integrate golang linters

.drone.yml

@@ -17,6 +17,16 @@ clone:
   depth: 1
 
 steps:
+  - name: lint
+    image: golangci/golangci-lint:v1.48-alpine
+    volumes:
+      - name: deps
+        path: /go
+    commands:
+      - golangci-lint run -v
+      - go install github.com/mgechev/revive@v1.2.3
+      - revive -config .revive.toml -formatter friendly ./...
+
   - name: test
     image: golang:1.19-alpine
     environment:

.golangci.yml

@@ -0,0 +1,31 @@
+linters:
+  enable:
+    - dogsled
+    - errname
+    - errorlint
+    - exportloopref
+    - funlen
+    - gocognit
+    - goconst
+    - gocritic
+    - gocyclo
+    - gofmt
+    - goimports
+    - staticcheck
+    - gosec
+    - govet
+    - misspell
+    - nestif
+    - prealloc
+    - unconvert
+    - unparam
+
+run:
+  timeout: 5m
+
+issues:
+  exclude-rules:
+    - linters:
+        - funlen
+        - gosec
+      path: _test\.go

.revive.toml

@@ -0,0 +1,44 @@
+ignoreGeneratedHeader = false
+severity = "warning"
+confidence = 0.8
+errorCode = 1
+warningCode = 1
+
+#Recommended rules
+[rule.blank-imports]
+[rule.context-as-argument]
+[rule.context-keys-type]
+[rule.dot-imports]
+[rule.error-return]
+[rule.error-strings]
+[rule.error-naming]
+[rule.if-return]
+[rule.increment-decrement]
+[rule.var-naming]
+[rule.var-declaration]
+[rule.package-comments]
+[rule.range]
+[rule.receiver-naming]
+[rule.time-naming]
+[rule.unexported-return]
+[rule.indent-error-flow]
+[rule.errorf]
+[rule.empty-block]
+[rule.superfluous-else]
+[rule.unused-parameter]
+[rule.unreachable-code]
+[rule.redefines-builtin-id]
+
+#Custom rules
+[rule.modifies-parameter]
+[rule.unnecessary-stmt]
+[rule.modifies-value-receiver]
+[rule.range-val-in-closure]
+[rule.range-val-address]
+[rule.waitgroup-by-value]
+[rule.atomic]
+[rule.unused-receiver]
+[rule.early-return]
+[rule.unconditional-recursion]
+[rule.identical-branches]
+[rule.defer] 

https.go

@@ -42,7 +42,7 @@ func newHTTPS(from string, client dnsClient, opts ...httpsOption) *HTTPS {
 var _ plugin.Handler = (*HTTPS)(nil)
 
 // Name implements plugin.Handler.
-func (h *HTTPS) Name() string { return "https" }
+func (*HTTPS) Name() string { return "https" }
 
 // ServeDNS implements plugin.Handler.
 func (h *HTTPS) ServeDNS(ctx context.Context, w dns.ResponseWriter, r *dns.Msg) (status int, err error) {

policy_test.go

@@ -31,8 +31,8 @@ func TestRandomPolicy(t *testing.T) {
 			name:    "OneElement",
 			poolLen: 1,
 			expected: [][]int{
-				[]int{0},
-				[]int{0},
+				{0},
+				{0},
 			},
 		},
 		{
@@ -92,27 +92,27 @@ func TestRoundRobinPolicy(t *testing.T) {
 			name:    "OneElement",
 			poolLen: 1,
 			expected: [][]int{
-				[]int{0},
-				[]int{0},
+				{0},
+				{0},
 			},
 		},
 		{
 			name:    "TwoElements",
 			poolLen: 2,
 			expected: [][]int{
-				[]int{0, 1},
-				[]int{1, 0},
-				[]int{0, 1},
+				{0, 1},
+				{1, 0},
+				{0, 1},
 			},
 		},
 		{
 			name:    "ThreeElements",
 			poolLen: 3,
 			expected: [][]int{
-				[]int{0, 1, 2},
-				[]int{1, 2, 0},
-				[]int{2, 0, 1},
-				[]int{0, 1, 2},
+				{0, 1, 2},
+				{1, 2, 0},
+				{2, 0, 1},
+				{0, 1, 2},
 			},
 		},
 	}
@@ -152,24 +152,24 @@ func TestSequentialPolicy(t *testing.T) {
 			name:    "OneElement",
 			poolLen: 1,
 			expected: [][]int{
-				[]int{0},
-				[]int{0},
+				{0},
+				{0},
 			},
 		},
 		{
 			name:    "TwoElements",
 			poolLen: 2,
 			expected: [][]int{
-				[]int{0, 1},
-				[]int{0, 1},
+				{0, 1},
+				{0, 1},
 			},
 		},
 		{
 			name:    "ThreeElements",
 			poolLen: 3,
 			expected: [][]int{
-				[]int{0, 1, 2},
-				[]int{0, 1, 2},
+				{0, 1, 2},
+				{0, 1, 2},
 			},
 		},
 	}

proxy.go

@@ -163,12 +163,15 @@ func withLbMaxFails(maxFails int) lbDNSClientOption {
 func (c *lbDNSClient) Query(ctx context.Context, dnsreq []byte) (r *dns.Msg, err error) {
 	ids := c.p.List(len(c.clients))
 	for i := 0; i < c.maxFails; i++ {
-		ctx, cancel := context.WithTimeout(ctx, c.timeout)
-		defer cancel()
-		if r, err = c.clients[ids[i]].Query(ctx, dnsreq); err == nil {
+		if r, err = c.query(ctx, dnsreq, ids[i]); err == nil {
 			return
 		}
-		cancel()
 	}
 	return
 }
+
+func (c *lbDNSClient) query(ctx context.Context, dnsreq []byte, clientID int) (*dns.Msg, error) {
+	ctx, cancel := context.WithTimeout(ctx, c.timeout)
+	defer cancel()
+	return c.clients[clientID].Query(ctx, dnsreq)
+}

proxy_test.go

@@ -5,7 +5,6 @@ import (
 	"context"
 	"errors"
 	"io"
-	"io/ioutil"
 	"net"
 	"net/http"
 	"strings"
@@ -70,7 +69,7 @@ func TestDNSClient(t *testing.T) {
 		require.Equal(t, []byte("abc"), buf, "invalid request body")
 
 		resp = &http.Response{
-			Body:       ioutil.NopCloser(bytes.NewReader(packMsg(t, expectedMsg))),
+			Body:       io.NopCloser(bytes.NewReader(packMsg(t, expectedMsg))),
 			StatusCode: http.StatusOK,
 		}
 		return
@@ -101,7 +100,7 @@ func TestDNSClientHttpClientError(t *testing.T) {
 	httpClient := mockHTTPClientFunc(func(req *http.Request) (resp *http.Response, err error) {
 		err = errors.New("http error")
 		resp = &http.Response{
-			Body:       ioutil.NopCloser(bytes.NewReader(packMsg(t, newExpectedDNSMsg()))),
+			Body:       io.NopCloser(bytes.NewReader(packMsg(t, newExpectedDNSMsg()))),
 			StatusCode: http.StatusOK,
 		}
 		return
@@ -115,7 +114,7 @@ func TestDNSClientHttpClientError(t *testing.T) {
 func TestDNSClientHttpStatusError(t *testing.T) {
 	httpClient := mockHTTPClientFunc(func(req *http.Request) (resp *http.Response, err error) {
 		resp = &http.Response{
-			Body:       ioutil.NopCloser(bytes.NewReader(packMsg(t, newExpectedDNSMsg()))),
+			Body:       io.NopCloser(bytes.NewReader(packMsg(t, newExpectedDNSMsg()))),
 			StatusCode: http.StatusInternalServerError,
 		}
 		return
@@ -147,7 +146,7 @@ func TestDNSClientResponseReadError(t *testing.T) {
 			err:      errors.New("io error"),
 		}
 		resp = &http.Response{
-			Body:       ioutil.NopCloser(reader),
+			Body:       io.NopCloser(reader),
 			StatusCode: http.StatusOK,
 		}
 		return
@@ -161,7 +160,7 @@ func TestDNSClientResponseReadError(t *testing.T) {
 func TestDNSClientMsgUnpackError(t *testing.T) {
 	httpClient := mockHTTPClientFunc(func(req *http.Request) (resp *http.Response, err error) {
 		resp = &http.Response{
-			Body:       ioutil.NopCloser(strings.NewReader("def")),
+			Body:       io.NopCloser(strings.NewReader("def")),
 			StatusCode: http.StatusOK,
 		}
 		return
@@ -173,15 +172,15 @@ func TestDNSClientMsgUnpackError(t *testing.T) {
 }
 
 func TestDNSClientLargeResponseError(t *testing.T) {
-	//create large buffer with the correct DNS message at the beginning
+	// create large buffer with the correct DNS message at the beginning
 	var buf bytes.Buffer
 	dnsMsg := packMsg(t, newExpectedDNSMsg())
 	buf.Write(dnsMsg)
 	buf.WriteString(strings.Repeat("a", maxDNSMessageSize))
 
 	httpClient := mockHTTPClientFunc(func(req *http.Request) (resp *http.Response, err error) {
 		resp = &http.Response{
-			Body:       ioutil.NopCloser(&buf),
+			Body:       io.NopCloser(&buf),
 			StatusCode: http.StatusOK,
 		}
 		return
@@ -289,6 +288,7 @@ func TestLoadBalanceDNSClientMaxFails(t *testing.T) {
 
 			lbClient := newLoadBalanceDNSClient(clients,
 				withLbPolicy(newSequentialPolicy()),
+				withLbRequestTimeout(defaultRequestTimeout),
 				withLbMaxFails(tt.maxFails))
 
 			result, err := lbClient.Query(context.Background(), []byte("abc"))