chore(all): review error wrappings

- remove repetitive `cannot` and `failed` prefixes
- rename `unmarshaling` to `decoding`

internal/wireguard/config.go

@@ -11,12 +11,12 @@ import (
 func configureDevice(client *wgctrl.Client, settings Settings) (err error) {
 	deviceConfig, err := makeDeviceConfig(settings)
 	if err != nil {
-		return fmt.Errorf("cannot make device configuration: %w", err)
+		return fmt.Errorf("making device configuration: %w", err)
 	}
 
 	err = client.ConfigureDevice(settings.InterfaceName, deviceConfig)
 	if err != nil {
-		return fmt.Errorf("cannot configure device: %w", err)
+		return fmt.Errorf("configuring device: %w", err)
 	}
 
 	return nil

internal/wireguard/netlink_integration_test.go

@@ -117,5 +117,5 @@ func Test_netlink_Wireguard_addRule(t *testing.T) {
 		_ = nilCleanup() // in case it succeeds
 	}
 	require.Error(t, err)
-	assert.Equal(t, "cannot add rule ip rule 10000: from all to all table 999: file exists", err.Error())
+	assert.EqualError(t, err, "adding rule ip rule 10000: from all to all table 999: file exists")
 }

internal/wireguard/route.go

@@ -20,7 +20,7 @@ func (w *Wireguard) addRoute(link netlink.Link, dst *net.IPNet,
 	err = w.netlink.RouteAdd(route)
 	if err != nil {
 		return fmt.Errorf(
-			"cannot add route for link %s, destination %s and table %d: %w",
+			"adding route for link %s, destination %s and table %d: %w",
 			link.Attrs().Name, dst, firewallMark, err)
 	}
 

internal/wireguard/route_test.go

@@ -53,7 +53,7 @@ func Test_Wireguard_addRoute(t *testing.T) {
 				Table:     firewallMark,
 			},
 			routeAddErr: errDummy,
-			err:         errors.New("cannot add route for link a_bridge, destination 1.2.3.4/32 and table 51820: dummy"), //nolint:lll
+			err:         errors.New("adding route for link a_bridge, destination 1.2.3.4/32 and table 51820: dummy"), //nolint:lll
 		},
 	}
 

internal/wireguard/rule.go

@@ -15,13 +15,13 @@ func (w *Wireguard) addRule(rulePriority, firewallMark, family int) (
 	rule.Table = firewallMark
 	rule.Family = family
 	if err := w.netlink.RuleAdd(rule); err != nil {
-		return nil, fmt.Errorf("cannot add rule %s: %w", rule, err)
+		return nil, fmt.Errorf("adding rule %s: %w", rule, err)
 	}
 
 	cleanup = func() error {
 		err := w.netlink.RuleDel(rule)
 		if err != nil {
-			return fmt.Errorf("cannot delete rule %s: %w", rule, err)
+			return fmt.Errorf("deleting rule %s: %w", rule, err)
 		}
 		return nil
 	}

internal/wireguard/rule_test.go

@@ -55,7 +55,7 @@ func Test_Wireguard_addRule(t *testing.T) {
 				Family:            family,
 			},
 			ruleAddErr: errDummy,
-			err:        errors.New("cannot add rule ip rule 987: from all to all table 456: dummy"),
+			err:        errors.New("adding rule ip rule 987: from all to all table 456: dummy"),
 		},
 		"rule delete error": {
 			expectedRule: &netlink.Rule{
@@ -71,7 +71,7 @@ func Test_Wireguard_addRule(t *testing.T) {
 				Family:            family,
 			},
 			ruleDelErr: errDummy,
-			cleanupErr: errors.New("cannot delete rule ip rule 987: from all to all table 456: dummy"),
+			cleanupErr: errors.New("deleting rule ip rule 987: from all to all table 456: dummy"),
 		},
 	}