Describe("BuildConfigFromCP", func() {
 		var clusterProfile *v1alpha1.ClusterProfile
 
+		additionalCLIArgsData, _ := yaml.Marshal([]string{"--audience", "audience"})
+		additionalEnvVarsData, _ := yaml.Marshal(map[string]string{"CLIENT_ID": "client-id", "TENANT_ID": "tenant-id"})
 		ginkgo.BeforeEach(func() {
 			clusterProfile = &v1alpha1.ClusterProfile{
 				ObjectMeta: metav1.ObjectMeta{
@@ -298,6 +317,26 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 								Server:                   "https://test-server.com",
 								CertificateAuthorityData: []byte("test-ca-data"),
 								ProxyURL:                 "http://proxy.example.com",
+								Extensions: []clientcmdv1.NamedExtension{
+									{
+										Name: clusterExecExtensionKey,
+										Extension: runtime.RawExtension{
+											Raw: []byte("arbitrary-data"),
+										},
+									},
+									{
+										Name: additionalCLIArgsExtensionKey,
+										Extension: runtime.RawExtension{
+											Raw: additionalCLIArgsData,
+										},
+									},
+									{
+										Name: additionalEnvVarsExtensionKey,
+										Extension: runtime.RawExtension{
+											Raw: additionalEnvVarsData,
+										},
+									},
+								},
 							},
 						},
 					},
@@ -327,7 +366,7 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 			gomega.Expect(err.Error()).To(gomega.ContainSubstring("no exec credentials found for provider"))
 		})
 
-		ginkgo.It("should build config successfully", func() {
+		ginkgo.It("should build config successfully (no additional CLI args/env vars)", func() {
 			cred := clientauthenticationv1.ExecCredential{
 				TypeMeta: metav1.TypeMeta{
 					APIVersion: "client.authentication.k8s.io/v1",
@@ -355,6 +394,61 @@ var _ = ginkgo.Describe("CredentialsProvider", func() {
 			gomega.Expect(config).NotTo(gomega.BeNil())
 			gomega.Expect(config.Host).To(gomega.Equal("https://test-server.com"))
 			gomega.Expect(config.TLSClientConfig.CAData).To(gomega.Equal([]byte("test-ca-data")))
+			gomega.Expect(config.ExecProvider.Command).To(gomega.Equal("cat"))
+			gomega.Expect(config.ExecProvider.Args).To(gomega.Equal([]string{testFile}))
+		})
+
+		ginkgo.It("should build config successfully (with additional CLI args/env vars)", func() {
+			cred := clientauthenticationv1.ExecCredential{
+				TypeMeta: metav1.TypeMeta{
+					APIVersion: "client.authentication.k8s.io/v1",
+					Kind:       "ExecCredential",
+				},
+				Status: &clientauthenticationv1.ExecCredentialStatus{
+					Token: "test-token",
+				},
+			}
+			jsonData, err := json.Marshal(cred)
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+			testFile := filepath.Join(tempDir, "test-config.json")
+			err = os.WriteFile(testFile, jsonData, 0644)
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+			execCP := New([]Provider{
+				{
+					Name: "test-provider-1",
+					ExecConfig: &clientcmdapi.ExecConfig{
+						APIVersion: "client.authentication.k8s.io/v1",
+						Command:    "cat",
+						Args:       []string{testFile},
+						Env: []clientcmdapi.ExecEnvVar{
+							{
+								Name:  "CLIENT_ID",
+								Value: "None",
+							},
+						},
+					},
+					AdditionalCLIArgEnvVarExtensionFlag: AdditionalCLIArgEnvVarExtensionFlagAllow,
+				},
+			})
+
+			config, err := execCP.BuildConfigFromCP(clusterProfile)
+			gomega.Expect(err).NotTo(gomega.HaveOccurred())
+			gomega.Expect(config).NotTo(gomega.BeNil())
+			gomega.Expect(config.Host).To(gomega.Equal("https://test-server.com"))
+			gomega.Expect(config.TLSClientConfig.CAData).To(gomega.Equal([]byte("test-ca-data")))
+			gomega.Expect(config.ExecProvider.Command).To(gomega.Equal("cat"))
+			gomega.Expect(config.ExecProvider.Args).To(gomega.Equal([]string{testFile, "--audience", "audience"}))
+			gomega.Expect(len(config.ExecProvider.Env)).To(gomega.Equal(2))
+			gomega.Expect(config.ExecProvider.Env).To(gomega.ContainElements(
+				clientcmdapi.ExecEnvVar{
+					Name:  "CLIENT_ID",
+					Value: "client-id",
+				},
+				clientcmdapi.ExecEnvVar{
+					Name:  "TENANT_ID",
+					Value: "tenant-id",
+				},
+			))
 		})
 	})
 })