Add linters that check for bugs (#779)

Author: lucacome

.golangci.yml

@@ -37,14 +37,19 @@ linters:
     - asasalint
     - asciicheck
     - bidichk
+    - contextcheck
     - dupword
+    - durationcheck
     - errcheck
+    - errchkjson
     - errname
     - errorlint
     - exportloopref
     - fatcontext
     - forcetypeassert
     - gocheckcompilerdirectives
+    - gochecksumtype
+    - gocritic
     - godot
     - gofmt
     - gofumpt
@@ -58,6 +63,7 @@ linters:
     - loggercheck
     - makezero
     - misspell
+    - musttag
     - nilerr
     - noctx
     - nolintlint

collector/nginx_plus.go

@@ -251,8 +251,11 @@ func NewVariableLabelNames(upstreamServerVariableLabelNames []string, serverZone
 
 // NewNginxPlusCollector creates an NginxPlusCollector.
 func NewNginxPlusCollector(nginxClient *plusclient.NginxClient, namespace string, variableLabelNames VariableLabelNames, constLabels map[string]string, logger log.Logger) *NginxPlusCollector {
-	upstreamServerVariableLabelNames := append(variableLabelNames.UpstreamServerVariableLabelNames, variableLabelNames.UpstreamServerPeerVariableLabelNames...)
-	streamUpstreamServerVariableLabelNames := append(variableLabelNames.StreamUpstreamServerVariableLabelNames, variableLabelNames.StreamUpstreamServerPeerVariableLabelNames...)
+	upstreamServerVariableLabelNames := variableLabelNames.UpstreamServerVariableLabelNames
+	streamUpstreamServerVariableLabelNames := variableLabelNames.StreamUpstreamServerVariableLabelNames
+
+	upstreamServerVariableLabelNames = append(upstreamServerVariableLabelNames, variableLabelNames.UpstreamServerPeerVariableLabelNames...)
+	streamUpstreamServerVariableLabelNames = append(streamUpstreamServerVariableLabelNames, variableLabelNames.StreamUpstreamServerPeerVariableLabelNames...)
 	return &NginxPlusCollector{
 		variableLabelNames:             variableLabelNames,
 		upstreamServerLabels:           make(map[string][]string),