fix: Ensure the squid exporter wrapper properly brackets ipv6 addresses [backport] (#5205)

Ensure that the squid exporter component properly brackets IPv6 addresses when passing the hostname to the exporter module.

Co-authored-by: Sam DeHaan <sam.dehaan@grafana.com>

Author: jharvey10

internal/static/integrations/squid_exporter/squid_exporter.go

@@ -4,6 +4,7 @@ import (
 	"errors"
 	"fmt"
 	"net"
+	"net/netip"
 	"strconv"
 
 	se "github.com/boynux/squid-exporter/collector"
@@ -44,7 +45,13 @@ func (c *Config) validate() error {
 	if host == "" {
 		return ErrNoHostname
 	}
-	c.Host = host
+
+	if ip, err := netip.ParseAddr(host); err == nil && ip.IsValid() && ip.Is6() {
+		// Restore the explicit brackets for IPv6 addresses
+		c.Host = fmt.Sprintf("[%s]", host)
+	} else {
+		c.Host = host
+	}
 
 	if port == "" {
 		return ErrNoPort
@@ -95,7 +102,7 @@ func New(c *Config) (integrations.Integration, error) {
 	}
 
 	seExporter := se.New(&se.CollectorConfig{
-		Hostname: c.Host,
+		Hostname: fmt.Sprintf("[%s]", c.Host),
 		Port:     c.Port,
 		Login:    c.Username,
 		Password: string(c.Password),

internal/static/integrations/squid_exporter/squid_exporter_test.go

@@ -12,9 +12,10 @@ import (
 
 func TestConfigValidate(t *testing.T) {
 	cases := []struct {
-		name        string
-		getConfig   func() Config
-		expectedErr error
+		name         string
+		getConfig    func() Config
+		expectedErr  error
+		expectedHost string
 	}{
 		{
 			name: "valid",
@@ -64,17 +65,30 @@ func TestConfigValidate(t *testing.T) {
 			},
 			expectedErr: errors.New("address a@#$%:asdf::12312: too many colons in address"),
 		},
+		{
+			name: "valid ipv6",
+			getConfig: func() Config {
+				cfg := Config{}
+				cfg.Address = "[::1]:51001"
+				return cfg
+			},
+			expectedHost: "[::1]",
+		},
 	}
 
 	for _, tc := range cases {
 		t.Run(tc.name, func(t *testing.T) {
 			cfg := tc.getConfig()
 			err := cfg.validate()
-			if tc.expectedErr == nil {
-				require.NoError(t, err)
+			if tc.expectedErr != nil {
+				require.ErrorContains(t, err, tc.expectedErr.Error())
 				return
 			}
-			require.ErrorContains(t, err, tc.expectedErr.Error())
+
+			require.NoError(t, err)
+			if tc.expectedHost != "" {
+				require.Equal(t, tc.expectedHost, cfg.Host)
+			}
 		})
 	}
 }