diff --git a/go/master/client.go b/go/master/client.go
index de883bf4b9a3de8d6d6e35e8e808dcf7ba54cb46..90b99470978d21480eb2d8097e7dec217b9524eb 100644
--- a/go/master/client.go
+++ b/go/master/client.go
@@ -69,7 +69,10 @@ func (c *Client) getRecords() {
 		// We treat a task as finished whenever the last data
 		// instance of the task is read. This is not exactly
 		// correct, but a reasonable approximation.
-		c.taskFinished(t.Meta.ID)
+		err = c.taskFinished(t.Meta.ID)
+		if err != nil {
+			log.Errorln(err)
+		}
 	}
 }
 
diff --git a/go/master/client_internal_test.go b/go/master/client_internal_test.go
index 49263474c8fe2410ffb6db93a9647f5ab066b06b..70dc09bf9461142ff6498355a5858ba9a1320510 100644
--- a/go/master/client_internal_test.go
+++ b/go/master/client_internal_test.go
@@ -66,11 +66,21 @@ func TestGetFinishTask(t *testing.T) {
 
 	for i := 0; i < totalTask*chunkPerTask; i++ {
 		w := recordio.NewWriter(f, -1, -1)
-		w.Write(nil)
+		_, err = w.Write(nil)
+		if err != nil {
+			panic(err)
+		}
+
 		// call Close to force RecordIO writing a chunk.
-		w.Close()
+		err = w.Close()
+		if err != nil {
+			panic(err)
+		}
+	}
+	err = f.Close()
+	if err != nil {
+		panic(err)
 	}
-	f.Close()
 
 	// Manually intialize client to avoid calling c.getRecords()
 	c := &Client{}
@@ -79,7 +89,11 @@ func TestGetFinishTask(t *testing.T) {
 	ch := make(chan string, 1)
 	ch <- addr
 	go c.monitorMaster(ch)
-	c.SetDataset([]string{path})
+	err = c.SetDataset([]string{path})
+	if err != nil {
+		panic(err)
+	}
+
 	checkOnePass := func(i int) {
 		var tasks []Task
 		for idx := 0; idx < totalTask; idx++ {
diff --git a/go/master/client_test.go b/go/master/client_test.go
index 6666d3860c412daa8711fbfa2d729a261b3fd887..bc92dc5ac973d62434b71e09705143ac8fbbd2fa 100644
--- a/go/master/client_test.go
+++ b/go/master/client_test.go
@@ -57,14 +57,30 @@ func TestNextRecord(t *testing.T) {
 
 	w := recordio.NewWriter(f, -1, -1)
 	for i := 0; i < total; i++ {
-		w.Write([]byte{byte(i)})
+		_, err = w.Write([]byte{byte(i)})
+		if err != nil {
+			panic(err)
+		}
+	}
+
+	err = w.Close()
+	if err != nil {
+		panic(err)
+	}
+
+	err = f.Close()
+	if err != nil {
+		panic(err)
 	}
-	w.Close()
-	f.Close()
+
 	curAddr := make(chan string, 1)
 	curAddr <- fmt.Sprintf(":%d", p)
 	c := master.NewClient(curAddr, 10)
-	c.SetDataset([]string{path})
+	err = c.SetDataset([]string{path})
+	if err != nil {
+		panic(err)
+	}
+
 	for pass := 0; pass < 50; pass++ {
 		received := make(map[byte]bool)
 		for i := 0; i < total; i++ {
diff --git a/go/pserver/client/client.go b/go/pserver/client/client.go
index aa8bfe30c26fcc0875ad479ecd562700ccefa5a3..b4a45e1c21056550ef9264746bcf58a8abb369a1 100644
--- a/go/pserver/client/client.go
+++ b/go/pserver/client/client.go
@@ -233,7 +233,7 @@ func (c *Client) Save(path string) error {
 
 func strHash(s string) uint32 {
 	h := fnv.New32a()
-	h.Write([]byte(s))
+	_, _ = h.Write([]byte(s))
 	return h.Sum32()
 }
 
diff --git a/go/pserver/client/client_test.go b/go/pserver/client/client_test.go
index aab91556b4b91fab6de66322987eabe24f1b0f70..5c89882a297323034be2875a6d4cb71d715eb0c2 100644
--- a/go/pserver/client/client_test.go
+++ b/go/pserver/client/client_test.go
@@ -79,15 +79,33 @@ func initEtcdClient() {
 		log.Errorf("err %v", err)
 	}
 	ctx, cancel := context.WithTimeout(context.Background(), timeout)
-	client.Delete(ctx, pserver.PsDesired)
-	client.Delete(ctx, pserver.PsPath)
-	client.Put(ctx, pserver.PsDesired, strconv.Itoa(numPserver))
+	_, err = client.Delete(ctx, pserver.PsDesired)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = client.Delete(ctx, pserver.PsPath)
+	if err != nil {
+		panic(err)
+	}
+
+	_, err = client.Put(ctx, pserver.PsDesired, strconv.Itoa(numPserver))
+	if err != nil {
+		panic(err)
+	}
+
 	ports := initClient()
 	for i := 0; i < numPserver; i++ {
-		client.Put(ctx, pserver.PsPath+strconv.Itoa(i), ":"+strconv.Itoa(ports[i]))
+		_, err = client.Put(ctx, pserver.PsPath+strconv.Itoa(i), ":"+strconv.Itoa(ports[i]))
+		if err != nil {
+			panic(err)
+		}
 	}
 	cancel()
-	client.Close()
+	err = client.Close()
+	if err != nil {
+		panic(err)
+	}
 }
 
 type selector bool
diff --git a/go/pserver/service.go b/go/pserver/service.go
index fec2ec61dc67756439d9fa478788d1f155876538..5cb0293b9724c57607053bef312a90adaa21811b 100644
--- a/go/pserver/service.go
+++ b/go/pserver/service.go
@@ -219,7 +219,7 @@ func (s *Service) GetParam(name string, parameter *Parameter) error {
 }
 
 // pserver save checkpoint
-func (s *Service) doCheckpoint() error {
+func (s *Service) doCheckpoint() (err error) {
 	<-s.initialized
 	s.mu.Lock()
 	defer s.mu.Unlock()
@@ -237,9 +237,9 @@ func (s *Service) doCheckpoint() error {
 	}
 	var buf bytes.Buffer
 	encoder := gob.NewEncoder(&buf)
-	err := encoder.Encode(cp)
+	err = encoder.Encode(cp)
 	if err != nil {
-		return err
+		return
 	}
 
 	cpMeta := checkpointMeta{}
@@ -248,10 +248,14 @@ func (s *Service) doCheckpoint() error {
 	h := md5.New()
 	cpMeta.MD5 = hex.EncodeToString(h.Sum(buf.Bytes()))
 
-	cpMetajson, _ := json.Marshal(cpMeta)
+	cpMetajson, err := json.Marshal(cpMeta)
+	if err != nil {
+		return
+	}
+
 	err = s.client.PutKey(filepath.Join(PsCheckpoint, strconv.Itoa(s.idx)), cpMetajson, 3*time.Second)
 	if err != nil {
-		return err
+		return
 	}
 	if _, err = os.Stat(cpMeta.UUID); os.IsNotExist(err) {
 		log.Info("checkpoint does not exists.")
@@ -264,15 +268,32 @@ func (s *Service) doCheckpoint() error {
 		}
 	}
 	f, err := os.Create(cpMeta.UUID)
-	defer f.Close()
 	if err != nil {
-		return err
+		return
 	}
+
+	defer func() {
+		closeErr := f.Close()
+		if closeErr != nil {
+			if err != nil {
+				log.Errorln(closeErr)
+			} else {
+				// Set closeErr as return value.
+				err = closeErr
+			}
+		}
+	}()
+
 	writer := bufio.NewWriter(f)
 	_, err = writer.Write(buf.Bytes())
-	writer.Flush()
 	if err != nil {
-		return err
+		return
 	}
-	return nil
+
+	err = writer.Flush()
+	if err != nil {
+		return
+	}
+
+	return
 }