chore(errors): review all errors in codebase

internal/vpn/openvpn.go

@@ -2,7 +2,6 @@ package vpn
 
 import (
 	"context"
-	"errors"
 	"fmt"
 
 	"github.com/qdm12/gluetun/internal/configuration/settings"
@@ -12,14 +11,6 @@ import (
 	"github.com/qdm12/golibs/command"
 )
 
-var (
-	errServerConn  = errors.New("failed finding a valid server connection")
-	errBuildConfig = errors.New("failed building configuration")
-	errWriteConfig = errors.New("failed writing configuration to file")
-	errWriteAuth   = errors.New("failed writing auth to file")
-	errFirewall    = errors.New("failed allowing VPN connection through firewall")
-)
-
 // setupOpenVPN sets OpenVPN up using the configurators and settings given.
 // It returns a serverName for port forwarding (PIA) and an error if it fails.
 func setupOpenVPN(ctx context.Context, fw firewall.VPNConnectionSetter,
@@ -28,27 +19,27 @@ func setupOpenVPN(ctx context.Context, fw firewall.VPNConnectionSetter,
 	runner vpnRunner, serverName string, err error) {
 	connection, err := providerConf.GetConnection(settings.Provider.ServerSelection)
 	if err != nil {
-		return nil, "", fmt.Errorf("%w: %s", errServerConn, err)
+		return nil, "", fmt.Errorf("failed finding a valid server connection: %w", err)
 	}
 
 	lines, err := providerConf.BuildConf(connection, settings.OpenVPN)
 	if err != nil {
-		return nil, "", fmt.Errorf("%w: %s", errBuildConfig, err)
+		return nil, "", fmt.Errorf("failed building configuration: %w", err)
 	}
 
 	if err := openvpnConf.WriteConfig(lines); err != nil {
-		return nil, "", fmt.Errorf("%w: %s", errWriteConfig, err)
+		return nil, "", fmt.Errorf("failed writing configuration to file: %w", err)
 	}
 
 	if settings.OpenVPN.User != "" {
 		err := openvpnConf.WriteAuthFile(settings.OpenVPN.User, settings.OpenVPN.Password)
 		if err != nil {
-			return nil, "", fmt.Errorf("%w: %s", errWriteAuth, err)
+			return nil, "", fmt.Errorf("failed writing auth to file: %w", err)
 		}
 	}
 
 	if err := fw.SetVPNConnection(ctx, connection, settings.OpenVPN.Interface); err != nil {
-		return nil, "", fmt.Errorf("%w: %s", errFirewall, err)
+		return nil, "", fmt.Errorf("failed allowing VPN connection through firewall: %w", err)
 	}
 
 	runner = openvpn.NewRunner(settings.OpenVPN, starter, logger)