refactor: move from io/ioutil to io and os package

The io/ioutil package has been deprecated in Go 1.16. This commit
replaces the existing io/ioutil functions with their new definitions in
io and os packages.

Signed-off-by: Eng Zer Jun <engzerjun@gmail.com>

7 files changed, 22 insertions, 27 deletions

diff --git a/integration/plugin/authz/authz_plugin_test.go b/integration/plugin/authz/authz_plugin_test.go
index 6cce66cd6c..3c8cfc6a65 100644
--- a/integration/plugin/authz/authz_plugin_test.go
+++ b/integration/plugin/authz/authz_plugin_test.go
@@ -7,7 +7,6 @@ import (
 	"context"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"net/http/httputil"
@@ -61,7 +60,7 @@ func setupTestV1(t *testing.T) func() {
 	assert.NilError(t, err)
 
 	fileName := fmt.Sprintf("/etc/docker/plugins/%s.spec", testAuthZPlugin)
-	err = ioutil.WriteFile(fileName, []byte(server.URL), 0644)
+	err = os.WriteFile(fileName, []byte(server.URL), 0644)
 	assert.NilError(t, err)
 
 	return func() {
@@ -336,7 +335,7 @@ func TestAuthZPluginEnsureLoadImportWorking(t *testing.T) {
 	c := d.NewClientT(t)
 	ctx := context.Background()
 
-	tmp, err := ioutil.TempDir("", "test-authz-load-import")
+	tmp, err := os.MkdirTemp("", "test-authz-load-import")
 	assert.NilError(t, err)
 	defer os.RemoveAll(tmp)
 
@@ -370,11 +369,11 @@ func TestAuthzPluginEnsureContainerCopyToFrom(t *testing.T) {
 	ctrl.resRes.Allow = true
 	d.StartWithBusybox(t, "--authorization-plugin="+testAuthZPlugin, "--authorization-plugin="+testAuthZPlugin)
 
-	dir, err := ioutil.TempDir("", t.Name())
+	dir, err := os.MkdirTemp("", t.Name())
 	assert.NilError(t, err)
 	defer os.RemoveAll(dir)
 
-	f, err := ioutil.TempFile(dir, "send")
+	f, err := os.CreateTemp(dir, "send")
 	assert.NilError(t, err)
 	defer f.Close()
 
@@ -409,7 +408,7 @@ func TestAuthzPluginEnsureContainerCopyToFrom(t *testing.T) {
 
 	rdr, _, err := c.CopyFromContainer(ctx, cID, "/test")
 	assert.NilError(t, err)
-	_, err = io.Copy(ioutil.Discard, rdr)
+	_, err = io.Copy(io.Discard, rdr)
 	assert.NilError(t, err)
 }
 
diff --git a/integration/plugin/authz/authz_plugin_v2_test.go b/integration/plugin/authz/authz_plugin_v2_test.go
index f567f5a448..173d0a5df6 100644
--- a/integration/plugin/authz/authz_plugin_v2_test.go
+++ b/integration/plugin/authz/authz_plugin_v2_test.go
@@ -6,7 +6,7 @@ package authz // import "github.com/docker/docker/integration/plugin/authz"
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"strings"
 	"testing"
@@ -166,6 +166,6 @@ func pluginInstallGrantAllPermissions(client client.APIClient, name string) erro
 	// we have to read the response out here because the client API
 	// actually starts a goroutine which we can only be sure has
 	// completed when we get EOF from reading responseBody
-	_, err = ioutil.ReadAll(responseReader)
+	_, err = io.ReadAll(responseReader)
 	return err
 }
diff --git a/integration/plugin/authz/main_test.go b/integration/plugin/authz/main_test.go
index ff39d61372..b4e6564081 100644
--- a/integration/plugin/authz/main_test.go
+++ b/integration/plugin/authz/main_test.go
@@ -6,7 +6,7 @@ package authz // import "github.com/docker/docker/integration/plugin/authz"
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -77,7 +77,7 @@ func setupSuite() {
 
 	mux.HandleFunc("/AuthZPlugin.AuthZReq", func(w http.ResponseWriter, r *http.Request) {
 		defer r.Body.Close()
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			panic("could not read body for /AuthZPlugin.AuthZReq: " + err.Error())
 		}
@@ -115,7 +115,7 @@ func setupSuite() {
 
 	mux.HandleFunc("/AuthZPlugin.AuthZRes", func(w http.ResponseWriter, r *http.Request) {
 		defer r.Body.Close()
-		body, err := ioutil.ReadAll(r.Body)
+		body, err := io.ReadAll(r.Body)
 		if err != nil {
 			panic("could not read body for /AuthZPlugin.AuthZRes: " + err.Error())
 		}
diff --git a/integration/plugin/common/plugin_test.go b/integration/plugin/common/plugin_test.go
index 83e060f82e..72b1b8264d 100644
--- a/integration/plugin/common/plugin_test.go
+++ b/integration/plugin/common/plugin_test.go
@@ -6,7 +6,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
@@ -81,7 +80,7 @@ func TestPluginInstall(t *testing.T) {
 		assert.NilError(t, err)
 		defer rdr.Close()
 
-		_, err = io.Copy(ioutil.Discard, rdr)
+		_, err = io.Copy(io.Discard, rdr)
 		assert.NilError(t, err)
 
 		_, _, err = client.PluginInspectWithRaw(ctx, repo)
@@ -110,7 +109,7 @@ func TestPluginInstall(t *testing.T) {
 		assert.NilError(t, err)
 		defer rdr.Close()
 
-		_, err = io.Copy(ioutil.Discard, rdr)
+		_, err = io.Copy(io.Discard, rdr)
 		assert.NilError(t, err)
 
 		_, _, err = client.PluginInspectWithRaw(ctx, repo)
@@ -158,7 +157,7 @@ func TestPluginInstall(t *testing.T) {
 		assert.NilError(t, err)
 		defer rdr.Close()
 
-		_, err = io.Copy(ioutil.Discard, rdr)
+		_, err = io.Copy(io.Discard, rdr)
 		assert.NilError(t, err)
 
 		_, _, err = client.PluginInspectWithRaw(ctx, repo)
@@ -172,7 +171,7 @@ func TestPluginsWithRuntimes(t *testing.T) {
 	skip.If(t, testEnv.IsRootless, "Test not supported on rootless due to buggy daemon setup in rootless mode due to daemon restart")
 	skip.If(t, testEnv.OSType == "windows")
 
-	dir, err := ioutil.TempDir("", t.Name())
+	dir, err := os.MkdirTemp("", t.Name())
 	assert.NilError(t, err)
 	defer os.RemoveAll(dir)
 
@@ -202,7 +201,7 @@ func TestPluginsWithRuntimes(t *testing.T) {
 	exec runc $@
 	`, dir)
 
-	assert.NilError(t, ioutil.WriteFile(p, []byte(script), 0777))
+	assert.NilError(t, os.WriteFile(p, []byte(script), 0777))
 
 	type config struct {
 		Runtimes map[string]types.Runtime `json:"runtimes"`
@@ -215,7 +214,7 @@ func TestPluginsWithRuntimes(t *testing.T) {
 		},
 	})
 	configPath := filepath.Join(dir, "config.json")
-	ioutil.WriteFile(configPath, cfg, 0644)
+	os.WriteFile(configPath, cfg, 0644)
 
 	t.Run("No Args", func(t *testing.T) {
 		d.Restart(t, "--default-runtime=myrt", "--config-file="+configPath)
diff --git a/integration/plugin/graphdriver/external_test.go b/integration/plugin/graphdriver/external_test.go
index 87ce1b82d7..57fb27856d 100644
--- a/integration/plugin/graphdriver/external_test.go
+++ b/integration/plugin/graphdriver/external_test.go
@@ -5,7 +5,6 @@ import (
 	"encoding/json"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"net/http/httptest"
 	"os"
@@ -145,7 +144,7 @@ func setupPlugin(t *testing.T, ec map[string]*graphEventsCounter, ext string, mu
 		return nil
 	}
 
-	base, err := ioutil.TempDir("", name)
+	base, err := os.MkdirTemp("", name)
 	assert.NilError(t, err)
 	vfsProto, err := vfs.Init(base, []string{}, nil, nil)
 	assert.NilError(t, err, "error initializing graph driver")
@@ -349,7 +348,7 @@ func setupPlugin(t *testing.T, ec map[string]*graphEventsCounter, ext string, mu
 	assert.NilError(t, err)
 
 	specFile := "/etc/docker/plugins/" + name + "." + ext
-	err = ioutil.WriteFile(specFile, b, 0644)
+	err = os.WriteFile(specFile, b, 0644)
 	assert.NilError(t, err)
 }
 
@@ -397,7 +396,7 @@ func testGraphDriverPull(c client.APIClient, d *daemon.Daemon) func(*testing.T)
 
 		r, err := c.ImagePull(ctx, "busybox:latest@sha256:95cf004f559831017cdf4628aaf1bb30133677be8702a8c5f2994629f637a209", types.ImagePullOptions{})
 		assert.NilError(t, err)
-		_, err = io.Copy(ioutil.Discard, r)
+		_, err = io.Copy(io.Discard, r)
 		assert.NilError(t, err)
 
 		container.Run(ctx, t, c, container.WithImage("busybox:latest@sha256:95cf004f559831017cdf4628aaf1bb30133677be8702a8c5f2994629f637a209"))
@@ -428,7 +427,7 @@ func TestGraphdriverPluginV2(t *testing.T) {
 	assert.NilError(t, err)
 	defer responseReader.Close()
 	// ensure it's done by waiting for EOF on the response
-	_, err = io.Copy(ioutil.Discard, responseReader)
+	_, err = io.Copy(io.Discard, responseReader)
 	assert.NilError(t, err)
 
 	// restart the daemon with the plugin set as the storage driver
diff --git a/integration/plugin/logging/cmd/discard/driver.go b/integration/plugin/logging/cmd/discard/driver.go
index e02b56e88f..bbdebaf443 100644
--- a/integration/plugin/logging/cmd/discard/driver.go
+++ b/integration/plugin/logging/cmd/discard/driver.go
@@ -3,7 +3,6 @@ package main
 import (
 	"encoding/json"
 	"io"
-	"io/ioutil"
 	"net/http"
 	"os"
 	"sync"
@@ -47,7 +46,7 @@ func handle(mux *http.ServeMux) {
 		d.logs[req.File] = f
 		d.mu.Unlock()
 
-		go io.Copy(ioutil.Discard, f)
+		go io.Copy(io.Discard, f)
 		respond(err, w)
 	})
 
diff --git a/integration/plugin/volumes/mounts_test.go b/integration/plugin/volumes/mounts_test.go
index 991b1e1105..c80c4cd79c 100644
--- a/integration/plugin/volumes/mounts_test.go
+++ b/integration/plugin/volumes/mounts_test.go
@@ -2,7 +2,6 @@ package volumes
 
 import (
 	"context"
-	"io/ioutil"
 	"os"
 	"testing"
 
@@ -28,7 +27,7 @@ func TestPluginWithDevMounts(t *testing.T) {
 	c := d.NewClientT(t)
 	ctx := context.Background()
 
-	testDir, err := ioutil.TempDir("", "test-dir")
+	testDir, err := os.MkdirTemp("", "test-dir")
 	assert.NilError(t, err)
 	defer os.RemoveAll(testDir)