Add delayed fetching of sources

altsrc.go

@@ -6,6 +6,8 @@ import (
 	"os"
 	"runtime"
 	"strings"
+
+	"github.com/urfave/cli/v3"
 )
 
 var (
@@ -80,3 +82,72 @@ func NestedVal(name string, tree map[any]any) (any, bool) {
 	}
 	return nil, false
 }
+
+type Sourcer interface {
+	SourceURI() string
+}
+
+type StringSourcer string
+
+func (s StringSourcer) SourceURI() string {
+	return string(s)
+}
+
+type StringPtrSourcer struct {
+	ptr *string
+}
+
+func NewStringPtrSourcer(p *string) StringPtrSourcer {
+	return StringPtrSourcer{
+		ptr: p,
+	}
+}
+
+func (s StringPtrSourcer) SourceURI() string {
+	return *s.ptr
+}
+
+type valueSource struct {
+	key     string
+	desc    string
+	sourcer Sourcer
+	um      func([]byte, any) error
+}
+
+func (vs *valueSource) Lookup() (string, bool) {
+	maafsc := NewMapAnyAnyURISourceCache(vs.sourcer.SourceURI(), vs.um)
+	if v, ok := NestedVal(vs.key, maafsc.Get()); ok {
+		return fmt.Sprintf("%[1]v", v), ok
+	}
+
+	return "", false
+}
+
+func (vs *valueSource) String() string {
+	return fmt.Sprintf("%s file %[2]q at key %[3]q", vs.desc, vs.sourcer.SourceURI(), vs.key)
+}
+
+func (vs *valueSource) GoString() string {
+	return fmt.Sprintf("%sValueSource{file:%[2]q,keyPath:%[3]q}", vs.desc, vs.sourcer.SourceURI(), vs.key)
+}
+
+func NewValueSource(f func([]byte, any) error, desc string, key string, uriSrc Sourcer) cli.ValueSource {
+	return &valueSource{
+		sourcer: uriSrc,
+		key:     key,
+		desc:    desc,
+		um:      f,
+	}
+}
+
+func NewValueSourceChain(f func([]byte, any) error, desc string, key string, uris ...Sourcer) cli.ValueSourceChain {
+	vs := []cli.ValueSource{}
+
+	for _, uri := range uris {
+		vs = append(vs, NewValueSource(f, desc, key, uri))
+	}
+
+	return cli.ValueSourceChain{
+		Chain: vs,
+	}
+}

go.mod

@@ -7,6 +7,7 @@ require github.com/stretchr/testify v1.9.0
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/urfave/cli/v3 v3.0.0-beta1 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
 

go.sum

@@ -4,6 +4,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
+github.com/urfave/cli/v3 v3.0.0-beta1 h1:6DTaaUarcM0wX7qj5Hcvs+5Dm3dyUTBbEwIWAjcw9Zg=
+github.com/urfave/cli/v3 v3.0.0-beta1/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

json/examples_test.go

@@ -22,9 +22,9 @@ var (
 )
 
 func ExampleJSON() {
-	configFiles := []string{
-		filepath.Join(testdataDir, "config.json"),
-		filepath.Join(testdataDir, "alt-config.json"),
+	configFiles := []altsrc.Sourcer{
+		altsrc.StringSourcer(filepath.Join(testdataDir, "config.json")),
+		altsrc.StringSourcer(filepath.Join(testdataDir, "alt-config.json")),
 	}
 
 	app := &cli.Command{

json/go.mod

@@ -4,14 +4,15 @@ go 1.23.2
 
 require (
 	github.com/stretchr/testify v1.9.0
+	github.com/urfave/cli-altsrc/v3 v3.0.0-alpha9.3
 	github.com/urfave/cli-altsrc/yaml v0.0.1
-	github.com/urfave/cli/v3 v3.0.0-alpha9.3
+	github.com/urfave/cli/v3 v3.0.0-beta1
+	gopkg.in/yaml.v2 v2.4.0
 )
 
 require (
 	github.com/davecgh/go-spew v1.1.1 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
-	github.com/urfave/cli-altsrc/v3 v3.0.0-alpha9.3 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
 

json/go.sum

@@ -4,9 +4,11 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/urfave/cli/v3 v3.0.0-alpha9.3 h1:RfQlgUHMRxDMwEEmGsrHd+mXYJpWpXlcJM8w86cpjGs=
-github.com/urfave/cli/v3 v3.0.0-alpha9.3/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
+github.com/urfave/cli/v3 v3.0.0-beta1 h1:6DTaaUarcM0wX7qj5Hcvs+5Dm3dyUTBbEwIWAjcw9Zg=
+github.com/urfave/cli/v3 v3.0.0-beta1/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
+gopkg.in/yaml.v2 v2.4.0 h1:D8xgwECY7CYvx+Y2n4sBz93Jn9JRvxdiyyo8CTfuKaY=
+gopkg.in/yaml.v2 v2.4.0/go.mod h1:RDklbk79AGWmwhnvt/jBztapEOGDOx6ZbXqjP6csGnQ=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=
 gopkg.in/yaml.v3 v3.0.1/go.mod h1:K4uyk7z7BCEPqu6E+C64Yfv1cQ7kz7rIZviUmN+EgEM=

json/json_value_source.go

@@ -1,12 +1,13 @@
 package json
 
 import (
-	yaml "github.com/urfave/cli-altsrc/yaml"
+	altsrc "github.com/urfave/cli-altsrc/v3"
 	"github.com/urfave/cli/v3"
+	"gopkg.in/yaml.v2"
 )
 
 // JSON is a helper function that wraps the YAML helper function
 // and loads via yaml.Unmarshal
-func JSON(key string, paths ...string) cli.ValueSourceChain {
-	return yaml.YAML(key, paths...)
+func JSON(key string, sources ...altsrc.Sourcer) cli.ValueSourceChain {
+	return altsrc.NewValueSourceChain(yaml.Unmarshal, "json", key, sources...)
 }

json/json_value_source_test.go

@@ -28,15 +28,15 @@ func TestJSON(t *testing.T) {
 
 	vsc := yaml.YAML(
 		"water_fountain.water",
-		"/dev/null/nonexistent.json",
-		configPath,
-		altConfigPath,
+		altsrc.StringSourcer("/dev/null/nonexistent.json"),
+		altsrc.StringSourcer(configPath),
+		altsrc.StringSourcer(altConfigPath),
 	)
 	v, ok := vsc.Lookup()
 	r.Equal("false", v)
 	r.True(ok)
 
 	yvs := vsc.Chain[0]
 	r.Equal("yaml file \"/dev/null/nonexistent.json\" at key \"water_fountain.water\"", yvs.String())
-	r.Equal("&yamlValueSource{file:\"/dev/null/nonexistent.json\",keyPath:\"water_fountain.water\"}", yvs.GoString())
+	r.Equal("yamlValueSource{file:\"/dev/null/nonexistent.json\",keyPath:\"water_fountain.water\"}", yvs.GoString())
 }

toml/examples_test.go

@@ -22,9 +22,9 @@ var (
 )
 
 func ExampleTOML() {
-	configFiles := []string{
-		filepath.Join(testdataDir, "config.toml"),
-		filepath.Join(testdataDir, "alt-config.toml"),
+	configFiles := []altsrc.Sourcer{
+		altsrc.StringSourcer(filepath.Join(testdataDir, "config.toml")),
+		altsrc.StringSourcer(filepath.Join(testdataDir, "alt-config.toml")),
 	}
 
 	app := &cli.Command{

toml/go.mod

@@ -5,8 +5,8 @@ go 1.23.2
 require (
 	github.com/BurntSushi/toml v1.4.0
 	github.com/stretchr/testify v1.9.0
-	github.com/urfave/cli/v3 v3.0.0-alpha9.3
-    github.com/urfave/cli-altsrc/v3 v3.0.0-alpha9
+	github.com/urfave/cli-altsrc/v3 v3.0.0-alpha9
+	github.com/urfave/cli/v3 v3.0.0-beta1
 )
 
 require (
@@ -15,4 +15,4 @@ require (
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 )
 
-replace github.com/urfave/cli-altsrc/v3 v3.0.0-alpha9 => ../
+replace github.com/urfave/cli-altsrc/v3 v3.0.0-alpha9 => ../

toml/go.sum

@@ -6,8 +6,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/urfave/cli/v3 v3.0.0-alpha9.3 h1:RfQlgUHMRxDMwEEmGsrHd+mXYJpWpXlcJM8w86cpjGs=
-github.com/urfave/cli/v3 v3.0.0-alpha9.3/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
+github.com/urfave/cli/v3 v3.0.0-beta1 h1:6DTaaUarcM0wX7qj5Hcvs+5Dm3dyUTBbEwIWAjcw9Zg=
+github.com/urfave/cli/v3 v3.0.0-beta1/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=

toml/toml_value_source.go

@@ -1,53 +1,13 @@
 package toml
 
 import (
-	"fmt"
-
 	"github.com/BurntSushi/toml"
 	altsrc "github.com/urfave/cli-altsrc/v3"
 	"github.com/urfave/cli/v3"
 )
 
-type tomlMapFileSourceCache = altsrc.FileSourceCache[tomlMap]
-
 // TOML is a helper function to encapsulate a number of
 // tomlValueSource together as a cli.ValueSourceChain
-func TOML(key string, paths ...string) cli.ValueSourceChain {
-	vsc := cli.ValueSourceChain{Chain: []cli.ValueSource{}}
-
-	for _, path := range paths {
-		vsc.Chain = append(
-			vsc.Chain,
-			&tomlValueSource{
-				file: path,
-				key:  key,
-				tmc:  *altsrc.NewFileSourceCache[tomlMap](path, toml.Unmarshal),
-			},
-		)
-	}
-
-	return vsc
-}
-
-type tomlValueSource struct {
-	file string
-	key  string
-
-	tmc tomlMapFileSourceCache
-}
-
-func (tvs *tomlValueSource) Lookup() (string, bool) {
-	if v, ok := altsrc.NestedVal(tvs.key, tvs.tmc.Get().Map); ok {
-		return fmt.Sprintf("%[1]v", v), ok
-	}
-
-	return "", false
-}
-
-func (tvs *tomlValueSource) String() string {
-	return fmt.Sprintf("toml file %[1]q at key %[2]q", tvs.file, tvs.key)
-}
-
-func (tvs *tomlValueSource) GoString() string {
-	return fmt.Sprintf("&tomlValueSource{file:%[1]q,keyPath:%[2]q}", tvs.file, tvs.key)
+func TOML(key string, sources ...altsrc.Sourcer) cli.ValueSourceChain {
+	return altsrc.NewValueSourceChain(toml.Unmarshal, "toml", key, sources...)
 }

toml/toml_value_source_test.go

@@ -27,15 +27,15 @@ func TestTOML(t *testing.T) {
 
 	vsc := TOML(
 		"water_fountain.water",
-		"/dev/null/nonexistent.toml",
-		configPath,
-		altConfigPath,
+		altsrc.StringSourcer("/dev/null/nonexistent.toml"),
+		altsrc.StringSourcer(configPath),
+		altsrc.StringSourcer(altConfigPath),
 	)
 	v, ok := vsc.Lookup()
 	r.Equal("false", v)
 	r.True(ok)
 
-	tvs := vsc.Chain[0].(*tomlValueSource)
+	tvs := vsc.Chain[0]
 	r.Equal("toml file \"/dev/null/nonexistent.toml\" at key \"water_fountain.water\"", tvs.String())
-	r.Equal("&tomlValueSource{file:\"/dev/null/nonexistent.toml\",keyPath:\"water_fountain.water\"}", tvs.GoString())
+	r.Equal("tomlValueSource{file:\"/dev/null/nonexistent.toml\",keyPath:\"water_fountain.water\"}", tvs.GoString())
 }

uri_source_cache.go

@@ -39,25 +39,25 @@ func readURI(uriString string) ([]byte, error) {
 }
 
 type URISourceCache[T any] struct {
-	file         string
+	uri          string
 	m            *T
 	unmarshaller func([]byte, any) error
 }
 
-func NewURISourceCache[T any](file string, f func([]byte, any) error) *URISourceCache[T] {
+func NewURISourceCache[T any](uri string, f func([]byte, any) error) *URISourceCache[T] {
 	return &URISourceCache[T]{
-		file:         file,
+		uri:          uri,
 		unmarshaller: f,
 	}
 }
 
 func (fsc *URISourceCache[T]) Get() T {
 	if fsc.m == nil {
 		res := new(T)
-		if b, err := readURI(fsc.file); err != nil {
-			tracef("failed to read uri %[1]q: %[2]v", fsc.file, err)
+		if b, err := readURI(fsc.uri); err != nil {
+			tracef("failed to read uri %[1]q: %[2]v", fsc.uri, err)
 		} else if err := fsc.unmarshaller(b, res); err != nil {
-			tracef("failed to unmarshal from file %[1]q: %[2]v", fsc.file, err)
+			tracef("failed to unmarshal from file %[1]q: %[2]v", fsc.uri, err)
 		} else {
 			fsc.m = res
 		}

yaml/examples_test.go

@@ -22,9 +22,9 @@ var (
 )
 
 func ExampleYAML() {
-	configFiles := []string{
-		filepath.Join(testdataDir, "config.yaml"),
-		filepath.Join(testdataDir, "alt-config.yaml"),
+	configFiles := []altsrc.Sourcer{
+		altsrc.StringSourcer(filepath.Join(testdataDir, "config.yaml")),
+		altsrc.StringSourcer(filepath.Join(testdataDir, "alt-config.yaml")),
 	}
 
 	app := &cli.Command{

yaml/go.mod

@@ -5,7 +5,7 @@ go 1.23.2
 require (
 	github.com/stretchr/testify v1.9.0
 	github.com/urfave/cli-altsrc/v3 v3.0.0-alpha2
-	github.com/urfave/cli/v3 v3.0.0-alpha9.3
+	github.com/urfave/cli/v3 v3.0.0-beta1
 	gopkg.in/yaml.v3 v3.0.1
 )
 

yaml/go.sum

@@ -4,8 +4,8 @@ github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZb
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
 github.com/stretchr/testify v1.9.0 h1:HtqpIVDClZ4nwg75+f6Lvsy/wHu+3BoSGCbBAcpTsTg=
 github.com/stretchr/testify v1.9.0/go.mod h1:r2ic/lqez/lEtzL7wO/rwa5dbSLXVDPFyf8C91i36aY=
-github.com/urfave/cli/v3 v3.0.0-alpha9.3 h1:RfQlgUHMRxDMwEEmGsrHd+mXYJpWpXlcJM8w86cpjGs=
-github.com/urfave/cli/v3 v3.0.0-alpha9.3/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
+github.com/urfave/cli/v3 v3.0.0-beta1 h1:6DTaaUarcM0wX7qj5Hcvs+5Dm3dyUTBbEwIWAjcw9Zg=
+github.com/urfave/cli/v3 v3.0.0-beta1/go.mod h1:FnIeEMYu+ko8zP1F9Ypr3xkZMIDqW3DR92yUtY39q1Y=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405 h1:yhCVgyC4o1eVCa2tZl7eS0r+SDo693bJlVdllGtEeKM=
 gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0=
 gopkg.in/yaml.v3 v3.0.1 h1:fxVm/GzAzEWqLHuvctI91KS9hhNmmWOoWu0XTYJS7CA=