enable more linters

Signed-off-by: Matthieu MOREL <matthieu.morel35@gmail.com>

.github/workflows/golangci-lint.yml

@@ -27,4 +27,5 @@ jobs:
       - name: Lint
         uses: golangci/golangci-lint-action@v3.4.0
         with:
+          args: --verbose
           version: v1.51.2

.golangci.yml

@@ -0,0 +1,20 @@
+linters:
+  enable:
+    - gocritic
+    - gofumpt
+    - goimports
+    - gosimple
+    - misspell
+    - revive
+    - unconvert
+    - unused
+
+linters-settings:
+  goimports:
+    local-prefixes: github.com/prometheus
+
+output:
+  sort-results: true
+
+run:
+  timeout: 5m

config/generate.go

@@ -71,7 +71,6 @@ func SerialNumber() *big.Int {
 	serialNumber.Add(&serial, big.NewInt(1))
 
 	return &serial
-
 }
 
 func GenerateCertificateAuthority(commonName string, parentCert *x509.Certificate, parentKey *rsa.PrivateKey) (*x509.Certificate, *rsa.PrivateKey, error) {
@@ -170,7 +169,7 @@ func writeCertificateAndKey(path string, cert *x509.Certificate, key *rsa.Privat
 		return err
 	}
 
-	if err := os.WriteFile(fmt.Sprintf("%s.crt", path), b.Bytes(), 0644); err != nil {
+	if err := os.WriteFile(fmt.Sprintf("%s.crt", path), b.Bytes(), 0o644); err != nil {
 		return err
 	}
 
@@ -179,7 +178,7 @@ func writeCertificateAndKey(path string, cert *x509.Certificate, key *rsa.Privat
 		return err
 	}
 
-	if err := os.WriteFile(fmt.Sprintf("%s.key", path), b.Bytes(), 0644); err != nil {
+	if err := os.WriteFile(fmt.Sprintf("%s.key", path), b.Bytes(), 0o644); err != nil {
 		return err
 	}
 
@@ -239,7 +238,7 @@ func main() {
 		log.Fatal(err)
 	}
 
-	if err := os.WriteFile("testdata/tls-ca-chain.pem", b.Bytes(), 0644); err != nil {
+	if err := os.WriteFile("testdata/tls-ca-chain.pem", b.Bytes(), 0o644); err != nil {
 		log.Fatal(err)
 	}
 }

config/http_config.go

@@ -70,7 +70,7 @@ var TLSVersions = map[string]TLSVersion{
 
 func (tv *TLSVersion) UnmarshalYAML(unmarshal func(interface{}) error) error {
 	var s string
-	err := unmarshal((*string)(&s))
+	err := unmarshal(&s)
 	if err != nil {
 		return err
 	}
@@ -251,12 +251,12 @@ func (o *OAuth2) UnmarshalJSON(data []byte) error {
 }
 
 // SetDirectory joins any relative file paths with dir.
-func (a *OAuth2) SetDirectory(dir string) {
-	if a == nil {
+func (o *OAuth2) SetDirectory(dir string) {
+	if o == nil {
 		return
 	}
-	a.ClientSecretFile = JoinDir(dir, a.ClientSecretFile)
-	a.TLSConfig.SetDirectory(dir)
+	o.ClientSecretFile = JoinDir(dir, o.ClientSecretFile)
+	o.TLSConfig.SetDirectory(dir)
 }
 
 // LoadHTTPConfig parses the YAML input s into a HTTPClientConfig.
@@ -845,11 +845,12 @@ func NewTLSConfig(cfg *TLSConfig) (*tls.Config, error) {
 		tlsConfig.ServerName = cfg.ServerName
 	}
 	// If a client cert & key is provided then configure TLS config accordingly.
-	if len(cfg.CertFile) > 0 && len(cfg.KeyFile) == 0 {
+	switch {
+	case len(cfg.CertFile) > 0 && len(cfg.KeyFile) == 0:
 		return nil, fmt.Errorf("client cert file %q specified without client key file", cfg.CertFile)
-	} else if len(cfg.KeyFile) > 0 && len(cfg.CertFile) == 0 {
+	case len(cfg.KeyFile) > 0 && len(cfg.CertFile) == 0:
 		return nil, fmt.Errorf("client key file %q specified without client cert file", cfg.KeyFile)
-	} else if len(cfg.CertFile) > 0 && len(cfg.KeyFile) > 0 {
+	case len(cfg.CertFile) > 0 && len(cfg.KeyFile) > 0:
 		// Verify that client cert and key are valid.
 		if _, err := cfg.getClientCertificate(nil); err != nil {
 			return nil, err
@@ -1014,9 +1015,9 @@ func (t *tlsRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
 	}
 
 	t.mtx.RLock()
-	equal := bytes.Equal(caHash[:], t.hashCAFile) &&
-		bytes.Equal(certHash[:], t.hashCertFile) &&
-		bytes.Equal(keyHash[:], t.hashKeyFile)
+	equal := bytes.Equal(caHash, t.hashCAFile) &&
+		bytes.Equal(certHash, t.hashCertFile) &&
+		bytes.Equal(keyHash, t.hashKeyFile)
 	rt := t.rt
 	t.mtx.RUnlock()
 	if equal {
@@ -1039,9 +1040,9 @@ func (t *tlsRoundTripper) RoundTrip(req *http.Request) (*http.Response, error) {
 
 	t.mtx.Lock()
 	t.rt = rt
-	t.hashCAFile = caHash[:]
-	t.hashCertFile = certHash[:]
-	t.hashKeyFile = keyHash[:]
+	t.hashCAFile = caHash
+	t.hashCertFile = certHash
+	t.hashKeyFile = keyHash
 	t.mtx.Unlock()
 
 	return rt.RoundTrip(req)