chore: Upgrade golangci-lint to v2

- Migrate the configuration file
- Update the tooling version and CI
- Apply auto-fixes

Signed-off-by: Kemal Akkoyun <kemal.akkoyun@datadoghq.com>

.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

@@ -1,32 +1,47 @@
+version: "2"
 linters:
   enable:
     - depguard
-    - goimports
     - misspell
     - revive
-
-issues:
-  exclude-rules:
-    - path: _test.go
-      linters:
-        - errcheck
-
-linters-settings:
-  depguard:
+  settings:
+    depguard:
+      rules:
+        no_exec_policy:
+          files:
+            - '!$test'
+          deny:
+            - pkg: os/exec
+              desc: Using os/exec to run sub processes it not allowed by policy
+    errcheck:
+      exclude-functions:
+        - (net/http.ResponseWriter).Write
+    revive:
+      rules:
+        - name: unused-parameter
+          severity: warning
+          disabled: true
+  exclusions:
+    generated: lax
+    presets:
+      - comments
+      - common-false-positives
+      - legacy
+      - std-error-handling
     rules:
-      no_exec_policy:
-        files:
-          - "!$test"
-        deny:
-          - pkg: "os/exec"
-            desc: "Using os/exec to run sub processes it not allowed by policy"
-  errcheck:
-    exclude-functions:
-      # Used in HTTP handlers, any error is handled by the server itself.
-      - (net/http.ResponseWriter).Write
-  revive:
-    rules:
-      # https://github.com/mgechev/revive/blob/master/RULES_DESCRIPTIONS.md#unused-parameter
-      - name: unused-parameter
-        severity: warning
-        disabled: true
+      - linters:
+          - errcheck
+        path: _test.go
+    paths:
+      - third_party$
+      - builtin$
+      - examples$
+formatters:
+  enable:
+    - goimports
+  exclusions:
+    generated: lax
+    paths:
+      - third_party$
+      - builtin$
+      - examples$

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))

collector/boot_time_bsd.go

@@ -18,9 +18,10 @@
 package collector
 
 import (
+	"log/slog"
+
 	"github.com/prometheus/client_golang/prometheus"
 	"golang.org/x/sys/unix"
-	"log/slog"
 )
 
 type bootTimeCollector struct {

collector/meminfo_darwin.go

@@ -52,7 +52,7 @@ func (c *meminfoCollector) getMemInfo() (map[string]float64, error) {
 		&infoCount,
 	)
 	if ret != C.KERN_SUCCESS {
-		return nil, fmt.Errorf("Couldn't get memory statistics, host_statistics returned %d", ret)
+		return nil, fmt.Errorf("couldn't get memory statistics, host_statistics returned %d", ret)
 	}
 	totalb, err := unix.Sysctl("hw.memsize")
 	if err != nil {

node_exporter.go

@@ -112,7 +112,7 @@ func (h *handler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
 	if err != nil {
 		h.logger.Warn("Couldn't create filtered metrics handler:", "err", err)
 		w.WriteHeader(http.StatusBadRequest)
-		w.Write([]byte(fmt.Sprintf("Couldn't create filtered metrics handler: %s", err)))
+		fmt.Fprintf(w, "Couldn't create filtered metrics handler: %s", err)
 		return
 	}
 	filteredHandler.ServeHTTP(w, r)