From 223e58cde9a6e5db7a6b23d4c60a786f20e9db8f Mon Sep 17 00:00:00 2001
From: Masahiro Nagano <m-nagano@sakura.ad.jp>
Date: Thu, 30 Jul 2026 22:15:22 +0900
Subject: [PATCH] add lint and fix some issue

---
 .golangci.yml  | 35 +++++++++++++++++++++++++++++++++++
 Makefile       |  2 ++
 statsfile.go   |  4 ++--
 usageplugin.go |  9 +++++----
 4 files changed, 44 insertions(+), 6 deletions(-)
 create mode 100644 .golangci.yml

diff --git a/.golangci.yml b/.golangci.yml
new file mode 100644
index 0000000..4a1cef4
--- /dev/null
+++ b/.golangci.yml
@@ -0,0 +1,35 @@
+version: "2"
+run:
+  tests: true
+linters:
+  enable:
+    - govet
+    - ineffassign
+    - staticcheck
+    - unused
+    - bodyclose
+    - gocognit
+    - dupl
+    - errcheck
+    - modernize
+    - errname
+    - errorlint
+    - prealloc
+
+  settings:
+    gocognit:
+      min-complexity: 15
+    dupl:
+      threshold: 100
+    modernize:
+      disable:
+        - plusbuild
+    errcheck:
+      exclude-functions:
+        - fmt.Fprintf
+        - (io.Closer).Close
+        - (*os.File).Close
+        - (*net.TCPConn).Close
+        - (*net.TCPListener).Close
+        - (*bytes.Buffer).Write
+        - (*strings.Builder).WriteString
diff --git a/Makefile b/Makefile
index 7c18567..1af928d 100644
--- a/Makefile
+++ b/Makefile
@@ -15,3 +15,5 @@ check:
 	go test -v ./...
 	go test -race ./...
 
+lint:
+	golangci-lint run --timeout 5m ./...
\ No newline at end of file
diff --git a/statsfile.go b/statsfile.go
index 93851c6..197c1fe 100644
--- a/statsfile.go
+++ b/statsfile.go
@@ -29,13 +29,13 @@ func writeStats(dir, filename string, st procfs.CPUStat) error {
 	err = je.Encode(stats{st, n})
 	if err != nil {
 		newFile.Close()
-		os.Remove(newFile.Name())
+		_ = os.Remove(newFile.Name())
 		return err
 	}
 
 	err = newFile.Close()
 	if err != nil {
-		os.Remove(newFile.Name())
+		_ = os.Remove(newFile.Name())
 		return err
 	}
 
diff --git a/usageplugin.go b/usageplugin.go
index 835d6a5..cf6b70f 100644
--- a/usageplugin.go
+++ b/usageplugin.go
@@ -131,11 +131,12 @@ func (u LinuxUsagePlugin) gaugeNetMetrics(pf procfs.FS) (map[string]float64, err
 	if err != nil {
 		return res, err
 	}
-	if psnmp.Tcp.ActiveOpens != nil {
-		res["active"] = *psnmp.Tcp.ActiveOpens
+	tcp := psnmp.Tcp
+	if tcp.ActiveOpens != nil {
+		res["active"] = *tcp.ActiveOpens
 	}
-	if psnmp.Tcp.PassiveOpens != nil {
-		res["passive"] = *psnmp.Tcp.PassiveOpens
+	if tcp.PassiveOpens != nil {
+		res["passive"] = *tcp.PassiveOpens
 	}
 	if pnetstat.ListenOverflows != nil {
 		res["overflows"] = *pnetstat.ListenOverflows