Materialized path key traversal.

Allows deep access of config settings via a dot-delimited materialized path.
Environment variables may also be set to corresponding deep keys using double
underscores in place of the usual period delimiter. E.g:

  clothing.jacket => CLOTHING__JACKET

viper.go

@@ -25,6 +25,7 @@ import (
 	"os"
 	"path"
 	"path/filepath"
+	"reflect"
 	"runtime"
 	"strings"
 	"time"
@@ -50,6 +51,7 @@ var configFile string
 var configType string
 
 var config map[string]interface{} = make(map[string]interface{})
+var config_index map[string]interface{} = make(map[string]interface{})
 var override map[string]interface{} = make(map[string]interface{})
 var env map[string]string = make(map[string]string)
 var defaults map[string]interface{} = make(map[string]interface{})
@@ -133,7 +135,7 @@ func Marshal(rawVal interface{}) error {
 		return err
 	}
 
-	insensativiseMaps()
+	indexMaps()
 
 	return nil
 }
@@ -172,7 +174,7 @@ func BindEnv(input ...string) (err error) {
 	key = input[0]
 
 	if len(input) == 1 {
-		envkey = strings.ToUpper(key)
+		envkey = strings.Replace(strings.ToUpper(key), ".", "__", -1)
 	} else {
 		envkey = input[1]
 	}
@@ -204,6 +206,8 @@ func find(key string) interface{} {
 		return val
 	}
 
+	// Periods are not supported. Allow the usage of double underscores to specify
+	// nested configuration options.
 	envkey, exists := env[key]
 	if exists {
 		jww.TRACE.Println(key, "registered as env var", envkey)
@@ -215,7 +219,7 @@ func find(key string) interface{} {
 		}
 	}
 
-	val, exists = config[key]
+	val, exists = config_index[key]
 	if exists {
 		jww.TRACE.Println(key, "found in config:", val)
 		return val
@@ -265,7 +269,7 @@ func IsSet(key string) bool {
 // Have viper check ENV variables for all
 // keys set in config, default & flags
 func AutomaticEnv() {
-	for _, x := range AllKeys() {
+	for _, x := range AllDeepKeys() {
 		BindEnv(x)
 	}
 }
@@ -286,8 +290,8 @@ func registerAlias(alias string, key string) {
 			// name, we'll never be able to get that value using the original
 			// name, so move the config value to the new realkey.
 			if val, ok := config[alias]; ok {
-				delete(config, alias)
-				config[key] = val
+				delete(config_index, alias)
+				config_index[key] = val
 			}
 			if val, ok := defaults[alias]; ok {
 				delete(defaults, alias)
@@ -327,7 +331,7 @@ func InConfig(key string) bool {
 func SetDefault(key string, value interface{}) {
 	// If alias passed in, then set the proper default
 	key = realKey(strings.ToLower(key))
-	defaults[key] = value
+	defaults[strings.ToLower(key)] = value
 }
 
 // The user provided value (via flag)
@@ -382,25 +386,70 @@ func MarshallReader(in io.Reader) {
 		}
 	}
 
-	insensativiseMap(config)
+	indexMap(config, "", config_index)
 }
 
-func insensativiseMaps() {
-	insensativiseMap(config)
-	insensativiseMap(defaults)
-	insensativiseMap(override)
+func indexMaps() {
+	indexMap(config, "", config_index)
 }
 
-func insensativiseMap(m map[string]interface{}) {
+// Creates a flat index consisting of materialized paths into the potentially
+// nested config structure we've loaded from various sources. The index allows us
+// to access the original map contents in a case insensitive manner without
+// having to modify the original keys - which may lead to unexpected results
+// depending on how a user intends to use the config variable (e.g. passing the
+// entire map to function that may not be case-insensitive) or accessing nested
+// keys via materialized paths.
+func indexMap(m map[string]interface{}, path string, index map[string]interface{}) {
 	for key, val := range m {
 		lower := strings.ToLower(key)
-		if key != lower {
-			delete(m, key)
-			m[lower] = val
+		var joined_key string
+		if len(path) > 0 {
+			joined_key = path + "." + lower
+		} else {
+			joined_key = lower
+		}
+		index[joined_key] = val
+		if reflect.TypeOf(val).Kind() == reflect.Map {
+			// YAML maps may be map[interface{}]interface{}
+			indexMap(cast.ToStringMap(val), joined_key, index)
 		}
 	}
 }
 
+// AllDeepKeys returns all keys, including deep materialized paths.
+func AllDeepKeys() []string {
+	all := map[string]struct{}{}
+	var traverse func(m map[string]interface{}, path string)
+	traverse = func(m map[string]interface{}, path string) {
+		for key, val := range m {
+			lower := strings.ToLower(key)
+			var joined_key string
+			if len(path) > 0 {
+				joined_key = path + "." + lower
+			} else {
+				joined_key = lower
+			}
+
+			all[joined_key] = struct{}{}
+			if reflect.TypeOf(val).Kind() == reflect.Map {
+				traverse(cast.ToStringMap(val), joined_key)
+			}
+		}
+	}
+
+	traverse(defaults, "")
+	traverse(config, "")
+	traverse(override, "")
+
+	a := []string{}
+	for x, _ := range all {
+		a = append(a, x)
+	}
+
+	return a
+}
+
 func AllKeys() []string {
 	m := map[string]struct{}{}
 
@@ -418,7 +467,8 @@ func AllKeys() []string {
 
 	a := []string{}
 	for x, _ := range m {
-		a = append(a, x)
+		// LowerCase the key for backwards-compatibility.
+		a = append(a, strings.ToLower(x))
 	}
 
 	return a
@@ -614,6 +664,7 @@ func Reset() {
 	configType = ""
 
 	config = make(map[string]interface{})
+	config_index = make(map[string]interface{})
 	override = make(map[string]interface{})
 	env = make(map[string]string)
 	defaults = make(map[string]interface{})

viper_test.go

@@ -149,7 +149,7 @@ func TestEnv(t *testing.T) {
 func TestAllKeys(t *testing.T) {
 	ks := sort.StringSlice{"title", "owner", "name", "beard", "ppu", "batters", "hobbies", "clothing", "age", "hacker", "id", "type"}
 	dob, _ := time.Parse(time.RFC3339, "1979-05-27T07:32:00Z")
-	all := map[string]interface{}{"hacker": true, "beard": true, "batters": map[string]interface{}{"batter": []interface{}{map[string]interface{}{"type": "Regular"}, map[string]interface{}{"type": "Chocolate"}, map[string]interface{}{"type": "Blueberry"}, map[string]interface{}{"type": "Devil's Food"}}}, "hobbies": []interface{}{"skateboarding", "snowboarding", "go"}, "ppu": 0.55, "clothing": map[interface{}]interface{}{"jacket": "leather", "trousers": "denim"}, "name": "crunk", "owner": map[string]interface{}{"organization": "MongoDB", "Bio": "MongoDB Chief Developer Advocate & Hacker at Large", "dob": dob}, "id": "13", "title": "TOML Example", "age": 35, "type": "donut"}
+	all := map[string]interface{}{"beard": true, "batters": map[string]interface{}{"batter": []interface{}{map[string]interface{}{"type": "Regular"}, map[string]interface{}{"type": "Chocolate"}, map[string]interface{}{"type": "Blueberry"}, map[string]interface{}{"type": "Devil's Food"}}}, "hacker": true, "hobbies": []interface{}{"skateboarding", "snowboarding", "go"}, "id": "13", "type": "donut", "owner": map[string]interface{}{"organization": "MongoDB", "Bio": "MongoDB Chief Developer Advocate & Hacker at Large", "dob": dob}, "ppu": 0.55, "age": 35, "title": "TOML Example", "clothing": map[interface{}]interface{}{"jacket": "leather", "trousers": "denim"}, "name": "crunk"}
 
 	var allkeys sort.StringSlice
 	allkeys = AllKeys()
@@ -202,3 +202,19 @@ func TestMarshal(t *testing.T) {
 	}
 	assert.Equal(t, &C, &config{Name: "Steve", Port: 1234})
 }
+
+func TestDeepAccess(t *testing.T) {
+	assert.Equal(t, "leather", Get("clothing.jacket"))
+}
+
+func TestDeepBindEnv(t *testing.T) {
+	BindEnv("clothing.jacket")
+	os.Setenv("CLOTHING__JACKET", "peacoat")
+	assert.Equal(t, "peacoat", Get("clothing.jacket"))
+}
+
+func TestDeepAutomaticEnv(t *testing.T) {
+	AutomaticEnv()
+	os.Setenv("CLOTHING__JACKET", "jean")
+	assert.Equal(t, "jean", Get("clothing.jacket"))
+}