refactor: move from io/ioutil to io and os packages (#1096)

The io/ioutil package has been deprecated as of Go 1.16, see
https://golang.org/doc/go1.16#ioutil. 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>

cni/network/multitenancy.go

@@ -5,7 +5,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"os"
@@ -86,7 +86,7 @@ func (m *Multitenancy) DetermineSnatFeatureOnHost(snatFile, nmAgentSupportedApis
 
 	// Check if we've already retrieved NMAgent version and determined whether to disable snat on host
 	if jsonFile, retrieveSnatConfigErr = os.Open(snatFile); retrieveSnatConfigErr == nil {
-		bytes, _ := ioutil.ReadAll(jsonFile)
+		bytes, _ := io.ReadAll(jsonFile)
 		jsonFile.Close()
 		if retrieveSnatConfigErr = json.Unmarshal(bytes, &snatConfig); retrieveSnatConfigErr != nil {
 			log.Errorf("[cni-net] failed to unmarshal to snatConfig with error %v",
@@ -110,7 +110,7 @@ func (m *Multitenancy) DetermineSnatFeatureOnHost(snatFile, nmAgentSupportedApis
 			if resp.StatusCode == http.StatusOK {
 				var bodyBytes []byte
 				// if the list of APIs (strings) contains the nmAgentSnatSupportAPI we will disable snat on host
-				if bodyBytes, retrieveSnatConfigErr = ioutil.ReadAll(resp.Body); retrieveSnatConfigErr == nil {
+				if bodyBytes, retrieveSnatConfigErr = io.ReadAll(resp.Body); retrieveSnatConfigErr == nil {
 					bodyStr := string(bodyBytes)
 					if !strings.Contains(bodyStr, nmAgentSnatAndDnsSupportAPI) {
 						snatConfig.EnableSnatForDns = true

cni/network/plugin/main.go

@@ -6,7 +6,7 @@ package main
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"reflect"
 	"time"
@@ -78,7 +78,7 @@ func validateConfig(jsonBytes []byte) error {
 
 func getCmdArgsFromEnv() (string, *skel.CmdArgs, error) {
 	log.Printf("Going to read from stdin")
-	stdinData, err := ioutil.ReadAll(os.Stdin)
+	stdinData, err := io.ReadAll(os.Stdin)
 	if err != nil {
 		return "", nil, fmt.Errorf("error reading from stdin: %v", err)
 	}

cnm/plugin.go

@@ -4,7 +4,6 @@
 package cnm
 
 import (
-	"io/ioutil"
 	"net/http"
 	"net/url"
 	"os"
@@ -90,7 +89,7 @@ func (plugin *Plugin) EnableDiscovery() error {
 	// Write the listener URL to the spec file.
 	fileName := path + plugin.Name + ".spec"
 	url := plugin.Listener.URL.String()
-	err := ioutil.WriteFile(fileName, []byte(url), 0o644)
+	err := os.WriteFile(fileName, []byte(url), 0o644)
 	return err
 }
 

cns/client/client_test.go

@@ -6,7 +6,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"net/url"
@@ -55,7 +55,7 @@ type mockdo struct {
 
 func (m *mockdo) Do(req *http.Request) (*http.Response, error) {
 	byteArray, _ := json.Marshal(m.objToReturn)
-	body := ioutil.NopCloser(bytes.NewReader(byteArray))
+	body := io.NopCloser(bytes.NewReader(byteArray))
 
 	return &http.Response{
 		StatusCode: m.httpStatusCodeToReturn,
@@ -146,8 +146,8 @@ func TestMain(m *testing.M) {
 		res  *http.Response
 	)
 
-	tmpFileState, err := ioutil.TempFile(os.TempDir(), "cns-*.json")
-	tmpLogDir, err := ioutil.TempDir("", "cns-")
+	tmpFileState, err := os.CreateTemp(os.TempDir(), "cns-*.json")
+	tmpLogDir, err := os.MkdirTemp("", "cns-")
 	fmt.Printf("logdir: %+v", tmpLogDir)
 
 	if err != nil {

cns/configuration/configuration.go

@@ -3,7 +3,6 @@ package configuration
 
 import (
 	"encoding/json"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -93,7 +92,7 @@ func ReadConfig() (*CNSConfig, error) {
 }
 
 func readConfigFromFile(f string) (*CNSConfig, error) {
-	content, err := ioutil.ReadFile(f)
+	content, err := os.ReadFile(f)
 	if err != nil {
 		return nil, errors.Wrapf(err, "failed to read config file %s", f)
 	}

cns/networkcontainers/networkcontainers.go

@@ -9,7 +9,6 @@ import (
 	"errors"
 	"fmt"
 	"go/types"
-	"io/ioutil"
 	"net"
 	"os"
 	"os/exec"
@@ -112,7 +111,7 @@ func DeleteLoopbackAdapter(adapterName string) error {
 
 // This function gets the flattened network configuration (compliant with azure cni) in byte array format
 func getNetworkConfig(configFilePath string) ([]byte, error) {
-	content, err := ioutil.ReadFile(configFilePath)
+	content, err := os.ReadFile(configFilePath)
 	if err != nil {
 		return nil, err
 	}

common/utils.go

@@ -8,7 +8,7 @@ import (
 	"encoding/json"
 	"encoding/xml"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"net"
 	"net/http"
 	"os"
@@ -169,7 +169,7 @@ func StartProcess(path string, args []string) error {
 
 // GetHostMetadata - retrieve VM metadata from wireserver
 func GetHostMetadata(fileName string) (Metadata, error) {
-	content, err := ioutil.ReadFile(fileName)
+	content, err := os.ReadFile(fileName)
 	if err == nil {
 		var metadata Metadata
 		if err = json.Unmarshal(content, &metadata); err == nil {
@@ -225,7 +225,7 @@ func SaveHostMetadata(metadata Metadata, fileName string) error {
 		return fmt.Errorf("[Telemetry] marshal data failed with err %+v", err)
 	}
 
-	if err = ioutil.WriteFile(fileName, dataBytes, 0o644); err != nil {
+	if err = os.WriteFile(fileName, dataBytes, 0o644); err != nil {
 		log.Printf("[Telemetry] Writing metadata to file failed: %v", err)
 	}
 
@@ -257,7 +257,7 @@ func GetAzureCloud(url string) (string, error) {
 		return "", fmt.Errorf("Bad http status:%v", resp.Status)
 	}
 
-	bodyBytes, err := ioutil.ReadAll(resp.Body)
+	bodyBytes, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return "", err
 	}

ipam/fileIpam.go

@@ -6,8 +6,8 @@ package ipam
 import (
 	"encoding/json"
 	"errors"
-	"io/ioutil"
 	"net"
+	"os"
 	"runtime"
 	"strings"
 
@@ -123,7 +123,7 @@ func (source *fileIpamSource) refresh() error {
 }
 
 func getSDNInterfaces(fileLocation string) (*NetworkInterfaces, error) {
-	data, err := ioutil.ReadFile(fileLocation)
+	data, err := os.ReadFile(fileLocation)
 	if err != nil {
 		return nil, err
 	}

log/logger_test.go

@@ -5,7 +5,6 @@ package log
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strings"
 	"testing"
@@ -65,7 +64,7 @@ func TestPid(t *testing.T) {
 	fn := l.GetLogDirectory() + logName + ".log"
 	defer os.Remove(fn)
 
-	logBytes, err := ioutil.ReadFile(fn)
+	logBytes, err := os.ReadFile(fn)
 	if err != nil {
 		t.Fatalf("Failed to read log, %v", err)
 	}

npm/cmd/debug_test.go

@@ -2,7 +2,7 @@ package main
 
 import (
 	"bytes"
-	"io/ioutil"
+	"io"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -51,7 +51,7 @@ func testCommand(t *testing.T, tests []*testCases) {
 
 			require.NoError(t, err)
 
-			out, err := ioutil.ReadAll(b)
+			out, err := io.ReadAll(b)
 			require.NoError(t, err)
 			if tt.wantErr {
 				require.NotEmpty(t, out)

npm/http/server/server_test.go

@@ -2,7 +2,7 @@ package server
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"io"
 	"net/http"
 	"net/http/httptest"
 	"testing"
@@ -35,7 +35,7 @@ func TestGetNPMCacheHandler(t *testing.T) {
 			status, http.StatusOK)
 	}
 
-	byteArray, err := ioutil.ReadAll(rr.Body)
+	byteArray, err := io.ReadAll(rr.Body)
 	if err != nil {
 		t.Errorf("failed to read response's data : %w", err)
 	}

npm/pkg/controlplane/controllers/v1/translatePolicy_test.go

@@ -2,7 +2,7 @@ package controllers
 
 import (
 	"encoding/json"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"reflect"
 	"testing"
@@ -1116,7 +1116,7 @@ func TestTranslateEgress(t *testing.T) {
 func readPolicyYaml(policyYaml string) (*networkingv1.NetworkPolicy, error) {
 	decode := scheme.Codecs.UniversalDeserializer().Decode
 	policyYamlLocation := filepath.Join(testPolicyDir, policyYaml)
-	b, err := ioutil.ReadFile(policyYamlLocation)
+	b, err := os.ReadFile(policyYamlLocation)
 	if err != nil {
 		return nil, err
 	}

npm/pkg/dataplane/debug/converter.go

@@ -5,9 +5,10 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"log"
 	"net/http"
+	"os"
 	"os/exec"
 	"strconv"
 	"strings"
@@ -31,7 +32,7 @@ type Converter struct {
 
 // NpmCacheFromFile initialize NPM cache from file.
 func (c *Converter) NpmCacheFromFile(npmCacheJSONFile string) error {
-	byteArray, err := ioutil.ReadFile(npmCacheJSONFile)
+	byteArray, err := os.ReadFile(npmCacheJSONFile)
 	if err != nil {
 		return fmt.Errorf("failed to read %s file : %w", npmCacheJSONFile, err)
 	}
@@ -60,7 +61,7 @@ func (c *Converter) NpmCache() error {
 		return fmt.Errorf("failed to request NPM Cache : %w", err)
 	}
 	defer resp.Body.Close()
-	byteArray, err := ioutil.ReadAll(resp.Body)
+	byteArray, err := io.ReadAll(resp.Body)
 	if err != nil {
 		return fmt.Errorf("failed to read response's data : %w", err)
 	}

npm/pkg/dataplane/parse/parser.go

@@ -3,7 +3,7 @@ package parse
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"os/exec"
 
 	NPMIPtable "github.com/Azure/azure-container-networking/npm/pkg/dataplane/iptables"
@@ -44,7 +44,7 @@ func Iptables(tableName string) (*NPMIPtable.Table, error) {
 // IptablesFile creates a Go object from specified iptable by reading from an iptables-save file.
 func IptablesFile(tableName string, iptableSaveFile string) (*NPMIPtable.Table, error) {
 	iptableBuffer := bytes.NewBuffer(nil)
-	byteArray, err := ioutil.ReadFile(iptableSaveFile)
+	byteArray, err := os.ReadFile(iptableSaveFile)
 	if err != nil {
 		return nil, fmt.Errorf("%w", err)
 	}

platform/os_linux.go

@@ -6,7 +6,6 @@ package platform
 import (
 	"bytes"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"os/exec"
 	"strings"
@@ -38,7 +37,7 @@ const (
 
 // GetOSInfo returns OS version information.
 func GetOSInfo() string {
-	info, err := ioutil.ReadFile("/proc/version")
+	info, err := os.ReadFile("/proc/version")
 	if err != nil {
 		return "unknown"
 	}

processlock/filelock_test.go

@@ -1,7 +1,6 @@
 package processlock
 
 import (
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -73,7 +72,7 @@ func TestFileLock(t *testing.T) {
 				require.NoError(t, err, "Calling Release lock again should not throw error for already released lock:%v", err)
 
 				// read lockfile contents to check if contents match with pid of current process
-				b, errRead := ioutil.ReadFile(tt.lockfileName)
+				b, errRead := os.ReadFile(tt.lockfileName)
 				require.NoError(t, errRead, "Got error reading lockfile:%v", errRead)
 				pidStr := string(b)
 				pid, _ := strconv.Atoi(pidStr)

server/tls/tlscertificate_retriever_linux.go

@@ -7,7 +7,7 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
+	"os"
 )
 
 const (
@@ -52,7 +52,7 @@ func (fcert *linuxTlsCertificateRetriever) GetPrivateKey() (crypto.PrivateKey, e
 
 // ReadFile reads a from disk
 func (fcert *linuxTlsCertificateRetriever) readFile() ([]byte, error) {
-	content, err := ioutil.ReadFile(fcert.settings.TLSCertificatePath)
+	content, err := os.ReadFile(fcert.settings.TLSCertificatePath)
 	if err != nil {
 		return nil, fmt.Errorf("Error reading file from path %s with error: %+v ", fcert.settings.TLSCertificatePath, err)
 	}

server/tls/tlscertificate_retriever_linux_test.go

@@ -9,7 +9,6 @@ import (
 	"crypto/x509/pkix"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
 	"math/big"
 	"os"
 	"testing"
@@ -25,7 +24,7 @@ func TestPemConsumptionLinux(t *testing.T) {
 	currentDirectory, _ := os.Getwd()
 	pemLocation := fmt.Sprintf("%s/%s.Pem", currentDirectory, commonName)
 
-	ioutil.WriteFile(pemLocation, pemContent, 0o644)
+	os.WriteFile(pemLocation, pemContent, 0o644)
 	defer os.Remove(pemLocation)
 
 	config := TlsSettings{

server/tls/tlscertificate_retriever_windows.go

@@ -7,7 +7,7 @@ import (
 	"crypto/x509"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"strings"
 
 	"github.com/billgraziano/dpapi"
@@ -55,7 +55,7 @@ func (wtls *windowsTlsCertificateRetriever) GetPrivateKey() (crypto.PrivateKey,
 
 // ReadFile reads a from disk
 func (wtls *windowsTlsCertificateRetriever) readFile() ([]byte, error) {
-	content, err := ioutil.ReadFile(wtls.settings.TLSCertificatePath)
+	content, err := os.ReadFile(wtls.settings.TLSCertificatePath)
 	if err != nil {
 		return nil, fmt.Errorf("Error reading file from path %s with error: %+v ", wtls.settings.TLSCertificatePath, err)
 	}

server/tls/tlscertificate_retriever_windows_test.go

@@ -9,7 +9,6 @@ import (
 	"crypto/x509/pkix"
 	"encoding/pem"
 	"fmt"
-	"io/ioutil"
 	"math/big"
 	"os"
 	"testing"
@@ -28,7 +27,7 @@ func TestPemConsumptionWindows(t *testing.T) {
 	pemLocation := fmt.Sprintf("%s/%s.Pem", currentDirectory, commonName)
 
 	encryptedPem, _ := dpapi.Encrypt(string(pemContent))
-	ioutil.WriteFile(pemLocation, []byte(encryptedPem), 0o644)
+	os.WriteFile(pemLocation, []byte(encryptedPem), 0o644)
 	defer os.Remove(pemLocation)
 
 	config := TlsSettings{

store/json.go

@@ -6,7 +6,7 @@ package store
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"path/filepath"
 	"sync"
@@ -71,7 +71,7 @@ func (kvs *jsonFileStore) Read(key string, value interface{}) error {
 		}
 		defer file.Close()
 
-		b, err := ioutil.ReadAll(file)
+		b, err := io.ReadAll(file)
 		if err != nil {
 			return err
 		}
@@ -133,7 +133,7 @@ func (kvs *jsonFileStore) flush() error {
 		dir = "."
 	}
 
-	f, err := ioutil.TempFile(dir, file)
+	f, err := os.CreateTemp(dir, file)
 	if err != nil {
 		return fmt.Errorf("cannot create temp file: %v", err)
 	}

telemetry/telemetrybuffer.go

@@ -7,7 +7,6 @@ import (
 	"bufio"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"net"
 	"os"
 	"path/filepath"
@@ -323,7 +322,7 @@ func StartTelemetryService(path string, args []string) error {
 func ReadConfigFile(filePath string) (TelemetryConfig, error) {
 	config := TelemetryConfig{}
 
-	b, err := ioutil.ReadFile(filePath)
+	b, err := os.ReadFile(filePath)
 	if err != nil {
 		log.Logf("[Telemetry] Failed to read telemetry config: %v", err)
 		return config, err

test/integration/portforward.go

@@ -5,7 +5,7 @@ package k8s
 import (
 	"context"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"math/rand"
 	"net/http"
 
@@ -74,7 +74,7 @@ func (p *PortForwarder) Forward(ctx context.Context, namespace, labelSelector st
 
 	dialer := spdy.NewDialer(p.upgrader, &http.Client{Transport: p.transport}, http.MethodPost, portForwardURL)
 	ports := []string{fmt.Sprintf("%d:%d", localPort, destPort)}
-	pf, err := portforward.New(dialer, ports, stopChan, readyChan, ioutil.Discard, ioutil.Discard)
+	pf, err := portforward.New(dialer, ports, stopChan, readyChan, io.Discard, io.Discard)
 	if err != nil {
 		return PortForwardStreamHandle{}, fmt.Errorf("could not create portforwarder: %v", err)
 	}

tools/acncli/installer/conflist.go

@@ -6,7 +6,7 @@ package installer
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"io"
 	"os"
 	"path/filepath"
 
@@ -33,7 +33,7 @@ func LoadConfList(conflistpath string) (rawConflist, error) {
 	}
 	defer jsonFile.Close()
 
-	byteValue, err := ioutil.ReadAll(jsonFile)
+	byteValue, err := io.ReadAll(jsonFile)
 	if err != nil {
 		return conflist, err
 	}
@@ -99,7 +99,7 @@ func ModifyConflists(conflistpath string, installerConf InstallerConfig, perm os
 	}
 
 	fmt.Printf("🚛 - Installing %v...\n", dstFile)
-	return ioutil.WriteFile(dstFile, filebytes, perm)
+	return os.WriteFile(dstFile, filebytes, perm)
 }
 
 func PrettyPrint(o interface{}) {

tools/acncli/installer/utils.go

@@ -5,7 +5,6 @@ package installer
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 
@@ -62,12 +61,12 @@ func copyBinaries(filePaths []string, installerConf InstallerConfig, perm os.Fil
 }
 
 func copyFile(src string, dst string, perm os.FileMode) error {
-	data, err := ioutil.ReadFile(src)
+	data, err := os.ReadFile(src)
 	if err != nil {
 		return err
 	}
 
-	err = ioutil.WriteFile(dst, data, perm)
+	err = os.WriteFile(dst, data, perm)
 	if err != nil {
 		return err
 	}