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Merge pull request #6059 from tstromberg/clock
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lock names: Remove uid suffix & hash entire path
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tstromberg authored Dec 11, 2019
2 parents 8666e22 + d811f6e commit 8d3fed0
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Showing 4 changed files with 36 additions and 52 deletions.
2 changes: 1 addition & 1 deletion pkg/minikube/bootstrapper/certs.go
Original file line number Diff line number Diff line change
Expand Up @@ -70,7 +70,7 @@ func SetupCerts(cmd command.Runner, k8s config.KubernetesConfig) error {
//
// If another process updates the shared certificate, it's invalid.
// TODO: Instead of racey manipulation of a shared certificate, use per-profile certs
spec := lock.UserMutexSpec(filepath.Join(localPath, "certs"))
spec := lock.PathMutexSpec(filepath.Join(localPath, "certs"))
glog.Infof("acquiring lock: %+v", spec)
releaser, err := mutex.Acquire(spec)
if err != nil {
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2 changes: 1 addition & 1 deletion pkg/minikube/kubeconfig/settings.go
Original file line number Diff line number Diff line change
Expand Up @@ -119,7 +119,7 @@ func PopulateFromSettings(cfg *Settings, apiCfg *api.Config) error {
// activeContext is true when minikube is the CurrentContext
// If no CurrentContext is set, the given name will be used.
func Update(kcs *Settings) error {
spec := lock.UserMutexSpec(filepath.Join(kcs.filePath(), "settings.Update"))
spec := lock.PathMutexSpec(filepath.Join(kcs.filePath(), "settings.Update"))
glog.Infof("acquiring lock: %+v", spec)
releaser, err := mutex.Acquire(spec)
if err != nil {
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46 changes: 8 additions & 38 deletions pkg/util/lock/lock.go
Original file line number Diff line number Diff line change
Expand Up @@ -17,12 +17,10 @@ limitations under the License.
package lock

import (
"crypto/sha1"
"fmt"
"io/ioutil"
"os"
"os/user"
"regexp"
"strings"
"time"

"github.com/golang/glog"
Expand All @@ -31,42 +29,27 @@ import (
"github.com/pkg/errors"
)

var (
// nonString is characters to strip from lock names
nonString = regexp.MustCompile(`[\W_]+`)
// forceID is a user id for consistent testing
forceID = ""
)

// WriteFile decorates ioutil.WriteFile with a file lock and retry
func WriteFile(filename string, data []byte, perm os.FileMode) error {
spec := UserMutexSpec(filename)
glog.Infof("acquiring lock for %s: %+v", filename, spec)
spec := PathMutexSpec(filename)
glog.Infof("WriteFile acquiring %s: %+v", filename, spec)
releaser, err := mutex.Acquire(spec)
if err != nil {
return errors.Wrapf(err, "error acquiring lock for %s", filename)
return errors.Wrapf(err, "failed to acquire lock for %s: %+v", filename, spec)
}

defer releaser.Release()

if err = ioutil.WriteFile(filename, data, perm); err != nil {
return errors.Wrapf(err, "error writing file %s", filename)
return errors.Wrapf(err, "writefile failed for %s", filename)
}
return err
}

// UserMutexSpec returns a mutex spec that will not collide with other users
func UserMutexSpec(path string) mutex.Spec {
id := forceID
if forceID == "" {
u, err := user.Current()
if err == nil {
id = u.Uid
}
}

// PathMutexSpec returns a mutex spec for a path
func PathMutexSpec(path string) mutex.Spec {
s := mutex.Spec{
Name: getMutexNameForPath(fmt.Sprintf("%s-%s", path, id)),
Name: fmt.Sprintf("mk%x", sha1.Sum([]byte(path)))[0:40],
Clock: clock.WallClock,
// Poll the lock twice a second
Delay: 500 * time.Millisecond,
Expand All @@ -75,16 +58,3 @@ func UserMutexSpec(path string) mutex.Spec {
}
return s
}

func getMutexNameForPath(path string) string {
// juju requires that names match ^[a-zA-Z][a-zA-Z0-9-]*$", and be under 40 chars long.
n := strings.Trim(nonString.ReplaceAllString(path, "-"), "-")
// we need to always guarantee an alphanumeric prefix
prefix := "m"

// Prefer the last 40 chars, as paths tend get more specific toward the end
if len(n) >= 40 {
return prefix + n[len(n)-39:]
}
return prefix + n
}
38 changes: 26 additions & 12 deletions pkg/util/lock/lock_test.go
Original file line number Diff line number Diff line change
Expand Up @@ -16,11 +16,13 @@ limitations under the License.

package lock

import "testing"
import (
"testing"

func TestUserMutexSpec(t *testing.T) {
forceID = "test"
"github.com/juju/mutex"
)

func TestUserMutexSpec(t *testing.T) {
var tests = []struct {
description string
path string
Expand All @@ -29,41 +31,53 @@ func TestUserMutexSpec(t *testing.T) {
{
description: "standard",
path: "/foo/bar",
expected: "mfoo-bar-test",
},
{
description: "deep directory",
path: "/foo/bar/baz/bat",
expected: "mfoo-bar-baz-bat-test",
},
{
description: "underscores",
path: "/foo_bar/baz",
expected: "mfoo-bar-baz-test",
},
{
description: "starts with number",
path: "/foo/2bar/baz",
expected: "mfoo-2bar-baz-test",
},
{
description: "starts with punctuation",
path: "/.foo/bar",
expected: "mfoo-bar-test",
},
{
description: "long filename",
path: "/very-very-very-very-very-very-very-very-long/bar",
expected: "m-very-very-very-very-very-long-bar-test",
},
{
description: "Windows kubeconfig",
path: `C:\Users\admin/.kube/config`,
},
{
description: "Windows json",
path: `C:\Users\admin\.minikube\profiles\containerd-20191210T212325.7356633-8584\config.json`,
},
}

seen := map[string]string{}

for _, tc := range tests {
t.Run(tc.description, func(t *testing.T) {
got := UserMutexSpec(tc.path)
if got.Name != tc.expected {
t.Errorf("%s mutex name = %q, expected %q", tc.path, got.Name, tc.expected)
got := PathMutexSpec(tc.path)
if len(got.Name) != 40 {
t.Errorf("%s is not 40 chars long", got.Name)
}
if seen[got.Name] != "" {
t.Fatalf("lock name collision between %s and %s", tc.path, seen[got.Name])
}
m, err := mutex.Acquire(got)
if err != nil {
t.Errorf("acquire for spec %+v failed: %v", got, err)
}
m.Release()
})
}
}

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