Fix problems signaled by new linter version v1.45.2

PR (linter: upgrade linter version #405) triggered lint job which failed
with many errors generated by various linters. Configurations were added to
golangcilint.yaml and several refactorings were made in order to improve the
results of the linter.

maintidx linter disabled

Signed-off-by: Alex Stan <alexandrustan96@yahoo.ro>

pkg/extensions/monitoring/extension.go

@@ -169,7 +169,7 @@ func IncDownloadCounter(ms MetricServer, repo string) {
 	})
 }
 
-func SetStorageUsage(ms MetricServer, rootDir string, repo string) {
+func SetStorageUsage(ms MetricServer, rootDir, repo string) {
 	ms.SendMetric(func() {
 		dir := path.Join(rootDir, repo)
 		repoSize, err := getDirSize(dir)

pkg/extensions/monitoring/minimal.go

@@ -235,7 +235,7 @@ func GetHistograms() map[string][]string {
 
 // return true if a metric does not have any labels or if the label
 // values for searched metric corresponds to the one in the cached slice.
-func isMetricMatch(lValues []string, metricValues []string) bool {
+func isMetricMatch(lValues, metricValues []string) bool {
 	if len(lValues) == len(metricValues) {
 		for i, v := range metricValues {
 			if v != lValues[i] {
@@ -400,7 +400,7 @@ func (ms *metricServer) HistogramObserve(hv *HistogramValue) {
 }
 
 // nolint: goerr113
-func sanityChecks(name string, knownLabels []string, found bool, labelNames []string, labelValues []string) error {
+func sanityChecks(name string, knownLabels []string, found bool, labelNames, labelValues []string) error {
 	if !found {
 		return fmt.Errorf("metric %s: not found", name)
 	}
@@ -479,7 +479,7 @@ func IncUploadCounter(ms MetricServer, repo string) {
 	ms.SendMetric(uCounter)
 }
 
-func SetStorageUsage(ms MetricServer, rootDir string, repo string) {
+func SetStorageUsage(ms MetricServer, rootDir, repo string) {
 	dir := path.Join(rootDir, repo)
 
 	repoSize, err := getDirSize(dir)

pkg/extensions/monitoring/minimal_client.go

@@ -38,7 +38,7 @@ type MetricsClient struct {
 }
 
 func newHTTPMetricsClient() *http.Client {
-	defaultTransport := http.DefaultTransport.(*http.Transport).Clone()
+	defaultTransport := http.DefaultTransport.(*http.Transport).Clone()      //nolint: forcetypeassert
 	defaultTransport.TLSClientConfig = &tls.Config{InsecureSkipVerify: true} //nolint: gosec
 
 	return &http.Client{