[receiver/statsdreceiver] add ability to customize socket permissions when transport is unixgram (open-telemetry#37807)

Signed-off-by: thomas-gouveia <[email protected]>

Author: thomas-gouveia

.chloggen/feat_37807_statsdreceiver_flexibility-socket-permissions.yaml

@@ -0,0 +1,8 @@
+change_type: enhancement
+component: statsdreceiver
+note: Add new config to customize socket permissions when transport is set to `unixgram`.
+issues:
+  - 37807
+
+subtext:
+change_logs: [user]

receiver/statsdreceiver/README.md

@@ -27,6 +27,8 @@ The Following settings are optional:
 
 - `transport` (default = `udp`): Protocol used by the StatsD server. Currently supported transports can be found in [this file](https://github.com/open-telemetry/opentelemetry-collector-contrib/blob/main/receiver/statsdreceiver/internal/transport/transport.go).
 
+- `socket_permissions` (default = `0622`): When transport is set to `unixgram`, can be used to customize permissions of the binded socket. 
+
 - `aggregation_interval: 70s`(default value is 60s): The aggregation time that the receiver aggregates the metrics (similar to the flush interval in StatsD server)
 
 - `enable_metric_type: true`(default value is false): Enable the statsd receiver to be able to emit the metric type(gauge, counter, timer(in the future), histogram(in the future)) as a label.

receiver/statsdreceiver/config.go

@@ -6,6 +6,7 @@ package statsdreceiver // import "github.com/open-telemetry/opentelemetry-collec
 import (
 	"errors"
 	"fmt"
+	"os"
 	"time"
 
 	"github.com/lightstep/go-expohisto/structure"
@@ -24,6 +25,8 @@ type Config struct {
 	EnableSimpleTags        bool                             `mapstructure:"enable_simple_tags"`
 	IsMonotonicCounter      bool                             `mapstructure:"is_monotonic_counter"`
 	TimerHistogramMapping   []protocol.TimerHistogramMapping `mapstructure:"timer_histogram_mapping"`
+	// Will only be used when transport set to 'unixgram'.
+	SocketPermissions os.FileMode `mapstructure:socket_permissions`
 }
 
 func (c *Config) Validate() error {

receiver/statsdreceiver/factory.go

@@ -21,6 +21,7 @@ const (
 	defaultAggregationInterval = 60 * time.Second
 	defaultEnableMetricType    = false
 	defaultIsMonotonicCounter  = false
+	defaultSocketPermissions   = 0622
 )
 
 var defaultTimerHistogramMapping = []protocol.TimerHistogramMapping{{StatsdType: "timer", ObserverType: "gauge"}, {StatsdType: "histogram", ObserverType: "gauge"}, {StatsdType: "distribution", ObserverType: "gauge"}}
@@ -44,6 +45,7 @@ func createDefaultConfig() component.Config {
 		EnableMetricType:      defaultEnableMetricType,
 		IsMonotonicCounter:    defaultIsMonotonicCounter,
 		TimerHistogramMapping: defaultTimerHistogramMapping,
+		SocketPermissions:     defaultSocketPermissions,
 	}
 }
 

receiver/statsdreceiver/internal/transport/uds_server.go

@@ -17,7 +17,7 @@ type udsServer struct {
 var _ (Server) = (*udsServer)(nil)
 
 // NewUDSServer creates a transport.Server using Unixgram as its transport.
-func NewUDSServer(transport Transport, socketPath string) (Server, error) {
+func NewUDSServer(transport Transport, socketPath string, socketPermissions os.FileMode) (Server, error) {
 	if !transport.IsPacketTransport() {
 		return nil, fmt.Errorf("NewUDSServer with %s: %w", transport.String(), ErrUnsupportedPacketTransport)
 	}
@@ -27,6 +27,10 @@ func NewUDSServer(transport Transport, socketPath string) (Server, error) {
 		return nil, fmt.Errorf("starting to listen %s socket: %w", transport.String(), err)
 	}
 
+	if err := os.Chmod(socketPath, socketPermissions); err != nil {
+		return nil, fmt.Errorf("running chmod %v: %w", socketPermissions, err)
+	}
+
 	return &udsServer{
 		packetServer: packetServer{
 			packetConn: conn,

receiver/statsdreceiver/internal/transport/uds_server_test.go

@@ -0,0 +1,58 @@
+// Copyright The OpenTelemetry Authors
+// SPDX-License-Identifier: Apache-2.0
+
+package transport
+
+import (
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+	"os"
+	"testing"
+)
+
+func Test_NewUDSServer_ListenPacketFailure(t *testing.T) {
+	invalidPath := "/invalid_path/test_socket"
+
+	server, err := NewUDSServer("unixgram", invalidPath, 0622)
+
+	assert.Error(t, err)
+	assert.Nil(t, server)
+	assert.Contains(t, err.Error(), "starting to listen")
+}
+
+func Test_UDSServer_Close(t *testing.T) {
+	socketPath := "/tmp/test_socket_close"
+	defer os.Remove(socketPath)
+
+	server, err := NewUDSServer("unixgram", socketPath, 0622)
+	require.NoError(t, err)
+	require.NotNil(t, server)
+
+	_, err = os.Stat(socketPath)
+	require.NoError(t, err)
+
+	err = server.Close()
+	assert.NoError(t, err)
+
+	_, err = os.Stat(socketPath)
+	assert.True(t, os.IsNotExist(err))
+}
+
+func Test_NewUDSServer_AppliesChmod(t *testing.T) {
+	socketPath := "/tmp/test_socket_chmod"
+	defer os.Remove(socketPath) // Cleanup after test
+
+	expectedPermissions := os.FileMode(0622)
+
+	server, err := NewUDSServer("unixgram", socketPath, expectedPermissions)
+	require.NoError(t, err)
+	require.NotNil(t, server)
+
+	fileInfo, err := os.Stat(socketPath)
+	require.NoError(t, err)
+
+	actualPermissions := fileInfo.Mode().Perm()
+	assert.Equal(t, expectedPermissions, actualPermissions, "Expected file permissions to be set correctly")
+
+	server.Close()
+}

receiver/statsdreceiver/receiver.go

@@ -92,7 +92,7 @@ func buildTransportServer(config Config) (transport.Server, error) {
 	case transport.TCP, transport.TCP4, transport.TCP6:
 		return transport.NewTCPServer(trans, config.NetAddr.Endpoint)
 	case transport.UDS:
-		return transport.NewUDSServer(trans, config.NetAddr.Endpoint)
+		return transport.NewUDSServer(trans, config.NetAddr.Endpoint, config.SocketPermissions)
 	}
 
 	return nil, fmt.Errorf("unsupported transport %q", string(config.NetAddr.Transport))