Vendor update with github.com/ugorji/go and github.com/apache/thrift pinning (#1805)

This fix is an vendor update. Both ugorji and thrift have to be pinned
to compile. The ugorji is from etcd and thrift is from zipkin.

This fix fixes #1802.

Signed-off-by: Yong Tang <yong.tang.github@outlook.com>

vendor/github.com/rcrowley/go-metrics/registry.go

@@ -54,7 +54,7 @@ type Registry interface {
 // of names to metrics.
 type StandardRegistry struct {
 	metrics map[string]interface{}
-	mutex   sync.Mutex
+	mutex   sync.RWMutex
 }
 
 // Create a new registry.
@@ -71,8 +71,8 @@ func (r *StandardRegistry) Each(f func(string, interface{})) {
 
 // Get the metric by the given name or nil if none is registered.
 func (r *StandardRegistry) Get(name string) interface{} {
-	r.mutex.Lock()
-	defer r.mutex.Unlock()
+	r.mutex.RLock()
+	defer r.mutex.RUnlock()
 	return r.metrics[name]
 }
 
@@ -81,6 +81,15 @@ func (r *StandardRegistry) Get(name string) interface{} {
 // The interface can be the metric to register if not found in registry,
 // or a function returning the metric for lazy instantiation.
 func (r *StandardRegistry) GetOrRegister(name string, i interface{}) interface{} {
+	// access the read lock first which should be re-entrant
+	r.mutex.RLock()
+	metric, ok := r.metrics[name]
+	r.mutex.RUnlock()
+	if ok {
+		return metric
+	}
+
+	// only take the write lock if we'll be modifying the metrics map
 	r.mutex.Lock()
 	defer r.mutex.Unlock()
 	if metric, ok := r.metrics[name]; ok {
@@ -103,8 +112,8 @@ func (r *StandardRegistry) Register(name string, i interface{}) error {
 
 // Run all registered healthchecks.
 func (r *StandardRegistry) RunHealthchecks() {
-	r.mutex.Lock()
-	defer r.mutex.Unlock()
+	r.mutex.RLock()
+	defer r.mutex.RUnlock()
 	for _, i := range r.metrics {
 		if h, ok := i.(Healthcheck); ok {
 			h.Check()