improve kubeconfig file modification time

Trades runtime complexity for spacial complexity when modifying
large amounts of contexts on a kubeconfig.

In cases where there are few destination filenames for a given
amount of contexts, but a large amount of contexts, this patch
prevents reading and writing to the same file (or small number
of files) over and over again needlessly.
This commit is contained in:
juanvallejo 2018-08-07 15:13:57 -04:00
parent 733a381ec4
commit d5651948cf
No known key found for this signature in database
GPG Key ID: 7D2C958002D6448D
2 changed files with 63 additions and 7 deletions

View File

@ -126,6 +126,46 @@ func TestMergeContext(t *testing.T) {
matchStringArg(namespace, actual, t)
}
func TestModifyContext(t *testing.T) {
expectedCtx := map[string]bool{
"updated": true,
"clean": true,
}
pathOptions := NewDefaultPathOptions()
config := createValidTestConfig()
// define new context and assign it - our path options config
config.Contexts["updated"] = &clientcmdapi.Context{
Cluster: "updated",
AuthInfo: "updated",
}
config.CurrentContext = "updated"
if err := ModifyConfig(pathOptions, *config, true); err != nil {
t.Errorf("Unexpected error: %v", err)
}
startingConfig, err := pathOptions.GetStartingConfig()
if err != nil {
t.Fatalf("Unexpected error: %v", err)
}
// make sure the current context was updated
matchStringArg("updated", startingConfig.CurrentContext, t)
// there should now be two contexts
if len(startingConfig.Contexts) != len(expectedCtx) {
t.Fatalf("unexpected nuber of contexts, expecting %v, but found %v", len(expectedCtx), len(startingConfig.Contexts))
}
for key := range startingConfig.Contexts {
if !expectedCtx[key] {
t.Fatalf("expected context %q to exist", key)
}
}
}
func TestCertificateData(t *testing.T) {
caData := []byte("ca-data")
certData := []byte("cert-data")

View File

@ -220,6 +220,9 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
}
}
// seenConfigs stores a map of config source filenames to computed config objects
seenConfigs := map[string]*clientcmdapi.Config{}
for key, context := range newConfig.Contexts {
startingContext, exists := startingConfig.Contexts[key]
if !reflect.DeepEqual(context, startingContext) || !exists {
@ -228,15 +231,28 @@ func ModifyConfig(configAccess ConfigAccess, newConfig clientcmdapi.Config, rela
destinationFile = configAccess.GetDefaultFilename()
}
configToWrite, err := getConfigFromFile(destinationFile)
if err != nil {
return err
// we only obtain a fresh config object from its source file
// if we have not seen it already - this prevents us from
// reading and writing to the same number of files repeatedly
// when multiple / all contexts share the same destination file.
configToWrite, seen := seenConfigs[destinationFile]
if !seen {
var err error
configToWrite, err = getConfigFromFile(destinationFile)
if err != nil {
return err
}
seenConfigs[destinationFile] = configToWrite
}
configToWrite.Contexts[key] = context
if err := WriteToFile(*configToWrite, destinationFile); err != nil {
return err
}
configToWrite.Contexts[key] = context
}
}
// actually persist config object changes
for destinationFile, configToWrite := range seenConfigs {
if err := WriteToFile(*configToWrite, destinationFile); err != nil {
return err
}
}