feat: add socks5 proxy support for kafka output plugin

go.mod

@@ -186,6 +186,7 @@ require (
 	github.com/apache/arrow/go/arrow v0.0.0-20211006091945-a69884db78f4 // indirect
 	github.com/aristanetworks/glog v0.0.0-20191112221043-67e8567f59f3 // indirect
 	github.com/armon/go-metrics v0.3.3 // indirect
+	github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 // indirect
 	github.com/aws/aws-sdk-go-v2/feature/dynamodb/attributevalue v1.2.0 // indirect
 	github.com/aws/aws-sdk-go-v2/feature/s3/manager v1.5.3 // indirect
 	github.com/aws/aws-sdk-go-v2/internal/configsources v1.1.3 // indirect

go.sum

@@ -287,6 +287,8 @@ github.com/armon/go-metrics v0.3.3 h1:a9F4rlj7EWWrbj7BYw8J8+x+ZZkJeqzNyRk8hdPF+r
 github.com/armon/go-metrics v0.3.3/go.mod h1:4O98XIr/9W0sxpJ8UaYkvjk10Iff7SnFrb4QAOwNTFc=
 github.com/armon/go-radix v0.0.0-20180808171621-7fddfc383310/go.mod h1:ufUuZ+zHj4x4TnLV4JWEpy2hxWSpsRywHrMgIH9cCH8=
 github.com/armon/go-radix v1.0.0/go.mod h1:ufUuZ+zHj4x4TnLV4JWEpy2hxWSpsRywHrMgIH9cCH8=
+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5 h1:0CwZNZbxp69SHPdPJAN/hZIm0C4OItdklCFmMRWYpio=
+github.com/armon/go-socks5 v0.0.0-20160902184237-e75332964ef5/go.mod h1:wHh0iHkYZB8zMSxRWpUBQtwG5a7fFgvEO+odwuTv2gs=
 github.com/aryann/difflib v0.0.0-20170710044230-e206f873d14a/go.mod h1:DAHtR1m6lCRdSC2Tm3DSWRPvIPr6xNKyeHdqDQSQT+A=
 github.com/asaskevich/govalidator v0.0.0-20180720115003-f9ffefc3facf/go.mod h1:lB+ZfQJz7igIIfQNfa7Ml4HSf2uFQQRzpGGRXenZAgY=
 github.com/asaskevich/govalidator v0.0.0-20190424111038-f61b66f89f4a/go.mod h1:lB+ZfQJz7igIIfQNfa7Ml4HSf2uFQQRzpGGRXenZAgY=

plugins/common/proxy/socks5.go

@@ -0,0 +1,22 @@
+package proxy
+
+import (
+	"golang.org/x/net/proxy"
+)
+
+type Socks5ProxyConfig struct {
+	Socks5ProxyEnable   *bool  `toml:"socks5_enable"`
+	Socks5ProxyAddress  string `toml:"socks5_address"`
+	Socks5ProxyUsername string `toml:"socks5_username"`
+	Socks5ProxyPassword string `toml:"socks5_password"`
+}
+
+func (c *Socks5ProxyConfig) GetDialer() (proxy.Dialer, error) {
+	var auth *proxy.Auth
+	if c.Socks5ProxyPassword != "" || c.Socks5ProxyUsername != "" {
+		auth = new(proxy.Auth)
+		auth.User = c.Socks5ProxyUsername
+		auth.Password = c.Socks5ProxyPassword
+	}
+	return proxy.SOCKS5("tcp", c.Socks5ProxyAddress, auth, proxy.Direct)
+}

plugins/common/proxy/socks5_test.go

@@ -0,0 +1,68 @@
+package proxy
+
+import (
+	"net"
+	"testing"
+	"time"
+
+	"github.com/armon/go-socks5"
+	"github.com/stretchr/testify/require"
+)
+
+func TestSocks5ProxyConfig(t *testing.T) {
+	const (
+		proxyAddress  = "0.0.0.0:12345"
+		proxyUsername = "user"
+		proxyPassword = "password"
+	)
+
+	l, err := net.Listen("tcp", "0.0.0.0:0")
+	require.NoError(t, err)
+
+	server, err := socks5.New(&socks5.Config{
+		AuthMethods: []socks5.Authenticator{socks5.UserPassAuthenticator{
+			Credentials: socks5.StaticCredentials{
+				proxyUsername: proxyPassword,
+			},
+		}},
+	})
+	require.NoError(t, err)
+
+	go func() { require.NoError(t, server.ListenAndServe("tcp", proxyAddress)) }()
+
+	enabled := true
+	conf := Socks5ProxyConfig{
+		Socks5ProxyEnable:   &enabled,
+		Socks5ProxyAddress:  proxyAddress,
+		Socks5ProxyUsername: proxyUsername,
+		Socks5ProxyPassword: proxyPassword,
+	}
+	dialer, err := conf.GetDialer()
+	require.NoError(t, err)
+
+	var proxyConn net.Conn
+	for i := 0; i < 10; i++ {
+		proxyConn, err = dialer.Dial("tcp", l.Addr().String())
+		if err != nil {
+			time.Sleep(10 * time.Millisecond)
+			continue
+		}
+		break
+	}
+	require.NotNil(t, proxyConn)
+	defer func() { require.NoError(t, proxyConn.Close()) }()
+
+	serverConn, err := l.Accept()
+	require.NoError(t, err)
+	defer func() { require.NoError(t, serverConn.Close()) }()
+
+	writePayload := []byte("test")
+	_, err = proxyConn.Write(writePayload)
+	require.NoError(t, err)
+
+	receivePayload := make([]byte, 4)
+	_, err = serverConn.Read(receivePayload)
+	require.NoError(t, err)
+
+	require.Equal(t, writePayload, receivePayload)
+}

plugins/outputs/kafka/kafka.go

@@ -11,6 +11,7 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/plugins/common/kafka"
+	"github.com/influxdata/telegraf/plugins/common/proxy"
 	"github.com/influxdata/telegraf/plugins/outputs"
 	"github.com/influxdata/telegraf/plugins/serializers"
 )
@@ -32,6 +33,8 @@ type Kafka struct {
 	RoutingTag      string      `toml:"routing_tag"`
 	RoutingKey      string      `toml:"routing_key"`
 
+	proxy.Socks5ProxyConfig
+
 	// Legacy TLS config options
 	// TLS client certificate
 	Certificate string
@@ -189,6 +192,12 @@ var sampleConfig = `
   ## Use TLS but skip chain & host verification
   # insecure_skip_verify = false
 
+  ## Optional SOCKS5 proxy to use when connecting to brokers
+  # socks5_enable = true
+  # socks5_address = "127.0.0.1:1080"
+  # socks5_username = "alice"
+  # socks5_password = "pass123"
+
   ## Optional SASL Config
   # sasl_username = "kafka"
   # sasl_password = "secret"
@@ -292,6 +301,16 @@ func (k *Kafka) Init() error {
 		k.TLSKey = k.Key
 	}
 
+	if k.Socks5ProxyEnable != nil && *k.Socks5ProxyEnable {
+		config.Net.Proxy.Enable = true
+
+		dialer, err := k.Socks5ProxyConfig.GetDialer()
+		if err != nil {
+			return fmt.Errorf("Error while connecting to proxy server: %s", err)
+		}
+		config.Net.Proxy.Dialer = dialer
+	}
+
 	return nil
 }