Merge pull request #65997 from tallclair/writer

Automatic merge from submit-queue (batch tested with PRs 66030, 65997). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Remove unused io util writer & volume host GetWriter()

Cleanup unused code.
Fixes https://github.com/kubernetes/kubernetes/issues/16971

**Release note**:
```release-note
NONE
```

/kind cleanup
/sig storage

cmd/kubelet/app/BUILD

@@ -62,7 +62,6 @@ go_library(
         "//pkg/util/filesystem:go_default_library",
         "//pkg/util/flag:go_default_library",
         "//pkg/util/flock:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/node:go_default_library",
         "//pkg/util/nsenter:go_default_library",

cmd/kubelet/app/server.go

@@ -87,7 +87,6 @@ import (
 	utilfs "k8s.io/kubernetes/pkg/util/filesystem"
 	utilflag "k8s.io/kubernetes/pkg/util/flag"
 	"k8s.io/kubernetes/pkg/util/flock"
-	kubeio "k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	nodeutil "k8s.io/kubernetes/pkg/util/node"
 	"k8s.io/kubernetes/pkg/util/nsenter"
@@ -359,7 +358,6 @@ func UnsecuredDependencies(s *options.KubeletServer) (*kubelet.Dependencies, err
 	}
 
 	mounter := mount.New(s.ExperimentalMounterPath)
-	var writer kubeio.Writer = &kubeio.StdWriter{}
 	var pluginRunner = exec.New()
 	if s.Containerized {
 		glog.V(2).Info("Running kubelet in containerized mode")
@@ -368,7 +366,6 @@ func UnsecuredDependencies(s *options.KubeletServer) (*kubelet.Dependencies, err
 			return nil, err
 		}
 		mounter = mount.NewNsenterMounter(s.RootDirectory, ne)
-		writer = kubeio.NewNsenterWriter(ne)
 		// an exec interface which can use nsenter for flex plugin calls
 		pluginRunner = nsenter.NewNsenterExecutor(nsenter.DefaultHostRootFsPath, exec.New())
 	}
@@ -395,7 +392,6 @@ func UnsecuredDependencies(s *options.KubeletServer) (*kubelet.Dependencies, err
 		Mounter:             mounter,
 		OOMAdjuster:         oom.NewOOMAdjuster(),
 		OSInterface:         kubecontainer.RealOS{},
-		Writer:              writer,
 		VolumePlugins:       ProbeVolumePlugins(),
 		DynamicPluginProber: GetDynamicPluginProber(s.VolumePluginDir, pluginRunner),
 		TLSOptions:          tlsOptions}, nil

pkg/controller/volume/attachdetach/BUILD

@@ -19,7 +19,6 @@ go_library(
         "//pkg/controller/volume/attachdetach/reconciler:go_default_library",
         "//pkg/controller/volume/attachdetach/statusupdater:go_default_library",
         "//pkg/controller/volume/attachdetach/util:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/volume:go_default_library",
         "//pkg/volume/util:go_default_library",

pkg/controller/volume/attachdetach/attach_detach_controller.go

@@ -44,7 +44,6 @@ import (
 	"k8s.io/kubernetes/pkg/controller/volume/attachdetach/reconciler"
 	"k8s.io/kubernetes/pkg/controller/volume/attachdetach/statusupdater"
 	"k8s.io/kubernetes/pkg/controller/volume/attachdetach/util"
-	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/volume"
 	volumeutil "k8s.io/kubernetes/pkg/volume/util"
@@ -561,10 +560,6 @@ func (adc *attachDetachController) GetMounter(pluginName string) mount.Interface
 	return nil
 }
 
-func (adc *attachDetachController) GetWriter() io.Writer {
-	return nil
-}
-
 func (adc *attachDetachController) GetHostName() string {
 	return ""
 }

pkg/controller/volume/expand/BUILD

@@ -18,7 +18,6 @@ go_library(
         "//pkg/controller:go_default_library",
         "//pkg/controller/volume/expand/cache:go_default_library",
         "//pkg/util/goroutinemap/exponentialbackoff:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/volume:go_default_library",
         "//pkg/volume/util:go_default_library",

pkg/controller/volume/expand/expand_controller.go

@@ -40,7 +40,6 @@ import (
 	"k8s.io/kubernetes/pkg/cloudprovider"
 	"k8s.io/kubernetes/pkg/controller"
 	"k8s.io/kubernetes/pkg/controller/volume/expand/cache"
-	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/volume"
 	"k8s.io/kubernetes/pkg/volume/util/operationexecutor"
@@ -268,10 +267,6 @@ func (expc *expandController) GetExec(pluginName string) mount.Exec {
 	return mount.NewOsExec()
 }
 
-func (expc *expandController) GetWriter() io.Writer {
-	return nil
-}
-
 func (expc *expandController) GetHostName() string {
 	return ""
 }

pkg/controller/volume/persistentvolume/BUILD

@@ -28,7 +28,6 @@ go_library(
         "//pkg/features:go_default_library",
         "//pkg/util/goroutinemap:go_default_library",
         "//pkg/util/goroutinemap/exponentialbackoff:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/volume:go_default_library",
         "//pkg/volume/util:go_default_library",

pkg/controller/volume/persistentvolume/volume_host.go

@@ -26,7 +26,6 @@ import (
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/record"
 	"k8s.io/kubernetes/pkg/cloudprovider"
-	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	vol "k8s.io/kubernetes/pkg/volume"
 )
@@ -79,10 +78,6 @@ func (ctrl *PersistentVolumeController) GetMounter(pluginName string) mount.Inte
 	return nil
 }
 
-func (ctrl *PersistentVolumeController) GetWriter() io.Writer {
-	return nil
-}
-
 func (ctrl *PersistentVolumeController) GetHostName() string {
 	return ""
 }

pkg/kubelet/BUILD

@@ -97,7 +97,6 @@ go_library(
         "//pkg/securitycontext:go_default_library",
         "//pkg/util/dbus:go_default_library",
         "//pkg/util/file:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/iptables:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/node:go_default_library",

pkg/kubelet/kubelet.go

@@ -102,7 +102,6 @@ import (
 	"k8s.io/kubernetes/pkg/security/apparmor"
 	sysctlwhitelist "k8s.io/kubernetes/pkg/security/podsecuritypolicy/sysctl"
 	utildbus "k8s.io/kubernetes/pkg/util/dbus"
-	kubeio "k8s.io/kubernetes/pkg/util/io"
 	utilipt "k8s.io/kubernetes/pkg/util/iptables"
 	"k8s.io/kubernetes/pkg/util/mount"
 	nodeutil "k8s.io/kubernetes/pkg/util/node"
@@ -247,7 +246,6 @@ type Dependencies struct {
 	OSInterface             kubecontainer.OSInterface
 	PodConfig               *config.PodConfig
 	Recorder                record.EventRecorder
-	Writer                  kubeio.Writer
 	VolumePlugins           []volume.VolumePlugin
 	DynamicPluginProber     volume.DynamicPluginProber
 	TLSOptions              *server.TLSOptions
@@ -522,7 +520,6 @@ func NewMainKubelet(kubeCfg *kubeletconfiginternal.KubeletConfiguration,
 		cgroupsPerQOS:              kubeCfg.CgroupsPerQOS,
 		cgroupRoot:                 kubeCfg.CgroupRoot,
 		mounter:                    kubeDeps.Mounter,
-		writer:                     kubeDeps.Writer,
 		maxPods:                    int(kubeCfg.MaxPods),
 		podsPerCore:                int(kubeCfg.PodsPerCore),
 		syncLoopMonitor:            atomic.Value{},
@@ -1062,9 +1059,6 @@ type Kubelet struct {
 	// Mounter to use for volumes.
 	mounter mount.Interface
 
-	// Writer interface to use for volumes.
-	writer kubeio.Writer
-
 	// Manager of non-Runtime containers.
 	containerManager cm.ContainerManager
 

pkg/kubelet/volume_host.go

@@ -36,7 +36,6 @@ import (
 	"k8s.io/kubernetes/pkg/kubelet/mountpod"
 	"k8s.io/kubernetes/pkg/kubelet/secret"
 	"k8s.io/kubernetes/pkg/kubelet/token"
-	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/volume"
 	"k8s.io/kubernetes/pkg/volume/util"
@@ -168,10 +167,6 @@ func (kvh *kubeletVolumeHost) GetMounter(pluginName string) mount.Interface {
 	return mount.NewExecMounter(exec, kvh.kubelet.mounter)
 }
 
-func (kvh *kubeletVolumeHost) GetWriter() io.Writer {
-	return kvh.kubelet.writer
-}
-
 func (kvh *kubeletVolumeHost) GetHostName() string {
 	return kvh.kubelet.hostname
 }

pkg/kubemark/BUILD

@@ -30,7 +30,6 @@ go_library(
         "//pkg/proxy:go_default_library",
         "//pkg/proxy/config:go_default_library",
         "//pkg/proxy/iptables:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/iptables:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/node:go_default_library",

pkg/kubemark/hollow_kubelet.go

@@ -30,7 +30,6 @@ import (
 	containertest "k8s.io/kubernetes/pkg/kubelet/container/testing"
 	"k8s.io/kubernetes/pkg/kubelet/dockershim"
 	kubetypes "k8s.io/kubernetes/pkg/kubelet/types"
-	kubeio "k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/util/oom"
 	"k8s.io/kubernetes/pkg/volume/empty_dir"
@@ -76,7 +75,6 @@ func NewHollowKubelet(
 		VolumePlugins:      volumePlugins,
 		TLSOptions:         nil,
 		OOMAdjuster:        oom.NewFakeOOMAdjuster(),
-		Writer:             &kubeio.StdWriter{},
 		Mounter:            mount.New("" /* default mount path */),
 	}
 

pkg/util/io/BUILD

@@ -7,15 +7,8 @@ load(
 
 go_library(
     name = "go_default_library",
-    srcs = [
+    srcs = ["consistentread.go"],
-        "consistentread.go",
-        "writer.go",
-    ],
     importpath = "k8s.io/kubernetes/pkg/util/io",
-    deps = [
-        "//pkg/util/nsenter:go_default_library",
-        "//vendor/github.com/golang/glog:go_default_library",
-    ],
 )
 
 filegroup(

pkg/util/io/writer.go

@@ -1,87 +0,0 @@
-/*
-Copyright 2015 The Kubernetes Authors.
-
-Licensed under the Apache License, Version 2.0 (the "License");
-you may not use this file except in compliance with the License.
-You may obtain a copy of the License at
-
-    http://www.apache.org/licenses/LICENSE-2.0
-
-Unless required by applicable law or agreed to in writing, software
-distributed under the License is distributed on an "AS IS" BASIS,
-WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-See the License for the specific language governing permissions and
-limitations under the License.
-*/
-
-package io
-
-import (
-	"bytes"
-	"fmt"
-	"io/ioutil"
-	"os"
-
-	"k8s.io/kubernetes/pkg/util/nsenter"
-
-	"github.com/golang/glog"
-)
-
-// Writer is an interface which allows to write data to a file.
-type Writer interface {
-	// WriteFile mimics ioutil.WriteFile.
-	WriteFile(filename string, data []byte, perm os.FileMode) error
-}
-
-// StdWriter implements Writer interface and uses standard libraries
-// for writing data to files.
-type StdWriter struct {
-}
-
-// WriteFile directly calls ioutil.WriteFile.
-func (writer *StdWriter) WriteFile(filename string, data []byte, perm os.FileMode) error {
-	return ioutil.WriteFile(filename, data, perm)
-}
-
-// NsenterWriter is implementation of Writer interface that allows writing data
-// to file using nsenter command.
-// If a program (e.g. kubelet) runs in a container it may want to write data to
-// a mounted device. Since in Docker, mount propagation mode is set to private,
-// it will not see the mounted device in its own namespace. To work around this
-// limitation one has to first enter hosts namespace (by using 'nsenter') and
-// only then write data.
-type NsenterWriter struct {
-	ne *nsenter.Nsenter
-}
-
-// NewNsenterWriter creates a new Writer that allows writing data to file using
-// nsenter command.
-func NewNsenterWriter(ne *nsenter.Nsenter) *NsenterWriter {
-	return &NsenterWriter{
-		ne: ne,
-	}
-}
-
-// WriteFile calls 'nsenter cat - > <the file>' and 'nsenter chmod' to create a
-// file on the host.
-func (writer *NsenterWriter) WriteFile(filename string, data []byte, perm os.FileMode) error {
-	echoArgs := []string{"-c", fmt.Sprintf("cat > %s", filename)}
-	glog.V(5).Infof("nsenter: write data to file %s by nsenter", filename)
-	command := writer.ne.Exec("sh", echoArgs)
-	command.SetStdin(bytes.NewBuffer(data))
-	outputBytes, err := command.CombinedOutput()
-	if err != nil {
-		glog.Errorf("Output from writing to %q: %v", filename, string(outputBytes))
-		return err
-	}
-
-	chmodArgs := []string{fmt.Sprintf("%o", perm), filename}
-	glog.V(5).Infof("nsenter: change permissions of file %s to %s", filename, chmodArgs[0])
-	outputBytes, err = writer.ne.Exec("chmod", chmodArgs).CombinedOutput()
-	if err != nil {
-		glog.Errorf("Output from chmod command: %v", string(outputBytes))
-		return err
-	}
-
-	return nil
-}

pkg/volume/BUILD

@@ -18,7 +18,6 @@ go_library(
     visibility = ["//visibility:public"],
     deps = [
         "//pkg/cloudprovider:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/volume/util/fs:go_default_library",
         "//pkg/volume/util/recyclerclient:go_default_library",

pkg/volume/configmap/BUILD

@@ -14,7 +14,6 @@ go_library(
     ],
     importpath = "k8s.io/kubernetes/pkg/volume/configmap",
     deps = [
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/strings:go_default_library",
         "//pkg/volume:go_default_library",

pkg/volume/configmap/configmap.go

@@ -24,7 +24,6 @@ import (
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
-	ioutil "k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/util/strings"
 	"k8s.io/kubernetes/pkg/volume"
@@ -93,7 +92,6 @@ func (plugin *configMapPlugin) NewMounter(spec *volume.Spec, pod *v1.Pod, opts v
 			pod.UID,
 			plugin,
 			plugin.host.GetMounter(plugin.GetPluginName()),
-			plugin.host.GetWriter(),
 			volume.MetricsNil{},
 		},
 		source:       *spec.Volume.ConfigMap,
@@ -110,7 +108,6 @@ func (plugin *configMapPlugin) NewUnmounter(volName string, podUID types.UID) (v
 			podUID,
 			plugin,
 			plugin.host.GetMounter(plugin.GetPluginName()),
-			plugin.host.GetWriter(),
 			volume.MetricsNil{},
 		},
 	}, nil
@@ -131,7 +128,6 @@ type configMapVolume struct {
 	podUID  types.UID
 	plugin  *configMapPlugin
 	mounter mount.Interface
-	writer  ioutil.Writer
 	volume.MetricsNil
 }
 

pkg/volume/plugins.go

@@ -33,7 +33,6 @@ import (
 	clientset "k8s.io/client-go/kubernetes"
 	"k8s.io/client-go/tools/record"
 	"k8s.io/kubernetes/pkg/cloudprovider"
-	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/volume/util/recyclerclient"
 )
@@ -319,9 +318,6 @@ type VolumeHost interface {
 	// Get mounter interface.
 	GetMounter(pluginName string) mount.Interface
 
-	// Get writer interface for writing data to disk.
-	GetWriter() io.Writer
-
 	// Returns the hostname of the host kubelet is running on
 	GetHostName() string
 

pkg/volume/secret/BUILD

@@ -14,7 +14,6 @@ go_library(
     ],
     importpath = "k8s.io/kubernetes/pkg/volume/secret",
     deps = [
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/strings:go_default_library",
         "//pkg/volume:go_default_library",

pkg/volume/secret/secret.go

@@ -24,7 +24,6 @@ import (
 	"k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/types"
-	ioutil "k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	"k8s.io/kubernetes/pkg/util/strings"
 	"k8s.io/kubernetes/pkg/volume"
@@ -100,7 +99,6 @@ func (plugin *secretPlugin) NewMounter(spec *volume.Spec, pod *v1.Pod, opts volu
 			pod.UID,
 			plugin,
 			plugin.host.GetMounter(plugin.GetPluginName()),
-			plugin.host.GetWriter(),
 			volume.NewCachedMetrics(volume.NewMetricsDu(getPath(pod.UID, spec.Name(), plugin.host))),
 		},
 		source:    *spec.Volume.Secret,
@@ -117,7 +115,6 @@ func (plugin *secretPlugin) NewUnmounter(volName string, podUID types.UID) (volu
 			podUID,
 			plugin,
 			plugin.host.GetMounter(plugin.GetPluginName()),
-			plugin.host.GetWriter(),
 			volume.NewCachedMetrics(volume.NewMetricsDu(getPath(podUID, volName, plugin.host))),
 		},
 	}, nil
@@ -140,7 +137,6 @@ type secretVolume struct {
 	podUID  types.UID
 	plugin  *secretPlugin
 	mounter mount.Interface
-	writer  ioutil.Writer
 	volume.MetricsProvider
 }
 

pkg/volume/testing/BUILD

@@ -14,7 +14,6 @@ go_library(
     importpath = "k8s.io/kubernetes/pkg/volume/testing",
     deps = [
         "//pkg/cloudprovider:go_default_library",
-        "//pkg/util/io:go_default_library",
         "//pkg/util/mount:go_default_library",
         "//pkg/util/strings:go_default_library",
         "//pkg/volume:go_default_library",

pkg/volume/testing/testing.go

@@ -37,7 +37,6 @@ import (
 	"k8s.io/client-go/tools/record"
 	utiltesting "k8s.io/client-go/util/testing"
 	"k8s.io/kubernetes/pkg/cloudprovider"
-	"k8s.io/kubernetes/pkg/util/io"
 	"k8s.io/kubernetes/pkg/util/mount"
 	utilstrings "k8s.io/kubernetes/pkg/util/strings"
 	. "k8s.io/kubernetes/pkg/volume"
@@ -54,7 +53,6 @@ type fakeVolumeHost struct {
 	cloud      cloudprovider.Interface
 	mounter    mount.Interface
 	exec       mount.Exec
-	writer     io.Writer
 	nodeLabels map[string]string
 	nodeName   string
 }
@@ -82,7 +80,6 @@ func NewFakeVolumeHostWithNodeName(rootDir string, kubeClient clientset.Interfac
 func newFakeVolumeHost(rootDir string, kubeClient clientset.Interface, plugins []VolumePlugin, cloud cloudprovider.Interface) *fakeVolumeHost {
 	host := &fakeVolumeHost{rootDir: rootDir, kubeClient: kubeClient, cloud: cloud}
 	host.mounter = &mount.FakeMounter{}
-	host.writer = &io.StdWriter{}
 	host.exec = mount.NewFakeExec(nil)
 	host.pluginMgr.InitPlugins(plugins, nil /* prober */, host)
 	return host
@@ -124,10 +121,6 @@ func (f *fakeVolumeHost) GetMounter(pluginName string) mount.Interface {
 	return f.mounter
 }
 
-func (f *fakeVolumeHost) GetWriter() io.Writer {
-	return f.writer
-}
-
 func (f *fakeVolumeHost) NewWrapperMounter(volName string, spec Spec, pod *v1.Pod, opts VolumeOptions) (Mounter, error) {
 	// The name of wrapper volume is set to "wrapped_{wrapped_volume_name}"
 	wrapperVolumeName := "wrapped_" + volName