Update go dependencies

vendor/k8s.io/utils/OWNERS

@@ -1,4 +1,5 @@
 # See the OWNERS docs at https://go.k8s.io/owners
+
 approvers:
 - apelisse
 - dashpole
@@ -6,6 +7,7 @@ approvers:
 - lavalamp
 - mengqiy
 - thockin
+- dims
 reviewers:
 - apelisse
 - dashpole
@@ -16,3 +18,4 @@ reviewers:
 - andrewsykim
 - cheftako
 - mcrute
+- dims

vendor/k8s.io/utils/SECURITY_CONTACTS

@@ -0,0 +1,13 @@
+# Defined below are the security contacts for this repo.
+#
+# They are the contact point for the Product Security Committee to reach out
+# to for triaging and handling of incoming issues.
+#
+# The below names agree to abide by the
+# [Embargo Policy](https://git.k8s.io/security/private-distributors-list.md#embargo-policy)
+# and will be removed and replaced if they violate that agreement.
+#
+# DO NOT REPORT SECURITY VULNERABILITIES DIRECTLY TO THESE NAMES, FOLLOW THE
+# INSTRUCTIONS AT https://kubernetes.io/security/
+
+liggitt

vendor/k8s.io/utils/buffer/ring_growing.go

@@ -0,0 +1,72 @@
+/*
+Copyright 2017 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 buffer
+
+// RingGrowing is a growing ring buffer.
+// Not thread safe.
+type RingGrowing struct {
+	data     []interface{}
+	n        int // Size of Data
+	beg      int // First available element
+	readable int // Number of data items available
+}
+
+// NewRingGrowing constructs a new RingGrowing instance with provided parameters.
+func NewRingGrowing(initialSize int) *RingGrowing {
+	return &RingGrowing{
+		data: make([]interface{}, initialSize),
+		n:    initialSize,
+	}
+}
+
+// ReadOne reads (consumes) first item from the buffer if it is available, otherwise returns false.
+func (r *RingGrowing) ReadOne() (data interface{}, ok bool) {
+	if r.readable == 0 {
+		return nil, false
+	}
+	r.readable--
+	element := r.data[r.beg]
+	r.data[r.beg] = nil // Remove reference to the object to help GC
+	if r.beg == r.n-1 {
+		// Was the last element
+		r.beg = 0
+	} else {
+		r.beg++
+	}
+	return element, true
+}
+
+// WriteOne adds an item to the end of the buffer, growing it if it is full.
+func (r *RingGrowing) WriteOne(data interface{}) {
+	if r.readable == r.n {
+		// Time to grow
+		newN := r.n * 2
+		newData := make([]interface{}, newN)
+		to := r.beg + r.readable
+		if to <= r.n {
+			copy(newData, r.data[r.beg:to])
+		} else {
+			copied := copy(newData, r.data[r.beg:])
+			copy(newData[copied:], r.data[:(to%r.n)])
+		}
+		r.beg = 0
+		r.data = newData
+		r.n = newN
+	}
+	r.data[(r.readable+r.beg)%r.n] = data
+	r.readable++
+}

vendor/k8s.io/utils/integer/integer.go

@@ -0,0 +1,73 @@
+/*
+Copyright 2016 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 integer
+
+// IntMax returns the maximum of the params
+func IntMax(a, b int) int {
+	if b > a {
+		return b
+	}
+	return a
+}
+
+// IntMin returns the minimum of the params
+func IntMin(a, b int) int {
+	if b < a {
+		return b
+	}
+	return a
+}
+
+// Int32Max returns the maximum of the params
+func Int32Max(a, b int32) int32 {
+	if b > a {
+		return b
+	}
+	return a
+}
+
+// Int32Min returns the minimum of the params
+func Int32Min(a, b int32) int32 {
+	if b < a {
+		return b
+	}
+	return a
+}
+
+// Int64Max returns the maximum of the params
+func Int64Max(a, b int64) int64 {
+	if b > a {
+		return b
+	}
+	return a
+}
+
+// Int64Min returns the minimum of the params
+func Int64Min(a, b int64) int64 {
+	if b < a {
+		return b
+	}
+	return a
+}
+
+// RoundToInt32 rounds floats into integer numbers.
+func RoundToInt32(a float64) int32 {
+	if a < 0 {
+		return int32(a - 0.5)
+	}
+	return int32(a + 0.5)
+}

vendor/k8s.io/utils/io/consistentread.go

@@ -0,0 +1,55 @@
+/*
+Copyright 2017 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"
+)
+
+// ConsistentRead repeatedly reads a file until it gets the same content twice.
+// This is useful when reading files in /proc that are larger than page size
+// and kernel may modify them between individual read() syscalls.
+func ConsistentRead(filename string, attempts int) ([]byte, error) {
+	return consistentReadSync(filename, attempts, nil)
+}
+
+// consistentReadSync is the main functionality of ConsistentRead but
+// introduces a sync callback that can be used by the tests to mutate the file
+// from which the test data is being read
+func consistentReadSync(filename string, attempts int, sync func(int)) ([]byte, error) {
+	oldContent, err := ioutil.ReadFile(filename)
+	if err != nil {
+		return nil, err
+	}
+	for i := 0; i < attempts; i++ {
+		if sync != nil {
+			sync(i)
+		}
+		newContent, err := ioutil.ReadFile(filename)
+		if err != nil {
+			return nil, err
+		}
+		if bytes.Compare(oldContent, newContent) == 0 {
+			return newContent, nil
+		}
+		// Files are different, continue reading
+		oldContent = newContent
+	}
+	return nil, fmt.Errorf("could not get consistent content of %s after %d attempts", filename, attempts)
+}

vendor/k8s.io/utils/keymutex/hashed.go

@@ -0,0 +1,58 @@
+/*
+Copyright 2018 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 keymutex
+
+import (
+	"hash/fnv"
+	"runtime"
+	"sync"
+)
+
+// NewHashed returns a new instance of KeyMutex which hashes arbitrary keys to
+// a fixed set of locks. `n` specifies number of locks, if n <= 0, we use
+// number of cpus.
+// Note that because it uses fixed set of locks, different keys may share same
+// lock, so it's possible to wait on same lock.
+func NewHashed(n int) KeyMutex {
+	if n <= 0 {
+		n = runtime.NumCPU()
+	}
+	return &hashedKeyMutex{
+		mutexes: make([]sync.Mutex, n),
+	}
+}
+
+type hashedKeyMutex struct {
+	mutexes []sync.Mutex
+}
+
+// Acquires a lock associated with the specified ID.
+func (km *hashedKeyMutex) LockKey(id string) {
+	km.mutexes[km.hash(id)%uint32(len(km.mutexes))].Lock()
+}
+
+// Releases the lock associated with the specified ID.
+func (km *hashedKeyMutex) UnlockKey(id string) error {
+	km.mutexes[km.hash(id)%uint32(len(km.mutexes))].Unlock()
+	return nil
+}
+
+func (km *hashedKeyMutex) hash(id string) uint32 {
+	h := fnv.New32a()
+	h.Write([]byte(id))
+	return h.Sum32()
+}

vendor/k8s.io/utils/keymutex/keymutex.go

@@ -0,0 +1,27 @@
+/*
+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 keymutex
+
+// KeyMutex is a thread-safe interface for acquiring locks on arbitrary strings.
+type KeyMutex interface {
+	// Acquires a lock associated with the specified ID, creates the lock if one doesn't already exist.
+	LockKey(id string)
+
+	// Releases the lock associated with the specified ID.
+	// Returns an error if the specified ID doesn't exist.
+	UnlockKey(id string) error
+}

vendor/k8s.io/utils/nsenter/OWNERS

@@ -0,0 +1,10 @@
+# See the OWNERS docs at https://go.k8s.io/owners
+
+reviewers:
+  - jsafrane
+  - msau42
+  - cofyc
+approvers:
+  - jsafrane
+  - msau42
+  - cofyc

vendor/k8s.io/utils/nsenter/nsenter.go

@@ -0,0 +1,258 @@
+// +build linux
+
+/*
+Copyright 2017 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 nsenter
+
+import (
+	"context"
+	"errors"
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+
+	"k8s.io/klog"
+	"k8s.io/utils/exec"
+)
+
+const (
+	// DefaultHostRootFsPath is path to host's filesystem mounted into container
+	// with kubelet.
+	DefaultHostRootFsPath = "/rootfs"
+	// mountNsPath is the default mount namespace of the host
+	mountNsPath = "/proc/1/ns/mnt"
+	// nsenterPath is the default nsenter command
+	nsenterPath = "nsenter"
+)
+
+// Nsenter is a type alias for backward compatibility
+type Nsenter = NSEnter
+
+// NSEnter is part of experimental support for running the kubelet
+// in a container.
+//
+// NSEnter requires:
+//
+// 1.  Docker >= 1.6 due to the dependency on the slave propagation mode
+//     of the bind-mount of the kubelet root directory in the container.
+//     Docker 1.5 used a private propagation mode for bind-mounts, so mounts
+//     performed in the host's mount namespace do not propagate out to the
+//     bind-mount in this docker version.
+// 2.  The host's root filesystem must be available at /rootfs
+// 3.  The nsenter binary must be on the Kubelet process' PATH in the container's
+//     filesystem.
+// 4.  The Kubelet process must have CAP_SYS_ADMIN (required by nsenter); at
+//     the present, this effectively means that the kubelet is running in a
+//     privileged container.
+// 5.  The volume path used by the Kubelet must be the same inside and outside
+//     the container and be writable by the container (to initialize volume)
+//     contents. TODO: remove this requirement.
+// 6.  The host image must have "mount", "findmnt", "umount", "stat", "touch",
+//     "mkdir", "ls", "sh" and "chmod" binaries in /bin, /usr/sbin, or /usr/bin
+// 7.  The host image should have systemd-run in /bin, /usr/sbin, or /usr/bin if
+//     systemd is installed/enabled in the operating system.
+// For more information about mount propagation modes, see:
+//   https://www.kernel.org/doc/Documentation/filesystems/sharedsubtree.txt
+type NSEnter struct {
+	// a map of commands to their paths on the host filesystem
+	paths map[string]string
+
+	// Path to the host filesystem, typically "/rootfs". Used only for testing.
+	hostRootFsPath string
+
+	// Exec implementation
+	executor exec.Interface
+}
+
+// NewNsenter constructs a new instance of NSEnter
+func NewNsenter(hostRootFsPath string, executor exec.Interface) (*NSEnter, error) {
+	ne := &NSEnter{
+		hostRootFsPath: hostRootFsPath,
+		executor:       executor,
+	}
+	if err := ne.initPaths(); err != nil {
+		return nil, err
+	}
+	return ne, nil
+}
+
+func (ne *NSEnter) initPaths() error {
+	ne.paths = map[string]string{}
+	binaries := []string{
+		"mount",
+		"findmnt",
+		"umount",
+		"systemd-run",
+		"stat",
+		"touch",
+		"mkdir",
+		"sh",
+		"chmod",
+		"realpath",
+	}
+	// search for the required commands in other locations besides /usr/bin
+	for _, binary := range binaries {
+		// check for binary under the following directories
+		for _, path := range []string{"/", "/bin", "/usr/sbin", "/usr/bin"} {
+			binPath := filepath.Join(path, binary)
+			if _, err := os.Stat(filepath.Join(ne.hostRootFsPath, binPath)); err != nil {
+				continue
+			}
+			ne.paths[binary] = binPath
+			break
+		}
+		// systemd-run is optional, bailout if we don't find any of the other binaries
+		if ne.paths[binary] == "" && binary != "systemd-run" {
+			return fmt.Errorf("unable to find %v", binary)
+		}
+	}
+	return nil
+}
+
+// Exec executes nsenter commands in hostProcMountNsPath mount namespace
+func (ne *NSEnter) Exec(cmd string, args []string) exec.Cmd {
+	hostProcMountNsPath := filepath.Join(ne.hostRootFsPath, mountNsPath)
+	fullArgs := append([]string{fmt.Sprintf("--mount=%s", hostProcMountNsPath), "--"},
+		append([]string{ne.AbsHostPath(cmd)}, args...)...)
+	klog.V(5).Infof("Running nsenter command: %v %v", nsenterPath, fullArgs)
+	return ne.executor.Command(nsenterPath, fullArgs...)
+}
+
+// Command returns a command wrapped with nsenter
+func (ne *NSEnter) Command(cmd string, args ...string) exec.Cmd {
+	return ne.Exec(cmd, args)
+}
+
+// CommandContext returns a CommandContext wrapped with nsenter
+func (ne *NSEnter) CommandContext(ctx context.Context, cmd string, args ...string) exec.Cmd {
+	hostProcMountNsPath := filepath.Join(ne.hostRootFsPath, mountNsPath)
+	fullArgs := append([]string{fmt.Sprintf("--mount=%s", hostProcMountNsPath), "--"},
+		append([]string{ne.AbsHostPath(cmd)}, args...)...)
+	klog.V(5).Infof("Running nsenter command: %v %v", nsenterPath, fullArgs)
+	return ne.executor.CommandContext(ctx, nsenterPath, fullArgs...)
+}
+
+// LookPath returns a LookPath wrapped with nsenter
+func (ne *NSEnter) LookPath(file string) (string, error) {
+	return "", fmt.Errorf("not implemented, error looking up : %s", file)
+}
+
+// AbsHostPath returns the absolute runnable path for a specified command
+func (ne *NSEnter) AbsHostPath(command string) string {
+	path, ok := ne.paths[command]
+	if !ok {
+		return command
+	}
+	return path
+}
+
+// SupportsSystemd checks whether command systemd-run exists
+func (ne *NSEnter) SupportsSystemd() (string, bool) {
+	systemdRunPath, ok := ne.paths["systemd-run"]
+	return systemdRunPath, ok && systemdRunPath != ""
+}
+
+// EvalSymlinks returns the path name on the host after evaluating symlinks on the
+// host.
+// mustExist makes EvalSymlinks to return error when the path does not
+// exist. When it's false, it evaluates symlinks of the existing part and
+// blindly adds the non-existing part:
+// pathname: /mnt/volume/non/existing/directory
+//     /mnt/volume exists
+//                non/existing/directory does not exist
+// -> It resolves symlinks in /mnt/volume to say /mnt/foo and returns
+//    /mnt/foo/non/existing/directory.
+//
+// BEWARE! EvalSymlinks is not able to detect symlink looks with mustExist=false!
+// If /tmp/link is symlink to /tmp/link, EvalSymlinks(/tmp/link/foo) returns /tmp/link/foo.
+func (ne *NSEnter) EvalSymlinks(pathname string, mustExist bool) (string, error) {
+	var args []string
+	if mustExist {
+		// "realpath -e: all components of the path must exist"
+		args = []string{"-e", pathname}
+	} else {
+		// "realpath -m: no path components need exist or be a directory"
+		args = []string{"-m", pathname}
+	}
+	outBytes, err := ne.Exec("realpath", args).CombinedOutput()
+	if err != nil {
+		klog.Infof("failed to resolve symbolic links on %s: %v", pathname, err)
+		return "", err
+	}
+	return strings.TrimSpace(string(outBytes)), nil
+}
+
+// KubeletPath returns the path name that can be accessed by containerized
+// kubelet. It is recommended to resolve symlinks on the host by EvalSymlinks
+// before calling this function
+func (ne *NSEnter) KubeletPath(pathname string) string {
+	return filepath.Join(ne.hostRootFsPath, pathname)
+}
+
+// NewFakeNsenter returns a NSEnter that does not run "nsenter --mount=... --",
+// but runs everything in the same mount namespace as the unit test binary.
+// rootfsPath is supposed to be a symlink, e.g. /tmp/xyz/rootfs -> /.
+// This fake NSEnter is enough for most operations, e.g. to resolve symlinks,
+// but it's not enough to call /bin/mount - unit tests don't run as root.
+func NewFakeNsenter(rootfsPath string) (*NSEnter, error) {
+	executor := &fakeExec{
+		rootfsPath: rootfsPath,
+	}
+	// prepare /rootfs/bin, usr/bin and usr/sbin
+	bin := filepath.Join(rootfsPath, "bin")
+	if err := os.Symlink("/bin", bin); err != nil {
+		return nil, err
+	}
+
+	usr := filepath.Join(rootfsPath, "usr")
+	if err := os.Mkdir(usr, 0755); err != nil {
+		return nil, err
+	}
+	usrbin := filepath.Join(usr, "bin")
+	if err := os.Symlink("/usr/bin", usrbin); err != nil {
+		return nil, err
+	}
+	usrsbin := filepath.Join(usr, "sbin")
+	if err := os.Symlink("/usr/sbin", usrsbin); err != nil {
+		return nil, err
+	}
+
+	return NewNsenter(rootfsPath, executor)
+}
+
+type fakeExec struct {
+	rootfsPath string
+}
+
+func (f fakeExec) Command(cmd string, args ...string) exec.Cmd {
+	// This will intentionaly panic if NSEnter does not provide enough arguments.
+	realCmd := args[2]
+	realArgs := args[3:]
+	return exec.New().Command(realCmd, realArgs...)
+}
+
+func (fakeExec) LookPath(file string) (string, error) {
+	return "", errors.New("not implemented")
+}
+
+func (fakeExec) CommandContext(ctx context.Context, cmd string, args ...string) exec.Cmd {
+	return nil
+}
+
+var _ exec.Interface = fakeExec{}
+var _ exec.Interface = &NSEnter{}

vendor/k8s.io/utils/nsenter/nsenter_unsupported.go

@@ -0,0 +1,79 @@
+// +build !linux
+
+/*
+Copyright 2017 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 nsenter
+
+import (
+	"context"
+	"fmt"
+
+	"k8s.io/utils/exec"
+)
+
+const (
+	// DefaultHostRootFsPath is path to host's filesystem mounted into container
+	// with kubelet.
+	DefaultHostRootFsPath = "/rootfs"
+)
+
+// Nsenter is a type alias for backward compatibility
+type Nsenter = NSEnter
+
+// NSEnter is part of experimental support for running the kubelet
+// in a container.
+type NSEnter struct {
+	// a map of commands to their paths on the host filesystem
+	Paths map[string]string
+}
+
+// NewNsenter constructs a new instance of NSEnter
+func NewNsenter(hostRootFsPath string, executor exec.Interface) (*Nsenter, error) {
+	return &Nsenter{}, nil
+}
+
+// Exec executes nsenter commands in hostProcMountNsPath mount namespace
+func (ne *NSEnter) Exec(cmd string, args []string) exec.Cmd {
+	return nil
+}
+
+// AbsHostPath returns the absolute runnable path for a specified command
+func (ne *NSEnter) AbsHostPath(command string) string {
+	return ""
+}
+
+// SupportsSystemd checks whether command systemd-run exists
+func (ne *NSEnter) SupportsSystemd() (string, bool) {
+	return "", false
+}
+
+// Command returns a command wrapped with nenter
+func (ne *NSEnter) Command(cmd string, args ...string) exec.Cmd {
+	return nil
+}
+
+// CommandContext returns a CommandContext wrapped with nsenter
+func (ne *NSEnter) CommandContext(ctx context.Context, cmd string, args ...string) exec.Cmd {
+	return nil
+}
+
+// LookPath returns a LookPath wrapped with nsenter
+func (ne *NSEnter) LookPath(file string) (string, error) {
+	return "", fmt.Errorf("not implemented, error looking up : %s", file)
+}
+
+var _ exec.Interface = &NSEnter{}

vendor/k8s.io/utils/path/file.go

@@ -0,0 +1,78 @@
+/*
+Copyright 2017 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 path
+
+import (
+	"errors"
+	"os"
+)
+
+// LinkTreatment is the base type for constants used by Exists that indicate
+// how symlinks are treated for existence checks.
+type LinkTreatment int
+
+const (
+	// CheckFollowSymlink follows the symlink and verifies that the target of
+	// the symlink exists.
+	CheckFollowSymlink LinkTreatment = iota
+
+	// CheckSymlinkOnly does not follow the symlink and verfies only that they
+	// symlink itself exists.
+	CheckSymlinkOnly
+)
+
+// ErrInvalidLinkTreatment indicates that the link treatment behavior requested
+// is not a valid behavior.
+var ErrInvalidLinkTreatment = errors.New("unknown link behavior")
+
+// Exists checks if specified file, directory, or symlink exists. The behavior
+// of the test depends on the linkBehaviour argument. See LinkTreatment for
+// more details.
+func Exists(linkBehavior LinkTreatment, filename string) (bool, error) {
+	var err error
+
+	if linkBehavior == CheckFollowSymlink {
+		_, err = os.Stat(filename)
+	} else if linkBehavior == CheckSymlinkOnly {
+		_, err = os.Lstat(filename)
+	} else {
+		return false, ErrInvalidLinkTreatment
+	}
+
+	if os.IsNotExist(err) {
+		return false, nil
+	} else if err != nil {
+		return false, err
+	}
+	return true, nil
+}
+
+// ReadDirNoStat returns a string of files/directories contained
+// in dirname without calling lstat on them.
+func ReadDirNoStat(dirname string) ([]string, error) {
+	if dirname == "" {
+		dirname = "."
+	}
+
+	f, err := os.Open(dirname)
+	if err != nil {
+		return nil, err
+	}
+	defer f.Close()
+
+	return f.Readdirnames(-1)
+}

vendor/k8s.io/utils/trace/trace.go

@@ -0,0 +1,96 @@
+/*
+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 trace
+
+import (
+	"bytes"
+	"fmt"
+	"math/rand"
+	"time"
+
+	"k8s.io/klog"
+)
+
+type traceStep struct {
+	stepTime time.Time
+	msg      string
+}
+
+// Trace keeps track of a set of "steps" and allows us to log a specific
+// step if it took longer than its share of the total allowed time
+type Trace struct {
+	name      string
+	startTime time.Time
+	steps     []traceStep
+}
+
+// New creates a Trace with the specified name
+func New(name string) *Trace {
+	return &Trace{name, time.Now(), nil}
+}
+
+// Step adds a new step with a specific message
+func (t *Trace) Step(msg string) {
+	if t.steps == nil {
+		// traces almost always have less than 6 steps, do this to avoid more than a single allocation
+		t.steps = make([]traceStep, 0, 6)
+	}
+	t.steps = append(t.steps, traceStep{time.Now(), msg})
+}
+
+// Log is used to dump all the steps in the Trace
+func (t *Trace) Log() {
+	// an explicit logging request should dump all the steps out at the higher level
+	t.logWithStepThreshold(0)
+}
+
+func (t *Trace) logWithStepThreshold(stepThreshold time.Duration) {
+	var buffer bytes.Buffer
+	tracenum := rand.Int31()
+	endTime := time.Now()
+
+	totalTime := endTime.Sub(t.startTime)
+	buffer.WriteString(fmt.Sprintf("Trace[%d]: %q (started: %v) (total time: %v):\n", tracenum, t.name, t.startTime, totalTime))
+	lastStepTime := t.startTime
+	for _, step := range t.steps {
+		stepDuration := step.stepTime.Sub(lastStepTime)
+		if stepThreshold == 0 || stepDuration > stepThreshold || klog.V(4) {
+			buffer.WriteString(fmt.Sprintf("Trace[%d]: [%v] [%v] %v\n", tracenum, step.stepTime.Sub(t.startTime), stepDuration, step.msg))
+		}
+		lastStepTime = step.stepTime
+	}
+	stepDuration := endTime.Sub(lastStepTime)
+	if stepThreshold == 0 || stepDuration > stepThreshold || klog.V(4) {
+		buffer.WriteString(fmt.Sprintf("Trace[%d]: [%v] [%v] END\n", tracenum, endTime.Sub(t.startTime), stepDuration))
+	}
+
+	klog.Info(buffer.String())
+}
+
+// LogIfLong is used to dump steps that took longer than its share
+func (t *Trace) LogIfLong(threshold time.Duration) {
+	if time.Since(t.startTime) >= threshold {
+		// if any step took more than it's share of the total allowed time, it deserves a higher log level
+		stepThreshold := threshold / time.Duration(len(t.steps)+1)
+		t.logWithStepThreshold(stepThreshold)
+	}
+}
+
+// TotalTime can be used to figure out how long it took since the Trace was created
+func (t *Trace) TotalTime() time.Duration {
+	return time.Since(t.startTime)
+}