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Lock all possible kubecfg files at the beginning of ModifyConfig. #28232

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merged 1 commit into from
Jun 30, 2016
Merged

Lock all possible kubecfg files at the beginning of ModifyConfig. #28232

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85 changes: 69 additions & 16 deletions pkg/client/unversioned/clientcmd/config.go
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Original file line number Diff line number Diff line change
Expand Up @@ -22,6 +22,7 @@ import (
"path"
"path/filepath"
"reflect"
"sort"

"github.com/golang/glog"

Expand Down Expand Up @@ -153,6 +154,17 @@ func NewDefaultPathOptions() *PathOptions {
// that means that this code will only write into a single file. If you want to relativizePaths, you must provide a fully qualified path in any
// modified element.
func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, relativizePaths bool) error {
possibleSources := configAccess.GetLoadingPrecedence()
// sort the possible kubeconfig files so we always "lock" in the same order
// to avoid deadlock (note: this can fail w/ symlinks, but... come on).
sort.Strings(possibleSources)
for _, filename := range possibleSources {
if err := lockFile(filename); err != nil {
return err
}
defer unlockFile(filename)
}

startingConfig, err := configAccess.GetStartingConfig()
if err != nil {
return err
Expand Down Expand Up @@ -186,7 +198,10 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}

configToWrite := GetConfigFromFileOrDie(destinationFile)
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
t := *cluster

configToWrite.Clusters[key] = &t
Expand All @@ -211,7 +226,10 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}

configToWrite := GetConfigFromFileOrDie(destinationFile)
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
configToWrite.Contexts[key] = context

if err := WriteToFile(*configToWrite, destinationFile); err != nil {
Expand All @@ -228,7 +246,10 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}

configToWrite := GetConfigFromFileOrDie(destinationFile)
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
t := *authInfo
configToWrite.AuthInfos[key] = &t
configToWrite.AuthInfos[key].LocationOfOrigin = destinationFile
Expand All @@ -251,7 +272,10 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}

configToWrite := GetConfigFromFileOrDie(destinationFile)
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
delete(configToWrite.Clusters, key)

if err := WriteToFile(*configToWrite, destinationFile); err != nil {
Expand All @@ -267,7 +291,10 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}

configToWrite := GetConfigFromFileOrDie(destinationFile)
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
delete(configToWrite.Contexts, key)

if err := WriteToFile(*configToWrite, destinationFile); err != nil {
Expand All @@ -283,7 +310,10 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}

configToWrite := GetConfigFromFileOrDie(destinationFile)
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
delete(configToWrite.AuthInfos, key)

if err := WriteToFile(*configToWrite, destinationFile); err != nil {
Expand Down Expand Up @@ -330,7 +360,10 @@ func writeCurrentContext(configAccess ConfigAccess, newCurrentContext string) er

if configAccess.IsExplicitFile() {
file := configAccess.GetExplicitFile()
currConfig := GetConfigFromFileOrDie(file)
currConfig, err := getConfigFromFile(file)
if err != nil {
return err
}
currConfig.CurrentContext = newCurrentContext
if err := WriteToFile(*currConfig, file); err != nil {
return err
Expand All @@ -341,7 +374,10 @@ func writeCurrentContext(configAccess ConfigAccess, newCurrentContext string) er

if len(newCurrentContext) > 0 {
destinationFile := configAccess.GetDefaultFilename()
config := GetConfigFromFileOrDie(destinationFile)
config, err := getConfigFromFile(destinationFile)
if err != nil {
return err
}
config.CurrentContext = newCurrentContext

if err := WriteToFile(*config, destinationFile); err != nil {
Expand All @@ -354,7 +390,10 @@ func writeCurrentContext(configAccess ConfigAccess, newCurrentContext string) er
// we're supposed to be clearing the current context. We need to find the first spot in the chain that is setting it and clear it
for _, file := range configAccess.GetLoadingPrecedence() {
if _, err := os.Stat(file); err == nil {
currConfig := GetConfigFromFileOrDie(file)
currConfig, err := getConfigFromFile(file)
if err != nil {
return err
}

if len(currConfig.CurrentContext) > 0 {
currConfig.CurrentContext = newCurrentContext
Expand All @@ -379,7 +418,10 @@ func writePreferences(configAccess ConfigAccess, newPrefs clientcmdapi.Preferenc

if configAccess.IsExplicitFile() {
file := configAccess.GetExplicitFile()
currConfig := GetConfigFromFileOrDie(file)
currConfig, err := getConfigFromFile(file)
if err != nil {
return err
}
currConfig.Preferences = newPrefs
if err := WriteToFile(*currConfig, file); err != nil {
return err
Expand All @@ -389,7 +431,10 @@ func writePreferences(configAccess ConfigAccess, newPrefs clientcmdapi.Preferenc
}

for _, file := range configAccess.GetLoadingPrecedence() {
currConfig := GetConfigFromFileOrDie(file)
currConfig, err := getConfigFromFile(file)
if err != nil {
return err
}

if !reflect.DeepEqual(currConfig.Preferences, newPrefs) {
currConfig.Preferences = newPrefs
Expand All @@ -404,15 +449,23 @@ func writePreferences(configAccess ConfigAccess, newPrefs clientcmdapi.Preferenc
return errors.New("no config found to write preferences")
}

// GetConfigFromFileOrDie tries to read a kubeconfig file and if it can't, it calls exit. One exception, missing files result in empty configs, not an exit
func GetConfigFromFileOrDie(filename string) *clientcmdapi.Config {
// getConfigFromFile tries to read a kubeconfig file and if it can't, returns an error. One exception, missing files result in empty configs, not an error.
func getConfigFromFile(filename string) (*clientcmdapi.Config, error) {
config, err := LoadFromFile(filename)
if err != nil && !os.IsNotExist(err) {
glog.FatalDepth(1, err)
return nil, err
}

if config == nil {
return clientcmdapi.NewConfig()
config = clientcmdapi.NewConfig()
}
return config, nil
}

// GetConfigFromFileOrDie tries to read a kubeconfig file and if it can't, it calls exit. One exception, missing files result in empty configs, not an exit
func GetConfigFromFileOrDie(filename string) *clientcmdapi.Config {
config, err := getConfigFromFile(filename)
if err != nil {
glog.FatalDepth(1, err)
}

return config
Expand Down
14 changes: 8 additions & 6 deletions pkg/client/unversioned/clientcmd/loader.go
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Original file line number Diff line number Diff line change
Expand Up @@ -382,12 +382,6 @@ func WriteToFile(config clientcmdapi.Config, filename string) error {
}
}

err = lockFile(filename)
if err != nil {
return err
}
defer unlockFile(filename)

if err := ioutil.WriteFile(filename, content, 0600); err != nil {
return err
}
Expand All @@ -397,6 +391,14 @@ func WriteToFile(config clientcmdapi.Config, filename string) error {
func lockFile(filename string) error {
// TODO: find a way to do this with actual file locks. Will
// probably need seperate solution for windows and linux.

// Make sure the dir exists before we try to create a lock file.
dir := filepath.Dir(filename)
if _, err := os.Stat(dir); os.IsNotExist(err) {
if err = os.MkdirAll(dir, 0755); err != nil {
return err
}
}
f, err := os.OpenFile(lockName(filename), os.O_CREATE|os.O_EXCL, 0)
if err != nil {
return err
Expand Down