Update Go

* Update Go build to 1.24.
* Update minimum Go to 1.23.0.
* Update golangci-lint to v2.
* Fixup linter issues.

Signed-off-by: SuperQ <superq@gmail.com>

.circleci/config.yml

@@ -5,7 +5,7 @@ executors:
   # Whenever the Go version is updated here, .promu.yml should also be updated.
   golang:
     docker:
-      - image: cimg/go:1.23
+      - image: cimg/go:1.24
 jobs:
   test:
     executor: golang

.github/workflows/golangci-lint.yml

@@ -33,7 +33,7 @@ jobs:
         run: sudo apt-get update && sudo apt-get -y install libsnmp-dev
         if: github.repository == 'prometheus/snmp_exporter'
       - name: Lint
-        uses: golangci/golangci-lint-action@55c2c1448f86e01eaae002a5a3a9624417608d84 # v6.5.2
+        uses: golangci/golangci-lint-action@1481404843c368bc19ca9406f87d6e0fc97bdcfd # v7.0.0
         with:
           args: --verbose
-          version: v1.64.6
+          version: v2.0.2

.golangci.yml

@@ -1,26 +1,36 @@
+version: "2"
 run:
   issues-exit-code: 1
   tests: true
 linters:
+  enable:
+    - nakedret
+    - whitespace
   disable:
     - errcheck
-  enable:
-    - goimports
-    - gosimple
-    - govet
-    - ineffassign
-    - nakedret
-    - staticcheck
-    - unused
-    - whitespace
-linters-settings:
-  govet:
-    enable-all: true
-    disable:
-      - fieldalignment
+  settings:
+    govet:
+      disable:
+        - fieldalignment
+      enable-all: true
+  exclusions:
+    generated: lax
+    rules:
+      - path: (.+)\.go$
+        text: 'shadow: declaration of "err" shadows declaration at line (\d+)'
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
 issues:
-  exclude-use-default: false
-  exclude:
-    - 'shadow: declaration of "err" shadows declaration at line (\d+)'
   max-issues-per-linter: 0
   max-same-issues: 0
+formatters:
+  enable:
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$

.promu.yml

@@ -1,7 +1,7 @@
 go:
     # Whenever the Go version is updated here, .circle/config.yml should also
     # be updated.
-    version: 1.23
+    version: 1.24
 repository:
     path: github.com/prometheus/statsd_exporter
 build:

Makefile.common

@@ -61,7 +61,7 @@ PROMU_URL     := https://github.com/prometheus/promu/releases/download/v$(PROMU_
 SKIP_GOLANGCI_LINT :=
 GOLANGCI_LINT :=
 GOLANGCI_LINT_OPTS ?=
-GOLANGCI_LINT_VERSION ?= v1.64.6
+GOLANGCI_LINT_VERSION ?= v2.0.2
 # golangci-lint only supports linux, darwin and windows platforms on i386/amd64/arm64.
 # windows isn't included here because of the path separator being different.
 ifeq ($(GOHOSTOS),$(filter $(GOHOSTOS),linux darwin))

go.mod

@@ -1,6 +1,6 @@
 module github.com/prometheus/statsd_exporter
 
-go 1.22
+go 1.23.0
 
 require (
 	github.com/alecthomas/kingpin/v2 v2.4.0

pkg/mapper/fsm/dump.go

@@ -31,18 +31,18 @@ func (f *FSM) DumpFSM(w io.Writer) {
 	for idx < len(states) {
 		for field, transition := range states[idx].transitions {
 			states[len(states)] = transition
-			w.Write([]byte(fmt.Sprintf("%d -> %d  [label = \"%s\"];\n", idx, len(states)-1, field)))
+			fmt.Fprintf(w, "%d -> %d  [label = \"%s\"];\n", idx, len(states)-1, field)
 			if idx == 0 {
 				// color for metric types
-				w.Write([]byte(fmt.Sprintf("%d [color=\"#D6B656\",fillcolor=\"#FFF2CC\"];\n", len(states)-1)))
+				fmt.Fprintf(w, "%d [color=\"#D6B656\",fillcolor=\"#FFF2CC\"];\n", len(states)-1)
 			} else if len(transition.transitions) == 0 {
 				// color for end state
-				w.Write([]byte(fmt.Sprintf("%d [color=\"#82B366\",fillcolor=\"#D5E8D4\"];\n", len(states)-1)))
+				fmt.Fprintf(w, "%d [color=\"#82B366\",fillcolor=\"#D5E8D4\"];\n", len(states)-1)
 			}
 		}
 		idx++
 	}
 	// color for start state
-	w.Write([]byte(fmt.Sprintln("0 [color=\"#a94442\",fillcolor=\"#f2dede\"];")))
+	fmt.Fprintln(w, "0 [color=\"#a94442\",fillcolor=\"#f2dede\"];")
 	w.Write([]byte("}"))
 }

pkg/mapper/fsm/formatter.go

@@ -46,9 +46,9 @@ func NewTemplateFormatter(template string, captureCount int) *TemplateFormatter
 		if err != nil || idx > captureCount || idx < 1 {
 			// if index larger than captured count or using unsupported named capture group,
 			// replace with empty string
-			valueFormatter = strings.Replace(valueFormatter, match[0], "", -1)
+			valueFormatter = strings.ReplaceAll(valueFormatter, match[0], "")
 		} else {
-			valueFormatter = strings.Replace(valueFormatter, match[0], "%s", -1)
+			valueFormatter = strings.ReplaceAll(valueFormatter, match[0], "%s")
 			// note: the regex reference variable $? starts from 1
 			indexes = append(indexes, idx-1)
 		}

pkg/mapper/fsm/fsm.go

@@ -243,8 +243,8 @@ func TestIfNeedBacktracking(mappings []string, orderingDisabled bool, logger *sl
 		l := len(strings.Split(mapping, "."))
 		ruleByLength[l] = append(ruleByLength[l], mapping)
 
-		metricRe := strings.Replace(mapping, ".", "\\.", -1)
-		metricRe = strings.Replace(metricRe, "*", "([^.]*)", -1)
+		metricRe := strings.ReplaceAll(mapping, ".", "\\.")
+		metricRe = strings.ReplaceAll(metricRe, "*", "([^.]*)")
 		regex, err := regexp.Compile("^" + metricRe + "$")
 		if err != nil {
 			logger.Warn("Invalid match, cannot compile regex in mapping", "mapping", mapping, "err", err)
@@ -272,8 +272,8 @@ func TestIfNeedBacktracking(mappings []string, orderingDisabled bool, logger *sl
 				}
 				// translate the substring of r1 from 0 to the index of current * into regex
 				// A.B.C.*.E.* will becomes ^A\.B\.C\. and ^A\.B\.C\.\*\.E\.
-				reStr := strings.Replace(r1[:index], ".", "\\.", -1)
-				reStr = strings.Replace(reStr, "*", "\\*", -1)
+				reStr := strings.ReplaceAll(r1[:index], ".", "\\.")
+				reStr = strings.ReplaceAll(reStr, "*", "\\*")
 				re := regexp.MustCompile("^" + reStr)
 				for i2, r2 := range rules {
 					if i2 == i1 {