Merge pull request #57259 from ericchiang/client-go-no-cache-import

Automatic merge from submit-queue. 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>.

client-go: remove import of github.com/gregjones/httpcache

Moves NewCacheRoundTripper from `k8s.io/client-go/transport` to its own package. This prevents Kubernetes clients from requiring its dependencies.

This change removes the following transitive imports from `k8s.io/client-go/kubernetes`

```
github.com/google/btree
github.com/gregjones/httpcache
github.com/gregjones/httpcache/diskcache
github.com/peterbourgon/diskv
```

```release-note
NONE
```

Kubernetes-commit: 4a77bd53e88a719c612086df69a52899bbdd85af

vendor/k8s.io/client-go/rest/config.go

@@ -71,10 +71,6 @@ type Config struct {
 	// TODO: demonstrate an OAuth2 compatible client.
 	BearerToken string
 
-	// CacheDir is the directory where we'll store HTTP cached responses.
-	// If set to empty string, no caching mechanism will be used.
-	CacheDir string
-
 	// Impersonate is the configuration that RESTClient will use for impersonation.
 	Impersonate ImpersonationConfig
 
@@ -434,7 +430,6 @@ func CopyConfig(config *Config) *Config {
 		Username:      config.Username,
 		Password:      config.Password,
 		BearerToken:   config.BearerToken,
-		CacheDir:      config.CacheDir,
 		Impersonate: ImpersonationConfig{
 			Groups:   config.Impersonate.Groups,
 			Extra:    config.Impersonate.Extra,

vendor/k8s.io/client-go/rest/transport.go

@@ -89,7 +89,6 @@ func (c *Config) TransportConfig() (*transport.Config, error) {
 		},
 		Username:    c.Username,
 		Password:    c.Password,
-		CacheDir:    c.CacheDir,
 		BearerToken: c.BearerToken,
 		Impersonate: transport.ImpersonationConfig{
 			UserName: c.Impersonate.UserName,

vendor/k8s.io/client-go/transport/BUILD

@@ -28,9 +28,6 @@ go_library(
     importpath = "k8s.io/client-go/transport",
     deps = [
         "//vendor/github.com/golang/glog:go_default_library",
-        "//vendor/github.com/gregjones/httpcache:go_default_library",
-        "//vendor/github.com/gregjones/httpcache/diskcache:go_default_library",
-        "//vendor/github.com/peterbourgon/diskv:go_default_library",
         "//vendor/k8s.io/apimachinery/pkg/util/net:go_default_library",
     ],
 )

vendor/k8s.io/client-go/transport/config.go

@@ -37,10 +37,6 @@ type Config struct {
 	// Bearer token for authentication
 	BearerToken string
 
-	// CacheDir is the directory where we'll store HTTP cached responses.
-	// If set to empty string, no caching mechanism will be used.
-	CacheDir string
-
 	// Impersonate is the config that this Config will impersonate using
 	Impersonate ImpersonationConfig
 

vendor/k8s.io/client-go/transport/round_trippers.go

@@ -19,14 +19,10 @@ package transport
 import (
 	"fmt"
 	"net/http"
-	"path/filepath"
 	"strings"
 	"time"
 
 	"github.com/golang/glog"
-	"github.com/gregjones/httpcache"
-	"github.com/gregjones/httpcache/diskcache"
-	"github.com/peterbourgon/diskv"
 
 	utilnet "k8s.io/apimachinery/pkg/util/net"
 )
@@ -60,9 +56,6 @@ func HTTPWrappersForConfig(config *Config, rt http.RoundTripper) (http.RoundTrip
 		len(config.Impersonate.Extra) > 0 {
 		rt = NewImpersonatingRoundTripper(config.Impersonate, rt)
 	}
-	if len(config.CacheDir) > 0 {
-		rt = NewCacheRoundTripper(config.CacheDir, rt)
-	}
 	return rt, nil
 }
 
@@ -86,30 +79,6 @@ type requestCanceler interface {
 	CancelRequest(*http.Request)
 }
 
-type cacheRoundTripper struct {
-	rt *httpcache.Transport
-}
-
-// NewCacheRoundTripper creates a roundtripper that reads the ETag on
-// response headers and send the If-None-Match header on subsequent
-// corresponding requests.
-func NewCacheRoundTripper(cacheDir string, rt http.RoundTripper) http.RoundTripper {
-	d := diskv.New(diskv.Options{
-		BasePath: cacheDir,
-		TempDir:  filepath.Join(cacheDir, ".diskv-temp"),
-	})
-	t := httpcache.NewTransport(diskcache.NewWithDiskv(d))
-	t.Transport = rt
-
-	return &cacheRoundTripper{rt: t}
-}
-
-func (rt *cacheRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
-	return rt.rt.RoundTrip(req)
-}
-
-func (rt *cacheRoundTripper) WrappedRoundTripper() http.RoundTripper { return rt.rt.Transport }
-
 type authProxyRoundTripper struct {
 	username string
 	groups   []string