Fix DD_AGENT_HOST variable support

DD_AGENT_HOST did not support UDS or NamedPipe

README.md

@@ -43,7 +43,8 @@ Find a list of all the available options for your DogStatsD Client in the [Datad
 
 ### Supported environment variables
 
-* If the `addr` parameter is empty, the client uses the `DD_AGENT_HOST` and (optionally) the `DD_DOGSTATSD_PORT` environment variables to build a target address.
+* If the `addr` parameter is empty, the client uses the `DD_AGENT_HOST` environment variables to build a target address.
+  Example: `DD_AGENT_HOST=127.0.0.1:8125` for UDP, `DD_AGENT_HOST=unix:///path/to/socket` for UDS and `DD_AGENT_HOST=\\.\pipe\my_windows_pipe` for Windows
 * If the `DD_ENTITY_ID` environment variable is found, its value is injected as a global `dd.internal.entity_id` tag. The Datadog Agent uses this tag to insert container tags into the metrics. To avoid overwriting this global tag, only `append` to the `c.Tags` slice.
 
 To enable origin detection and set the `DD_ENTITY_ID` environment variable, add the following lines to your application manifest:

statsd/pipe_windows_test.go

@@ -10,94 +10,103 @@ import (
 	"time"
 
 	"github.com/Microsoft/go-winio"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
+func createNamedPipe(t *testing.T) (string, *os.File, net.Listener) {
+	f, err := ioutil.TempFile("", "test-pipe-")
+	require.Nil(t, err)
+
+	pipepath := WindowsPipeAddressPrefix + f.Name()
+	ln, err := winio.ListenPipe(pipepath, &winio.PipeConfig{
+		SecurityDescriptor: "D:AI(A;;GA;;;WD)",
+		InputBufferSize:    1_000_000,
+	})
+	if err != nil {
+		os.Remove(f.Name())
+		t.Fatal(err)
+	}
+	return pipepath, f, ln
+}
+
 // acceptOne accepts one single connection from ln, reads 512 bytes from it
 // and sends it to the out channel, afterwards closing the connection.
 func acceptOne(t *testing.T, ln net.Listener, out chan string) {
 	conn, err := ln.Accept()
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.Nil(t, err)
+
 	buf := make([]byte, 512)
 	n, err := conn.Read(buf)
-	if err != nil {
-		t.Fatal(err)
-	}
+	require.Nil(t, err)
+
 	conn.Close()
 	out <- string(buf[:n])
 }
 
 func TestPipeWriter(t *testing.T) {
-	f, err := ioutil.TempFile("", "test-pipe-")
-	if err != nil {
-		t.Fatal(err)
-	}
+	pipepath, f, ln := createNamedPipe(t)
 	defer os.Remove(f.Name())
-	pipepath := WindowsPipeAddressPrefix + f.Name()
-	ln, err := winio.ListenPipe(pipepath, &winio.PipeConfig{
-		SecurityDescriptor: "D:AI(A;;GA;;;WD)",
-		InputBufferSize:    1_000_000,
-	})
-	if err != nil {
-		t.Fatal(err)
-	}
+
 	out := make(chan string)
 	go acceptOne(t, ln, out)
 
 	client, err := New(pipepath)
-	if err != nil {
-		t.Fatal(err)
-	}
-	if err := client.Gauge("metric", 1, []string{"key:val"}, 1); err != nil {
-		t.Fatal(err)
-	}
+	require.Nil(t, err)
+
+	err = client.Gauge("metric", 1, []string{"key:val"}, 1)
+	require.Nil(t, err)
+
 	got := <-out
-	if exp := "metric:1|g|#key:val"; got != exp {
-		t.Fatalf("Expected %q, got %q", exp, got)
-	}
+	assert.Equal(t, got, "metric:1|g|#key:val")
+}
+
+func TestPipeWriterEnv(t *testing.T) {
+	pipepath, f, ln := createNamedPipe(t)
+	defer os.Remove(f.Name())
+
+	out := make(chan string)
+	go acceptOne(t, ln, out)
+
+	os.Setenv(agentHostEnvVarName, pipepath)
+	defer os.Unsetenv(agentHostEnvVarName)
+
+	client, err := New("")
+	require.Nil(t, err)
+
+	err = client.Gauge("metric", 1, []string{"key:val"}, 1)
+	require.Nil(t, err)
+
+	got := <-out
+	assert.Equal(t, got, "metric:1|g|#key:val")
 }
 
 func TestPipeWriterReconnect(t *testing.T) {
-	f, err := ioutil.TempFile("", "test-pipe-")
-	if err != nil {
-		t.Fatal(err)
-	}
+	pipepath, f, ln := createNamedPipe(t)
 	defer os.Remove(f.Name())
-	pipepath := WindowsPipeAddressPrefix + f.Name()
-	ln, err := winio.ListenPipe(pipepath, &winio.PipeConfig{
-		SecurityDescriptor: "D:AI(A;;GA;;;WD)",
-		InputBufferSize:    1_000_000,
-	})
-	if err != nil {
-		t.Fatalf("Listen: %s", err)
-	}
+
 	out := make(chan string)
 	go acceptOne(t, ln, out)
 	client, err := New(pipepath)
-	if err != nil {
-		t.Fatalf("New: %s", err)
-	}
+	require.Nil(t, err)
 
 	// first attempt works, then connection closes
-	if err := client.Gauge("metric", 1, []string{"key:val"}, 1); err != nil {
-		t.Fatalf("Failed to send gauge: %s", err)
-	}
+	err = client.Gauge("metric", 1, []string{"key:val"}, 1)
+	require.Nil(t, err, "Failed to send gauge: %s", err)
+
 	timeout := time.After(1 * time.Second)
 	select {
 	case got := <-out:
-		if exp := "metric:1|g|#key:val"; got != exp {
-			t.Fatalf("Expected %q, got %q", exp, got)
-		}
+		assert.Equal(t, got, "metric:1|g|#key:val")
 	case <-timeout:
-		t.Fatal("timeout1")
+		t.Fatal("timeout receiving the first metric")
 	}
 
 	// second attempt fails by attempting the same connection
 	go acceptOne(t, ln, out)
-	if err := client.Gauge("metric", 2, []string{"key:val"}, 1); err != nil {
-		t.Fatalf("Failed to send second gauge: %s", err)
-	}
+	err = client.Gauge("metric", 2, []string{"key:val"}, 1)
+	require.Nil(t, err, "Failed to send second gauge: %s", err)
+
 	timeout = time.After(100 * time.Millisecond)
 	select {
 	case <-out:
@@ -108,15 +117,13 @@ func TestPipeWriterReconnect(t *testing.T) {
 
 	// subsequent attempts succeed with new connection
 	for n := 0; n < 3; n++ {
-		if err := client.Gauge("metric", 3, []string{"key:val"}, 1); err != nil {
-			t.Fatalf("Failed to send second gauge: %s", err)
-		}
+		err = client.Gauge("metric", 3, []string{"key:val"}, 1)
+		require.Nil(t, err, "Failed to send second gauge: %s", err)
+
 		timeout = time.After(500 * time.Millisecond)
 		select {
 		case got := <-out:
-			if exp := "metric:3|g|#key:val"; got != exp {
-				t.Fatalf("Expected %q, got %q", exp, got)
-			}
+			assert.Equal(t, got, "metric:3|g|#key:val")
 			return
 		case <-timeout:
 			continue

statsd/statsd.go

@@ -11,6 +11,7 @@ statsd is based on go-statsd-client.
 package statsd
 
 import (
+	"errors"
 	"fmt"
 	"os"
 	"strings"
@@ -61,6 +62,12 @@ traffic instead of UDP.
 */
 const WindowsPipeAddressPrefix = `\\.\pipe\`
 
+const (
+	agentHostEnvVarName = "DD_AGENT_HOST"
+	agentPortEnvVarName = "DD_DOGSTATSD_PORT"
+	defaultUDPPort      = "8125"
+)
+
 /*
 ddEnvTagsMapping is a mapping of each "DD_" prefixed environment variable
 to a specific tag name.
@@ -228,7 +235,35 @@ type ClientMetrics struct {
 // https://golang.org/doc/faq#guarantee_satisfies_interface
 var _ ClientInterface = &Client{}
 
-func resolveAddr(addr string) (statsdWriter, string, error) {
+func resolveAddr(addr string) string {
+	envPort := ""
+	if addr == "" {
+		addr = os.Getenv(agentHostEnvVarName)
+		envPort = os.Getenv(agentPortEnvVarName)
+	}
+
+	if addr == "" {
+		return ""
+	}
+
+	if !strings.HasPrefix(addr, WindowsPipeAddressPrefix) && !strings.HasPrefix(addr, UnixAddressPrefix) {
+		if !strings.Contains(addr, ":") {
+			if envPort != "" {
+				addr = fmt.Sprintf("%s:%s", addr, envPort)
+			} else {
+				addr = fmt.Sprintf("%s:%s", addr, defaultUDPPort)
+			}
+		}
+	}
+	return addr
+}
+
+func createWriter(addr string) (statsdWriter, string, error) {
+	addr = resolveAddr(addr)
+	if addr == "" {
+		return nil, "", errors.New("No address passed and autodetection from environment failed")
+	}
+
 	switch {
 	case strings.HasPrefix(addr, WindowsPipeAddressPrefix):
 		w, err := newWindowsPipeWriter(addr)
@@ -250,7 +285,7 @@ func New(addr string, options ...Option) (*Client, error) {
 		return nil, err
 	}
 
-	w, writerType, err := resolveAddr(addr)
+	w, writerType, err := createWriter(addr)
 	if err != nil {
 		return nil, err
 	}

statsd/statsd_test.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 	"io"
 	"net"
+	"os"
 	"sync"
 	"testing"
 	"time"
@@ -179,3 +180,50 @@ func TestCloneWithExtraOptions(t *testing.T) {
 	assert.Equal(t, cloneClient.addrOption, addr)
 	assert.Len(t, cloneClient.options, 3)
 }
+
+func TestResolveAddressFromEnvironment(t *testing.T) {
+	hostInitialValue, hostInitiallySet := os.LookupEnv(agentHostEnvVarName)
+	if hostInitiallySet {
+		defer os.Setenv(agentHostEnvVarName, hostInitialValue)
+	} else {
+		defer os.Unsetenv(agentHostEnvVarName)
+	}
+	portInitialValue, portInitiallySet := os.LookupEnv(agentPortEnvVarName)
+	if portInitiallySet {
+		defer os.Setenv(agentPortEnvVarName, portInitialValue)
+	} else {
+		defer os.Unsetenv(agentPortEnvVarName)
+	}
+
+	for _, tc := range []struct {
+		name         string
+		addrParam    string
+		hostEnv      string
+		portEnv      string
+		expectedAddr string
+	}{
+		{"UPD Nominal case", "127.0.0.1:1234", "", "", "127.0.0.1:1234"},
+		{"UPD Parameter overrides environment", "127.0.0.1:8125", "10.12.16.9", "1234", "127.0.0.1:8125"},
+		{"UPD Host and port passed as env", "", "10.12.16.9", "1234", "10.12.16.9:1234"},
+		{"UPD Host env, default port", "", "10.12.16.9", "", "10.12.16.9:8125"},
+		{"UPD Host passed, ignore env port", "10.12.16.9", "", "1234", "10.12.16.9:8125"},
+
+		{"UDS socket passed", "unix://test/path.socket", "", "", "unix://test/path.socket"},
+		{"UDS socket env", "", "unix://test/path.socket", "", "unix://test/path.socket"},
+		{"UDS socket env with port", "", "unix://test/path.socket", "8125", "unix://test/path.socket"},
+
+		{"Pipe passed", "\\\\.\\pipe\\my_pipe", "", "", "\\\\.\\pipe\\my_pipe"},
+		{"Pipe env", "", "\\\\.\\pipe\\my_pipe", "", "\\\\.\\pipe\\my_pipe"},
+		{"Pipe env with port", "", "\\\\.\\pipe\\my_pipe", "8125", "\\\\.\\pipe\\my_pipe"},
+
+		{"No autodetection failed", "", "", "", ""},
+	} {
+		t.Run(tc.name, func(t *testing.T) {
+			os.Setenv(agentHostEnvVarName, tc.hostEnv)
+			os.Setenv(agentPortEnvVarName, tc.portEnv)
+
+			addr := resolveAddr(tc.addrParam)
+			assert.Equal(t, tc.expectedAddr, addr)
+		})
+	}
+}

statsd/telemetry.go

@@ -51,7 +51,7 @@ func newTelemetryClient(c *Client, transport string, devMode bool) *telemetryCli
 }
 
 func newTelemetryClientWithCustomAddr(c *Client, transport string, devMode bool, telemetryAddr string, pool *bufferPool) (*telemetryClient, error) {
-	telemetryWriter, _, err := resolveAddr(telemetryAddr)
+	telemetryWriter, _, err := createWriter(telemetryAddr)
 	if err != nil {
 		return nil, fmt.Errorf("Could not resolve telemetry address: %v", err)
 	}

statsd/udp.go

@@ -2,32 +2,17 @@ package statsd
 
 import (
 	"errors"
-	"fmt"
 	"net"
-	"os"
 	"time"
 )
 
-const (
-	autoHostEnvName = "DD_AGENT_HOST"
-	autoPortEnvName = "DD_DOGSTATSD_PORT"
-	defaultUDPPort  = "8125"
-)
-
 // udpWriter is an internal class wrapping around management of UDP connection
 type udpWriter struct {
 	conn net.Conn
 }
 
 // New returns a pointer to a new udpWriter given an addr in the format "hostname:port".
 func newUDPWriter(addr string) (*udpWriter, error) {
-	if addr == "" {
-		addr = addressFromEnvironment()
-	}
-	if addr == "" {
-		return nil, errors.New("No address passed and autodetection from environment failed")
-	}
-
 	udpAddr, err := net.ResolveUDPAddr("udp", addr)
 	if err != nil {
 		return nil, err
@@ -53,21 +38,3 @@ func (w *udpWriter) Write(data []byte) (int, error) {
 func (w *udpWriter) Close() error {
 	return w.conn.Close()
 }
-
-func (w *udpWriter) remoteAddr() net.Addr {
-	return w.conn.RemoteAddr()
-}
-
-func addressFromEnvironment() string {
-	autoHost := os.Getenv(autoHostEnvName)
-	if autoHost == "" {
-		return ""
-	}
-
-	autoPort := os.Getenv(autoPortEnvName)
-	if autoPort == "" {
-		autoPort = defaultUDPPort
-	}
-
-	return fmt.Sprintf("%s:%s", autoHost, autoPort)
-}