ioutil: Switch away from deprecated package

ioutil has been deprecated since golang 1.16.
This commit uses the replacement methods from the os or io packages.
This should fix some golangci-lint CI failures.

Signed-off-by: Christophe Fergeau <cfergeau@redhat.com>

cmd/ssh-over-vsock/client.go

@@ -2,8 +2,8 @@ package main
 
 import (
 	"fmt"
-	"io/ioutil"
 	"net"
+	"os"
 	"time"
 
 	"golang.org/x/crypto/ssh"
@@ -27,7 +27,7 @@ func newClient(conn net.Conn, user string, key string) (*client, error) {
 }
 
 func newConfig(user string, keyFile string) (*ssh.ClientConfig, error) {
-	key, err := ioutil.ReadFile(keyFile)
+	key, err := os.ReadFile(keyFile)
 	if err != nil {
 		return nil, err
 	}

pkg/client/client.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"strings"
 
@@ -52,7 +52,7 @@ func (c *Client) Expose(req *types.ExposeRequest) error {
 	}
 	defer res.Body.Close()
 	if res.StatusCode != http.StatusOK {
-		err, readErr := ioutil.ReadAll(res.Body)
+		err, readErr := io.ReadAll(res.Body)
 		if readErr != nil {
 			return fmt.Errorf("error while reading error message: %v", readErr)
 		}
@@ -72,7 +72,7 @@ func (c *Client) Unexpose(req *types.UnexposeRequest) error {
 	}
 	defer res.Body.Close()
 	if res.StatusCode != http.StatusOK {
-		err, readErr := ioutil.ReadAll(res.Body)
+		err, readErr := io.ReadAll(res.Body)
 		if readErr != nil {
 			return fmt.Errorf("error while reading error message: %v", readErr)
 		}

pkg/sshclient/bastion.go

@@ -4,7 +4,6 @@ import (
 	"bufio"
 	"context"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"net/url"
 	"os"
@@ -39,7 +38,7 @@ type Bastion struct {
 type ConnectCallback func(ctx context.Context, bastion *Bastion) (net.Conn, error)
 
 func PublicKey(path string, passphrase []byte) (ssh.Signer, error) {
-	key, err := ioutil.ReadFile(path)
+	key, err := os.ReadFile(path)
 	if err != nil {
 		return nil, err
 	}

test-win-sshproxy/basic_test.go

@@ -5,7 +5,6 @@ package e2e
 import (
 	"context"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"os"
@@ -80,7 +79,7 @@ var _ = Describe("connectivity", func() {
 		reader, err := cmd.StdoutPipe()
 		Expect(err).ShouldNot(HaveOccurred())
 		cmd.Start()
-		output, err := ioutil.ReadAll(reader)
+		output, err := io.ReadAll(reader)
 		Expect(err).ShouldNot(HaveOccurred())
 		cmd.Wait()
 		Expect(strings.Contains(string(output), `[info ] test: Listening on: \\.\pipe\fake_docker_engine`)).Should(BeTrue())

test-win-sshproxy/suite_test.go

@@ -5,7 +5,6 @@ package e2e
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -39,7 +38,7 @@ func init() {
 	flag.StringVar(&binDir, "bin", "../bin", "directory with compiled binaries")
 	_ = os.MkdirAll(tmpDir, 0755)
 	keyFile = filepath.Join(tmpDir, "id.key")
-	_ = ioutil.WriteFile(keyFile, []byte(fakeHostKey), 0600)
+	_ = os.WriteFile(keyFile, []byte(fakeHostKey), 0600)
 	winSshProxy = filepath.Join(binDir, "win-sshproxy.exe")
 	tidFile = filepath.Join(tmpDir, "win-sshproxy.tid")
 }
@@ -59,7 +58,7 @@ func startProxy() error {
 }
 
 func readTid() (uint32, uint32, error) {
-	contents, err := ioutil.ReadFile(tidFile)
+	contents, err := os.ReadFile(tidFile)
 	if err != nil {
 		return 0, 0, err
 	}

test/fcos_amd64.go

@@ -3,7 +3,7 @@ package e2e
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net/http"
 
 	"github.com/coreos/stream-metadata-go/fedoracoreos"
@@ -19,7 +19,7 @@ func getFCOSDownload() (*fcosDownloadInfo, error) {
 	if err != nil {
 		return nil, err
 	}
-	body, err := ioutil.ReadAll(resp.Body)
+	body, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return nil, err
 	}

test/ignition.go

@@ -2,8 +2,8 @@ package e2e
 
 import (
 	"encoding/json"
-	"io/ioutil"
 	"net/url"
+	"os"
 )
 
 var (
@@ -142,7 +142,7 @@ ExecStart=/usr/bin/sleep infinity
 	}
 
 	// #nosec
-	return ioutil.WriteFile(ignitionFile, contents, 0644)
+	return os.WriteFile(ignitionFile, contents, 0644)
 }
 
 func dir(path string) Directory {

test/suite_test.go

@@ -4,7 +4,6 @@ import (
 	"flag"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"path/filepath"
@@ -176,7 +175,7 @@ func createSSHKeys() (string, error) {
 }
 
 func readPublicKey() (string, error) {
-	publicKey, err := ioutil.ReadFile(publicKeyFile)
+	publicKey, err := os.ReadFile(publicKeyFile)
 	if err != nil {
 		return "", nil
 	}