Add global timeout flag

This patch adds a global timeout flag (viewable with `kubectl -h`) with
a default value of `0s` (meaning no timeout).

The timeout value is added to the default http client, so that zero
values and default behavior are enforced by the client.

**Example**
```
$ kubectl get pods # no timeout flag set - default to 0s (which means no
timeout)
NAME                      READY     STATUS    RESTARTS   AGE
docker-registry-1-h7etw   1/1       Running   1          2h
router-1-uv0f9            1/1       Running   1          2h

$ kubectl get pods --timeout=0 # zero means no timeout no timeout flag set
NAME                      READY     STATUS    RESTARTS   AGE
docker-registry-1-h7etw   1/1       Running   1          2h
router-1-uv0f9            1/1       Running   1          2h

$kubectl get pods --timeout=1ms
Unable to connect to the server: net/http: request canceled while
waiting for connection (Client.Timeout exceeded while awaiting headers)
```

hack/make-rules/test-cmd.sh

@@ -1033,6 +1033,32 @@ __EOF__
   # Clean up
   kubectl delete deployment nginx "${kube_flags[@]}"
 
+  ##################
+  # Global timeout #
+  ##################
+
+  ### Test global request timeout option
+  # Pre-condition: no POD exists
+  create_and_use_new_namespace
+  kube::test::get_object_assert pods "{{range.items}}{{$id_field}}:{{end}}" ''
+  # Command
+  kubectl create "${kube_flags[@]}" -f test/fixtures/doc-yaml/admin/limitrange/valid-pod.yaml
+  # Post-condition: valid-pod POD is created
+  kubectl get "${kube_flags[@]}" pods -o json
+  kube::test::get_object_assert pods "{{range.items}}{{$id_field}}:{{end}}" 'valid-pod:'
+
+  ## check --request-timeout on 'get pod'
+  output_message=$(kubectl get pod valid-pod --request-timeout=1s)
+  kube::test::if_has_string "${output_message}" 'valid-pod'
+
+  ## check --request-timeout on 'get pod' with --watch
+  output_message=$(! kubectl get pod valid-pod --request-timeout=1s --watch 2>&1)
+  kube::test::if_has_string "${output_message}" 'Timeout exceeded while reading body'
+
+  ## check argument validation for --request-timeout flag
+  output_message=$(! kubectl get pod valid-pod --request-timeout=1)
+  kube::test::if_has_string "${output_message}" 'invalid argument "1"'
+
   ###############
   # Kubectl get #
   ###############

pkg/client/restclient/config.go

@@ -25,6 +25,7 @@ import (
 	"path"
 	gruntime "runtime"
 	"strings"
+	"time"
 
 	"github.com/golang/glog"
 
@@ -109,6 +110,9 @@ type Config struct {
 	// Rate limiter for limiting connections to the master from this client. If present overwrites QPS/Burst
 	RateLimiter flowcontrol.RateLimiter
 
+	// The maximum length of time to wait before giving up on a server request. A value of zero means no timeout.
+	Timeout time.Duration
+
 	// Version forces a specific version to be used (if registered)
 	// Do we need this?
 	// Version string
@@ -185,6 +189,9 @@ func RESTClientFor(config *Config) (*RESTClient, error) {
 	var httpClient *http.Client
 	if transport != http.DefaultTransport {
 		httpClient = &http.Client{Transport: transport}
+		if config.Timeout > 0 {
+			httpClient.Timeout = config.Timeout
+		}
 	}
 
 	return NewRESTClient(baseURL, versionedAPIPath, config.ContentConfig, qps, burst, config.RateLimiter, httpClient)
@@ -210,6 +217,9 @@ func UnversionedRESTClientFor(config *Config) (*RESTClient, error) {
 	var httpClient *http.Client
 	if transport != http.DefaultTransport {
 		httpClient = &http.Client{Transport: transport}
+		if config.Timeout > 0 {
+			httpClient.Timeout = config.Timeout
+		}
 	}
 
 	versionConfig := config.ContentConfig

pkg/client/unversioned/clientcmd/client_config.go

@@ -108,6 +108,7 @@ func (config *DirectClientConfig) ClientConfig() (*restclient.Config, error) {
 
 	clientConfig := &restclient.Config{}
 	clientConfig.Host = configClusterInfo.Server
+	clientConfig.Timeout = config.overrides.Timeout
 	if u, err := url.ParseRequestURI(clientConfig.Host); err == nil && u.Opaque == "" && len(u.Path) > 1 {
 		u.RawQuery = ""
 		u.Fragment = ""

pkg/client/unversioned/clientcmd/overrides.go

@@ -18,6 +18,7 @@ package clientcmd
 
 import (
 	"strconv"
+	"time"
 
 	"github.com/spf13/pflag"
 
@@ -33,6 +34,7 @@ type ConfigOverrides struct {
 	ClusterInfo     clientcmdapi.Cluster
 	Context         clientcmdapi.Context
 	CurrentContext  string
+	Timeout         time.Duration
 }
 
 // ConfigOverrideFlags holds the flag names to be used for binding command line flags.  Notice that this structure tightly
@@ -42,6 +44,7 @@ type ConfigOverrideFlags struct {
 	ClusterOverrideFlags ClusterOverrideFlags
 	ContextOverrideFlags ContextOverrideFlags
 	CurrentContext       FlagInfo
+	Timeout              FlagInfo
 }
 
 // AuthOverrideFlags holds the flag names to be used for binding command line flags for AuthInfo objects
@@ -105,6 +108,20 @@ func (f FlagInfo) BindBoolFlag(flags *pflag.FlagSet, target *bool) {
 	}
 }
 
+// BindDurationFlag binds the flag based on the provided info.  If LongName == "", nothing is registered
+func (f FlagInfo) BindDurationFlag(flags *pflag.FlagSet, target *time.Duration) {
+	// you can't register a flag without a long name
+	if len(f.LongName) > 0 {
+		// try to parse Default as a Duration.  If it fails, default to 0s
+		durationVal, err := time.ParseDuration(f.Default)
+		if err != nil {
+			durationVal = 0
+		}
+
+		flags.DurationVarP(target, f.LongName, f.ShortName, durationVal, f.Description)
+	}
+}
+
 const (
 	FlagClusterName  = "cluster"
 	FlagAuthInfoName = "user"
@@ -121,6 +138,7 @@ const (
 	FlagImpersonate  = "as"
 	FlagUsername     = "username"
 	FlagPassword     = "password"
+	FlagTimeout      = "request-timeout"
 )
 
 // RecommendedAuthOverrideFlags is a convenience method to return recommended flag names prefixed with a string of your choosing
@@ -151,7 +169,9 @@ func RecommendedConfigOverrideFlags(prefix string) ConfigOverrideFlags {
 		AuthOverrideFlags:    RecommendedAuthOverrideFlags(prefix),
 		ClusterOverrideFlags: RecommendedClusterOverrideFlags(prefix),
 		ContextOverrideFlags: RecommendedContextOverrideFlags(prefix),
-		CurrentContext:       FlagInfo{prefix + FlagContext, "", "", "The name of the kubeconfig context to use"},
+
+		CurrentContext: FlagInfo{prefix + FlagContext, "", "", "The name of the kubeconfig context to use"},
+		Timeout:        FlagInfo{prefix + FlagTimeout, "", "", "The length of time to wait before giving up on a single server request. Non-zero values should contain a corresponding time unit (e.g. 1s, 2m, 3h). A value of zero means don't timeout requests."},
 	}
 }
 
@@ -190,6 +210,7 @@ func BindOverrideFlags(overrides *ConfigOverrides, flags *pflag.FlagSet, flagNam
 	BindClusterFlags(&overrides.ClusterInfo, flags, flagNames.ClusterOverrideFlags)
 	BindContextFlags(&overrides.Context, flags, flagNames.ContextOverrideFlags)
 	flagNames.CurrentContext.BindStringFlag(flags, &overrides.CurrentContext)
+	flagNames.Timeout.BindDurationFlag(flags, &overrides.Timeout)
 }
 
 // BindFlags is a convenience method to bind the specified flags to their associated variables