Enable Go linters

.golangci.yml

@@ -0,0 +1,71 @@
+run:
+  issues-exit-code: 0
+
+linters:
+  disable-all: true
+  enable:
+    - staticcheck
+    - gosimple
+    - ineffassign
+    - errcheck
+    - misspell
+    - unparam
+    - gofmt
+    - goimports
+    - deadcode
+    - nestif
+    - govet
+    - golint
+    - prealloc
+    - depguard
+    - dogsled
+    - dupl
+    - goconst
+    - gocritic
+    - gocyclo
+    - goprintffuncname
+    - gosec
+    - nakedret
+    - rowserrcheck
+    - scopelint
+    - structcheck
+    - stylecheck
+    - typecheck
+    - unconvert
+    - varcheck
+    - exhaustive
+    - exportloopref
+    - goerr113
+    - gofumpt
+    - unused
+
+run:
+  tests: false
+
+issues:
+  exclude-rules:
+    - linters:
+      - goerr113
+      text: "err113: do not define dynamic errors"
+    - linters:
+      - exhaustive
+      text: "missing cases in switch of type keyboard.Key"
+
+linters-settings:
+  dupl:
+    threshold: 100
+  funlen:
+    lines: 100
+    statements: 50
+  goconst:
+    min-len: 2
+    min-occurrences: 2
+  goimports:
+    local-prefixes: github.com/nakabonne/gosivy
+  golint:
+    min-confidence: 0.3
+  maligned:
+    suggest-new: true
+  misspell:
+    locale: US
+

main.go

@@ -61,7 +61,11 @@ func main() {
 	if err != nil {
 		os.Exit(0)
 	}
-	os.Exit(c.run(flagSet.Args()))
+	code := c.run(flagSet.Args())
+	if code != 0 {
+		c.usage()
+		os.Exit(code)
+	}
 }
 
 func parseFlags(stdout, stderr io.Writer) (*cli, error) {
@@ -84,13 +88,6 @@ func parseFlags(stdout, stderr io.Writer) (*cli, error) {
 	return c, nil
 }
 
-func (c *cli) validate() error {
-	if c.scrapeInterval < time.Second {
-		return fmt.Errorf(`"--scrape-interval" must be >= 1s`)
-	}
-	return nil
-}
-
 func (c *cli) run(args []string) int {
 	if c.version {
 		fmt.Fprintf(c.stderr, "version=%s, commit=%s, buildDate=%s, os=%s, arch=%s\n", version, commit, date, runtime.GOOS, runtime.GOARCH)
@@ -108,11 +105,12 @@ func (c *cli) run(args []string) int {
 		c.listProcesses()
 		return 0
 	}
+
+	// Try to run diagnoser
 	var addr *net.TCPAddr
-	if len(args) <= 0 {
+	if len(args) == 0 {
 		// TODO: Make sure to use the process where the agent runs on.
 		addr = &net.TCPAddr{}
-		return 0
 	} else {
 		var err error
 		addr, err = targetToAddr(args[0])
@@ -123,12 +121,18 @@ func (c *cli) run(args []string) int {
 	}
 	if err := diagnoser.Run(addr, c.scrapeInterval); err != nil {
 		fmt.Fprintf(c.stderr, "failed to start diagnoser: %s\n", err.Error())
-		c.usage()
 		return 1
 	}
 	return 0
 }
 
+func (c *cli) validate() error {
+	if c.scrapeInterval < time.Second {
+		return fmt.Errorf(`"--scrape-interval" must be >= 1s`)
+	}
+	return nil
+}
+
 // targetToAddr parses the target string (pid or host:port),
 // and converts it into the address of a TCP end point.
 func targetToAddr(target string) (*net.TCPAddr, error) {