chore(inputs.net_response): Use Init to check configuration issues (#12690)

plugins/inputs/net_response/net_response.go

@@ -5,6 +5,7 @@ import (
 	"bufio"
 	_ "embed"
 	"errors"
+	"fmt"
 	"net"
 	"net/textproto"
 	"regexp"
@@ -12,6 +13,7 @@ import (
 
 	"github.com/influxdata/telegraf"
 	"github.com/influxdata/telegraf/config"
+	"github.com/influxdata/telegraf/internal/choice"
 	"github.com/influxdata/telegraf/plugins/inputs"
 )
 
@@ -164,10 +166,9 @@ func (n *NetResponse) UDPGather() (map[string]string, map[string]interface{}, er
 	return tags, fields, nil
 }
 
-// Gather is called by telegraf when the plugin is executed on its interval.
-// It will call either UDPGather or TCPGather based on the configuration and
-// also fill an Accumulator that is supplied.
-func (n *NetResponse) Gather(acc telegraf.Accumulator) error {
+// Init performs one time setup of the plugin and returns an error if the
+// configuration is invalid.
+func (n *NetResponse) Init() error {
 	// Set default values
 	if n.Timeout == 0 {
 		n.Timeout = config.Duration(time.Second)
@@ -191,8 +192,26 @@ func (n *NetResponse) Gather(acc telegraf.Accumulator) error {
 		n.Address = "localhost:" + port
 	}
 	if port == "" {
-		return errors.New("bad port")
+		return errors.New("bad port in config option address")
 	}
+
+	if err := choice.Check(n.Protocol, []string{"tcp", "udp"}); err != nil {
+		return fmt.Errorf("config option protocol: %w", err)
+	}
+
+	return nil
+}
+
+// Gather is called by telegraf when the plugin is executed on its interval.
+// It will call either UDPGather or TCPGather based on the configuration and
+// also fill an Accumulator that is supplied.
+func (n *NetResponse) Gather(acc telegraf.Accumulator) error {
+	// Prepare host and port
+	host, port, err := net.SplitHostPort(n.Address)
+	if err != nil {
+		return err
+	}
+
 	// Prepare data
 	tags := map[string]string{"server": host, "port": port}
 	var fields map[string]interface{}
@@ -212,8 +231,6 @@ func (n *NetResponse) Gather(acc telegraf.Accumulator) error {
 			return err
 		}
 		tags["protocol"] = "udp"
-	default:
-		return errors.New("bad protocol")
 	}
 
 	// Merge the tags

plugins/inputs/net_response/net_response_test.go

@@ -13,42 +13,38 @@ import (
 )
 
 func TestBadProtocol(t *testing.T) {
-	var acc testutil.Accumulator
 	// Init plugin
 	c := NetResponse{
 		Protocol: "unknownprotocol",
 		Address:  ":9999",
 	}
 	// Error
-	err := c.Gather(&acc)
+	err := c.Init()
 	require.Error(t, err)
-	require.Equal(t, "bad protocol", err.Error())
+	require.Equal(t, "config option protocol: unknown choice unknownprotocol", err.Error())
 }
 
 func TestNoPort(t *testing.T) {
-	var acc testutil.Accumulator
 	c := NetResponse{
 		Protocol: "tcp",
 		Address:  ":",
 	}
-	err := c.Gather(&acc)
+	err := c.Init()
 	require.Error(t, err)
-	require.Equal(t, "bad port", err.Error())
+	require.Equal(t, "bad port in config option address", err.Error())
 }
 
 func TestAddressOnly(t *testing.T) {
-	var acc testutil.Accumulator
 	c := NetResponse{
 		Protocol: "tcp",
 		Address:  "127.0.0.1",
 	}
-	err := c.Gather(&acc)
+	err := c.Init()
 	require.Error(t, err)
 	require.Equal(t, "address 127.0.0.1: missing port in address", err.Error())
 }
 
 func TestSendExpectStrings(t *testing.T) {
-	var acc testutil.Accumulator
 	tc := NetResponse{
 		Protocol: "udp",
 		Address:  "127.0.0.1:7",
@@ -61,10 +57,10 @@ func TestSendExpectStrings(t *testing.T) {
 		Send:     "toast",
 		Expect:   "",
 	}
-	err := tc.Gather(&acc)
+	err := tc.Init()
 	require.Error(t, err)
 	require.Equal(t, "send string cannot be empty", err.Error())
-	err = uc.Gather(&acc)
+	err = uc.Init()
 	require.Error(t, err)
 	require.Equal(t, "expected string cannot be empty", err.Error())
 }
@@ -77,6 +73,7 @@ func TestTCPError(t *testing.T) {
 		Address:  ":9999",
 		Timeout:  config.Duration(time.Second * 30),
 	}
+	require.NoError(t, c.Init())
 	// Gather
 	require.NoError(t, c.Gather(&acc))
 	acc.AssertContainsTaggedFields(t,
@@ -86,7 +83,7 @@ func TestTCPError(t *testing.T) {
 			"result_type": "connection_failed",
 		},
 		map[string]string{
-			"server":   "",
+			"server":   "localhost",
 			"port":     "9999",
 			"protocol": "tcp",
 			"result":   "connection_failed",
@@ -106,6 +103,7 @@ func TestTCPOK1(t *testing.T) {
 		Timeout:     config.Duration(time.Second),
 		Protocol:    "tcp",
 	}
+	require.NoError(t, c.Init())
 	// Start TCP server
 	wg.Add(1)
 	go TCPServer(t, &wg)
@@ -150,6 +148,7 @@ func TestTCPOK2(t *testing.T) {
 		Timeout:     config.Duration(time.Second),
 		Protocol:    "tcp",
 	}
+	require.NoError(t, c.Init())
 	// Start TCP server
 	wg.Add(1)
 	go TCPServer(t, &wg)
@@ -192,6 +191,7 @@ func TestUDPError(t *testing.T) {
 		Expect:   "test",
 		Protocol: "udp",
 	}
+	require.NoError(t, c.Init())
 	// Gather
 	require.NoError(t, c.Gather(&acc))
 	acc.Wait(1)
@@ -211,7 +211,7 @@ func TestUDPError(t *testing.T) {
 		},
 		map[string]string{
 			"result":   "read_failed",
-			"server":   "",
+			"server":   "localhost",
 			"port":     "9999",
 			"protocol": "udp",
 		},
@@ -230,6 +230,7 @@ func TestUDPOK1(t *testing.T) {
 		Timeout:     config.Duration(time.Second),
 		Protocol:    "udp",
 	}
+	require.NoError(t, c.Init())
 	// Start UDP server
 	wg.Add(1)
 	go UDPServer(t, &wg)