add socket listener & writer (#2094)

closes #1516 
closes #1711 
closes #1721 
closes #1526

plugins/outputs/socket_writer/socket_writer_test.go

@@ -0,0 +1,187 @@
+package socket_writer
+
+import (
+	"bufio"
+	"bytes"
+	"net"
+	"os"
+	"sync"
+	"testing"
+
+	"github.com/influxdata/telegraf"
+	"github.com/influxdata/telegraf/testutil"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSocketWriter_tcp(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+
+	sw := newSocketWriter()
+	sw.Address = "tcp://" + listener.Addr().String()
+
+	err = sw.Connect()
+	require.NoError(t, err)
+
+	lconn, err := listener.Accept()
+	require.NoError(t, err)
+
+	testSocketWriter_stream(t, sw, lconn)
+}
+
+func TestSocketWriter_udp(t *testing.T) {
+	listener, err := net.ListenPacket("udp", "127.0.0.1:0")
+	require.NoError(t, err)
+
+	sw := newSocketWriter()
+	sw.Address = "udp://" + listener.LocalAddr().String()
+
+	err = sw.Connect()
+	require.NoError(t, err)
+
+	testSocketWriter_packet(t, sw, listener)
+}
+
+func TestSocketWriter_unix(t *testing.T) {
+	defer os.Remove("/tmp/telegraf_test.sock")
+	listener, err := net.Listen("unix", "/tmp/telegraf_test.sock")
+	require.NoError(t, err)
+
+	sw := newSocketWriter()
+	sw.Address = "unix:///tmp/telegraf_test.sock"
+
+	err = sw.Connect()
+	require.NoError(t, err)
+
+	lconn, err := listener.Accept()
+	require.NoError(t, err)
+
+	testSocketWriter_stream(t, sw, lconn)
+}
+
+func TestSocketWriter_unixgram(t *testing.T) {
+	defer os.Remove("/tmp/telegraf_test.sock")
+	listener, err := net.ListenPacket("unixgram", "/tmp/telegraf_test.sock")
+	require.NoError(t, err)
+
+	sw := newSocketWriter()
+	sw.Address = "unixgram:///tmp/telegraf_test.sock"
+
+	err = sw.Connect()
+	require.NoError(t, err)
+
+	testSocketWriter_packet(t, sw, listener)
+}
+
+func testSocketWriter_stream(t *testing.T, sw *SocketWriter, lconn net.Conn) {
+	metrics := []telegraf.Metric{}
+	metrics = append(metrics, testutil.TestMetric(1, "test"))
+	mbs1out, _ := sw.Serialize(metrics[0])
+	metrics = append(metrics, testutil.TestMetric(2, "test"))
+	mbs2out, _ := sw.Serialize(metrics[1])
+
+	err := sw.Write(metrics)
+	require.NoError(t, err)
+
+	scnr := bufio.NewScanner(lconn)
+	require.True(t, scnr.Scan())
+	mstr1in := scnr.Text() + "\n"
+	require.True(t, scnr.Scan())
+	mstr2in := scnr.Text() + "\n"
+
+	assert.Equal(t, string(mbs1out), mstr1in)
+	assert.Equal(t, string(mbs2out), mstr2in)
+}
+
+func testSocketWriter_packet(t *testing.T, sw *SocketWriter, lconn net.PacketConn) {
+	metrics := []telegraf.Metric{}
+	metrics = append(metrics, testutil.TestMetric(1, "test"))
+	mbs1out, _ := sw.Serialize(metrics[0])
+	metrics = append(metrics, testutil.TestMetric(2, "test"))
+	mbs2out, _ := sw.Serialize(metrics[1])
+
+	err := sw.Write(metrics)
+	require.NoError(t, err)
+
+	buf := make([]byte, 256)
+	var mstrins []string
+	for len(mstrins) < 2 {
+		n, _, err := lconn.ReadFrom(buf)
+		require.NoError(t, err)
+		for _, bs := range bytes.Split(buf[:n], []byte{'\n'}) {
+			if len(bs) == 0 {
+				continue
+			}
+			mstrins = append(mstrins, string(bs)+"\n")
+		}
+	}
+	require.Len(t, mstrins, 2)
+
+	assert.Equal(t, string(mbs1out), mstrins[0])
+	assert.Equal(t, string(mbs2out), mstrins[1])
+}
+
+func TestSocketWriter_Write_err(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+
+	sw := newSocketWriter()
+	sw.Address = "tcp://" + listener.Addr().String()
+
+	err = sw.Connect()
+	require.NoError(t, err)
+	sw.Conn.(*net.TCPConn).SetReadBuffer(256)
+
+	lconn, err := listener.Accept()
+	require.NoError(t, err)
+	lconn.(*net.TCPConn).SetWriteBuffer(256)
+
+	metrics := []telegraf.Metric{testutil.TestMetric(1, "testerr")}
+
+	// close the socket to generate an error
+	lconn.Close()
+	sw.Close()
+	err = sw.Write(metrics)
+	require.Error(t, err)
+	assert.Nil(t, sw.Conn)
+}
+
+func TestSocketWriter_Write_reconnect(t *testing.T) {
+	listener, err := net.Listen("tcp", "127.0.0.1:0")
+	require.NoError(t, err)
+
+	sw := newSocketWriter()
+	sw.Address = "tcp://" + listener.Addr().String()
+
+	err = sw.Connect()
+	require.NoError(t, err)
+	sw.Conn.(*net.TCPConn).SetReadBuffer(256)
+
+	lconn, err := listener.Accept()
+	require.NoError(t, err)
+	lconn.(*net.TCPConn).SetWriteBuffer(256)
+	lconn.Close()
+	sw.Conn = nil
+
+	wg := sync.WaitGroup{}
+	wg.Add(1)
+	var lerr error
+	go func() {
+		lconn, lerr = listener.Accept()
+		wg.Done()
+	}()
+
+	metrics := []telegraf.Metric{testutil.TestMetric(1, "testerr")}
+	err = sw.Write(metrics)
+	require.NoError(t, err)
+
+	wg.Wait()
+	assert.NoError(t, lerr)
+
+	mbsout, _ := sw.Serialize(metrics[0])
+	buf := make([]byte, 256)
+	n, err := lconn.Read(buf)
+	require.NoError(t, err)
+	assert.Equal(t, string(mbsout), string(buf[:n]))
+}