Add flags to airshipctl get-kubeconfig cmd

* This commits add --file and --merge flags to
  airshipctl get-kubeconfig cmd

Change-Id: I919d4f068d3ef9bcda6b3a7c9aeb0826a4e5c0d4
Signed-off-by: bijayasharma <vetbijaya@gmail.com>
Relates-To: #495
Closes: #495

cmd/cluster/get_kubeconfig.go

@@ -37,6 +37,14 @@ Retrieve target-cluster kubeconfig
 
 Retrieve kubeconfig for the entire site; the kubeconfig will have context for every cluster
 # airshipctl cluster get-kubeconfig
+
+Specify a file where kubeconfig should be written
+# airshipctl cluster get-kubeconfig --file ~/my-kubeconfig
+
+Merge site kubeconfig with existing kubeconfig file.
+Keep in mind that this can override a context if it has the same name
+Airshipctl will overwrite the contents of the file, if you want merge with existing file, specify "--merge" flag
+# airshipctl cluster get-kubeconfig --file ~/.airship/kubeconfig --merge
 `
 )
 
@@ -53,6 +61,21 @@ func NewGetKubeconfigCommand(cfgFactory config.Factory) *cobra.Command {
 			return opts.RunE(cfgFactory, cmd.OutOrStdout())
 		},
 	}
+	flags := cmd.Flags()
+
+	flags.StringVarP(
+		&opts.File,
+		"file",
+		"f",
+		"",
+		"specify where to write kubeconfig file. If flag isn't specified, airshipctl will write it to stdout",
+	)
+	flags.BoolVar(
+		&opts.Merge,
+		"merge",
+		false,
+		"specify if you want to merge kubeconfig with the one that exists at --file location",
+	)
 	return cmd
 }
 

cmd/cluster/testdata/TestNewKubeConfigCommandCmdGoldenOutput/cluster-get-kubeconfig-cmd-with-help.golden

@@ -17,6 +17,16 @@ Retrieve target-cluster kubeconfig
 Retrieve kubeconfig for the entire site; the kubeconfig will have context for every cluster
 # airshipctl cluster get-kubeconfig
 
+Specify a file where kubeconfig should be written
+# airshipctl cluster get-kubeconfig --file ~/my-kubeconfig
+
+Merge site kubeconfig with existing kubeconfig file.
+Keep in mind that this can override a context if it has the same name
+Airshipctl will overwrite the contents of the file, if you want merge with existing file, specify "--merge" flag
+# airshipctl cluster get-kubeconfig --file ~/.airship/kubeconfig --merge
+
 
 Flags:
+  -f, --file string   specify where to write kubeconfig file. If flag isn't specified, airshipctl will write it to stdout
   -h, --help          help for get-kubeconfig
+      --merge         specify if you want to merge kubeconfig with the one that exists at --file location

docs/source/cli/airshipctl_cluster_get-kubeconfig.md

@@ -27,12 +27,22 @@ Retrieve target-cluster kubeconfig
 Retrieve kubeconfig for the entire site; the kubeconfig will have context for every cluster
 # airshipctl cluster get-kubeconfig
 
+Specify a file where kubeconfig should be written
+# airshipctl cluster get-kubeconfig --file ~/my-kubeconfig
+
+Merge site kubeconfig with existing kubeconfig file.
+Keep in mind that this can override a context if it has the same name
+Airshipctl will overwrite the contents of the file, if you want merge with existing file, specify "--merge" flag
+# airshipctl cluster get-kubeconfig --file ~/.airship/kubeconfig --merge
+
 ```
 
 ### Options
 
 ```
+  -f, --file string   specify where to write kubeconfig file. If flag isn't specified, airshipctl will write it to stdout
   -h, --help          help for get-kubeconfig
+      --merge         specify if you want to merge kubeconfig with the one that exists at --file location
 ```
 
 ### Options inherited from parent commands

pkg/cluster/command.go

@@ -57,9 +57,12 @@ func StatusRunner(o StatusOptions, w io.Writer) error {
 // GetKubeconfigCommand holds options for get kubeconfig command
 type GetKubeconfigCommand struct {
 	ClusterName string
+	File        string
+	Merge       bool
 }
 
-// RunE creates new kubeconfig interface object from secret and prints its content to writer
+// RunE creates new kubeconfig interface object from secret, options hold the writer and merge(bool)
+// to merge the kubeconfig. Writer in options is ignored if a file is provided.
 func (cmd *GetKubeconfigCommand) RunE(cfgFactory config.Factory, writer io.Writer) error {
 	cfg, err := cfgFactory()
 	if err != nil {
@@ -89,5 +92,8 @@ func (cmd *GetKubeconfigCommand) RunE(cfgFactory config.Factory, writer io.Write
 		SiteWide(siteWide).
 		Build()
 
+	if cmd.File != "" {
+		return kubeconf.WriteFile(cmd.File, kubeconfig.WriteOptions{Merge: cmd.Merge})
+	}
 	return kubeconf.Write(writer)
 }

pkg/k8s/kubeconfig/builder_test.go

@@ -215,7 +215,7 @@ func TestBuilderClusterctl(t *testing.T) {
 				MockTempFile: func(s1, s2 string) (fs.File, error) {
 					return testfs.TestFile{
 						MockName:  func() string { return kubeconfigPath },
-						MockWrite: func() (int, error) { return 0, nil },
+						MockWrite: func([]byte) (int, error) { return 0, nil },
 						MockClose: func() error { return nil },
 					}, nil
 				},

pkg/k8s/kubeconfig/kubeconfig.go

@@ -24,6 +24,7 @@ import (
 	corev1 "k8s.io/client-go/kubernetes/typed/core/v1"
 	"k8s.io/client-go/tools/clientcmd"
 	"k8s.io/client-go/tools/clientcmd/api"
+
 	"sigs.k8s.io/yaml"
 
 	"opendev.org/airship/airshipctl/pkg/api/v1alpha1"
@@ -48,7 +49,8 @@ type Interface interface {
 	// Write will write kubeconfig to the provided writer
 	Write(w io.Writer) error
 	// WriteFile will write kubeconfig data to specified path
-	WriteFile(path string) error
+	// WriteOptions holds additional option when writing kubeconfig to file
+	WriteFile(path string, options WriteOptions) error
 	// WriteTempFile writes a file a temporary file, returns path to it, cleanup function and error
 	// it is responsibility of the caller to use the cleanup function to make sure that there are no leftovers
 	WriteTempFile(dumpRoot string) (string, Cleanup, error)
@@ -65,6 +67,11 @@ type kubeConfig struct {
 	sourceFunc KubeSourceFunc
 }
 
+// WriteOptions holds additional option while writing kubeconfig to the file
+type WriteOptions struct {
+	Merge bool
+}
+
 // NewKubeConfig serves as a constructor for kubeconfig Interface
 // first argument is a function that should return bytes with kubeconfig and error
 // see FromByte() FromAPIalphaV1() FromFile() functions or extend with your own
@@ -206,8 +213,14 @@ func InjectFilePath(path string, fSys fs.FileSystem) Option {
 	}
 }
 
-func (k *kubeConfig) WriteFile(path string) (err error) {
-	data, err := k.bytes()
+func (k *kubeConfig) WriteFile(path string, options WriteOptions) error {
+	var data []byte
+	var err error
+	if options.Merge && path != "" {
+		data, err = k.mergedBytes(path)
+	} else {
+		data, err = k.bytes()
+	}
 	if err != nil {
 		return err
 	}
@@ -253,6 +266,24 @@ func (k *kubeConfig) bytes() ([]byte, error) {
 	return k.savedByes, err
 }
 
+// mergedBytes takes the file path and return byte data of the kubeconfig file to be written
+func (k *kubeConfig) mergedBytes(path string) ([]byte, error) {
+	kFile, cleanup, err := k.WriteTempFile(k.dumpRoot)
+	if err != nil {
+		return []byte{}, err
+	}
+	defer cleanup()
+
+	rules := clientcmd.ClientConfigLoadingRules{
+		Precedence: []string{path, kFile},
+	}
+	mergedConfig, err := rules.Load()
+	if err != nil {
+		return []byte{}, err
+	}
+	return clientcmd.Write(*mergedConfig)
+}
+
 // GetFile checks if path to kubeconfig is already set and returns it no cleanup is necessary,
 // and Cleanup() method will do nothing.
 // If path is not set kubeconfig will be written to temporary file system, returned path will

pkg/k8s/kubeconfig/kubeconfig_test.go

@@ -62,6 +62,52 @@ users:
   user:
     client-certificate-data: cert-data
     client-key-data: client-keydata
+`
+	testValidKubeconfigTwo = `
+apiVersion: v1
+clusters:
+- cluster:
+    server: https://10.0.1.7:6443
+  name: kubernetes_target
+contexts:
+- context:
+    cluster: kubernetes_target
+    user: kubernetes-admin
+  name: kubernetes-admin@kubernetes
+current-context: ""
+kind: Config
+preferences: {}
+users:
+- name: kubernetes-admin
+  user: {}
+`
+	//testMergedValidKubeconfig tests to confirm whether two kubeconfig got merged or not
+	testMergedValidKubeconfig = `
+apiVersion: v1
+clusters:
+- cluster:
+    server: https://10.23.25.101:6443
+  name: dummycluster_ephemeral
+- cluster:
+    server: https://10.0.1.7:6443
+  name: kubernetes_target
+contexts:
+- context:
+    cluster: dummycluster_ephemeral
+    user: kubernetes-admin
+  name: dummy_cluster
+- context:
+    cluster: kubernetes_target
+    user: kubernetes-admin
+  name: kubernetes-admin@kubernetes
+current-context: dummy_cluster
+kind: Config
+preferences: {}
+users:
+- name: kubernetes-admin
+  user:
+    client-certificate-data: dGVzdAo=
+    client-key-data: dGVzdAo=
 `
 )
 
@@ -297,7 +343,7 @@ func TestNewKubeConfig(t *testing.T) {
 						MockTempFile: func(root, pattern string) (fs.File, error) {
 							return testfs.TestFile{
 								MockName:  func() string { return "kubeconfig-142398" },
-								MockWrite: func() (int, error) { return 0, nil },
+								MockWrite: func([]byte) (int, error) { return 0, nil },
 								MockClose: func() error { return nil },
 							}, nil
 						},
@@ -322,7 +368,7 @@ func TestNewKubeConfig(t *testing.T) {
 							}
 							return testfs.TestFile{
 								MockName:  func() string { return "kubeconfig-142398" },
-								MockWrite: func() (int, error) { return 0, nil },
+								MockWrite: func([]byte) (int, error) { return 0, nil },
 								MockClose: func() error { return nil },
 							}, nil
 						},
@@ -440,6 +486,7 @@ func TestKubeConfigWriteFile(t *testing.T) {
 		expectedContent       string
 		path                  string
 		expectedErrorContains string
+		merge                 bool
 
 		fs  fs.FileSystem
 		src kubeconfig.KubeSourceFunc
@@ -448,26 +495,52 @@ func TestKubeConfigWriteFile(t *testing.T) {
 			name:            "Basic write file",
 			src:             kubeconfig.FromByte([]byte(testValidKubeconfig)),
 			expectedContent: testValidKubeconfig,
+			merge:           false,
 			fs:              fsWithFile(t, "/test-path"),
 			path:            "/test-path",
 		},
+		{
+			name:            "Basic merge write file",
+			src:             kubeconfig.FromByte([]byte(testValidKubeconfigTwo)),
+			expectedContent: testMergedValidKubeconfig,
+			merge:           true,
+			fs:              fs.NewDocumentFs(),
+			path:            "testdata/kubeconfig-test",
+		},
 		{
 			name:                  "Source error",
 			src:                   func() ([]byte, error) { return nil, errSourceFunc },
 			expectedErrorContains: errSourceFunc.Error(),
+			merge:                 false,
 		},
 	}
 	for _, tt := range tests {
 		tt := tt
 		t.Run(tt.name, func(t *testing.T) {
-			kubeconf := kubeconfig.NewKubeConfig(tt.src, kubeconfig.InjectFileSystem(tt.fs))
-			err := kubeconf.WriteFile(tt.path)
+			kubeconf := kubeconfig.NewKubeConfig(tt.src,
+				kubeconfig.InjectTempRoot("testdata/"),
+				kubeconfig.InjectFileSystem(tt.fs))
+			options := kubeconfig.WriteOptions{
+				Merge: tt.merge,
+			}
+			if tt.merge {
+				_, clean, err := kubeconf.GetFile()
+				require.NoError(t, err)
+				defer clean()
+				original, err := ioutil.ReadFile(tt.path)
+				require.NoError(t, err)
+				defer func() {
+					err = ioutil.WriteFile(tt.path, original, 0600)
+					require.NoError(t, err)
+				}()
+			}
+			err := kubeconf.WriteFile(tt.path, options)
 			if tt.expectedErrorContains != "" {
 				require.Error(t, err)
 				assert.Contains(t, err.Error(), tt.expectedErrorContains)
 			} else {
 				require.NoError(t, err)
-				assert.Equal(t, tt.expectedContent, readFile(t, tt.path, tt.fs))
+				assert.YAMLEq(t, tt.expectedContent, readFile(t, tt.path, tt.fs))
 			}
 		})
 	}
@@ -486,11 +559,19 @@ func read(t *testing.T, r io.Reader) string {
 }
 
 func fsWithFile(t *testing.T, path string) fs.FileSystem {
+	memFs := kustfs.MakeFsInMemory()
 	fSys := testfs.MockFileSystem{
-		FileSystem: kustfs.MakeFsInMemory(),
+		FileSystem: memFs,
 		MockRemoveAll: func() error {
 			return nil
 		},
+		MockTempFile: func(root, pattern string) (fs.File, error) {
+			return testfs.TestFile{
+				MockName:  func() string { return "kubeconfig-142398" },
+				MockWrite: func(b []byte) (int, error) { return 0, memFs.WriteFile("kubeconfig-142398", b) },
+				MockClose: func() error { return nil },
+			}, nil
+		},
 	}
 	err := fSys.WriteFile(path, []byte(testValidKubeconfig))
 	require.NoError(t, err)

pkg/k8s/kubeconfig/testdata/kubeconfig-test

@@ -0,0 +1,18 @@
+  apiVersion: v1
+  kind: Config
+  clusters:
+  - cluster:
+      server: https://10.23.25.101:6443
+    name: dummycluster_ephemeral
+  contexts:
+  - context:
+      cluster: dummycluster_ephemeral
+      user: kubernetes-admin
+    name: dummy_cluster
+  current-context: dummy_cluster
+  preferences: {}
+  users:
+  - name: kubernetes-admin
+    user:
+      client-certificate-data: dGVzdAo=
+      client-key-data: dGVzdAo=

pkg/k8s/kubectl/kubectl_test.go

@@ -83,7 +83,7 @@ func TestApply(t *testing.T) {
 				MockTempFile: func(string, string) (fs.File, error) {
 					return testfs.TestFile{
 						MockName:  func() string { return filenameRC },
-						MockWrite: func() (int, error) { return 0, nil },
+						MockWrite: func([]byte) (int, error) { return 0, nil },
 						MockClose: func() error { return nil },
 					}, nil
 				},
@@ -100,7 +100,7 @@ func TestApply(t *testing.T) {
 				MockRemoveAll: func() error { return nil },
 				MockTempFile: func(string, string) (fs.File, error) {
 					return testfs.TestFile{
-						MockWrite: func() (int, error) { return 0, ErrTempFileError },
+						MockWrite: func([]byte) (int, error) { return 0, ErrTempFileError },
 						MockName:  func() string { return filenameRC },
 						MockClose: func() error { return nil },
 					}, nil

pkg/phase/executors/clusterctl_test.go

@@ -154,7 +154,7 @@ func TestClusterctlExecutorRun(t *testing.T) {
 				MockTempFile: func(string, string) (fs.File, error) {
 					return testfs.TestFile{
 						MockName:  func() string { return "filename" },
-						MockWrite: func() (int, error) { return 0, nil },
+						MockWrite: func([]byte) (int, error) { return 0, nil },
 						MockClose: func() error { return nil },
 					}, nil
 				},

pkg/phase/executors/container_test.go

@@ -346,7 +346,7 @@ type fakeKubeConfig struct {
 
 func (k fakeKubeConfig) GetFile() (string, kubeconfig.Cleanup, error)        { return k.getFile() }
 func (k fakeKubeConfig) Write(_ io.Writer) error                             { return nil }
-func (k fakeKubeConfig) WriteFile(_ string) error                     { return nil }
+func (k fakeKubeConfig) WriteFile(_ string, _ kubeconfig.WriteOptions) error { return nil }
 func (k fakeKubeConfig) WriteTempFile(_ string) (string, kubeconfig.Cleanup, error) {
 	return k.getFile()
 }

pkg/phase/executors/k8s_applier_test.go

@@ -290,7 +290,7 @@ func testKubeconfig(stringData string) kubeconfig.Interface {
 				MockTempFile: func(root, pattern string) (fs.File, error) {
 					return testfs.TestFile{
 						MockName:  func() string { return "kubeconfig-142398" },
-						MockWrite: func() (int, error) { return 0, nil },
+						MockWrite: func([]byte) (int, error) { return 0, nil },
 						MockClose: func() error { return nil },
 					}, nil
 				},

testutil/fs/fs.go

@@ -62,7 +62,7 @@ func (fsys MockFileSystem) Dir(path string) string {
 type TestFile struct {
 	fs.File
 	MockName  func() string
-	MockWrite func() (int, error)
+	MockWrite func([]byte) (int, error)
 	MockClose func() error
 }
 
@@ -70,7 +70,7 @@ type TestFile struct {
 func (f TestFile) Name() string { return f.MockName() }
 
 // Write File interface implementation
-func (f TestFile) Write([]byte) (int, error) { return f.MockWrite() }
+func (f TestFile) Write(b []byte) (int, error) { return f.MockWrite(b) }
 
 // Close File interface implementation
 func (f TestFile) Close() error { return f.MockClose() }