ci: Use golangci's github action for linting (#3794)

* ci: Use golangci's github action for linting

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix most of the staticcheck lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the prealloc lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the misspell lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the varcheck lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the errcheck lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the bodyclose lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the deadcode lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the unused lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the gosec lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the gosimple lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the ineffassign lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Fix the staticcheck lint errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Revert the misspell change, use a neutral English

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Remove broken golangci-lint CI job

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Re-add errantly-removed weakrand initialization

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* don't break the loop and return

* Removing extra handling for null rootKey

* unignore RegisterModule/RegisterAdapter

Co-authored-by: Mohammed Al Sahaf <msaa1990@gmail.com>

* single-line log message

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

* Fix lint after a1808b0dbf209c615e438a496d257ce5e3acdce2 was merged

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Revert ticker change, ignore it instead

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Ignore some of the write errors

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Remove blank line

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Use lifetime

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* close immediately

Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

* Preallocate configVals

Signed-off-by: Dave Henderson <dhenderson@gmail.com>

* Update modules/caddytls/distributedstek/distributedstek.go

Co-authored-by: Mohammed Al Sahaf <msaa1990@gmail.com>
Co-authored-by: Matt Holt <mholt@users.noreply.github.com>

7 files changed, 45 insertions, 37 deletions

diff --git a/modules/caddyhttp/reverseproxy/fastcgi/client.go b/modules/caddyhttp/reverseproxy/fastcgi/client.go
index ae0de00..94df0c7 100644
--- a/modules/caddyhttp/reverseproxy/fastcgi/client.go
+++ b/modules/caddyhttp/reverseproxy/fastcgi/client.go
@@ -242,13 +242,6 @@ func (c *FCGIClient) writeBeginRequest(role uint16, flags uint8) error {
 	return c.writeRecord(BeginRequest, b[:])
 }
 
-func (c *FCGIClient) writeEndRequest(appStatus int, protocolStatus uint8) error {
-	b := make([]byte, 8)
-	binary.BigEndian.PutUint32(b, uint32(appStatus))
-	b[4] = protocolStatus
-	return c.writeRecord(EndRequest, b)
-}
-
 func (c *FCGIClient) writePairs(recType uint8, pairs map[string]string) error {
 	w := newWriter(c, recType)
 	b := make([]byte, 8)
diff --git a/modules/caddyhttp/reverseproxy/healthchecks.go b/modules/caddyhttp/reverseproxy/healthchecks.go
index 4e93320..285834b 100644
--- a/modules/caddyhttp/reverseproxy/healthchecks.go
+++ b/modules/caddyhttp/reverseproxy/healthchecks.go
@@ -263,7 +263,7 @@ func (h *Handler) doActiveHealthCheck(dialInfo DialInfo, hostAddr string, host H
 	}
 	defer func() {
 		// drain any remaining body so connection could be re-used
-		io.Copy(ioutil.Discard, body)
+		_, _ = io.Copy(ioutil.Discard, body)
 		resp.Body.Close()
 	}()
 
diff --git a/modules/caddyhttp/reverseproxy/httptransport.go b/modules/caddyhttp/reverseproxy/httptransport.go
index d2a9951..61e9054 100644
--- a/modules/caddyhttp/reverseproxy/httptransport.go
+++ b/modules/caddyhttp/reverseproxy/httptransport.go
@@ -173,6 +173,7 @@ func (h *HTTPTransport) NewTransport(ctx caddy.Context) (*http.Transport, error)
 		dialer.Resolver = &net.Resolver{
 			PreferGo: true,
 			Dial: func(ctx context.Context, _, _ string) (net.Conn, error) {
+				//nolint:gosec
 				addr := h.Resolver.netAddrs[weakrand.Intn(len(h.Resolver.netAddrs))]
 				return d.DialContext(ctx, addr.Network, addr.JoinHostPort(0))
 			},
diff --git a/modules/caddyhttp/reverseproxy/reverseproxy.go b/modules/caddyhttp/reverseproxy/reverseproxy.go
index 7fc61ae..bed5289 100644
--- a/modules/caddyhttp/reverseproxy/reverseproxy.go
+++ b/modules/caddyhttp/reverseproxy/reverseproxy.go
@@ -314,7 +314,7 @@ func (h *Handler) Cleanup() error {
 
 	// remove hosts from our config from the pool
 	for _, upstream := range h.Upstreams {
-		hosts.Delete(upstream.String())
+		_, _ = hosts.Delete(upstream.String())
 	}
 
 	return nil
@@ -339,7 +339,7 @@ func (h *Handler) ServeHTTP(w http.ResponseWriter, r *http.Request, next caddyht
 		buf := bufPool.Get().(*bytes.Buffer)
 		buf.Reset()
 		defer bufPool.Put(buf)
-		io.Copy(buf, r.Body)
+		_, _ = io.Copy(buf, r.Body)
 		r.Body.Close()
 		r.Body = ioutil.NopCloser(buf)
 	}
@@ -518,7 +518,8 @@ func (h Handler) prepareRequest(req *http.Request) error {
 // (This method is mostly the beginning of what was borrowed from the net/http/httputil package in the
 // Go standard library which was used as the foundation.)
 func (h *Handler) reverseProxy(rw http.ResponseWriter, req *http.Request, di DialInfo, next caddyhttp.Handler) error {
-	di.Upstream.Host.CountRequest(1)
+	_ = di.Upstream.Host.CountRequest(1)
+	//nolint:errcheck
 	defer di.Upstream.Host.CountRequest(-1)
 
 	// point the request to this upstream
@@ -742,16 +743,6 @@ func copyHeader(dst, src http.Header) {
 	}
 }
 
-func cloneHeader(h http.Header) http.Header {
-	h2 := make(http.Header, len(h))
-	for k, vv := range h {
-		vv2 := make([]string, len(vv))
-		copy(vv2, vv)
-		h2[k] = vv2
-	}
-	return h2
-}
-
 func upgradeType(h http.Header) string {
 	if !httpguts.HeaderValuesContainsToken(h["Connection"], "Upgrade") {
 		return ""
@@ -759,18 +750,6 @@ func upgradeType(h http.Header) string {
 	return strings.ToLower(h.Get("Upgrade"))
 }
 
-func singleJoiningSlash(a, b string) string {
-	aslash := strings.HasSuffix(a, "/")
-	bslash := strings.HasPrefix(b, "/")
-	switch {
-	case aslash && bslash:
-		return a + b[1:]
-	case !aslash && !bslash:
-		return a + "/" + b
-	}
-	return a + b
-}
-
 // removeConnectionHeaders removes hop-by-hop headers listed in the "Connection" header of h.
 // See RFC 7230, section 6.1
 func removeConnectionHeaders(h http.Header) {
diff --git a/modules/caddyhttp/reverseproxy/selectionpolicies.go b/modules/caddyhttp/reverseproxy/selectionpolicies.go
index a1010f4..a391b2f 100644
--- a/modules/caddyhttp/reverseproxy/selectionpolicies.go
+++ b/modules/caddyhttp/reverseproxy/selectionpolicies.go
@@ -536,7 +536,7 @@ func hostByHashing(pool []*Upstream, s string) *Upstream {
 // hash calculates a fast hash based on s.
 func hash(s string) uint32 {
 	h := fnv.New32a()
-	h.Write([]byte(s))
+	_, _ = h.Write([]byte(s))
 	return h.Sum32()
 }
 
diff --git a/modules/caddyhttp/reverseproxy/streaming.go b/modules/caddyhttp/reverseproxy/streaming.go
index 4004b7a..f108a97 100644
--- a/modules/caddyhttp/reverseproxy/streaming.go
+++ b/modules/caddyhttp/reverseproxy/streaming.go
@@ -138,9 +138,9 @@ func (h Handler) copyResponse(dst io.Writer, src io.Reader, flushInterval time.D
 		}
 	}
 
-	buf := streamingBufPool.Get().([]byte)
+	buf := streamingBufPool.Get().(*[]byte)
 	defer streamingBufPool.Put(buf)
-	_, err := h.copyBuffer(dst, src, buf)
+	_, err := h.copyBuffer(dst, src, *buf)
 	return err
 }
 
@@ -255,7 +255,12 @@ func (c switchProtocolCopier) copyToBackend(errc chan<- error) {
 
 var streamingBufPool = sync.Pool{
 	New: func() interface{} {
-		return make([]byte, defaultBufferSize)
+		// The Pool's New function should generally only return pointer
+		// types, since a pointer can be put into the return interface
+		// value without an allocation
+		// - (from the package docs)
+		b := make([]byte, defaultBufferSize)
+		return &b
 	},
 }
 
diff --git a/modules/caddyhttp/reverseproxy/streaming_test.go b/modules/caddyhttp/reverseproxy/streaming_test.go
new file mode 100644
index 0000000..4ed1f1e
--- /dev/null
+++ b/modules/caddyhttp/reverseproxy/streaming_test.go
@@ -0,0 +1,30 @@
+package reverseproxy
+
+import (
+	"bytes"
+	"strings"
+	"testing"
+)
+
+func TestHandlerCopyResponse(t *testing.T) {
+	h := Handler{}
+	testdata := []string{
+		"",
+		strings.Repeat("a", defaultBufferSize),
+		strings.Repeat("123456789 123456789 123456789 12", 3000),
+	}
+	dst := bytes.NewBuffer(nil)
+
+	for _, d := range testdata {
+		src := bytes.NewBuffer([]byte(d))
+		dst.Reset()
+		err := h.copyResponse(dst, src, 0)
+		if err != nil {
+			t.Errorf("failed with error: %v", err)
+		}
+		out := dst.String()
+		if out != d {
+			t.Errorf("bad read: got %q", out)
+		}
+	}
+}