chore(errors): review all errors in codebase

internal/configuration/sources/env/dns.go

@@ -20,7 +20,7 @@ func (r *Reader) readDNS() (dns settings.DNS, err error) {
 
 	dns.DoT, err = r.readDoT()
 	if err != nil {
-		return dns, fmt.Errorf("cannot read DoT settings: %w", err)
+		return dns, fmt.Errorf("DoT settings: %w", err)
 	}
 
 	return dns, nil

internal/configuration/sources/env/firewall.go

@@ -55,8 +55,7 @@ func stringsToPorts(ss []string) (ports []uint16, err error) {
 	for i, s := range ss {
 		port, err := strconv.Atoi(s)
 		if err != nil {
-			return nil, fmt.Errorf("%w: %s: %s",
-				ErrPortParsing, s, err)
+			return nil, fmt.Errorf("%w: %s: %s", ErrPortParsing, s, err)
 		} else if port < 1 || port > 65535 {
 			return nil, fmt.Errorf("%w: must be between 1 and 65535: %d",
 				ErrPortValue, port)
@@ -66,10 +65,6 @@ func stringsToPorts(ss []string) (ports []uint16, err error) {
 	return ports, nil
 }
 
-var (
-	ErrIPNetParsing = errors.New("cannot parse IP network")
-)
-
 func stringsToIPNets(ss []string) (ipNets []net.IPNet, err error) {
 	if len(ss) == 0 {
 		return nil, nil
@@ -78,8 +73,7 @@ func stringsToIPNets(ss []string) (ipNets []net.IPNet, err error) {
 	for i, s := range ss {
 		ip, ipNet, err := net.ParseCIDR(s)
 		if err != nil {
-			return nil, fmt.Errorf("%w: %s: %s",
-				ErrIPNetParsing, s, err)
+			return nil, fmt.Errorf("cannot parse IP network %q: %w", s, err)
 		}
 		ipNet.IP = ip
 		ipNets[i] = *ipNet

internal/configuration/sources/env/health.go

@@ -38,9 +38,7 @@ func (r *Reader) readDurationWithRetro(envKey, retroEnvKey string) (d *time.Dura
 	d = new(time.Duration)
 	*d, err = time.ParseDuration(s)
 	if err != nil {
-		return nil, fmt.Errorf(
-			"environment variable %s: %w",
-			envKey, err)
+		return nil, fmt.Errorf("environment variable %s: %w", envKey, err)
 	}
 
 	return d, nil

internal/configuration/sources/env/helpers.go

@@ -2,7 +2,6 @@ package env
 
 import (
 	"encoding/base64"
-	"errors"
 	"fmt"
 	"os"
 	"strconv"
@@ -115,13 +114,11 @@ func lowerAndSplit(csv string) (values []string) {
 	return strings.Split(csv, ",")
 }
 
-var ErrDecodeBase64 = errors.New("cannot decode base64 string")
-
 func decodeBase64(b64String string) (decoded string, err error) {
 	b, err := base64.StdEncoding.DecodeString(b64String)
 	if err != nil {
-		return "", fmt.Errorf("%w: %s: %s",
-			ErrDecodeBase64, b64String, err)
+		return "", fmt.Errorf("cannot decode base64 string %q: %w",
+			b64String, err)
 	}
 	return string(b), nil
 }

internal/configuration/sources/env/log.go

@@ -48,7 +48,7 @@ func parseLogLevel(s string) (level logging.Level, err error) {
 		return logging.LevelError, nil
 	default:
 		return level, fmt.Errorf(
-			"%w: %s: can be one of: debug, info, warning or error",
+			"%w: %q is not valid and can be one of debug, info, warning or error",
 			ErrLogLevelUnknown, s)
 	}
 }

internal/configuration/sources/env/provider.go

@@ -18,12 +18,12 @@ func (r *Reader) readProvider(vpnType string) (provider settings.Provider, err e
 
 	provider.ServerSelection, err = r.readServerSelection(providerName, vpnType)
 	if err != nil {
-		return provider, fmt.Errorf("cannot read server selection settings: %w", err)
+		return provider, fmt.Errorf("server selection: %w", err)
 	}
 
 	provider.PortForwarding, err = r.readPortForward()
 	if err != nil {
-		return provider, fmt.Errorf("cannot read port forwarding settings: %w", err)
+		return provider, fmt.Errorf("port forwarding: %w", err)
 	}
 
 	return provider, nil

internal/configuration/sources/env/vpn.go

@@ -13,17 +13,17 @@ func (r *Reader) readVPN() (vpn settings.VPN, err error) {
 
 	vpn.Provider, err = r.readProvider(vpn.Type)
 	if err != nil {
-		return vpn, fmt.Errorf("cannot read provider settings: %w", err)
+		return vpn, fmt.Errorf("VPN provider: %w", err)
 	}
 
 	vpn.OpenVPN, err = r.readOpenVPN()
 	if err != nil {
-		return vpn, fmt.Errorf("cannot read OpenVPN settings: %w", err)
+		return vpn, fmt.Errorf("OpenVPN: %w", err)
 	}
 
 	vpn.Wireguard, err = r.readWireguard()
 	if err != nil {
-		return vpn, fmt.Errorf("cannot read Wireguard settings: %w", err)
+		return vpn, fmt.Errorf("wireguard: %w", err)
 	}
 
 	return vpn, nil

internal/configuration/sources/files/openvpn.go

@@ -16,12 +16,12 @@ const (
 func (r *Reader) readOpenVPN() (settings settings.OpenVPN, err error) {
 	settings.ClientKey, err = ReadFromFile(OpenVPNClientKeyPath)
 	if err != nil {
-		return settings, fmt.Errorf("cannot read client key: %w", err)
+		return settings, fmt.Errorf("client key: %w", err)
 	}
 
 	settings.ClientCrt, err = ReadFromFile(OpenVPNClientCertificatePath)
 	if err != nil {
-		return settings, fmt.Errorf("cannot read client certificate: %w", err)
+		return settings, fmt.Errorf("client certificate: %w", err)
 	}
 
 	return settings, nil

internal/configuration/sources/files/vpn.go

@@ -9,7 +9,7 @@ import (
 func (r *Reader) readVPN() (vpn settings.VPN, err error) {
 	vpn.OpenVPN, err = r.readOpenVPN()
 	if err != nil {
-		return vpn, fmt.Errorf("cannot read OpenVPN settings: %w", err)
+		return vpn, fmt.Errorf("OpenVPN: %w", err)
 	}
 
 	return vpn, nil

internal/configuration/sources/mux/reader.go

@@ -26,7 +26,7 @@ func (r *Reader) Read() (settings settings.Settings, err error) {
 	for _, source := range r.sources {
 		settingsFromSource, err := source.Read()
 		if err != nil {
-			return settings, fmt.Errorf("cannot read from source %T: %w", source, err)
+			return settings, fmt.Errorf("reading from source %T: %w", source, err)
 		}
 		settings.MergeWith(settingsFromSource)
 	}
@@ -42,7 +42,7 @@ func (r *Reader) ReadHealth() (settings settings.Health, err error) {
 	for _, source := range r.sources {
 		settingsFromSource, err := source.ReadHealth()
 		if err != nil {
-			return settings, fmt.Errorf("cannot read from source %T: %w", source, err)
+			return settings, fmt.Errorf("reading from source %T: %w", source, err)
 		}
 		settings.MergeWith(settingsFromSource)
 	}