diff --git a/apis/filters/parse.go b/apis/filters/parse.go
index 49108587d..00988861d 100644
--- a/apis/filters/parse.go
+++ b/apis/filters/parse.go
@@ -152,10 +152,7 @@ func FromParam(p string) (Args, error) {
 
 	raw := []byte(p)
 	err := json.Unmarshal(raw, &args)
-	if err != nil {
-		return args, err
-	}
-	return args, nil
+	return args, err
 }
 
 // FromFilterOpts parse key=value to Args string from cli opts
diff --git a/apis/opts/config/blkio.go b/apis/opts/config/blkio.go
index c355c08ce..7f25dac4c 100644
--- a/apis/opts/config/blkio.go
+++ b/apis/opts/config/blkio.go
@@ -66,9 +66,7 @@ func (w *WeightDevice) Type() string {
 // Value returns all values as type WeightDevice
 func (w *WeightDevice) Value() []*types.WeightDevice {
 	var weightDevice []*types.WeightDevice
-	for _, v := range w.values {
-		weightDevice = append(weightDevice, v)
-	}
+	weightDevice = append(weightDevice, w.values...)
 
 	return weightDevice
 }
@@ -124,9 +122,7 @@ func (t *ThrottleBpsDevice) Type() string {
 // Value returns all values as type ThrottleDevice
 func (t *ThrottleBpsDevice) Value() []*types.ThrottleDevice {
 	var throttleDevice []*types.ThrottleDevice
-	for _, v := range t.values {
-		throttleDevice = append(throttleDevice, v)
-	}
+	throttleDevice = append(throttleDevice, t.values...)
 
 	return throttleDevice
 }
@@ -182,9 +178,7 @@ func (t *ThrottleIOpsDevice) Type() string {
 // Value returns all values
 func (t *ThrottleIOpsDevice) Value() []*types.ThrottleDevice {
 	var throttleDevice []*types.ThrottleDevice
-	for _, v := range t.values {
-		throttleDevice = append(throttleDevice, v)
-	}
+	throttleDevice = append(throttleDevice, t.values...)
 
 	return throttleDevice
 }
diff --git a/apis/opts/config/runtime.go b/apis/opts/config/runtime.go
index 72dbd8bae..cdfaf4197 100644
--- a/apis/opts/config/runtime.go
+++ b/apis/opts/config/runtime.go
@@ -47,7 +47,7 @@ func (r *Runtime) Set(val string) error {
 func (r *Runtime) String() string {
 	var str []string
 	for k := range *r.values {
-		str = append(str, fmt.Sprintf("%s", k))
+		str = append(str, k)
 	}
 
 	return fmt.Sprintf("%v", str)
diff --git a/apis/server/image_bridge.go b/apis/server/image_bridge.go
index c7bf01d6d..c198657f3 100644
--- a/apis/server/image_bridge.go
+++ b/apis/server/image_bridge.go
@@ -192,11 +192,8 @@ func (s *Server) saveImage(ctx context.Context, rw http.ResponseWriter, req *htt
 	defer r.Close()
 
 	output := newWriteFlusher(rw)
-	if _, err := io.Copy(output, r); err != nil {
-		return err
-	}
-
-	return nil
+	_, err = io.Copy(output, r)
+	return err
 }
 
 // getImageHistory gets image history.
diff --git a/cli/container.go b/cli/container.go
index 3b5c8bef7..b5f9cba0b 100644
--- a/cli/container.go
+++ b/cli/container.go
@@ -65,7 +65,7 @@ type container struct {
 	networks       []string
 	ports          []string
 	expose         []string
-	publicAll      bool
+	publishAll     bool
 	securityOpt    []string
 	capAdd         []string
 	capDrop        []string
diff --git a/cli/image_list.go b/cli/image_list.go
index f82d1a0c9..296152b1a 100644
--- a/cli/image_list.go
+++ b/cli/image_list.go
@@ -108,9 +108,9 @@ func (i *ImagesCommand) runImages(args []string) error {
 
 	for _, dimg := range dimgs {
 		if i.flagDigest {
-			display.AddRow([]string{dimg.id, dimg.name, dimg.digest, fmt.Sprintf("%s", dimg.size)})
+			display.AddRow([]string{dimg.id, dimg.name, dimg.digest, string(dimg.size)})
 		} else {
-			display.AddRow([]string{dimg.id, dimg.name, fmt.Sprintf("%s", dimg.size)})
+			display.AddRow([]string{dimg.id, dimg.name, string(dimg.size)})
 		}
 	}
 
diff --git a/cli/tag.go b/cli/tag.go
index cf4d7a47b..1bab23c80 100644
--- a/cli/tag.go
+++ b/cli/tag.go
@@ -12,7 +12,6 @@ var tagDescription = "tag command is to add tag reference for the existing image
 // TagCommand use to implement 'tag' command.
 type TagCommand struct {
 	baseCommand
-	args []string
 }
 
 // Init initialize tag command.
diff --git a/cli/top.go b/cli/top.go
index de72eabe5..048cb25fe 100644
--- a/cli/top.go
+++ b/cli/top.go
@@ -17,7 +17,6 @@ var topDescription = "top command is to display the running processes of a conta
 // TopCommand use to implement 'top' command, it displays all processes in a container.
 type TopCommand struct {
 	baseCommand
-	args []string
 }
 
 // Init initialize top command.
diff --git a/cli/update.go b/cli/update.go
index 8baf29188..6799a86d6 100644
--- a/cli/update.go
+++ b/cli/update.go
@@ -17,7 +17,6 @@ var updateDescription = "Update a container's configurations, including memory,
 type UpdateCommand struct {
 	baseCommand
 	container
-	image string
 }
 
 // Init initialize update command.
diff --git a/client/request.go b/client/request.go
index 984497346..c016432e9 100644
--- a/client/request.go
+++ b/client/request.go
@@ -102,10 +102,8 @@ func (client *APIClient) newRequest(method, path string, query url.Values, body
 		return nil, err
 	}
 
-	if header != nil {
-		for k, v := range header {
-			req.Header[k] = v
-		}
+	for k, v := range header {
+		req.Header[k] = v
 	}
 
 	return req, err
diff --git a/cri/criservice.go b/cri/criservice.go
index 3a9146431..6a9148b3e 100644
--- a/cri/criservice.go
+++ b/cri/criservice.go
@@ -39,7 +39,6 @@ func RunCriService(daemonconfig *config.Config, containerMgr mgr.ContainerMgr, i
 		readyCh <- false
 		err = fmt.Errorf("failed to start CRI service: invalid CRI version %s, expected to be v1alpha1 or v1alpha2", daemonconfig.CriConfig.CriVersion)
 	}
-	return
 }
 
 // Start CRI service with CRI version: v1alpha1
diff --git a/cri/stream/portforward/httpstream.go b/cri/stream/portforward/httpstream.go
index e6142df52..50be52df6 100644
--- a/cri/stream/portforward/httpstream.go
+++ b/cri/stream/portforward/httpstream.go
@@ -111,13 +111,6 @@ func (h *httpStreamHandler) getStreamPair(requestID string) (*httpStreamPair, bo
 	return pair, true
 }
 
-// hasStreamPair returns a bool indicating if a stream pair for requestID exists.
-func (h *httpStreamHandler) hasStreamPair(requestID string) bool {
-	_, ok := h.streamPairs.Get(requestID).Result()
-
-	return ok
-}
-
 // removeStreamPair removes the stream pair identified by requestID from streamPairs.
 func (h *httpStreamHandler) removeStreamPair(requestID string) {
 	h.streamPairs.Remove(requestID)
diff --git a/cri/stream/portforward/portforward.go b/cri/stream/portforward/portforward.go
index eae91821f..e99d6f093 100644
--- a/cri/stream/portforward/portforward.go
+++ b/cri/stream/portforward/portforward.go
@@ -28,6 +28,4 @@ func ServePortForward(ctx context.Context, w http.ResponseWriter, req *http.Requ
 		logrus.Errorf("failed to serve port forward: %v", err)
 		return
 	}
-
-	return
 }
diff --git a/ctrd/client.go b/ctrd/client.go
index d83fec8f9..19b3b518f 100644
--- a/ctrd/client.go
+++ b/ctrd/client.go
@@ -32,8 +32,6 @@ type Client struct {
 	watch *watch
 	lock  *containerLock
 
-	rpcAddr string
-
 	// containerd grpc pool
 	pool      []scheduler.Factory
 	scheduler scheduler.Scheduler
diff --git a/ctrd/container.go b/ctrd/container.go
index 53efb66e0..834cfdfc2 100644
--- a/ctrd/container.go
+++ b/ctrd/container.go
@@ -701,9 +701,8 @@ func (c *Client) waitContainer(ctx context.Context, id string) (types.ContainerW
 		return c.ProbeContainer(ctx, id, -1*time.Second)
 	}
 
-	var msg *Message
 	// wait for the task to exit.
-	msg = waitExit()
+	msg := waitExit()
 
 	errMsg := ""
 	err = msg.RawError()
diff --git a/ctrd/snapshot.go b/ctrd/snapshot.go
index 53f0fcc34..234840f88 100644
--- a/ctrd/snapshot.go
+++ b/ctrd/snapshot.go
@@ -32,10 +32,8 @@ func (c *Client) CreateSnapshot(ctx context.Context, id, ref string) error {
 	}
 
 	parent := identity.ChainID(diffIDs).String()
-	if _, err := wrapperCli.client.SnapshotService(defaultSnapshotterName).Prepare(ctx, id, parent); err != nil {
-		return err
-	}
-	return nil
+	_, err = wrapperCli.client.SnapshotService(defaultSnapshotterName).Prepare(ctx, id, parent)
+	return err
 }
 
 // GetSnapshot returns the snapshot's info by id.
diff --git a/daemon/config/config.go b/daemon/config/config.go
index b1012ff1f..7b456b107 100644
--- a/daemon/config/config.go
+++ b/daemon/config/config.go
@@ -179,7 +179,7 @@ func (cfg *Config) MergeConfigurations(flagSet *pflag.FlagSet) error {
 		return nil
 	}
 
-	fileFlags := make(map[string]interface{}, 0)
+	fileFlags := make(map[string]interface{})
 	flattenConfig(origin, fileFlags)
 
 	// check conflict in command line flags and config file
diff --git a/daemon/logger/jsonfile/jsonfile_read_test.go b/daemon/logger/jsonfile/jsonfile_read_test.go
index d8c9e5038..b41f97c4b 100644
--- a/daemon/logger/jsonfile/jsonfile_read_test.go
+++ b/daemon/logger/jsonfile/jsonfile_read_test.go
@@ -31,7 +31,7 @@ func TestReadLogMessagesWithRemoveFileInFollowMode(t *testing.T) {
 	os.RemoveAll(f.Name())
 
 	select {
-	case _, _ = <-watcher.Msgs:
+	case <-watcher.Msgs:
 	case <-time.After(250 * time.Millisecond):
 		// NOTE: watchTimeout is 200ms
 		t.Fatal("expected watcher.Msgs has been closed after removed file, but it's still alive")
@@ -64,7 +64,7 @@ func TestReadLogMessagesForEmptyFileWithoutFollow(t *testing.T) {
 	<-time.After(100 * time.Millisecond)
 
 	select {
-	case _, _ = <-watcher.Msgs:
+	case <-watcher.Msgs:
 	case <-time.After(100 * time.Millisecond):
 		t.Fatalf("expected watcher.Msgs has been closed after removed file, but it's still alive")
 	}
diff --git a/daemon/logger/jsonfile/utils_test.go b/daemon/logger/jsonfile/utils_test.go
index 8547530b3..32fdb3341 100644
--- a/daemon/logger/jsonfile/utils_test.go
+++ b/daemon/logger/jsonfile/utils_test.go
@@ -8,11 +8,14 @@ import (
 	"os"
 	"reflect"
 	"strings"
+	"sync"
 	"testing"
 	"time"
 
 	"github.com/alibaba/pouch/daemon/logger"
 	"github.com/alibaba/pouch/pkg/utils"
+
+	"github.com/pkg/errors"
 )
 
 var _ logger.LogDriver = &JSONLogFile{}
@@ -133,21 +136,25 @@ func TestFollowFile(t *testing.T) {
 	// create goroutine to read the file
 	watcher := logger.NewLogWatcher()
 	waitCh := make(chan struct{})
+	errchan := make(chan error)
+	var wg sync.WaitGroup
 	defer func() {
 		watcher.Close()
 		<-waitCh
 	}()
 
 	go func() {
-		// NOTE: make sure all the goutine exits
+		wg.Add(1)
+		// NOTE: make sure all the goroutine exits
 		defer func() {
 			waitCh <- struct{}{}
 		}()
 
 		newF, err := os.Open(f.Name())
 		if err != nil {
-			t.Fatalf("unexpected error during open file for followFile: %v", err)
+			errchan <- errors.Errorf("unexpected error during open file for followFile: %v", err)
 		}
+		wg.Done()
 
 		cfg := &logger.ReadConfig{
 			Since: generateTime(t, "2018-05-09T10:00:01.1Z"),
@@ -156,6 +163,15 @@ func TestFollowFile(t *testing.T) {
 		followFile(newF, cfg, newUnmarshal, watcher)
 	}()
 
+	go func() {
+		wg.Wait()
+		close(errchan)
+	}()
+
+	if err := <-errchan; err != nil {
+		t.Fatal(err)
+	}
+
 	// should read three log message
 	for _, el := range expectedMsgs[:2] {
 		checkExpectedLogMessage(t, watcher, el)
diff --git a/daemon/mgr/container.go b/daemon/mgr/container.go
index a952be283..6a03bb651 100644
--- a/daemon/mgr/container.go
+++ b/daemon/mgr/container.go
@@ -36,7 +36,6 @@ import (
 	containerdtypes "github.com/containerd/containerd/api/types"
 	"github.com/containerd/containerd/mount"
 	"github.com/docker/go-units"
-	"github.com/docker/libnetwork"
 	"github.com/go-openapi/strfmt"
 	ocispec "github.com/opencontainers/image-spec/specs-go/v1"
 	"github.com/pkg/errors"
@@ -1525,41 +1524,6 @@ func (mgr *ContainerManager) connectToNetwork(ctx context.Context, container *Co
 	return mgr.updateNetworkConfig(container, networkIDOrName, endpoint.EndpointConfig)
 }
 
-// FIXME: remove this useless functions
-func (mgr *ContainerManager) updateNetworkSettings(container *Container, n libnetwork.Network) error {
-	if container.NetworkSettings == nil {
-		container.NetworkSettings = &types.NetworkSettings{Networks: make(map[string]*types.EndpointSettings)}
-	}
-
-	if !IsHost(container.HostConfig.NetworkMode) && IsHost(n.Type()) {
-		return fmt.Errorf("container cannot be connected to host network")
-	}
-
-	for s := range container.NetworkSettings.Networks {
-		sn, err := mgr.NetworkMgr.Get(context.Background(), s)
-		if err != nil {
-			continue
-		}
-
-		if sn.Name == n.Name() {
-			// Avoid duplicate config
-			return nil
-		}
-		if !IsPrivate(sn.Type) || !IsPrivate(n.Type()) {
-			return fmt.Errorf("container sharing network namespace with another container or host cannot be connected to any other network")
-		}
-		if IsNone(sn.Name) || IsNone(n.Name()) {
-			return fmt.Errorf("container cannot be connected to multiple networks with one of the networks in none mode")
-		}
-	}
-
-	if _, ok := container.NetworkSettings.Networks[n.Name()]; !ok {
-		container.NetworkSettings.Networks[n.Name()] = new(types.EndpointSettings)
-	}
-
-	return nil
-}
-
 func (mgr *ContainerManager) initContainerIO(c *Container) (*containerio.IO, error) {
 	if io := mgr.IOs.Get(c.ID); io != nil {
 		return nil, errors.Wrap(errtypes.ErrConflict, "failed to create containerIO")
@@ -1814,7 +1778,6 @@ func (mgr *ContainerManager) resetContainerIOs(containerID string) {
 	}
 
 	io.Reset()
-	return
 }
 
 // buildContainerEndpoint builds Endpoints according to container
diff --git a/daemon/mgr/container_logger.go b/daemon/mgr/container_logger.go
index 22c3debc8..60da8941f 100644
--- a/daemon/mgr/container_logger.go
+++ b/daemon/mgr/container_logger.go
@@ -62,5 +62,4 @@ func (mgr *ContainerManager) SetContainerLogPath(c *Container) {
 	if c.HostConfig.LogConfig.LogDriver == "json-file" {
 		c.LogPath = filepath.Join(mgr.Config.HomeDir, "containers", c.ID, "json.log")
 	}
-	return
 }
diff --git a/daemon/mgr/container_storage.go b/daemon/mgr/container_storage.go
index 74ed67f8d..f85042331 100644
--- a/daemon/mgr/container_storage.go
+++ b/daemon/mgr/container_storage.go
@@ -736,7 +736,7 @@ func copyImageContent(source, destination string) error {
 
 		// destination directory is not exist, so mkdir for it.
 		logrus.Warnf("(%s) is not exist", destination)
-		if err := os.MkdirAll(destination, 755); err != nil && !os.IsExist(err) {
+		if err := os.MkdirAll(destination, 0755); err != nil && !os.IsExist(err) {
 			return err
 		}
 	} else if !fi.IsDir() {
diff --git a/daemon/mgr/container_types.go b/daemon/mgr/container_types.go
index b5472a11a..409a31654 100644
--- a/daemon/mgr/container_types.go
+++ b/daemon/mgr/container_types.go
@@ -452,7 +452,7 @@ func (c *Container) UnsetMergedDir() {
 // SetSnapshotterMeta sets snapshotter for container
 func (c *Container) SetSnapshotterMeta(mounts []mount.Mount) {
 	// TODO(ziren): now we only support overlayfs
-	data := make(map[string]string, 0)
+	data := make(map[string]string)
 	for _, opt := range mounts[0].Options {
 		if strings.HasPrefix(opt, "upperdir=") {
 			data["UpperDir"] = strings.TrimPrefix(opt, "upperdir=")
diff --git a/daemon/mgr/image_store.go b/daemon/mgr/image_store.go
index 0111dd1e6..045e99e2f 100644
--- a/daemon/mgr/image_store.go
+++ b/daemon/mgr/image_store.go
@@ -171,9 +171,8 @@ func (store *imageStore) Search(ref reference.Named) (digest.Digest, reference.N
 
 func (store *imageStore) searchIDs(refID string) (digest.Digest, error) {
 	var ids []digest.Digest
-	var id string
 
-	id = refID
+	id := refID
 	if !strings.HasPrefix(refID, digest.Canonical.String()) {
 		id = fmt.Sprintf("%s:%s", digest.Canonical.String(), refID)
 	}
diff --git a/lxcfs/lxcfs.go b/lxcfs/lxcfs.go
index d310e8cd8..92dcfb508 100644
--- a/lxcfs/lxcfs.go
+++ b/lxcfs/lxcfs.go
@@ -44,7 +44,7 @@ func CheckLxcfsMount() error {
 			break
 		}
 	}
-	if isMount == false {
+	if !isMount {
 		return fmt.Errorf("%s is not a mount point, please run \" lxcfs %s \" before Pouchd", LxcfsHomeDir, LxcfsHomeDir)
 	}
 	return nil
diff --git a/pkg/archive/archive.go b/pkg/archive/archive.go
index d7f493ab4..fceee88a4 100644
--- a/pkg/archive/archive.go
+++ b/pkg/archive/archive.go
@@ -50,11 +50,8 @@ func tarFromDir(src string, writer io.Writer) error {
 		defer f.Close()
 
 		// copy file data into tar writer
-		if _, err := io.Copy(tw, f); err != nil {
-			return err
-		}
-
-		return nil
+		_, err = io.Copy(tw, f)
+		return err
 	})
 }
 
diff --git a/pkg/kmutex/kmutex_test.go b/pkg/kmutex/kmutex_test.go
index 0c61e1203..dfd71aab3 100644
--- a/pkg/kmutex/kmutex_test.go
+++ b/pkg/kmutex/kmutex_test.go
@@ -5,12 +5,15 @@ import (
 	"sync"
 	"testing"
 	"time"
+
+	"github.com/pkg/errors"
 )
 
 func TestKMutex(t *testing.T) {
 	m := New()
 
 	var wg sync.WaitGroup
+	errchan := make(chan error)
 
 	for i := 0; i < 10; i++ {
 		wg.Add(1)
@@ -20,48 +23,58 @@ func TestKMutex(t *testing.T) {
 
 			k := strconv.Itoa(i)
 
-			if m.Trylock(k) == false {
-				t.Fatalf("failed to trylock: %d", i)
+			if !m.Trylock(k) {
+				errchan <- errors.Errorf("failed to trylock: %d", i)
 			}
-			if m.Trylock(k) == true {
-				t.Fatalf("trylock is error: %d", i)
+			if m.Trylock(k) {
+				errchan <- errors.Errorf("trylock is error: %d", i)
 			}
 
 			m.Unlock(k)
 
-			if m.Trylock(k) == false {
-				t.Fatalf("failed to trylock: %d", i)
+			if !m.Trylock(k) {
+				errchan <- errors.Errorf("failed to trylock: %d", i)
 			}
 		}(i)
 	}
 
-	wg.Wait()
+	go func() {
+		wg.Wait()
+		close(errchan)
+	}()
+
+	if err := <-errchan; err != nil {
+		t.Fatal(err)
+	}
 }
 
 func TestKMutexTimeout(t *testing.T) {
 	m := New()
 
 	running := make(chan struct{})
-	wait := make(chan struct{})
+	errchan := make(chan error)
+
 	go func() {
-		if m.Trylock("key") == false {
-			t.Fatalf("failed to trylock")
+		if !m.Trylock("key") {
+			errchan <- errors.New("failed to trylock")
+			return
 		}
 
 		close(running)
 
 		time.Sleep(time.Second * 10)
-		close(wait)
 	}()
 
-	<-running
-
 	go func() {
-		<-wait
-		t.Fatalf("failed to trylock with timeout")
+		<-running
+		close(errchan)
 	}()
 
-	if m.LockWithTimeout("key", time.Second*5) == true {
+	if err := <-errchan; err != nil {
+		t.Fatal(err)
+	}
+
+	if m.LockWithTimeout("key", time.Second*5) {
 		t.Fatalf("trylock with timeout is error")
 	}
 }
diff --git a/pkg/meta/local.go b/pkg/meta/local.go
index 727d6c3e5..89a17a94b 100644
--- a/pkg/meta/local.go
+++ b/pkg/meta/local.go
@@ -39,12 +39,9 @@ func NewLocalStore(cfg Config) (Backend, error) {
 
 	// initialize cache
 	handle := func(f os.FileInfo) error {
-		if _, err := s.Get(MetaJSONFile, f.Name()); err != nil {
-			return err
-		}
+		_, err := s.Get(MetaJSONFile, f.Name())
+		return err
 		// TODO maybe get other file.
-
-		return nil
 	}
 
 	if err := walkDir(s.base, handle); err != nil {
diff --git a/pkg/meta/store.go b/pkg/meta/store.go
index 13a034306..1d06a0019 100644
--- a/pkg/meta/store.go
+++ b/pkg/meta/store.go
@@ -260,10 +260,8 @@ func (s *Store) KeysWithPrefix(prefix string) ([]string, error) {
 	s.trieLock.Lock()
 	defer s.trieLock.Unlock()
 
-	if err := s.trie.VisitSubtree(patricia.Prefix(prefix), fn); err != nil {
-		return keys, err
-	}
-	return keys, nil
+	err := s.trie.VisitSubtree(patricia.Prefix(prefix), fn)
+	return keys, err
 }
 
 // Path returns the path with specified key.
diff --git a/pkg/netutils/interface_test.go b/pkg/netutils/interface_test.go
index 589781e53..ddc863bb1 100644
--- a/pkg/netutils/interface_test.go
+++ b/pkg/netutils/interface_test.go
@@ -299,10 +299,8 @@ func (validNetworkInterface) InterfaceByName(intfName string) (*net.Interface, e
 	return &upIntf, nil
 }
 func (validNetworkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{
-		addrStruct{val: "fe80::2f7:6fff:fe6e:2956/64"}, addrStruct{val: "10.254.71.145/17"}}
-	return ifat, nil
+	return []net.Addr{
+		addrStruct{val: "fe80::2f7:6fff:fe6e:2956/64"}, addrStruct{val: "10.254.71.145/17"}}, nil
 }
 func (validNetworkInterface) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{upIntf}, nil
@@ -316,11 +314,10 @@ func (v4v6NetworkInterface) InterfaceByName(intfName string) (*net.Interface, er
 	return &upIntf, nil
 }
 func (v4v6NetworkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{
-		addrStruct{val: "2001::10/64"}, addrStruct{val: "10.254.71.145/17"}}
-	return ifat, nil
+	return []net.Addr{
+		addrStruct{val: "2001::10/64"}, addrStruct{val: "10.254.71.145/17"}}, nil
 }
+
 func (v4v6NetworkInterface) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{upIntf}, nil
 }
@@ -333,9 +330,7 @@ func (ipv6NetworkInterface) InterfaceByName(intfName string) (*net.Interface, er
 	return &upIntf, nil
 }
 func (ipv6NetworkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{addrStruct{val: "2001::200/64"}}
-	return ifat, nil
+	return []net.Addr{addrStruct{val: "2001::200/64"}}, nil
 }
 
 func (ipv6NetworkInterface) Interfaces() ([]net.Interface, error) {
@@ -350,10 +345,9 @@ func (networkInterfaceWithOnlyLinkLocals) InterfaceByName(intfName string) (*net
 	return &upIntf, nil
 }
 func (networkInterfaceWithOnlyLinkLocals) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{addrStruct{val: "169.254.162.166/16"}, addrStruct{val: "fe80::200/10"}}
-	return ifat, nil
+	return []net.Addr{addrStruct{val: "169.254.162.166/16"}, addrStruct{val: "fe80::200/10"}}, nil
 }
+
 func (networkInterfaceWithOnlyLinkLocals) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{upIntf}, nil
 }
@@ -394,10 +388,8 @@ func (downNetworkInterface) InterfaceByName(intfName string) (*net.Interface, er
 	return &downIntf, nil
 }
 func (downNetworkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{
-		addrStruct{val: "fe80::2f7:6fff:fe6e:2956/64"}, addrStruct{val: "10.254.71.145/17"}}
-	return ifat, nil
+	return []net.Addr{
+		addrStruct{val: "fe80::2f7:6fff:fe6e:2956/64"}, addrStruct{val: "10.254.71.145/17"}}, nil
 }
 func (downNetworkInterface) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{downIntf}, nil
@@ -411,10 +403,8 @@ func (loopbackNetworkInterface) InterfaceByName(intfName string) (*net.Interface
 	return &loopbackIntf, nil
 }
 func (loopbackNetworkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{
-		addrStruct{val: "::1/128"}, addrStruct{val: "127.0.0.1/8"}}
-	return ifat, nil
+	return []net.Addr{
+		addrStruct{val: "::1/128"}, addrStruct{val: "127.0.0.1/8"}}, nil
 }
 func (loopbackNetworkInterface) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{loopbackIntf}, nil
@@ -428,10 +418,8 @@ func (p2pNetworkInterface) InterfaceByName(intfName string) (*net.Interface, err
 	return &p2pIntf, nil
 }
 func (p2pNetworkInterface) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{
-		addrStruct{val: "::1/128"}, addrStruct{val: "127.0.0.1/8"}}
-	return ifat, nil
+	return []net.Addr{
+		addrStruct{val: "::1/128"}, addrStruct{val: "127.0.0.1/8"}}, nil
 }
 func (p2pNetworkInterface) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{p2pIntf}, nil
@@ -459,8 +447,7 @@ func (networkInterfaceWithNoAddrs) InterfaceByName(intfName string) (*net.Interf
 	return &upIntf, nil
 }
 func (networkInterfaceWithNoAddrs) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	ifat := []net.Addr{}
-	return ifat, nil
+	return []net.Addr{}, nil
 }
 func (networkInterfaceWithNoAddrs) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{upIntf}, nil
@@ -474,9 +461,7 @@ func (networkInterfaceWithInvalidAddr) InterfaceByName(intfName string) (*net.In
 	return &upIntf, nil
 }
 func (networkInterfaceWithInvalidAddr) Addrs(intf *net.Interface) ([]net.Addr, error) {
-	var ifat []net.Addr
-	ifat = []net.Addr{addrStruct{val: "10.20.30.40.50/24"}}
-	return ifat, nil
+	return []net.Addr{addrStruct{val: "10.20.30.40.50/24"}}, nil
 }
 func (networkInterfaceWithInvalidAddr) Interfaces() ([]net.Interface, error) {
 	return []net.Interface{upIntf}, nil
diff --git a/pkg/user/user.go b/pkg/user/user.go
index 0f9ae9bc4..686a2532c 100644
--- a/pkg/user/user.go
+++ b/pkg/user/user.go
@@ -33,9 +33,6 @@ type uidParser struct {
 	placeholder string
 	uid         int
 	gid         int
-	finger      []string
-	userdir     string
-	shell       string
 }
 
 // gidParser defines lines in /etc/group, eg: root:x:0:.
@@ -43,7 +40,6 @@ type gidParser struct {
 	group       string
 	placeholder string
 	gid         int
-	otherGroup  []string
 }
 
 // Get accepts user and group slice, return valid uid, gid and additional gids.
diff --git a/pkg/utils/timeutils.go b/pkg/utils/timeutils.go
index 0e01036de..d37c0abc6 100644
--- a/pkg/utils/timeutils.go
+++ b/pkg/utils/timeutils.go
@@ -33,7 +33,7 @@ var errInvalid = errors.New("invalid time")
 // FormatTimeInterval is used to show the time interval from input time to now.
 func FormatTimeInterval(input int64) (formattedTime string, err error) {
 	start := time.Unix(0, input)
-	diff := time.Now().Sub(start)
+	diff := time.Since(start)
 
 	// That should not happen.
 	if diff < 0 {
diff --git a/pkg/utils/utils.go b/pkg/utils/utils.go
index bfd6fd7d3..bdd23a586 100644
--- a/pkg/utils/utils.go
+++ b/pkg/utils/utils.go
@@ -368,7 +368,7 @@ func ToStringMap(in map[string]interface{}) map[string]string {
 	if in == nil {
 		return nil
 	}
-	out := make(map[string]string, 0)
+	out := make(map[string]string)
 	for k, v := range in {
 		if s, ok := v.(string); ok {
 			out[k] = s
diff --git a/registry/auth.go b/registry/auth.go
index 26bd9b95c..590a85f15 100644
--- a/registry/auth.go
+++ b/registry/auth.go
@@ -1,7 +1,6 @@
 package registry
 
 import (
-	"crypto/tls"
 	"encoding/json"
 	"fmt"
 	"net/http"
@@ -22,9 +21,9 @@ type challengeClient struct {
 }
 
 type registryEndpoint struct {
-	version   string
-	url       *url.URL
-	tlsConfig *tls.Config
+	version string
+	url     *url.URL
+	// TODO: support tls for registry.
 }
 
 // token defines a token that registry may return after login successfully.
diff --git a/registry/auth_challenge.go b/registry/auth_challenge.go
index eea33d20d..b7aa53898 100644
--- a/registry/auth_challenge.go
+++ b/registry/auth_challenge.go
@@ -49,8 +49,8 @@ func init() {
 		var t octetType
 		isCtl := c <= 31 || c == 127
 		isChar := 0 <= c && c <= 127
-		isSeparator := strings.IndexRune(" \t\"(),/:;<=>?@[]\\{}", rune(c)) >= 0
-		if strings.IndexRune(" \t\r\n", rune(c)) >= 0 {
+		isSeparator := strings.ContainsRune(" \t\"(),/:;<=>?@[]\\{}", rune(c))
+		if strings.ContainsRune(" \t\r\n", rune(c)) {
 			t |= isSpace
 		}
 		if isChar && !isCtl && !isSeparator {
diff --git a/storage/plugins/client.go b/storage/plugins/client.go
index 75828b51a..86055a435 100644
--- a/storage/plugins/client.go
+++ b/storage/plugins/client.go
@@ -51,7 +51,7 @@ func NewPluginClient(addr string, tlsconfig *TLSConfig) (*PluginClient, error) {
 
 	// Scheme is https, generate the tls config
 	if url.Scheme == "https" {
-		if tlsconfig != nil && tlsconfig.InsecureSkipVerify == false {
+		if tlsconfig != nil && !tlsconfig.InsecureSkipVerify {
 			config, err = httputils.GenTLSConfig(tlsconfig.KeyFile, tlsconfig.CertFile, tlsconfig.CAFile)
 			if err != nil {
 				return nil, fmt.Errorf("failed to parse plugin tls config: %v", err)
diff --git a/storage/quota/grpquota.go b/storage/quota/grpquota.go
index a11a05480..c2a8582a7 100644
--- a/storage/quota/grpquota.go
+++ b/storage/quota/grpquota.go
@@ -90,7 +90,7 @@ func (quota *GrpQuotaDriver) EnforceQuota(dir string) (string, error) {
 			header[4] = 0x01
 		}
 
-		if writeErr := ioutil.WriteFile(filename, header, 644); writeErr != nil {
+		if writeErr := ioutil.WriteFile(filename, header, 0644); writeErr != nil {
 			return mountPoint, errors.Wrapf(writeErr, "failed to write file, filename: (%s), vfs version: (%s)",
 				filename, vfsVersion)
 		}
diff --git a/storage/quota/quota.go b/storage/quota/quota.go
index 5c316e4d3..25b100e7c 100644
--- a/storage/quota/quota.go
+++ b/storage/quota/quota.go
@@ -29,8 +29,6 @@ const (
 )
 
 var (
-	hasQuota bool
-
 	// GQuotaDriver represents global quota driver.
 	GQuotaDriver = NewQuotaDriver("")
 
@@ -344,7 +342,7 @@ func getOverlayMountInfo(basefs string) (*OverlayMount, error) {
 // #500      --   47504       0       0            101     0     0
 // #16777221 -- 3048576       0 3048576              8     0     0
 func loadQuotaIDs(repquotaOpt string) (map[uint32]struct{}, uint32, error) {
-	quotaIDs := make(map[uint32]struct{}, 0)
+	quotaIDs := make(map[uint32]struct{})
 
 	minID := QuotaMinID
 	exit, output, stderr, err := exec.Run(0, "repquota", repquotaOpt)
diff --git a/storage/volume/core_test.go b/storage/volume/core_test.go
index faff2de60..73a2224cc 100644
--- a/storage/volume/core_test.go
+++ b/storage/volume/core_test.go
@@ -170,7 +170,7 @@ func TestListVolumes(t *testing.T) {
 	for k := 0; k < len(volarray); k++ {
 		vol := volarray[k]
 		_, found := volmap[vol.Name]
-		if found == false {
+		if !found {
 			t.Fatalf("list volumes %v not found", vol)
 		}
 	}
@@ -253,7 +253,7 @@ func TestListVolumeName(t *testing.T) {
 	for k := 0; k < len(volarray); k++ {
 		vol := volarray[k]
 		_, found := volmap[vol.Name]
-		if found == false {
+		if !found {
 			t.Fatalf("list volumes %v not found", vol)
 		}
 	}
@@ -265,7 +265,7 @@ func TestListVolumeName(t *testing.T) {
 	}
 	for j := 0; j < len(volNames); j++ {
 		_, found := volmap[volNames[j]]
-		if found == false {
+		if !found {
 			t.Fatalf("list volumes name %s not found", volNames[j])
 		}
 	}
diff --git a/storage/volume/driver/driver.go b/storage/volume/driver/driver.go
index 5ff18fe7c..1ca193d0a 100644
--- a/storage/volume/driver/driver.go
+++ b/storage/volume/driver/driver.go
@@ -49,18 +49,12 @@ func (m VolumeStoreMode) Valid() bool {
 
 	// local store
 	if m.IsLocal() {
-		if m.CentralCreateDelete() {
-			return false
-		}
-		return true
+		return !m.CentralCreateDelete()
 	}
 
 	// remote store
 	if m.IsRemote() {
-		if m.UseLocalMeta() {
-			return false
-		}
-		return true
+		return !m.UseLocalMeta()
 	}
 
 	return false
@@ -225,11 +219,7 @@ func GetAll() ([]Driver, error) {
 // Exist return true if the backend driver is registered.
 func Exist(name string) bool {
 	_, err := Get(name)
-	if err != nil {
-		return false
-	}
-
-	return true
+	return err == nil
 }
 
 // AllDriversName return all registered backend driver's name.
diff --git a/storage/volume/driver/driver_test.go b/storage/volume/driver/driver_test.go
index 5e46be701..f5dee1ca7 100644
--- a/storage/volume/driver/driver_test.go
+++ b/storage/volume/driver/driver_test.go
@@ -26,7 +26,7 @@ func TestRegister(t *testing.T) {
 	}
 
 	success := Unregister(testDriverName)
-	if success == false {
+	if !success {
 		t.Fatal("failed to unregister testdriver")
 	}
 
@@ -49,7 +49,7 @@ func TestGetAll(t *testing.T) {
 	defer func() {
 		for _, name := range driverNames {
 			success := Unregister(name)
-			if success == false {
+			if !success {
 				t.Fatalf("failed to unregister driver: %s", name)
 			}
 		}
@@ -80,7 +80,7 @@ func TestAlias(t *testing.T) {
 	defer func() {
 		for _, name := range driverNames {
 			success := Unregister(name)
-			if success == false {
+			if !success {
 				t.Fatalf("failed to unregister driver: %s", name)
 			}
 		}
diff --git a/storage/volume/driver/remote.go b/storage/volume/driver/remote.go
index dd119d946..4c7af6a76 100644
--- a/storage/volume/driver/remote.go
+++ b/storage/volume/driver/remote.go
@@ -115,11 +115,7 @@ func (r *remoteDriverWrapper) Attach(ctx Context, v *types.Volume) error {
 	ctx.Log.Debugf("driver wrapper [%s] attach volume: %s", r.Name(ctx), v.Name)
 
 	_, err := r.proxy.Mount(v.Name, v.UID)
-	if err != nil {
-		return err
-	}
-
-	return nil
+	return err
 }
 
 // Detach a remote volume.
diff --git a/test/cli_exec_test.go b/test/cli_exec_test.go
index a9331b0c7..84499b85f 100644
--- a/test/cli_exec_test.go
+++ b/test/cli_exec_test.go
@@ -59,10 +59,10 @@ func (suite *PouchExecSuite) TestExecCommand(c *check.C) {
 
 func (suite *PouchExecSuite) TestExecNoCommand(c *check.C) {
 	cname := "TestExecNoCommand"
-	res := command.PouchRun("run", "-d", "--name", cname, busyboxImage, "sleep", "100000").Assert(c, icmd.Success)
+	command.PouchRun("run", "-d", "--name", cname, busyboxImage, "sleep", "100000").Assert(c, icmd.Success)
 	defer DelContainerForceMultyTime(c, cname)
 
-	res = command.PouchRun("exec", cname)
+	res := command.PouchRun("exec", cname)
 	expectedError := "requires at least 2 arg(s), only received 1"
 	if out := res.Combined(); !strings.Contains(out, expectedError) {
 		c.Fatalf("unexpected output %s, expected %s", out, expectedError)
diff --git a/test/cli_run_blkio_test.go b/test/cli_run_blkio_test.go
index c7e6992bb..add9fc827 100644
--- a/test/cli_run_blkio_test.go
+++ b/test/cli_run_blkio_test.go
@@ -79,7 +79,7 @@ func (suite *PouchRunBlkioSuite) TestRunBlockIOWeightDevice(c *check.C) {
 
 	SkipIfFalse(c, func() bool {
 		file := fmt.Sprintf("/sys/block/%s/queue/scheduler",
-			strings.Trim(testDisk, "/dev/"))
+			strings.TrimPrefix(testDisk, "/dev/"))
 		if data, err := ioutil.ReadFile(file); err == nil {
 			return strings.Contains(string(data), "[cfq]")
 		}
diff --git a/test/cli_run_cgroup_test.go b/test/cli_run_cgroup_test.go
index 520d65256..ccd563db3 100644
--- a/test/cli_run_cgroup_test.go
+++ b/test/cli_run_cgroup_test.go
@@ -55,9 +55,7 @@ func testRunWithCgroupParent(c *check.C, cgroupParent, name string) {
 	c.Assert(err, check.IsNil)
 
 	// this code slice may not robust, but for this test case is enough.
-	if strings.HasPrefix(cgroupParent, "/") {
-		cgroupParent = cgroupParent[1:]
-	}
+	cgroupParent = strings.TrimPrefix(cgroupParent, "/")
 
 	if cgroupParent == "" {
 		cgroupParent = "default"
diff --git a/test/daemon/daemon.go b/test/daemon/daemon.go
index 34ca7c7bb..030595d3c 100644
--- a/test/daemon/daemon.go
+++ b/test/daemon/daemon.go
@@ -168,8 +168,8 @@ func (d *Config) StartDaemon() error {
 		close(wait)
 	}()
 
-	if util.WaitTimeout(time.Duration(d.timeout)*time.Second, d.IsDaemonUp) == false {
-		if d.Debug == true {
+	if !util.WaitTimeout(time.Duration(d.timeout)*time.Second, d.IsDaemonUp) {
+		if d.Debug {
 			d.DumpLog()
 
 			fmt.Printf("\nFailed to launch pouchd:%v\n", d.Args)
@@ -201,7 +201,7 @@ func (d *Config) DumpLog() {
 
 // KillDaemon kill pouchd.
 func (d *Config) KillDaemon() {
-	if d.IsDaemonUp() == false {
+	if !d.IsDaemonUp() {
 		return
 	}
 
@@ -215,5 +215,4 @@ func (d *Config) KillDaemon() {
 
 		d.LogFile.Close()
 	}
-	return
 }
diff --git a/test/environment/env.go b/test/environment/env.go
index 9ccece111..8a6cef9bd 100644
--- a/test/environment/env.go
+++ b/test/environment/env.go
@@ -116,10 +116,7 @@ func IsLinux() bool {
 // IsAliKernel checks if the kernel of test environment is AliKernel.
 func IsAliKernel() bool {
 	cmd := "uname -r | grep -i alios"
-	if icmd.RunCommand("bash", "-c", cmd).ExitCode == 0 {
-		return true
-	}
-	return false
+	return icmd.RunCommand("bash", "-c", cmd).ExitCode == 0
 }
 
 // IsDumbInitExist checks if the dumb-init binary exists on host.
@@ -133,10 +130,7 @@ func IsDumbInitExist() bool {
 // IsRuncVersionSupportRichContianer checks if the version of runc supports rich container.
 func IsRuncVersionSupportRichContianer() bool {
 	cmd := "runc -v|grep 1.0.0-rc4-1"
-	if icmd.RunCommand("bash", "-c", cmd).ExitCode == 0 {
-		return true
-	}
-	return false
+	return icmd.RunCommand("bash", "-c", cmd).ExitCode == 0
 }
 
 // IsHubConnected checks if hub address can be connected.
@@ -147,10 +141,7 @@ func IsHubConnected() bool {
 
 // IsDiskQuota checks if it can use disk quota for container.
 func IsDiskQuota() bool {
-	if icmd.RunCommand("which", "quotaon").ExitCode == 0 {
-		return true
-	}
-	return false
+	return icmd.RunCommand("which", "quotaon").ExitCode == 0
 }
 
 // IsPrjquota checks if there is prjquota set on test machine
@@ -174,17 +165,11 @@ func IsLxcfsEnabled() bool {
 		return false
 	}
 	cmd := "ps -ef |grep pouchd |grep \"enable\\-lxcfs\""
-	if icmd.RunCommand("sh", "-c", cmd).ExitCode != 0 {
-		return false
-	}
-	return true
+	return icmd.RunCommand("sh", "-c", cmd).ExitCode == 0
 }
 
 // IsCRIUExist checks if criu exist on machine.
 func IsCRIUExist() bool {
 	_, err := exec.LookPath("criu")
-	if err != nil {
-		return false
-	}
-	return true
+	return err == nil
 }
diff --git a/test/util/util.go b/test/util/util.go
index 5346e0ba7..f610c5777 100644
--- a/test/util/util.go
+++ b/test/util/util.go
@@ -30,7 +30,7 @@ func WaitTimeout(timeout time.Duration, condition func() bool) bool {
 			fmt.Printf("condition failed to return true within %f seconds.\n", timeout.Seconds())
 			return false
 		case <-ticker.C:
-			if condition() == true {
+			if condition() {
 				ch <- true
 			}
 		}
diff --git a/test/utils.go b/test/utils.go
index 6840a8e72..421549ed9 100644
--- a/test/utils.go
+++ b/test/utils.go
@@ -69,7 +69,7 @@ type VerifyCondition func() bool
 // SkipIfFalse skips the suite, if any of the conditions is not satisfied.
 func SkipIfFalse(c *check.C, conditions ...VerifyCondition) {
 	for _, con := range conditions {
-		if con() == false {
+		if !con() {
 			c.Skip("Skip test as condition is not matched")
 		}
 	}