Add map value source

flag_bool_with_inverse.go

@@ -106,7 +106,7 @@ func (parent *BoolWithInverseFlag) initialize() {
 		sources := []ValueSource{}
 
 		for _, envVar := range child.GetEnvVars() {
-			sources = append(sources, &envVarValueSource{Key: strings.ToUpper(parent.InversePrefix) + envVar})
+			sources = append(sources, EnvVar(strings.ToUpper(parent.InversePrefix)+envVar))
 		}
 		parent.negativeFlag.Sources = NewValueSourceChain(sources...)
 	}

godoc-current.txt

@@ -591,6 +591,12 @@ type DocGenerationMultiValueFlag interface {
 
 type DurationFlag = FlagBase[time.Duration, NoConfig, durationValue]
 
+type EnvValueSource interface {
+	IsFromEnv() bool
+	Key() string
+}
+    EnvValueSource is to specifically detect env sources when printing help text
+
 type ErrorFormatter interface {
 	Format(s fmt.State, verb rune)
 }
@@ -848,6 +854,20 @@ func (i MapBase[T, C, VC]) ToString(t map[string]T) string
 func (i *MapBase[T, C, VC]) Value() map[string]T
     Value returns the mapping of values set by this flag
 
+type MapSource interface {
+	fmt.Stringer
+	fmt.GoStringer
+
+	// Lookup returns the value from the source based on key
+	// and if it was found
+	// or returns an empty string and false
+	Lookup(string) (any, bool)
+}
+    MapSource is a source which can be used to look up a value based on a key
+    typically for use with a cli.Flag
+
+func NewMapSource(name string, m map[any]any) MapSource
+
 type MultiError interface {
 	error
 	Errors() []error
@@ -1000,6 +1020,8 @@ func EnvVar(key string) ValueSource
 
 func File(path string) ValueSource
 
+func NewMapValueSource(key string, ms MapSource) ValueSource
+
 type ValueSourceChain struct {
 	Chain []ValueSource
 }

testdata/godoc-v3.x.txt

@@ -591,6 +591,12 @@ type DocGenerationMultiValueFlag interface {
 
 type DurationFlag = FlagBase[time.Duration, NoConfig, durationValue]
 
+type EnvValueSource interface {
+	IsFromEnv() bool
+	Key() string
+}
+    EnvValueSource is to specifically detect env sources when printing help text
+
 type ErrorFormatter interface {
 	Format(s fmt.State, verb rune)
 }
@@ -848,6 +854,20 @@ func (i MapBase[T, C, VC]) ToString(t map[string]T) string
 func (i *MapBase[T, C, VC]) Value() map[string]T
     Value returns the mapping of values set by this flag
 
+type MapSource interface {
+	fmt.Stringer
+	fmt.GoStringer
+
+	// Lookup returns the value from the source based on key
+	// and if it was found
+	// or returns an empty string and false
+	Lookup(string) (any, bool)
+}
+    MapSource is a source which can be used to look up a value based on a key
+    typically for use with a cli.Flag
+
+func NewMapSource(name string, m map[any]any) MapSource
+
 type MultiError interface {
 	error
 	Errors() []error
@@ -1000,6 +1020,8 @@ func EnvVar(key string) ValueSource
 
 func File(path string) ValueSource
 
+func NewMapValueSource(key string, ms MapSource) ValueSource
+
 type ValueSourceChain struct {
 	Chain []ValueSource
 }

value_source.go

@@ -17,6 +17,26 @@ type ValueSource interface {
 	Lookup() (string, bool)
 }
 
+// EnvValueSource is to specifically detect env sources when
+// printing help text
+type EnvValueSource interface {
+	IsFromEnv() bool
+	Key() string
+}
+
+// MapSource is a source which can be used to look up a value
+// based on a key
+// typically for use with a cli.Flag
+type MapSource interface {
+	fmt.Stringer
+	fmt.GoStringer
+
+	// Lookup returns the value from the source based on key
+	// and if it was found
+	// or returns an empty string and false
+	Lookup(string) (any, bool)
+}
+
 // ValueSourceChain contains an ordered series of ValueSource that
 // allows for lookup where the first ValueSource to resolve is
 // returned
@@ -38,8 +58,8 @@ func (vsc *ValueSourceChain) EnvKeys() []string {
 	vals := []string{}
 
 	for _, src := range vsc.Chain {
-		if v, ok := src.(*envVarValueSource); ok {
-			vals = append(vals, v.Key)
+		if v, ok := src.(EnvValueSource); ok && v.IsFromEnv() {
+			vals = append(vals, v.Key())
 		}
 	}
 
@@ -83,21 +103,29 @@ func (vsc *ValueSourceChain) LookupWithSource() (string, ValueSource, bool) {
 
 // envVarValueSource encapsulates a ValueSource from an environment variable
 type envVarValueSource struct {
-	Key string
+	key string
 }
 
 func (e *envVarValueSource) Lookup() (string, bool) {
-	return os.LookupEnv(strings.TrimSpace(string(e.Key)))
+	return os.LookupEnv(strings.TrimSpace(string(e.key)))
 }
 
-func (e *envVarValueSource) String() string { return fmt.Sprintf("environment variable %[1]q", e.Key) }
+func (e *envVarValueSource) IsFromEnv() bool {
+	return true
+}
+
+func (e *envVarValueSource) Key() string {
+	return e.key
+}
+
+func (e *envVarValueSource) String() string { return fmt.Sprintf("environment variable %[1]q", e.key) }
 func (e *envVarValueSource) GoString() string {
-	return fmt.Sprintf("&envVarValueSource{Key:%[1]q}", e.Key)
+	return fmt.Sprintf("&envVarValueSource{Key:%[1]q}", e.key)
 }
 
 func EnvVar(key string) ValueSource {
 	return &envVarValueSource{
-		Key: key,
+		key: key,
 	}
 }
 
@@ -107,7 +135,7 @@ func EnvVars(keys ...string) ValueSourceChain {
 	vsc := ValueSourceChain{Chain: []ValueSource{}}
 
 	for _, key := range keys {
-		vsc.Chain = append(vsc.Chain, &envVarValueSource{Key: key})
+		vsc.Chain = append(vsc.Chain, EnvVar(key))
 	}
 
 	return vsc
@@ -138,8 +166,85 @@ func Files(paths ...string) ValueSourceChain {
 	vsc := ValueSourceChain{Chain: []ValueSource{}}
 
 	for _, path := range paths {
-		vsc.Chain = append(vsc.Chain, &fileValueSource{Path: path})
+		vsc.Chain = append(vsc.Chain, File(path))
 	}
 
 	return vsc
 }
+
+type mapSource struct {
+	name string
+	m    map[any]any
+}
+
+func NewMapSource(name string, m map[any]any) MapSource {
+	return &mapSource{
+		name: name,
+		m:    m,
+	}
+}
+
+func (ms *mapSource) String() string { return fmt.Sprintf("map source %[1]q", ms.name) }
+func (ms *mapSource) GoString() string {
+	return fmt.Sprintf("&mapSource{name:%[1]q}", ms.name)
+}
+
+func (ms *mapSource) Lookup(name string) (any, bool) {
+	// nestedVal checks if the name has '.' delimiters.
+	// If so, it tries to traverse the tree by the '.' delimited sections to find
+	// a nested value for the key.
+	if sections := strings.Split(name, "."); len(sections) > 1 {
+		node := ms.m
+		for _, section := range sections[:len(sections)-1] {
+			child, ok := node[section]
+			if !ok {
+				return nil, false
+			}
+
+			switch child := child.(type) {
+			case map[string]any:
+				node = make(map[any]any, len(child))
+				for k, v := range child {
+					node[k] = v
+				}
+			case map[any]any:
+				node = child
+			default:
+				return nil, false
+			}
+		}
+		if val, ok := node[sections[len(sections)-1]]; ok {
+			return val, true
+		}
+	}
+
+	return nil, false
+}
+
+type mapValueSource struct {
+	key string
+	ms  MapSource
+}
+
+func NewMapValueSource(key string, ms MapSource) ValueSource {
+	return &mapValueSource{
+		key: key,
+		ms:  ms,
+	}
+}
+
+func (mvs *mapValueSource) String() string {
+	return fmt.Sprintf("key %[1]q from %[2]s", mvs.key, mvs.ms.String())
+}
+
+func (mvs *mapValueSource) GoString() string {
+	return fmt.Sprintf("&mapValueSource{key:%[1]q, src:%[2]s}", mvs.key, mvs.ms.GoString())
+}
+
+func (mvs *mapValueSource) Lookup() (string, bool) {
+	if v, ok := mvs.ms.Lookup(mvs.key); !ok {
+		return "", false
+	} else {
+		return fmt.Sprintf("%+v", v), true
+	}
+}