feat: add support for listen address and listen address slices flags

Author: gi8lino

listen_addr.go

@@ -0,0 +1,65 @@
+package dynflags
+
+import (
+	"fmt"
+	"net"
+)
+
+type ListenAddrValue struct {
+	Bound *string
+}
+
+func (l *ListenAddrValue) GetBound() any {
+	if l.Bound == nil {
+		return nil
+	}
+	return *l.Bound
+}
+
+func (l *ListenAddrValue) Parse(value string) (any, error) {
+	_, err := net.ResolveTCPAddr("tcp", value)
+	if err != nil {
+		return nil, fmt.Errorf("invalid listen address: %w", err)
+	}
+	return &value, nil
+}
+
+func (l *ListenAddrValue) Set(value any) error {
+	if str, ok := value.(*string); ok {
+		*l.Bound = *str
+		return nil
+	}
+	return fmt.Errorf("invalid value type: expected string pointer for listen address")
+}
+
+// ListenAddr defines a flag that validates a TCP listen address (host:port or :port).
+func (g *ConfigGroup) ListenAddr(name, defaultValue, usage string) *Flag {
+	bound := new(string)
+	if defaultValue != "" {
+		if _, err := net.ResolveTCPAddr("tcp", defaultValue); err != nil {
+			panic(fmt.Sprintf("%s has an invalid default listen address '%s': %v", name, defaultValue, err))
+		}
+		*bound = defaultValue // Copy the parsed ListenAddr into bound
+	}
+	flag := &Flag{
+		Type:    FlagTypeString,
+		Default: defaultValue,
+		Usage:   usage,
+		value:   &ListenAddrValue{Bound: bound},
+	}
+	g.Flags[name] = flag
+	g.flagOrder = append(g.flagOrder, name)
+	return flag
+}
+
+// GetListenAddr returns the string value of a validated listen address flag.
+func (pg *ParsedGroup) GetListenAddr(flagName string) (string, error) {
+	value, exists := pg.Values[flagName]
+	if !exists {
+		return "", fmt.Errorf("flag '%s' not found in group '%s'", flagName, pg.Name)
+	}
+	if str, ok := value.(string); ok {
+		return str, nil
+	}
+	return "", fmt.Errorf("flag '%s' is not a string listen address", flagName)
+}

listen_addr_slice.go

@@ -0,0 +1,75 @@
+package dynflags
+
+import (
+	"fmt"
+	"net"
+	"strings"
+)
+
+type ListenAddrSlicesValue struct {
+	Bound *[]string
+}
+
+func (s *ListenAddrSlicesValue) GetBound() any {
+	if s.Bound == nil {
+		return nil
+	}
+	return *s.Bound
+}
+
+func (s *ListenAddrSlicesValue) Parse(value string) (any, error) {
+	_, err := net.ResolveTCPAddr("tcp", value)
+	if err != nil {
+		return nil, fmt.Errorf("invalid listen address: %w", err)
+	}
+	return value, nil
+}
+
+func (s *ListenAddrSlicesValue) Set(value any) error {
+	if addr, ok := value.(string); ok {
+		*s.Bound = append(*s.Bound, addr)
+		return nil
+	}
+	return fmt.Errorf("invalid value type: expected string listen address")
+}
+
+// ListenAddrSlices defines a slice-of-listen-address flag with the specified name, default values, and usage.
+func (g *ConfigGroup) ListenAddrSlices(name string, value []string, usage string) *Flag {
+	bound := &value
+	defaultValue := strings.Join(value, ",")
+
+	// Validate all default addresses
+	for _, v := range value {
+		if _, err := net.ResolveTCPAddr("tcp", v); err != nil {
+			panic(fmt.Sprintf("%s has an invalid default listen address '%s': %v", name, v, err))
+		}
+	}
+
+	flag := &Flag{
+		Type:    FlagTypeStringSlice,
+		Default: defaultValue,
+		Usage:   usage,
+		value:   &ListenAddrSlicesValue{Bound: bound},
+	}
+	g.Flags[name] = flag
+	g.flagOrder = append(g.flagOrder, name)
+	return flag
+}
+
+// GetListenAddrSlices returns the []string value of a listen address slice flag.
+func (pg *ParsedGroup) GetListenAddrSlices(flagName string) ([]string, error) {
+	value, exists := pg.Values[flagName]
+	if !exists {
+		return nil, fmt.Errorf("flag '%s' not found in group '%s'", flagName, pg.Name)
+	}
+
+	if list, ok := value.([]string); ok {
+		return list, nil
+	}
+
+	if str, ok := value.(string); ok {
+		return []string{str}, nil
+	}
+
+	return nil, fmt.Errorf("flag '%s' is not a []string listen address slice", flagName)
+}

listen_addr_slice_test.go

@@ -0,0 +1,151 @@
+package dynflags_test
+
+import (
+	"testing"
+
+	"github.com/containeroo/dynflags"
+	"github.com/stretchr/testify/assert"
+)
+
+func TestListenAddrSlicesValue(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Parse valid listen address", func(t *testing.T) {
+		t.Parallel()
+
+		value := dynflags.ListenAddrSlicesValue{Bound: &[]string{}}
+		parsed, err := value.Parse(":8080")
+		assert.NoError(t, err)
+		assert.Equal(t, ":8080", parsed)
+	})
+
+	t.Run("Parse invalid listen address", func(t *testing.T) {
+		t.Parallel()
+
+		value := dynflags.ListenAddrSlicesValue{Bound: &[]string{}}
+		parsed, err := value.Parse("bad-address")
+		assert.Error(t, err)
+		assert.Nil(t, parsed)
+	})
+
+	t.Run("Set valid listen address", func(t *testing.T) {
+		t.Parallel()
+
+		bound := []string{":9090"}
+		value := dynflags.ListenAddrSlicesValue{Bound: &bound}
+
+		err := value.Set(":8080")
+		assert.NoError(t, err)
+		assert.Equal(t, []string{":9090", ":8080"}, bound)
+	})
+
+	t.Run("Set invalid type", func(t *testing.T) {
+		t.Parallel()
+
+		bound := []string{}
+		value := dynflags.ListenAddrSlicesValue{Bound: &bound}
+
+		err := value.Set(12345)
+		assert.Error(t, err)
+		assert.EqualError(t, err, "invalid value type: expected string listen address")
+	})
+}
+
+func TestGroupConfigListenAddrSlices(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Define listen address slices flag", func(t *testing.T) {
+		t.Parallel()
+
+		group := &dynflags.ConfigGroup{Flags: make(map[string]*dynflags.Flag)}
+		defaultValue := []string{":9090", "127.0.0.1:9091"}
+		group.ListenAddrSlices("listenSlice", defaultValue, "Multiple listen addresses")
+
+		assert.Contains(t, group.Flags, "listenSlice")
+		assert.Equal(t, "Multiple listen addresses", group.Flags["listenSlice"].Usage)
+		assert.Equal(t, ":9090,127.0.0.1:9091", group.Flags["listenSlice"].Default)
+	})
+
+	t.Run("Define listen address slices with invalid default", func(t *testing.T) {
+		t.Parallel()
+
+		group := &dynflags.ConfigGroup{Flags: make(map[string]*dynflags.Flag)}
+
+		assert.PanicsWithValue(t,
+			"listenSlice has an invalid default listen address 'bad-address': address bad-address: missing port in address",
+			func() {
+				group.ListenAddrSlices("listenSlice", []string{":8080", "bad-address"}, "Invalid default")
+			})
+	})
+}
+
+func TestGetListenAddrSlices(t *testing.T) {
+	t.Parallel()
+
+	t.Run("Retrieve []string listen address slice", func(t *testing.T) {
+		t.Parallel()
+
+		parsedGroup := &dynflags.ParsedGroup{
+			Name:   "testGroup",
+			Values: map[string]any{"flag1": []string{":8080", "127.0.0.1:9090"}},
+		}
+
+		result, err := parsedGroup.GetListenAddrSlices("flag1")
+		assert.NoError(t, err)
+		assert.Equal(t, []string{":8080", "127.0.0.1:9090"}, result)
+	})
+
+	t.Run("Retrieve single string as []string", func(t *testing.T) {
+		t.Parallel()
+
+		parsedGroup := &dynflags.ParsedGroup{
+			Name:   "testGroup",
+			Values: map[string]any{"flag1": ":8080"},
+		}
+
+		result, err := parsedGroup.GetListenAddrSlices("flag1")
+		assert.NoError(t, err)
+		assert.Equal(t, []string{":8080"}, result)
+	})
+
+	t.Run("Flag not found", func(t *testing.T) {
+		t.Parallel()
+
+		parsedGroup := &dynflags.ParsedGroup{
+			Name:   "testGroup",
+			Values: map[string]any{},
+		}
+
+		result, err := parsedGroup.GetListenAddrSlices("missingFlag")
+		assert.Error(t, err)
+		assert.Nil(t, result)
+		assert.EqualError(t, err, "flag 'missingFlag' not found in group 'testGroup'")
+	})
+
+	t.Run("Flag value is invalid type", func(t *testing.T) {
+		t.Parallel()
+
+		parsedGroup := &dynflags.ParsedGroup{
+			Name:   "testGroup",
+			Values: map[string]any{"flag1": 123},
+		}
+
+		result, err := parsedGroup.GetListenAddrSlices("flag1")
+		assert.Error(t, err)
+		assert.Nil(t, result)
+		assert.EqualError(t, err, "flag 'flag1' is not a []string listen address slice")
+	})
+}
+
+func TestListenAddrSlicesGetBound(t *testing.T) {
+	t.Run("ListenAddrSlicesValue - GetBound", func(t *testing.T) {
+		val := []string{":8080", "127.0.0.1:9090"}
+		bound := &val
+
+		value := dynflags.ListenAddrSlicesValue{Bound: bound}
+		assert.Equal(t, val, value.GetBound())
+
+		value = dynflags.ListenAddrSlicesValue{Bound: nil}
+		assert.Nil(t, value.GetBound())
+	})
+}