feat(inputs.http_listener_v2): Add unix socket mode

plugins/inputs/http_listener_v2/README.md

@@ -36,8 +36,19 @@ See the [CONFIGURATION.md][CONFIGURATION.md] for more details.
 ```toml @sample.conf
 # Generic HTTP write listener
 [[inputs.http_listener_v2]]
-  ## Address and port to host HTTP listener on
+  ## Address to host HTTP listener on
+  # can be prefixed by protocol tcp, or unix if not provided defaults to tcp
+  # if unix network type provided it should be followed by absolute path for unix socket
   service_address = ":8080"
+  # service_address = "tcp://:8443"
+  # service_address = "unix:///tmp/telegraf.sock"
+
+  ## Permission for unix sockets (only available for unix sockets)
+  ## This setting may not be respected by some platforms. To safely restrict
+  ## permissions it is recommended to place the socket into a previously
+  ## created directory with the desired permissions.
+  ##   ex: socket_mode = "777"
+  # socket_mode = ""
 
   ## Paths to listen to.
   # paths = ["/telegraf"]

plugins/inputs/http_listener_v2/http_listener_v2.go

@@ -7,10 +7,16 @@ import (
 	"crypto/tls"
 	_ "embed"
 	"errors"
+	"fmt"
 	"io"
 	"net"
 	"net/http"
 	"net/url"
+	"os"
+	"path/filepath"
+	"regexp"
+	"runtime"
+	"strconv"
 	"strings"
 	"sync"
 	"time"
@@ -47,6 +53,7 @@ type TimeFunc func() time.Time
 // HTTPListenerV2 is an input plugin that collects external metrics sent via HTTP
 type HTTPListenerV2 struct {
 	ServiceAddress string            `toml:"service_address"`
+	SocketMode     string            `toml:"socket_mode"`
 	Path           string            `toml:"path" deprecated:"1.20.0;1.35.0;use 'paths' instead"`
 	Paths          []string          `toml:"paths"`
 	PathTag        bool              `toml:"path_tag"`
@@ -151,18 +158,68 @@ func (h *HTTPListenerV2) Init() error {
 		return err
 	}
 
+	protoRegex := regexp.MustCompile(`\w://`)
+	if !protoRegex.MatchString(h.ServiceAddress) {
+		h.ServiceAddress = "tcp://" + h.ServiceAddress
+	}
+
+	var u *url.URL
+	// Parse and check the address
+	if runtime.GOOS == "windows" && strings.HasPrefix(h.ServiceAddress, "unix://") {
+		u = &url.URL{Scheme: "unix", Path: strings.TrimPrefix(h.ServiceAddress, "unix://")}
+	} else {
+		u, err = url.Parse(h.ServiceAddress)
+		if err != nil {
+			return fmt.Errorf("parsing address failed: %w", err)
+		}
+	}
+
+	address := u.Host
+
+	switch u.Scheme {
+	case "tcp":
+	case "unix":
+		path := filepath.FromSlash(u.Path)
+		if runtime.GOOS == "windows" && strings.Contains(path, ":") {
+			path = strings.TrimPrefix(path, `\`)
+		}
+		if err := os.Remove(path); err != nil && !errors.Is(err, os.ErrNotExist) {
+			return fmt.Errorf("removing socket failed: %w", err)
+		}
+		address = path
+	default:
+		return fmt.Errorf("unknown protocol %q", u.Scheme)
+	}
+
 	var listener net.Listener
 	if tlsConf != nil {
-		listener, err = tls.Listen("tcp", h.ServiceAddress, tlsConf)
+		listener, err = tls.Listen(u.Scheme, address, tlsConf)
 	} else {
-		listener, err = net.Listen("tcp", h.ServiceAddress)
+		listener, err = net.Listen(u.Scheme, address)
 	}
 	if err != nil {
 		return err
 	}
 	h.tlsConf = tlsConf
 	h.listener = listener
-	h.Port = listener.Addr().(*net.TCPAddr).Port
+
+	if u.Scheme == "tcp" {
+		h.Port = listener.Addr().(*net.TCPAddr).Port
+	}
+
+	if u.Scheme == "unix" && h.SocketMode != "" {
+		// Set permissions on socket
+		// Convert from octal in string to int
+		i, err := strconv.ParseUint(h.SocketMode, 8, 32)
+		if err != nil {
+			return fmt.Errorf("converting socket mode failed: %w", err)
+		}
+
+		perm := os.FileMode(uint32(i))
+		if err := os.Chmod(address, perm); err != nil {
+			return fmt.Errorf("changing socket permissions failed: %w", err)
+		}
+	}
 
 	if h.SuccessCode == 0 {
 		h.SuccessCode = http.StatusNoContent

plugins/inputs/http_listener_v2/http_listener_v2_test.go

@@ -2,12 +2,15 @@ package http_listener_v2
 
 import (
 	"bytes"
+	"context"
 	"crypto/tls"
 	"crypto/x509"
 	"fmt"
+	"net"
 	"net/http"
 	"net/url"
 	"os"
+	"path/filepath"
 	"runtime"
 	"strconv"
 	"sync"
@@ -724,6 +727,69 @@ func TestServerHeaders(t *testing.T) {
 	require.Equal(t, "value", resp.Header.Get("key"))
 }
 
+func TestUnixSocket(t *testing.T) {
+	listener, err := newTestHTTPListenerV2()
+	require.NoError(t, err)
+	file, err := os.CreateTemp("", "*.socket")
+	require.NoError(t, err)
+	require.NoError(t, file.Close())
+	defer os.Remove(file.Name())
+	socketName := file.Name()
+	listener.ServiceAddress = "unix://" + socketName
+	listener.SocketMode = "777"
+	acc := &testutil.Accumulator{}
+	require.NoError(t, listener.Init())
+	require.NoError(t, listener.Start(acc))
+	defer listener.Stop()
+	httpc := http.Client{
+		Transport: &http.Transport{
+			DialContext: func(_ context.Context, _, _ string) (net.Conn, error) {
+				return net.Dial("unix", socketName)
+			},
+		},
+	}
+	resp, err := httpc.Post(createURL(listener, "http", "/write", "db=mydb"), "", bytes.NewBufferString(testMsg))
+	require.NoError(t, err)
+	require.NoError(t, resp.Body.Close())
+	require.EqualValues(t, 204, resp.StatusCode)
+}
+
+func TestServiceAddressURL(t *testing.T) {
+	unixSocket := filepath.FromSlash(os.TempDir() + "/test.sock")
+	cases := []struct {
+		serviceAddress, expectedAddress string
+		expectedPort                    int
+		shouldError                     bool
+	}{
+		{":8080", "[::]:8080", 8080, false},
+		{"localhost:4123", "127.0.0.1:4123", 4123, false},
+		{"tcp://localhost:4321", "127.0.0.1:4321", 4321, false},
+		{"127.0.0.1:9443", "127.0.0.1:9443", 9443, false},
+		{"tcp://127.0.0.1:8443", "127.0.0.1:8443", 8443, false},
+		{"tcp://:8443", "[::]:8443", 8443, false},
+		// port not provided
+		{"8.8.8.8", "", 0, true},
+		{"unix://" + unixSocket, unixSocket, 0, false},
+		// wrong protocol
+		{"notexistent:///tmp/test.sock", "", 0, true},
+	}
+	for _, c := range cases {
+		listener, err := newTestHTTPListenerV2()
+		require.NoError(t, err)
+		listener.ServiceAddress = c.serviceAddress
+		err = listener.Init()
+		require.Equal(t, c.shouldError, err != nil, "Init returned wrong error result error is: %q", err)
+		if c.shouldError {
+			continue
+		}
+		acc := &testutil.Accumulator{}
+		require.NoError(t, listener.Start(acc))
+		require.Equal(t, c.expectedAddress, listener.listener.Addr().String())
+		require.Equal(t, c.expectedPort, listener.Port)
+		listener.Stop()
+	}
+}
+
 func mustReadHugeMetric() []byte {
 	filePath := "testdata/huge_metric"
 	data, err := os.ReadFile(filePath)

plugins/inputs/http_listener_v2/sample.conf

@@ -1,7 +1,18 @@
 # Generic HTTP write listener
 [[inputs.http_listener_v2]]
-  ## Address and port to host HTTP listener on
+  ## Address to host HTTP listener on
+  # can be prefixed by protocol tcp, or unix if not provided defaults to tcp
+  # if unix network type provided it should be followed by absolute path for unix socket
   service_address = ":8080"
+  # service_address = "tcp://:8443"
+  # service_address = "unix:///tmp/telegraf.sock"
+
+  ## Permission for unix sockets (only available for unix sockets)
+  ## This setting may not be respected by some platforms. To safely restrict
+  ## permissions it is recommended to place the socket into a previously
+  ## created directory with the desired permissions.
+  ##   ex: socket_mode = "777"
+  # socket_mode = ""
 
   ## Paths to listen to.
   # paths = ["/telegraf"]