chore(errors): review all errors in codebase

internal/wireguard/config.go

@@ -1,7 +1,6 @@
 package wireguard
 
 import (
-	"errors"
 	"fmt"
 	"net"
 
@@ -9,20 +8,15 @@ import (
 	"golang.zx2c4.com/wireguard/wgctrl/wgtypes"
 )
 
-var (
-	errMakeConfig      = errors.New("cannot make device configuration")
-	errConfigureDevice = errors.New("cannot configure device")
-)
-
 func configureDevice(client *wgctrl.Client, settings Settings) (err error) {
 	deviceConfig, err := makeDeviceConfig(settings)
 	if err != nil {
-		return fmt.Errorf("%w: %s", errMakeConfig, err)
+		return fmt.Errorf("cannot make device configuration: %w", err)
 	}
 
 	err = client.ConfigureDevice(settings.InterfaceName, deviceConfig)
 	if err != nil {
-		return fmt.Errorf("%w: %s", errConfigureDevice, err)
+		return fmt.Errorf("cannot configure device: %w", err)
 	}
 
 	return nil

internal/wireguard/ipv6.go

@@ -1,27 +1,21 @@
 package wireguard
 
 import (
-	"errors"
 	"fmt"
 
 	"github.com/qdm12/gluetun/internal/netlink"
 )
 
-var (
-	errLinkList  = errors.New("cannot list links")
-	errRouteList = errors.New("cannot list routes")
-)
-
 func (w *Wireguard) isIPv6Supported() (supported bool, err error) {
 	links, err := w.netlink.LinkList()
 	if err != nil {
-		return false, fmt.Errorf("%w: %s", errLinkList, err)
+		return false, fmt.Errorf("cannot list links: %w", err)
 	}
 
 	for _, link := range links {
 		routes, err := w.netlink.RouteList(link, netlink.FAMILY_V6)
 		if err != nil {
-			return false, fmt.Errorf("%w: %s", errRouteList, err)
+			return false, fmt.Errorf("cannot list routes: %w", err)
 		}
 
 		if len(routes) > 0 {

internal/wireguard/route.go

@@ -19,7 +19,7 @@ func (w *Wireguard) addRoute(link netlink.Link, dst *net.IPNet,
 
 	err = w.netlink.RouteAdd(route)
 	if err != nil {
-		return fmt.Errorf("%w: when adding route: %s", err, route)
+		return fmt.Errorf("cannot add route %s: %w", route, err)
 	}
 
 	return err

internal/wireguard/route_test.go

@@ -53,7 +53,7 @@ func Test_Wireguard_addRoute(t *testing.T) {
 				Table:     firewallMark,
 			},
 			routeAddErr: errDummy,
-			err:         errors.New("dummy: when adding route: {Ifindex: 88 Dst: 1.2.3.4/32 Src: <nil> Gw: <nil> Flags: [] Table: 51820 Realm: 0}"), //nolint:lll
+			err:         errors.New("cannot add route {Ifindex: 88 Dst: 1.2.3.4/32 Src: <nil> Gw: <nil> Flags: [] Table: 51820 Realm: 0}: dummy"), //nolint:lll
 		},
 	}
 

internal/wireguard/rule.go

@@ -14,13 +14,13 @@ func (w *Wireguard) addRule(rulePriority, firewallMark int) (
 	rule.Mark = firewallMark
 	rule.Table = firewallMark
 	if err := w.netlink.RuleAdd(rule); err != nil {
-		return nil, fmt.Errorf("%w: when adding rule: %s", err, rule)
+		return nil, fmt.Errorf("cannot add rule %s: %w", rule, err)
 	}
 
 	cleanup = func() error {
 		err := w.netlink.RuleDel(rule)
 		if err != nil {
-			return fmt.Errorf("%w: when deleting rule: %s", err, rule)
+			return fmt.Errorf("cannot delete rule %s: %w", rule, err)
 		}
 		return nil
 	}

internal/wireguard/rule_test.go

@@ -51,7 +51,7 @@ func Test_Wireguard_addRule(t *testing.T) {
 				SuppressPrefixlen: -1,
 			},
 			ruleAddErr: errDummy,
-			err:        errors.New("dummy: when adding rule: ip rule 987: from all to all table 456"),
+			err:        errors.New("cannot add rule ip rule 987: from all to all table 456: dummy"),
 		},
 		"rule delete error": {
 			expectedRule: &netlink.Rule{
@@ -66,7 +66,7 @@ func Test_Wireguard_addRule(t *testing.T) {
 				SuppressPrefixlen: -1,
 			},
 			ruleDelErr: errDummy,
-			cleanupErr: errors.New("dummy: when deleting rule: ip rule 987: from all to all table 456"),
+			cleanupErr: errors.New("cannot delete rule ip rule 987: from all to all table 456: dummy"),
 		},
 	}