[confignet] Add DialerTimeout config option (#9066)

**Description:** 
Adds a new `dialer_timeout` config option to `confignet` to allow
configuring the timeout of the connection.

**Link to tracking Issue:** 
Closes
#4331

**Testing:** 
Added new unit tests

**Documentation:** 
Updated readme

.chloggen/confignet-add-dialertimeout.yaml

@@ -0,0 +1,25 @@
+# Use this changelog template to create an entry for release notes.
+
+# One of 'breaking', 'deprecation', 'new_component', 'enhancement', 'bug_fix'
+change_type: enhancement
+
+# The name of the component, or a single word describing the area of concern, (e.g. otlpreceiver)
+component: confignet
+
+# A brief description of the change.  Surround your text with quotes ("") if it needs to start with a backtick (`).
+note: Add `dialer_timeout` config option.
+
+# One or more tracking issues or pull requests related to the change
+issues: [9066]
+
+# (Optional) One or more lines of additional information to render under the primary note.
+# These lines will be padded with 2 spaces and then inserted directly into the document.
+# Use pipe (|) for multiline entries.
+subtext:
+
+# Optional: The change log or logs in which this entry should be included.
+# e.g. '[user]' or '[user, api]'
+# Include 'user' if the change is relevant to end users.
+# Include 'api' if there is a change to a library API.
+# Default: '[user]'
+change_logs: []

config/confignet/README.md

@@ -13,6 +13,7 @@ leverage network configuration to set connection and transport information.
 - `transport`: Known protocols are "tcp", "tcp4" (IPv4-only), "tcp6"
   (IPv6-only), "udp", "udp4" (IPv4-only), "udp6" (IPv6-only), "ip", "ip4"
   (IPv4-only), "ip6" (IPv6-only), "unix", "unixgram" and "unixpacket".
+- `dialer_timeout`: DialerTimeout is the maximum amount of time a dial will wait for a connect to complete. The default is no timeout.
 
 Note that for TCP receivers only the `endpoint` configuration setting is
 required.

config/confignet/confignet.go

@@ -5,8 +5,16 @@ package confignet // import "go.opentelemetry.io/collector/config/confignet"
 
 import (
 	"net"
+	"time"
 )
 
+// DialerConfig contains options for connecting to an address.
+type DialerConfig struct {
+	// Timeout is the maximum amount of time a dial will wait for
+	// a connect to complete. The default is no timeout.
+	Timeout time.Duration `mapstructure:"timeout"`
+}
+
 // NetAddr represents a network endpoint address.
 type NetAddr struct {
 	// Endpoint configures the address for this network connection.
@@ -19,11 +27,14 @@ type NetAddr struct {
 	// Transport to use. Known protocols are "tcp", "tcp4" (IPv4-only), "tcp6" (IPv6-only), "udp", "udp4" (IPv4-only),
 	// "udp6" (IPv6-only), "ip", "ip4" (IPv4-only), "ip6" (IPv6-only), "unix", "unixgram" and "unixpacket".
 	Transport string `mapstructure:"transport"`
+
+	// DialerConfig contains options for connecting to an address.
+	DialerConfig DialerConfig `mapstructure:"dialer"`
 }
 
 // Dial equivalent with net.Dial for this address.
 func (na *NetAddr) Dial() (net.Conn, error) {
-	return net.Dial(na.Transport, na.Endpoint)
+	return net.DialTimeout(na.Transport, na.Endpoint, na.DialerConfig.Timeout)
 }
 
 // Listen equivalent with net.Listen for this address.
@@ -39,11 +50,14 @@ type TCPAddr struct {
 	// If the host is a literal IPv6 address it must be enclosed in square brackets, as in "[2001:db8::1]:80" or
 	// "[fe80::1%zone]:80". The zone specifies the scope of the literal IPv6 address as defined in RFC 4007.
 	Endpoint string `mapstructure:"endpoint"`
+
+	// DialerConfig contains options for connecting to an address.
+	DialerConfig DialerConfig `mapstructure:"dialer"`
 }
 
 // Dial equivalent with net.Dial for this address.
 func (na *TCPAddr) Dial() (net.Conn, error) {
-	return net.Dial("tcp", na.Endpoint)
+	return net.DialTimeout("tcp", na.Endpoint, na.DialerConfig.Timeout)
 }
 
 // Listen equivalent with net.Listen for this address.

config/confignet/confignet_test.go

@@ -4,12 +4,49 @@
 package confignet
 
 import (
+	"errors"
 	"net"
 	"testing"
+	"time"
 
 	"github.com/stretchr/testify/assert"
 )
 
+func TestNetAddrTimeout(t *testing.T) {
+	nac := &NetAddr{
+		Endpoint:  "localhost:0",
+		Transport: "tcp",
+		DialerConfig: DialerConfig{
+			Timeout: -1 * time.Second,
+		},
+	}
+	_, err := nac.Dial()
+	assert.Error(t, err)
+	var netErr net.Error
+	if errors.As(err, &netErr) {
+		assert.True(t, netErr.Timeout())
+	} else {
+		assert.Fail(t, "error should be a net.Error")
+	}
+}
+
+func TestTCPAddrTimeout(t *testing.T) {
+	nac := &TCPAddr{
+		Endpoint: "localhost:0",
+		DialerConfig: DialerConfig{
+			Timeout: -1 * time.Second,
+		},
+	}
+	_, err := nac.Dial()
+	assert.Error(t, err)
+	var netErr net.Error
+	if errors.As(err, &netErr) {
+		assert.True(t, netErr.Timeout())
+	} else {
+		assert.Fail(t, "error should be a net.Error")
+	}
+}
+
 func TestNetAddr(t *testing.T) {
 	nas := &NetAddr{
 		Endpoint:  "localhost:0",
@@ -45,7 +82,7 @@ func TestNetAddr(t *testing.T) {
 	assert.NoError(t, ln.Close())
 }
 
-func TestTcpAddr(t *testing.T) {
+func TestTCPAddr(t *testing.T) {
 	nas := &TCPAddr{
 		Endpoint: "localhost:0",
 	}