Merge pull request #3808 from dongjiang1989/drop-ioutil

chore: Replace deprecation `ioutil` fucntions and add depguard rules in `.golangci.yml`

.golangci.yml

@@ -46,15 +46,14 @@ linters:
     - goimports
     - govet
     # linters default enabled by golangci-lint .
-    - deadcode
     - depguard
     #- errcheck
     - gosimple
     - ineffassign
     - staticcheck
     - typecheck
+    # deadcode and varcheck is deprecated (since v1.49.0). Replaced by unused.
     - unused
-    - varcheck
     # other linters supported by golangci-lint.
     #- gosec
     #- revive
@@ -74,3 +73,5 @@ linters-settings:
         deny:
           - pkg: "k8s.io/klog$"
             desc: "k8s.io/klog is deprecated, use k8s.io/klog/v2 instead"
+          - pkg: "io/ioutil"
+            desc: "replaced by io and os packages since Go 1.16: https://tip.golang.org/doc/go1.16#ioutil"

pkg/metriccollect/local/memory.go

@@ -18,7 +18,6 @@ package local
 
 import (
 	"fmt"
-	"io/ioutil"
 	"os"
 	"path/filepath"
 	"strconv"
@@ -91,7 +90,7 @@ func (c *MemoryResourceCollector) CollectLocalMetrics(metricInfo *LocalMetricInf
 func getMemoryUsage(cgroupRoot string) (int64, error) {
 	usage := int64(0)
 	cgroupMemory := filepath.Join(cgroupRoot, cgroup.MemoryUsageFile)
-	date, err := ioutil.ReadFile(cgroupMemory)
+	date, err := os.ReadFile(cgroupMemory)
 	if err != nil {
 		return 0, err
 	}