Configuration package (#369)

internal/configuration/reader.go

@@ -0,0 +1,129 @@
+package configuration
+
+import (
+	"errors"
+	"fmt"
+	"net"
+	"strconv"
+	"strings"
+
+	"github.com/qdm12/golibs/logging"
+	"github.com/qdm12/golibs/os"
+	"github.com/qdm12/golibs/params"
+	"github.com/qdm12/golibs/verification"
+)
+
+type reader struct {
+	env    params.Env
+	logger logging.Logger
+	regex  verification.Regex
+	os     os.OS
+}
+
+func newReader(env params.Env, os os.OS, logger logging.Logger) reader {
+	return reader{
+		env:    env,
+		logger: logger,
+		regex:  verification.NewRegex(),
+		os:     os,
+	}
+}
+
+func (r *reader) onRetroActive(oldKey, newKey string) {
+	r.logger.Warn(
+		"You are using the old environment variable %s, please consider changing it to %s",
+		oldKey, newKey,
+	)
+}
+
+var (
+	ErrInvalidPort = errors.New("invalid port")
+)
+
+func readCSVPorts(env params.Env, key string) (ports []uint16, err error) {
+	s, err := env.Get(key)
+	if err != nil {
+		return nil, err
+	} else if len(s) == 0 {
+		return nil, nil
+	}
+
+	portsStr := strings.Split(s, ",")
+	ports = make([]uint16, len(portsStr))
+	for i, portStr := range portsStr {
+		portInt, err := strconv.Atoi(portStr)
+		if err != nil {
+			return nil, fmt.Errorf("%w: %q from environment variable %s: %s",
+				ErrInvalidPort, portStr, key, err)
+		} else if portInt <= 0 || portInt > 65535 {
+			return nil, fmt.Errorf("%w: %d from environment variable %s: must be between 1 and 65535",
+				ErrInvalidPort, portInt, key)
+		}
+		ports[i] = uint16(portInt)
+	}
+
+	return ports, nil
+}
+
+var (
+	ErrInvalidIPNet = errors.New("invalid IP network")
+)
+
+func readCSVIPNets(env params.Env, key string, options ...params.OptionSetter) (
+	ipNets []net.IPNet, err error) {
+	s, err := env.Get(key, options...)
+	if err != nil {
+		return nil, err
+	} else if s == "" {
+		return nil, nil
+	}
+
+	ipNetsStr := strings.Split(s, ",")
+	ipNets = make([]net.IPNet, len(ipNetsStr))
+	for i, ipNetStr := range ipNetsStr {
+		_, ipNet, err := net.ParseCIDR(ipNetStr)
+		if err != nil {
+			return nil, fmt.Errorf("%w: %q from environment variable %s: %s",
+				ErrInvalidIPNet, ipNetStr, key, err)
+		} else if ipNet == nil {
+			return nil, fmt.Errorf("%w: %q from environment variable %s: subnet is nil",
+				ErrInvalidIPNet, ipNetStr, key)
+		}
+		ipNets[i] = *ipNet
+	}
+
+	return ipNets, nil
+}
+
+var (
+	ErrInvalidIP = errors.New("invalid IP address")
+)
+
+func readIP(env params.Env, key string) (ip net.IP, err error) {
+	s, err := env.Get(key)
+	if len(s) == 0 {
+		return nil, nil
+	} else if err != nil {
+		return nil, err
+	}
+
+	ip = net.ParseIP(s)
+	if ip == nil {
+		return nil, fmt.Errorf("%w: %s", ErrInvalidIP, s)
+	}
+
+	return ip, nil
+}
+
+func readPortOrZero(env params.Env, key string) (port uint16, err error) {
+	s, err := env.Get(key)
+	if err != nil {
+		return 0, err
+	}
+
+	if len(s) == 0 || s == "0" {
+		return 0, nil
+	}
+
+	return env.Port(key)
+}