Fix the etcd version check and have it return the version string.

pkg/tools/etcd_tools.go

@@ -17,6 +17,7 @@ limitations under the License.
 package tools
 
 import (
+	"encoding/json"
 	"errors"
 	"fmt"
 	"io/ioutil"
@@ -24,7 +25,6 @@ import (
 	"os/exec"
 	"reflect"
 	"strconv"
-	"strings"
 
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/conversion"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
@@ -418,20 +418,35 @@ func (h *EtcdHelper) AtomicUpdate(key string, ptrToType runtime.Object, ignoreNo
 	}
 }
 
-func checkEtcd(host string) error {
+// GetEtcdVersion performs a version check against the provided Etcd server, returning a triplet
+// of the release version, internal version, and error (if any).
+func GetEtcdVersion(host string) (releaseVersion, internalVersion string, err error) {
 	response, err := http.Get(host + "/version")
 	if err != nil {
-		return err
+		return "", "", err
 	}
 	defer response.Body.Close()
+
 	body, err := ioutil.ReadAll(response.Body)
 	if err != nil {
-		return err
+		return "", "", err
 	}
-	if !strings.HasPrefix(string(body), "etcd") {
-		return fmt.Errorf("unknown server: %s", string(body))
+
+	var dat map[string]interface{}
+	if err := json.Unmarshal(body, &dat); err != nil {
+		return "", "", fmt.Errorf("unknown server: %s", string(body))
 	}
-	return nil
+	if obj := dat["releaseVersion"]; obj != nil {
+		if s, ok := obj.(string); ok {
+			releaseVersion = s
+		}
+	}
+	if obj := dat["internalVersion"]; obj != nil {
+		if s, ok := obj.(string); ok {
+			internalVersion = s
+		}
+	}
+	return
 }
 
 func startEtcd() (*exec.Cmd, error) {
@@ -444,7 +459,7 @@ func startEtcd() (*exec.Cmd, error) {
 }
 
 func NewEtcdClientStartServerIfNecessary(server string) (EtcdClient, error) {
-	err := checkEtcd(server)
+	_, _, err := GetEtcdVersion(server)
 	if err != nil {
 		glog.Infof("Failed to find etcd, attempting to start.")
 		_, err := startEtcd()

pkg/tools/etcd_tools_test.go

@@ -19,6 +19,8 @@ package tools
 import (
 	"errors"
 	"fmt"
+	"net/http"
+	"net/http/httptest"
 	"reflect"
 	"sync"
 	"testing"
@@ -29,6 +31,7 @@ import (
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/conversion"
 	"github.com/GoogleCloudPlatform/kubernetes/pkg/runtime"
 	"github.com/coreos/go-etcd/etcd"
+	"github.com/stretchr/testify/assert"
 )
 
 type TestResource struct {
@@ -608,3 +611,48 @@ func TestAtomicUpdate_CreateCollision(t *testing.T) {
 		t.Errorf("Some of the writes were lost. Stored value: %d", stored.Value)
 	}
 }
+
+func TestGetEtcdVersion_ValidVersion(t *testing.T) {
+	testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, "{\"releaseVersion\":\"2.0.3\",\"internalVersion\":\"2\"}")
+	}))
+	defer testServer.Close()
+
+	var relVersion string
+	var intVersion string
+	var err error
+	if relVersion, intVersion, err = GetEtcdVersion(testServer.URL); err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	assert.Equal(t, "2.0.3", relVersion, "Unexpected external version")
+	assert.Equal(t, "2", intVersion, "Unexpected internal version")
+	assert.Nil(t, err)
+}
+
+func TestGetEtcdVersion_UnknownVersion(t *testing.T) {
+	testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		fmt.Fprintln(w, "{\"unknownAttribute\":\"foobar\",\"internalVersion\":\"2\"}")
+	}))
+	defer testServer.Close()
+
+	var relVersion string
+	var intVersion string
+	var err error
+	if relVersion, intVersion, err = GetEtcdVersion(testServer.URL); err != nil {
+		t.Errorf("Unexpected error: %v", err)
+	}
+	assert.Equal(t, "", relVersion, "Unexpected external version")
+	assert.Equal(t, "2", intVersion, "Unexpected internal version")
+	assert.Nil(t, err)
+}
+
+func TestGetEtcdVersion_ErrorStatus(t *testing.T) {
+	testServer := httptest.NewServer(http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+		w.WriteHeader(http.StatusServiceUnavailable)
+	}))
+	defer testServer.Close()
+
+	var err error
+	_, _, err = GetEtcdVersion(testServer.URL)
+	assert.NotNil(t, err)
+}