Add API to get the Kubeconfig for an arbitrary UCP resource

fakes/config/kubeconfig-1.yaml

@@ -0,0 +1,51 @@
+apiVersion: v1
+kind: Config
+current-context: foo-context
+preferences:
+  colors: true
+clusters:
+  - cluster:
+      insecure-skip-tls-verify: true
+      server: https://bar.org:4443
+    name: bar-cluster
+  - cluster:
+      insecure-skip-tls-verify: true
+      server: https://foo.org:443
+    name: foo-cluster
+  - cluster:
+      insecure-skip-tls-verify: true
+      server: https://api.tanzu.cloud.vmware.com:443/org/fake-org-id
+    name: tanzu-cli-myucp/current
+contexts:
+  - context:
+      cluster: bar-cluster
+      namespace: chisel-ns
+      user: green-user
+    name: bar-context
+  - context:
+      cluster: foo-cluster
+      namespace: saw-ns
+      user: blue-user
+    name: foo-context
+  - context:
+      cluster: tanzu-cli-myucp/current
+      user: tanzu-cli-myucp-user
+    name: tanzu-cli-myucp
+users:
+  - name: blue-user
+    user:
+      token: blue-token
+  - name: green-user
+    user:
+      client-certificate-data: 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
+      client-key-data: 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
+  - name: tanzu-cli-myucp-user
+    user:
+      exec:
+        apiVersion: client.authentication.k8s.io/v1beta1
+        args:
+          - context
+          - get-token
+          - myucp
+        command: tanzu
+        env: []

ucp/internal/kubeconfig/kubeconfig.go

@@ -0,0 +1,86 @@
+// Copyright 2023 VMware, Inc. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+// Package kubeconfig provides the kubeconfig file access functionality
+package kubeconfig
+
+import (
+	"os"
+
+	"github.com/pkg/errors"
+	"gopkg.in/yaml.v3"
+)
+
+// ReadKubeConfig reads the kubeconfig file and returns the Config
+func ReadKubeConfig(path string) (*Config, error) {
+	kubeconfig, err := os.ReadFile(path)
+	if err != nil {
+		return nil, err
+	}
+	var config Config
+	err = yaml.Unmarshal(kubeconfig, &config)
+	if err != nil {
+		return nil, err
+	}
+
+	return &config, nil
+}
+
+// MinifyKubeConfig removes all information not used by the provided kubecontext name
+func MinifyKubeConfig(kubeconfig *Config, kubeContextName string) (*Config, error) {
+	context := GetContext(kubeconfig, kubeContextName)
+	if context == nil {
+		return nil, errors.Errorf("context %q missing in the kubeconfig", kubeContextName)
+	}
+
+	clusterName := context.Context.Cluster
+	userName := context.Context.AuthInfo
+
+	cluster := GetCluster(kubeconfig, clusterName)
+	if cluster == nil {
+		return nil, errors.Errorf("cluster %q missing in the kubeconfig", clusterName)
+	}
+	user := GetAuthInfo(kubeconfig, userName)
+	if user == nil {
+		return nil, errors.Errorf("user %q missing in the kubeconfig", userName)
+	}
+
+	return &Config{
+		Kind:           "Config",
+		APIVersion:     "v1",
+		Clusters:       []*Cluster{{Name: clusterName, Cluster: cluster.Cluster}},
+		AuthInfos:      []*AuthInfo{{Name: userName, AuthInfo: user.AuthInfo}},
+		Contexts:       []*Context{{Name: kubeContextName, Context: context.Context}},
+		CurrentContext: kubeContextName,
+	}, nil
+}
+
+// GetContext returns the Context information from the provided config
+func GetContext(kubeconfig *Config, kubeContextName string) *Context {
+	for idx := range kubeconfig.Contexts {
+		if kubeconfig.Contexts[idx].Name == kubeContextName {
+			return kubeconfig.Contexts[idx]
+		}
+	}
+	return nil
+}
+
+// GetCluster returns the Cluster information from the provided config
+func GetCluster(kubeconfig *Config, clusterName string) *Cluster {
+	for idx := range kubeconfig.Clusters {
+		if kubeconfig.Clusters[idx].Name == clusterName {
+			return kubeconfig.Clusters[idx]
+		}
+	}
+	return nil
+}
+
+// GetAuthInfo returns the AuthInfo information from the provided config
+func GetAuthInfo(kubeconfig *Config, userName string) *AuthInfo {
+	for idx := range kubeconfig.AuthInfos {
+		if kubeconfig.AuthInfos[idx].Name == userName {
+			return kubeconfig.AuthInfos[idx]
+		}
+	}
+	return nil
+}

ucp/internal/kubeconfig/kubeconfig_test.go

@@ -0,0 +1,106 @@
+// Copyright 2023 VMware, Inc. All Rights Reserved.
+// SPDX-License-Identifier: Apache-2.0
+
+package kubeconfig
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"gopkg.in/yaml.v3"
+)
+
+const ConfigFilePermissions = 0o600
+
+func copyFile(t *testing.T, sourceFile, destFile string) {
+	input, err := os.ReadFile(sourceFile)
+	assert.NoError(t, err)
+	err = os.WriteFile(destFile, input, ConfigFilePermissions)
+	assert.NoError(t, err)
+}
+
+func TestReadAndMinifyKubeConfig(t *testing.T) {
+	expectedMyucpKubeconfig := `
+kind: Config
+apiVersion: v1
+preferences: {}
+clusters:
+    - name: tanzu-cli-myucp/current
+      cluster:
+        server: https://api.tanzu.cloud.vmware.com:443/org/fake-org-id
+        insecure-skip-tls-verify: true
+users:
+    - name: tanzu-cli-myucp-user
+      user:
+        exec:
+            command: tanzu
+            args:
+                - context
+                - get-token
+                - myucp
+            env: []
+            apiVersion: client.authentication.k8s.io/v1beta1
+            provideClusterInfo: false
+contexts:
+    - name: tanzu-cli-myucp
+      context:
+        cluster: tanzu-cli-myucp/current
+        user: tanzu-cli-myucp-user
+current-context: tanzu-cli-myucp
+`
+
+	expectedFooContextKubeconfig := `
+kind: Config
+apiVersion: v1
+preferences: {}
+clusters:
+    - name: foo-cluster
+      cluster:
+        server: https://foo.org:443
+        insecure-skip-tls-verify: true
+users:
+    - name: blue-user
+      user:
+        token: blue-token
+contexts:
+    - name: foo-context
+      context:
+        cluster: foo-cluster
+        user: blue-user
+        namespace: saw-ns
+current-context: foo-context
+`
+
+	testKubeconfiFilePath := "../../../fakes/config/kubeconfig-1.yaml"
+	kubeconfigFilePath, err := os.CreateTemp("", "config")
+	assert.NoError(t, err)
+	copyFile(t, testKubeconfiFilePath, kubeconfigFilePath.Name())
+
+	defer func() {
+		_ = os.RemoveAll(kubeconfigFilePath.Name())
+	}()
+
+	config, err := ReadKubeConfig(kubeconfigFilePath.Name())
+	assert.NoError(t, err)
+
+	// Test with non-existing context
+	_, err = MinifyKubeConfig(config, "non-existing-context")
+	assert.Equal(t, err.Error(), `context "non-existing-context" missing in the kubeconfig`)
+
+	// Test reading and minifying the kubeconfig using Token as user(AuthInfo)
+	minifiedKubeconfig, err := MinifyKubeConfig(config, "foo-context")
+	assert.NoError(t, err)
+	wantKubeConfig := &Config{}
+	err = yaml.Unmarshal([]byte(expectedFooContextKubeconfig), wantKubeConfig)
+	assert.NoError(t, err)
+	assert.Equal(t, minifiedKubeconfig, wantKubeConfig)
+
+	// Test reading and minifying the kubeconfig having ExecConfig as user(AuthInfo)
+	minifiedKubeconfig, err = MinifyKubeConfig(config, "tanzu-cli-myucp")
+	assert.NoError(t, err)
+	wantKubeConfig = &Config{}
+	err = yaml.Unmarshal([]byte(expectedMyucpKubeconfig), wantKubeConfig)
+	assert.NoError(t, err)
+	assert.Equal(t, minifiedKubeconfig, wantKubeConfig)
+}