Fix gzip support in socket_listener with tcp sockets (#7446)

internal/content_coding.go

@@ -1,18 +1,78 @@
 package internal
 
 import (
+	"bufio"
 	"bytes"
 	"compress/gzip"
 	"errors"
 	"io"
 )
 
+// NewStreamContentDecoder returns a reader that will decode the stream
+// according to the encoding type.
+func NewStreamContentDecoder(encoding string, r io.Reader) (io.Reader, error) {
+	switch encoding {
+	case "gzip":
+		return NewGzipReader(r)
+	case "identity", "":
+		return r, nil
+	default:
+		return nil, errors.New("invalid value for content_encoding")
+	}
+}
+
+// GzipReader is similar to gzip.Reader but reads only a single gzip stream per read.
+type GzipReader struct {
+	r           io.Reader
+	z           *gzip.Reader
+	endOfStream bool
+}
+
+func NewGzipReader(r io.Reader) (io.Reader, error) {
+	// We need a read that implements ByteReader in order to line up the next
+	// stream.
+	br := bufio.NewReader(r)
+
+	// Reads the first gzip stream header.
+	z, err := gzip.NewReader(br)
+	if err != nil {
+		return nil, err
+	}
+
+	// Prevent future calls to Read from reading the following gzip header.
+	z.Multistream(false)
+
+	return &GzipReader{r: br, z: z}, nil
+}
+
+func (r *GzipReader) Read(b []byte) (int, error) {
+	if r.endOfStream {
+		// Reads the next gzip header and prepares for the next stream.
+		err := r.z.Reset(r.r)
+		if err != nil {
+			return 0, err
+		}
+		r.z.Multistream(false)
+		r.endOfStream = false
+	}
+
+	n, err := r.z.Read(b)
+
+	// Since multistream is disabled, io.EOF indicates the end of the gzip
+	// sequence.  On the next read we must read the next gzip header.
+	if err == io.EOF {
+		r.endOfStream = true
+		return n, nil
+	}
+	return n, err
+
+}
+
 // NewContentEncoder returns a ContentEncoder for the encoding type.
 func NewContentEncoder(encoding string) (ContentEncoder, error) {
 	switch encoding {
 	case "gzip":
 		return NewGzipEncoder()
-
 	case "identity", "":
 		return NewIdentityEncoder(), nil
 	default:

internal/content_coding_test.go

@@ -1,6 +1,8 @@
 package internal
 
 import (
+	"bytes"
+	"io/ioutil"
 	"testing"
 
 	"github.com/stretchr/testify/require"
@@ -56,3 +58,37 @@ func TestIdentityEncodeDecode(t *testing.T) {
 
 	require.Equal(t, "howdy", string(actual))
 }
+
+func TestStreamIdentityDecode(t *testing.T) {
+	var r bytes.Buffer
+	n, err := r.Write([]byte("howdy"))
+	require.NoError(t, err)
+	require.Equal(t, 5, n)
+
+	dec, err := NewStreamContentDecoder("identity", &r)
+	require.NoError(t, err)
+
+	data, err := ioutil.ReadAll(dec)
+	require.NoError(t, err)
+
+	require.Equal(t, []byte("howdy"), data)
+}
+
+func TestStreamGzipDecode(t *testing.T) {
+	enc, err := NewGzipEncoder()
+	require.NoError(t, err)
+	written, err := enc.Encode([]byte("howdy"))
+	require.NoError(t, err)
+
+	w := bytes.NewBuffer(written)
+
+	dec, err := NewStreamContentDecoder("gzip", w)
+	require.NoError(t, err)
+
+	b := make([]byte, 10)
+	n, err := dec.Read(b)
+	require.NoError(t, err)
+	require.Equal(t, 5, n)
+
+	require.Equal(t, []byte("howdy"), b[:n])
+}

plugins/inputs/socket_listener/socket_listener.go

@@ -111,7 +111,12 @@ func (ssl *streamSocketListener) read(c net.Conn) {
 	defer ssl.removeConnection(c)
 	defer c.Close()
 
-	scnr := bufio.NewScanner(c)
+	decoder, err := internal.NewStreamContentDecoder(ssl.ContentEncoding, c)
+	if err != nil {
+		ssl.Log.Error("Read error: %v", err)
+	}
+
+	scnr := bufio.NewScanner(decoder)
 	for {
 		if ssl.ReadTimeout != nil && ssl.ReadTimeout.Duration > 0 {
 			c.SetReadDeadline(time.Now().Add(ssl.ReadTimeout.Duration))
@@ -120,11 +125,7 @@ func (ssl *streamSocketListener) read(c net.Conn) {
 			break
 		}
 
-		body, err := ssl.decoder.Decode(scnr.Bytes())
-		if err != nil {
-			ssl.Log.Errorf("Unable to decode incoming line: %s", err.Error())
-			continue
-		}
+		body := scnr.Bytes()
 
 		metrics, err := ssl.Parse(body)
 		if err != nil {
@@ -149,6 +150,7 @@ func (ssl *streamSocketListener) read(c net.Conn) {
 type packetSocketListener struct {
 	net.PacketConn
 	*SocketListener
+	decoder internal.ContentDecoder
 }
 
 func (psl *packetSocketListener) listen() {
@@ -196,7 +198,6 @@ type SocketListener struct {
 	parsers.Parser
 	telegraf.Accumulator
 	io.Closer
-	decoder internal.ContentDecoder
 }
 
 func (sl *SocketListener) Description() string {
@@ -283,12 +284,6 @@ func (sl *SocketListener) Start(acc telegraf.Accumulator) error {
 	protocol := spl[0]
 	addr := spl[1]
 
-	var err error
-	sl.decoder, err = internal.NewContentDecoder(sl.ContentEncoding)
-	if err != nil {
-		return err
-	}
-
 	if protocol == "unix" || protocol == "unixpacket" || protocol == "unixgram" {
 		// no good way of testing for "file does not exist".
 		// Instead just ignore error and blow up when we try to listen, which will
@@ -298,16 +293,12 @@ func (sl *SocketListener) Start(acc telegraf.Accumulator) error {
 
 	switch protocol {
 	case "tcp", "tcp4", "tcp6", "unix", "unixpacket":
-		var (
-			err error
-			l   net.Listener
-		)
-
 		tlsCfg, err := sl.ServerConfig.TLSConfig()
 		if err != nil {
 			return err
 		}
 
+		var l net.Listener
 		if tlsCfg == nil {
 			l, err = net.Listen(protocol, addr)
 		} else {
@@ -344,6 +335,11 @@ func (sl *SocketListener) Start(acc telegraf.Accumulator) error {
 			ssl.listen()
 		}()
 	case "udp", "udp4", "udp6", "ip", "ip4", "ip6", "unixgram":
+		decoder, err := internal.NewContentDecoder(sl.ContentEncoding)
+		if err != nil {
+			return err
+		}
+
 		pc, err := udpListen(protocol, addr)
 		if err != nil {
 			return err
@@ -373,6 +369,7 @@ func (sl *SocketListener) Start(acc telegraf.Accumulator) error {
 		psl := &packetSocketListener{
 			PacketConn:     pc,
 			SocketListener: sl,
+			decoder:        decoder,
 		}
 
 		sl.Closer = psl

plugins/inputs/socket_listener/socket_listener_test.go

@@ -222,7 +222,7 @@ func TestSocketListenerDecode_udp(t *testing.T) {
 
 func testSocketListener(t *testing.T, sl *SocketListener, client net.Conn) {
 	mstr12 := []byte("test,foo=bar v=1i 123456789\ntest,foo=baz v=2i 123456790\n")
-	mstr3 := []byte("test,foo=zab v=3i 123456791")
+	mstr3 := []byte("test,foo=zab v=3i 123456791\n")
 
 	if sl.ContentEncoding == "gzip" {
 		encoder, err := internal.NewContentEncoder(sl.ContentEncoding)
@@ -238,10 +238,6 @@ func testSocketListener(t *testing.T, sl *SocketListener, client net.Conn) {
 
 	client.Write(mstr12)
 	client.Write(mstr3)
-	if client.LocalAddr().Network() != "udp" {
-		// stream connection. needs trailing newline to terminate mstr3
-		client.Write([]byte{'\n'})
-	}
 
 	acc := sl.Accumulator.(*testutil.Accumulator)