diff --git a/core/hash/consistenthash.go b/core/hash/consistenthash.go
index 7a652fd0..b719a672 100644
--- a/core/hash/consistenthash.go
+++ b/core/hash/consistenthash.go
@@ -11,6 +11,7 @@ import (
 )
 
 const (
+	// TopWeight is the top weight that one entry might set.
 	TopWeight = 100
 
 	minReplicas = 100
@@ -18,10 +19,12 @@ const (
 )
 
 type (
-	HashFunc func(data []byte) uint64
+	// Func defines the hash method.
+	Func func(data []byte) uint64
 
+	// A ConsistentHash is a ring hash implementation.
 	ConsistentHash struct {
-		hashFunc HashFunc
+		hashFunc Func
 		replicas int
 		keys     []uint64
 		ring     map[uint64][]interface{}
@@ -30,11 +33,13 @@ type (
 	}
 )
 
+// NewConsistentHash returns a ConsistentHash.
 func NewConsistentHash() *ConsistentHash {
 	return NewCustomConsistentHash(minReplicas, Hash)
 }
 
-func NewCustomConsistentHash(replicas int, fn HashFunc) *ConsistentHash {
+// NewCustomConsistentHash returns a ConsistentHash with given replicas and hash func.
+func NewCustomConsistentHash(replicas int, fn Func) *ConsistentHash {
 	if replicas < minReplicas {
 		replicas = minReplicas
 	}
@@ -92,6 +97,7 @@ func (h *ConsistentHash) AddWithWeight(node interface{}, weight int) {
 	h.AddWithReplicas(node, replicas)
 }
 
+// Get returns the corresponding node from h base on the given v.
 func (h *ConsistentHash) Get(v interface{}) (interface{}, bool) {
 	h.lock.RLock()
 	defer h.lock.RUnlock()
@@ -118,6 +124,7 @@ func (h *ConsistentHash) Get(v interface{}) (interface{}, bool) {
 	}
 }
 
+// Remove removes the given node from h.
 func (h *ConsistentHash) Remove(node interface{}) {
 	nodeRepr := repr(node)
 
diff --git a/core/hash/consistenthash_test.go b/core/hash/consistenthash_test.go
index 162d1704..989a8d51 100644
--- a/core/hash/consistenthash_test.go
+++ b/core/hash/consistenthash_test.go
@@ -132,8 +132,8 @@ func TestConsistentHash_RemoveInterface(t *testing.T) {
 	assert.Equal(t, 1, len(ch.nodes))
 	node, ok := ch.Get(1)
 	assert.True(t, ok)
-	assert.Equal(t, key, node.(*MockNode).Addr)
-	assert.Equal(t, 2, node.(*MockNode).Id)
+	assert.Equal(t, key, node.(*mockNode).addr)
+	assert.Equal(t, 2, node.(*mockNode).id)
 }
 
 func getKeysBeforeAndAfterFailure(t *testing.T, prefix string, index int) (map[int]string, map[int]string) {
@@ -164,18 +164,18 @@ func getKeysBeforeAndAfterFailure(t *testing.T, prefix string, index int) (map[i
 	return keys, newKeys
 }
 
-type MockNode struct {
-	Addr string
-	Id   int
+type mockNode struct {
+	addr string
+	id   int
 }
 
-func newMockNode(addr string, id int) *MockNode {
-	return &MockNode{
-		Addr: addr,
-		Id:   id,
+func newMockNode(addr string, id int) *mockNode {
+	return &mockNode{
+		addr: addr,
+		id:   id,
 	}
 }
 
-func (n *MockNode) String() string {
-	return n.Addr
+func (n *mockNode) String() string {
+	return n.addr
 }
diff --git a/core/hash/hash.go b/core/hash/hash.go
index 3cc562fd..8bd87b59 100644
--- a/core/hash/hash.go
+++ b/core/hash/hash.go
@@ -7,16 +7,19 @@ import (
 	"github.com/spaolacci/murmur3"
 )
 
+// Hash returns the hash value of data.
 func Hash(data []byte) uint64 {
 	return murmur3.Sum64(data)
 }
 
+// Md5 returns the md5 bytes of data.
 func Md5(data []byte) []byte {
 	digest := md5.New()
 	digest.Write(data)
 	return digest.Sum(nil)
 }
 
+// Md5Hex returns the md5 hex string of data.
 func Md5Hex(data []byte) string {
 	return fmt.Sprintf("%x", Md5(data))
 }