all: use os.{Read|Write}File instead of ioutil.{Read|Write}File

The ioutil.{Read|Write}File is deprecated since Go1.16 -
see https://tip.golang.org/doc/go1.16#ioutil

VictoriaMetrics needs at least Go1.18, so it is safe to remove ioutil usage
from source code.

This is a follow-up for 02ca2342ab

app/vmalert/config/config.go

@@ -4,8 +4,8 @@ import (
 	"crypto/md5"
 	"fmt"
 	"hash/fnv"
-	"io/ioutil"
 	"net/url"
+	"os"
 	"path/filepath"
 	"sort"
 	"strings"
@@ -214,7 +214,7 @@ func Parse(pathPatterns []string, validateTplFn ValidateTplFn, validateExpressio
 }
 
 func parseFile(path string) ([]Group, error) {
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("error reading alert rule file: %w", err)
 	}

app/vmalert/main_test.go

@@ -154,7 +154,7 @@ groups:
 
 func writeToFile(t *testing.T, file, b string) {
 	t.Helper()
-	err := ioutil.WriteFile(file, []byte(b), 0644)
+	err := os.WriteFile(file, []byte(b), 0644)
 	if err != nil {
 		t.Fatal(err)
 	}

app/vmalert/notifier/config.go

@@ -4,8 +4,8 @@ import (
 	"crypto/md5"
 	"fmt"
 	"gopkg.in/yaml.v2"
-	"io/ioutil"
 	"net/url"
+	"os"
 	"path"
 	"path/filepath"
 	"strings"
@@ -104,7 +104,7 @@ func (cfg *Config) UnmarshalYAML(unmarshal func(interface{}) error) error {
 }
 
 func parseConfig(path string) (*Config, error) {
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("error reading config file: %w", err)
 	}

app/vmalert/notifier/config_watcher_test.go

@@ -175,7 +175,7 @@ consul_sd_configs:
 
 func writeToFile(t *testing.T, file, b string) {
 	t.Helper()
-	checkErr(t, ioutil.WriteFile(file, []byte(b), 0644))
+	checkErr(t, os.WriteFile(file, []byte(b), 0644))
 }
 
 func checkErr(t *testing.T, err error) {

app/vmalert/utils/tls.go

@@ -4,8 +4,8 @@ import (
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
-	"io/ioutil"
 	"net/http"
+	"os"
 	"strings"
 )
 
@@ -38,7 +38,7 @@ func TLSConfig(certFile, keyFile, CAFile, serverName string, insecureSkipVerify
 
 	var rootCAs *x509.CertPool
 	if CAFile != "" {
-		pem, err := ioutil.ReadFile(CAFile)
+		pem, err := os.ReadFile(CAFile)
 		if err != nil {
 			return nil, fmt.Errorf("cannot read `ca_file` %q: %w", CAFile, err)
 		}

app/vmselect/promql/rollup_result_cache.go

@@ -4,7 +4,7 @@ import (
 	"crypto/rand"
 	"flag"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"sync"
 	"sync/atomic"
 	"time"
@@ -413,7 +413,7 @@ func mustLoadRollupResultCacheKeyPrefix(path string) {
 		rollupResultCacheKeyPrefix = newRollupResultCacheKeyPrefix()
 		return
 	}
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		logger.Errorf("cannot load %s: %s; reset rollupResult cache", path, err)
 		rollupResultCacheKeyPrefix = newRollupResultCacheKeyPrefix()

lib/awsapi/config.go

@@ -196,7 +196,7 @@ func (cfg *Config) getAPICredentials() (*credentials, error) {
 		SecretAccessKey: cfg.defaultSecretKey,
 	}
 	if len(cfg.webTokenPath) > 0 {
-		token, err := ioutil.ReadFile(cfg.webTokenPath)
+		token, err := os.ReadFile(cfg.webTokenPath)
 		if err != nil {
 			return nil, fmt.Errorf("cannot read webToken from path: %q, err: %w", cfg.webTokenPath, err)
 		}

lib/backup/fsremote/fsremote.go

@@ -3,7 +3,6 @@ package fsremote
 import (
 	"fmt"
 	"io"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strings"
@@ -218,7 +217,7 @@ func (fs *FS) CreateFile(filePath string, data []byte) error {
 	if err := fs.mkdirAll(path); err != nil {
 		return err
 	}
-	if err := ioutil.WriteFile(path, data, 0600); err != nil {
+	if err := os.WriteFile(path, data, 0600); err != nil {
 		return fmt.Errorf("cannot write %d bytes to %q: %w", len(data), path, err)
 	}
 	return nil

lib/cgroup/cpu.go

@@ -2,7 +2,6 @@ package cgroup
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"runtime"
 	"strconv"
@@ -80,7 +79,7 @@ func getCPUStat(statName string) (int64, error) {
 
 func getOnlineCPUCount() float64 {
 	// See https://github.com/VictoriaMetrics/VictoriaMetrics/issues/685#issuecomment-674423728
-	data, err := ioutil.ReadFile("/sys/devices/system/cpu/online")
+	data, err := os.ReadFile("/sys/devices/system/cpu/online")
 	if err != nil {
 		return -1
 	}

lib/cgroup/util.go

@@ -2,7 +2,7 @@ package cgroup
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path"
 	"strconv"
 	"strings"
@@ -23,11 +23,11 @@ func getStatGeneric(statName, sysfsPrefix, cgroupPath, cgroupGrepLine string) (i
 
 func getFileContents(statName, sysfsPrefix, cgroupPath, cgroupGrepLine string) (string, error) {
 	filepath := path.Join(sysfsPrefix, statName)
-	data, err := ioutil.ReadFile(filepath)
+	data, err := os.ReadFile(filepath)
 	if err == nil {
 		return string(data), nil
 	}
-	cgroupData, err := ioutil.ReadFile(cgroupPath)
+	cgroupData, err := os.ReadFile(cgroupPath)
 	if err != nil {
 		return "", err
 	}
@@ -36,7 +36,7 @@ func getFileContents(statName, sysfsPrefix, cgroupPath, cgroupGrepLine string) (
 		return "", fmt.Errorf("cannot find cgroup path for %q in %q: %w", cgroupGrepLine, cgroupPath, err)
 	}
 	filepath = path.Join(sysfsPrefix, subPath, statName)
-	data, err = ioutil.ReadFile(filepath)
+	data, err = os.ReadFile(filepath)
 	if err != nil {
 		return "", err
 	}

lib/fs/fs.go

@@ -390,7 +390,7 @@ func ReadFileOrHTTP(path string) ([]byte, error) {
 		}
 		return data, nil
 	}
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		return nil, fmt.Errorf("cannot read %q: %w", path, err)
 	}

lib/fs/reader_at_test.go

@@ -2,7 +2,7 @@ package fs
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -18,7 +18,7 @@ func testReaderAt(t *testing.T, bufSize int) {
 	path := "TestReaderAt"
 	const fileSize = 8 * 1024 * 1024
 	data := make([]byte, fileSize)
-	if err := ioutil.WriteFile(path, data, 0600); err != nil {
+	if err := os.WriteFile(path, data, 0600); err != nil {
 		t.Fatalf("cannot create %q: %s", path, err)
 	}
 	defer MustRemoveAll(path)

lib/fs/reader_at_timing_test.go

@@ -2,7 +2,7 @@ package fs
 
 import (
 	"fmt"
-	"io/ioutil"
+	"os"
 	"testing"
 )
 
@@ -25,7 +25,7 @@ func benchmarkReaderAtMustReadAt(b *testing.B, isMmap bool) {
 	path := "BenchmarkReaderAtMustReadAt"
 	const fileSize = 8 * 1024 * 1024
 	data := make([]byte, fileSize)
-	if err := ioutil.WriteFile(path, data, 0600); err != nil {
+	if err := os.WriteFile(path, data, 0600); err != nil {
 		b.Fatalf("cannot create %q: %s", path, err)
 	}
 	defer MustRemoveAll(path)

lib/mergeset/part_header.go

@@ -4,7 +4,7 @@ import (
 	"encoding/hex"
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
+	"os"
 	"path/filepath"
 	"strconv"
 	"strings"
@@ -124,7 +124,7 @@ func (ph *partHeader) ParseFromPath(partPath string) error {
 
 	// Read other ph fields from metadata.
 	metadataPath := partPath + "/metadata.json"
-	metadata, err := ioutil.ReadFile(metadataPath)
+	metadata, err := os.ReadFile(metadataPath)
 	if err != nil {
 		return fmt.Errorf("cannot read %q: %w", metadataPath, err)
 	}

lib/mergeset/table.go

@@ -3,7 +3,6 @@ package mergeset
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -1259,7 +1258,7 @@ func runTransaction(txnLock *sync.RWMutex, pathPrefix, txnPath string) error {
 	txnLock.RLock()
 	defer txnLock.RUnlock()
 
-	data, err := ioutil.ReadFile(txnPath)
+	data, err := os.ReadFile(txnPath)
 	if err != nil {
 		return fmt.Errorf("cannot read transaction file: %w", err)
 	}

lib/persistentqueue/persistentqueue.go

@@ -671,7 +671,7 @@ func (mi *metainfo) WriteToFile(path string) error {
 	if err != nil {
 		return fmt.Errorf("cannot marshal persistent queue metainfo %#v: %w", mi, err)
 	}
-	if err := ioutil.WriteFile(path, data, 0600); err != nil {
+	if err := os.WriteFile(path, data, 0600); err != nil {
 		return fmt.Errorf("cannot write persistent queue metainfo to %q: %w", path, err)
 	}
 	fs.MustSyncPath(path)
@@ -680,7 +680,7 @@ func (mi *metainfo) WriteToFile(path string) error {
 
 func (mi *metainfo) ReadFromFile(path string) error {
 	mi.Reset()
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		if os.IsNotExist(err) {
 			return err

lib/persistentqueue/persistentqueue_test.go

@@ -2,7 +2,6 @@ package persistentqueue
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strconv"
 	"testing"
@@ -371,7 +370,7 @@ func TestQueueLimitedSize(t *testing.T) {
 }
 
 func mustCreateFile(path, contents string) {
-	if err := ioutil.WriteFile(path, []byte(contents), 0600); err != nil {
+	if err := os.WriteFile(path, []byte(contents), 0600); err != nil {
 		panic(fmt.Errorf("cannot create file %q with %d bytes contents: %w", path, len(contents), err))
 	}
 }

lib/promscrape/discovery/azure/api.go

@@ -3,7 +3,6 @@ package azure
 import (
 	"encoding/json"
 	"fmt"
-	"io/ioutil"
 	"net/url"
 	"os"
 	"strconv"
@@ -145,7 +144,7 @@ func getCloudEnvByName(name string) (*cloudEnvironmentEndpoints, error) {
 }
 
 func readCloudEndpointsFromFile(filePath string) (*cloudEnvironmentEndpoints, error) {
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		return nil, fmt.Errorf("cannot file %q: %w", filePath, err)
 	}

lib/promscrape/discovery/consul/api.go

@@ -3,7 +3,6 @@ package consul
 import (
 	"flag"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"strconv"
 	"strings"
@@ -109,7 +108,7 @@ func getToken(token *promauth.Secret) (string, error) {
 		return token.String(), nil
 	}
 	if tokenFile := os.Getenv("CONSUL_HTTP_TOKEN_FILE"); tokenFile != "" {
-		data, err := ioutil.ReadFile(tokenFile)
+		data, err := os.ReadFile(tokenFile)
 		if err != nil {
 			return "", fmt.Errorf("cannot read consul token file %q; probably, `token` arg is missing in `consul_sd_config`? error: %w", tokenFile, err)
 		}

lib/promscrape/discovery/kubernetes/api_watcher.go

@@ -9,6 +9,7 @@ import (
 	"io/ioutil"
 	"net/http"
 	"net/url"
+	"os"
 	"reflect"
 	"strconv"
 	"strings"
@@ -66,7 +67,7 @@ func newAPIWatcher(apiServer string, ac *promauth.Config, sdc *SDConfig, swcFunc
 	namespaces := sdc.Namespaces.Names
 	if len(namespaces) == 0 {
 		if sdc.Namespaces.OwnNamespace {
-			namespace, err := ioutil.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace")
+			namespace, err := os.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace")
 			if err != nil {
 				logger.Fatalf("cannot determine namespace for the current pod according to `own_namespace: true` option in kubernetes_sd_config: %s", err)
 			}

lib/storage/part_header.go

@@ -3,7 +3,6 @@ package storage
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -131,7 +130,7 @@ func (ph *partHeader) Reset() {
 
 func (ph *partHeader) readMinDedupInterval(partPath string) error {
 	filePath := partPath + "/min_dedup_interval"
-	data, err := ioutil.ReadFile(filePath)
+	data, err := os.ReadFile(filePath)
 	if err != nil {
 		if errors.Is(err, os.ErrNotExist) {
 			// The minimum dedup interval may not exist for old parts.

lib/storage/partition.go

@@ -3,7 +3,6 @@ package storage
 import (
 	"errors"
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"sort"
@@ -1743,7 +1742,7 @@ func runTransaction(txnLock *sync.RWMutex, pathPrefix1, pathPrefix2, txnPath str
 	txnLock.RLock()
 	defer txnLock.RUnlock()
 
-	data, err := ioutil.ReadFile(txnPath)
+	data, err := os.ReadFile(txnPath)
 	if err != nil {
 		return fmt.Errorf("cannot read transaction file: %w", err)
 	}

lib/storage/storage.go

@@ -5,7 +5,6 @@ import (
 	"errors"
 	"fmt"
 	"io"
-	"io/ioutil"
 	"math"
 	"os"
 	"path/filepath"
@@ -845,7 +844,7 @@ func (s *Storage) mustLoadNextDayMetricIDs(date uint64) *byDateMetricIDEntry {
 		logger.Infof("nothing to load from %q", path)
 		return e
 	}
-	src, err := ioutil.ReadFile(path)
+	src, err := os.ReadFile(path)
 	if err != nil {
 		logger.Panicf("FATAL: cannot read %s: %s", path, err)
 	}
@@ -889,7 +888,7 @@ func (s *Storage) mustLoadHourMetricIDs(hour uint64, name string) *hourMetricIDs
 		logger.Infof("nothing to load from %q", path)
 		return hm
 	}
-	src, err := ioutil.ReadFile(path)
+	src, err := os.ReadFile(path)
 	if err != nil {
 		logger.Panicf("FATAL: cannot read %s: %s", path, err)
 	}
@@ -938,7 +937,7 @@ func (s *Storage) mustSaveNextDayMetricIDs(e *byDateMetricIDEntry) {
 	// Marshal e.v
 	dst = marshalUint64Set(dst, &e.v)
 
-	if err := ioutil.WriteFile(path, dst, 0644); err != nil {
+	if err := os.WriteFile(path, dst, 0644); err != nil {
 		logger.Panicf("FATAL: cannot write %d bytes to %q: %s", len(dst), path, err)
 	}
 	logger.Infof("saved %s to %q in %.3f seconds; entriesCount: %d; sizeBytes: %d", name, path, time.Since(startTime).Seconds(), e.v.Len(), len(dst))
@@ -961,7 +960,7 @@ func (s *Storage) mustSaveHourMetricIDs(hm *hourMetricIDs, name string) {
 	// Marshal hm.m
 	dst = marshalUint64Set(dst, hm.m)
 
-	if err := ioutil.WriteFile(path, dst, 0644); err != nil {
+	if err := os.WriteFile(path, dst, 0644); err != nil {
 		logger.Panicf("FATAL: cannot write %d bytes to %q: %s", len(dst), path, err)
 	}
 	logger.Infof("saved %s to %q in %.3f seconds; entriesCount: %d; sizeBytes: %d", name, path, time.Since(startTime).Seconds(), hm.m.Len(), len(dst))
@@ -1022,7 +1021,7 @@ func mustGetMinTimestampForCompositeIndex(metadataDir string, isEmptyDB bool) in
 }
 
 func loadMinTimestampForCompositeIndex(path string) (int64, error) {
-	data, err := ioutil.ReadFile(path)
+	data, err := os.ReadFile(path)
 	if err != nil {
 		return 0, err
 	}