Set a default user agent on all client.Client calls

Form:
  kube-controller-manager/v0.10.0 (linux/amd64) kubernetes/550b98e

  <basename(os.Argv)>/<gitVersion> (<GOOS>/<GOARCH>) kubernetes/<shortGitCommit>

Can be set by other clients

pkg/client/helper.go

@@ -21,8 +21,10 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/url"
+	"os"
 	"path"
 	"reflect"
+	gruntime "runtime"
 	"strings"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
@@ -68,6 +70,9 @@ type Config struct {
 	// certificate. For testing only.
 	Insecure bool
 
+	// UserAgent is an optional field that specifies the caller of this request.
+	UserAgent string
+
 	// Transport may be used for custom HTTP behavior. This attribute may not
 	// be specified with the TLS client certificate options.
 	Transport http.RoundTripper
@@ -151,6 +156,9 @@ func SetKubernetesDefaults(config *Config) error {
 	if config.Prefix == "" {
 		config.Prefix = "/api"
 	}
+	if len(config.UserAgent) == 0 {
+		config.UserAgent = DefaultKubernetesUserAgent()
+	}
 	if len(config.Version) == 0 {
 		config.Version = defaultVersionFor(config)
 	}
@@ -252,6 +260,9 @@ func HTTPWrappersForConfig(config *Config, rt http.RoundTripper) (http.RoundTrip
 	case hasBasicAuth:
 		rt = NewBasicAuthRoundTripper(config.Username, config.Password, rt)
 	}
+	if len(config.UserAgent) > 0 {
+		rt = NewUserAgentRoundTripper(config.UserAgent, rt)
+	}
 	return rt, nil
 }
 
@@ -353,3 +364,18 @@ func defaultVersionFor(config *Config) string {
 	}
 	return version
 }
+
+// DefaultKubernetesUserAgent returns the default user agent that clients can use.
+func DefaultKubernetesUserAgent() string {
+	commit := version.Get().GitCommit
+	if len(commit) > 7 {
+		commit = commit[:7]
+	}
+	if len(commit) == 0 {
+		commit = "unknown"
+	}
+	version := version.Get().GitVersion
+	seg := strings.SplitN(version, "-", 2)
+	version = seg[0]
+	return fmt.Sprintf("%s/%s (%s/%s) kubernetes/%s", path.Base(os.Args[0]), version, gruntime.GOOS, gruntime.GOARCH, commit)
+}

pkg/client/helper_test.go

@@ -18,7 +18,11 @@ package client
 
 import (
 	"net/http"
+	"reflect"
+	"strings"
 	"testing"
+
+	"github.com/GoogleCloudPlatform/kubernetes/pkg/api/latest"
 )
 
 const (
@@ -255,3 +259,57 @@ func TestIsConfigTransportTLS(t *testing.T) {
 		}
 	}
 }
+
+func TestSetKubernetesDefaults(t *testing.T) {
+	testCases := []struct {
+		Config Config
+		After  Config
+		Err    bool
+	}{
+		{
+			Config{},
+			Config{
+				Prefix:         "/api",
+				Version:        latest.Version,
+				Codec:          latest.Codec,
+				LegacyBehavior: (latest.Version == "v1beta1" || latest.Version == "v1beta2"),
+			},
+			false,
+		},
+		{
+			Config{
+				Version: "not_an_api",
+			},
+			Config{},
+			true,
+		},
+	}
+	for _, testCase := range testCases {
+		val := &testCase.Config
+		err := SetKubernetesDefaults(val)
+		val.UserAgent = ""
+		switch {
+		case err == nil && testCase.Err:
+			t.Errorf("expected error but was nil")
+			continue
+		case err != nil && !testCase.Err:
+			t.Errorf("unexpected error %v", err)
+			continue
+		case err != nil:
+			continue
+		}
+		if !reflect.DeepEqual(*val, testCase.After) {
+			t.Errorf("unexpected result object: %#v", val)
+		}
+	}
+}
+
+func TestSetKubernetesDefaultsUserAgent(t *testing.T) {
+	config := &Config{}
+	if err := SetKubernetesDefaults(config); err != nil {
+		t.Errorf("unexpected error: %v")
+	}
+	if !strings.Contains(config.UserAgent, "kubernetes/") {
+		t.Errorf("no user agent set: %#v", config)
+	}
+}

pkg/client/restclient_test.go

@@ -65,49 +65,6 @@ func TestSetsCodec(t *testing.T) {
 	}
 }
 
-func TestSetDefaults(t *testing.T) {
-	testCases := []struct {
-		Config Config
-		After  Config
-		Err    bool
-	}{
-		{
-			Config{},
-			Config{
-				Prefix:         "/api",
-				Version:        latest.Version,
-				Codec:          latest.Codec,
-				LegacyBehavior: (latest.Version == "v1beta1" || latest.Version == "v1beta2"),
-			},
-			false,
-		},
-		{
-			Config{
-				Version: "not_an_api",
-			},
-			Config{},
-			true,
-		},
-	}
-	for _, testCase := range testCases {
-		val := &testCase.Config
-		err := SetKubernetesDefaults(val)
-		switch {
-		case err == nil && testCase.Err:
-			t.Errorf("expected error but was nil")
-			continue
-		case err != nil && !testCase.Err:
-			t.Errorf("unexpected error %v", err)
-			continue
-		case err != nil:
-			continue
-		}
-		if !reflect.DeepEqual(*val, testCase.After) {
-			t.Errorf("unexpected result object: %#v", val)
-		}
-	}
-}
-
 func TestRESTClientRequires(t *testing.T) {
 	if _, err := RESTClientFor(&Config{Host: "127.0.0.1", Version: "", Codec: testapi.Codec()}); err == nil {
 		t.Errorf("unexpected non-error")

pkg/client/transport.go

@@ -23,6 +23,24 @@ import (
 	"net/http"
 )
 
+type userAgentRoundTripper struct {
+	agent string
+	rt    http.RoundTripper
+}
+
+func NewUserAgentRoundTripper(agent string, rt http.RoundTripper) http.RoundTripper {
+	return &userAgentRoundTripper{agent, rt}
+}
+
+func (rt *userAgentRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
+	if len(req.Header.Get("User-Agent")) != 0 {
+		return rt.rt.RoundTrip(req)
+	}
+	req = cloneRequest(req)
+	req.Header.Set("User-Agent", rt.agent)
+	return rt.rt.RoundTrip(req)
+}
+
 type basicAuthRoundTripper struct {
 	username string
 	password string

pkg/client/transport_test.go

@@ -69,3 +69,33 @@ func TestBasicAuthRoundTripper(t *testing.T) {
 		t.Errorf("unexpected authorization header: %#v", rt.Request)
 	}
 }
+
+func TestUserAgentRoundTripper(t *testing.T) {
+	rt := &testRoundTripper{}
+	req := &http.Request{
+		Header: make(http.Header),
+	}
+	req.Header.Set("User-Agent", "other")
+	NewUserAgentRoundTripper("test", rt).RoundTrip(req)
+	if rt.Request == nil {
+		t.Fatalf("unexpected nil request: %v", rt)
+	}
+	if rt.Request != req {
+		t.Fatalf("round tripper should not have copied request object: %#v", rt.Request)
+	}
+	if rt.Request.Header.Get("User-Agent") != "other" {
+		t.Errorf("unexpected user agent header: %#v", rt.Request)
+	}
+
+	req = &http.Request{}
+	NewUserAgentRoundTripper("test", rt).RoundTrip(req)
+	if rt.Request == nil {
+		t.Fatalf("unexpected nil request: %v", rt)
+	}
+	if rt.Request == req {
+		t.Fatalf("round tripper should have copied request object: %#v", rt.Request)
+	}
+	if rt.Request.Header.Get("User-Agent") != "test" {
+		t.Errorf("unexpected user agent header: %#v", rt.Request)
+	}
+}