enabled and fixed the errcheck linter rule

pkg/util/http.go

@@ -19,6 +19,8 @@ package util
 import (
 	"encoding/json"
 	"net/http"
+
+	"k8s.io/klog/v2"
 )
 
 // ReturnHTTPJson generates json http response.
@@ -30,11 +32,15 @@ func ReturnHTTPJson(w http.ResponseWriter, object interface{}) {
 	}
 	w.Header().Set("Content-type", "application/json")
 	w.WriteHeader(http.StatusOK)
-	w.Write(data)
+	if _, err := w.Write(data); err != nil {
+		klog.Errorf("Failed to write http response: %v", err)
+	}
 }
 
 // ReturnHTTPError generates error http response.
 func ReturnHTTPError(w http.ResponseWriter, err error) {
 	w.WriteHeader(http.StatusInternalServerError)
-	w.Write([]byte(err.Error()))
+	if _, err := w.Write([]byte(err.Error())); err != nil {
+		klog.Errorf("Failed to write http error response: %v", err)
+	}
 }

pkg/util/metrics/fakes_test.go

@@ -232,7 +232,9 @@ func TestFakeInt64Metric(t *testing.T) {
 			metric := NewFakeInt64Metric(test.metricName, test.aggregation, test.tagNames)
 
 			for _, record := range test.records {
-				metric.Record(record.tags, record.measurement)
+				if err := metric.Record(record.tags, record.measurement); err != nil {
+					t.Errorf("unexpected error: %v", err)
+				}
 			}
 
 			gotMetrics := metric.ListMetrics()

pkg/util/metrics/metric_float64.go

@@ -72,7 +72,9 @@ func NewFloat64Metric(metricID MetricID, viewName string, description string, un
 		Aggregation: aggregationMethod,
 		TagKeys:     tagKeys,
 	}
-	view.Register(newView)
+	if err := view.Register(newView); err != nil {
+		return nil, fmt.Errorf("failed to register view for metric %q: %v", viewName, err)
+	}
 
 	metric := Float64Metric{viewName, measure}
 	return &metric, nil

pkg/util/metrics/metric_int64.go

@@ -72,7 +72,9 @@ func NewInt64Metric(metricID MetricID, viewName string, description string, unit
 		Aggregation: aggregationMethod,
 		TagKeys:     tagKeys,
 	}
-	view.Register(newView)
+	if err := view.Register(newView); err != nil {
+		return nil, fmt.Errorf("failed to register view for metric %q: %v", viewName, err)
+	}
 
 	metric := Int64Metric{viewName, measure}
 	return &metric, nil

pkg/util/metrics/system/common.go

@@ -16,6 +16,8 @@ package system
 import (
 	"bufio"
 	"os"
+
+	"k8s.io/klog/v2"
 )
 
 // ReadFileIntoLines reads contents from a file and returns lines.
@@ -24,7 +26,11 @@ func ReadFileIntoLines(filename string) ([]string, error) {
 	if err != nil {
 		return nil, err
 	}
-	defer file.Close()
+	defer func() {
+		if err := file.Close(); err != nil {
+			klog.Errorf("Failed to close file %s: %v", filename, err)
+		}
+	}()
 
 	var result []string
 	s := bufio.NewScanner(file)