Merge remote-tracking branch 'wrobbins/master'

.gitignore

@@ -6,6 +6,7 @@
 # Folders
 _obj
 _test
+.idea
 
 # Architecture specific extensions/prefixes
 *.[568vq]

README.md

@@ -72,7 +72,7 @@ Examples:
 If you want to support a config file, Viper requires a minimal
 configuration so it knows where to look for the config file. Viper
 supports json, toml and yaml files. Viper can search multiple paths, but
-currently a single viper only supports a single config file.
+currently a single viper only supports a single config file, unless cascading is enabled.
 
 	viper.SetConfigName("config") // name of config file (without extension)
 	viper.AddConfigPath("/etc/appname/")   // path to look for the config file in
@@ -112,6 +112,22 @@ viper.ReadConfig(bytes.NewBuffer(yamlExample))
 viper.Get("name") // this would be "steve"
 ````
 
+#### Enabling Cascading
+
+By default Viper stops reading configuration once it encounters the first available configuration file.
+That means each configuration file must contain all configuration values you need.
+By enabling cascading you can create sparse configuration files. Configuration will cascade down in
+the order that files are added  by AddConfigPath. For more see viper_test's cascading tests.
+
+Consider:
+
+ * \etc\myapp\myapp.json
+ * ($GOPATH)\src\myapp\myapp.json
+
+You can check in a default myapp.json for development and only override certain kvps in production
+
+	viper.EnableCascading(true)
+
 ### Setting Overrides
 
 These could be from a command line flag, or from your own application logic.

viper.go

@@ -133,10 +133,13 @@ type Viper struct {
 	automaticEnvApplied bool
 	envKeyReplacer      *strings.Replacer
 
+	cascadeConfigurations bool
+
 	config           map[string]interface{}
 	override         map[string]interface{}
 	defaults         map[string]interface{}
 	kvstore          map[string]interface{}
+	cascadingConfigs map[string]map[string]interface{}
 	pflags           map[string]*pflag.Flag
 	env              map[string]string
 	aliases          map[string]string
@@ -154,6 +157,7 @@ func New() *Viper {
 	v.pflags = make(map[string]*pflag.Flag)
 	v.env = make(map[string]string)
 	v.aliases = make(map[string]string)
+	v.cascadeConfigurations = false
 
 	return v
 }
@@ -226,6 +230,13 @@ func (v *Viper) SetEnvPrefix(in string) {
 	}
 }
 
+// Enable cascading configuration values for files. Will traverse down
+// ConfigPaths in an attempt to find keys
+func EnableCascading(enable bool) { v.EnableCascading(enable) }
+func (v *Viper) EnableCascading(enable bool) {
+	v.cascadeConfigurations = enable
+}
+
 func (v *Viper) mergeWithEnvPrefix(in string) string {
 	if v.envPrefix != "" {
 		return strings.ToUpper(v.envPrefix + "_" + in)
@@ -474,7 +485,6 @@ func (v *Viper) MarshalKey(key string, rawVal interface{}) error {
 func Marshal(rawVal interface{}) error { return v.Marshal(rawVal) }
 func (v *Viper) Marshal(rawVal interface{}) error {
 	err := mapstructure.WeakDecode(v.AllSettings(), rawVal)
-
 	if err != nil {
 		return err
 	}
@@ -562,6 +572,7 @@ func (v *Viper) BindEnv(input ...string) (err error) {
 func (v *Viper) find(key string) interface{} {
 	var val interface{}
 	var exists bool
+	var file string
 
 	// if the requested key is an alias, then return the proper key
 	key = v.realKey(key)
@@ -607,6 +618,15 @@ func (v *Viper) find(key string) interface{} {
 		return val
 	}
 
+	if v.cascadeConfigurations {
+		//cascade down the rest of the files
+		val, exists, file = v.findCascading(key)
+		if exists {
+			jww.TRACE.Printf("%s found in config: %s (%s)", key, val, file)
+			return val
+		}
+	}
+
 	val, exists = v.kvstore[key]
 	if exists {
 		jww.TRACE.Println(key, "found in key/value store:", val)
@@ -622,6 +642,53 @@ func (v *Viper) find(key string) interface{} {
 	return nil
 }
 
+func (v *Viper) findCascading(key string) (interface{}, bool, string) {
+
+	configFiles := v.findAllConfigFiles()
+
+	if v.cascadingConfigs == nil {
+		v.cascadingConfigs = make(map[string]map[string]interface{})
+	}
+
+	for _, configFile := range configFiles {
+		config := v.cascadingConfigs[configFile]
+
+		if config == nil {
+			var err error
+			config, err = readConfigFile(configFile)
+			if err != nil {
+				jww.ERROR.Print(err)
+				continue
+			}
+			v.cascadingConfigs[configFile] = config
+		}
+
+		jww.TRACE.Printf("Looking in %s for key %s", configFile, key)
+		result := config[key]
+		if result != nil {
+			return result, true, configFile
+		}
+
+	}
+
+	return "", false, ""
+}
+
+func readConfigFile(configFile string) (map[string]interface{}, error) {
+	jww.TRACE.Printf("marshalling %s ", configFile)
+
+	file, err := ioutil.ReadFile(configFile)
+	if err != nil {
+		return nil, err
+	}
+
+	var config = make(map[string]interface{})
+
+	marshallConfigReader(bytes.NewReader(file), config, filepath.Ext(configFile)[1:])
+
+	return config, nil
+}
+
 // Check to see if the key has been set in any of the data locations
 func IsSet(key string) bool { return v.IsSet(key) }
 func (v *Viper) IsSet(key string) bool {
@@ -986,10 +1053,23 @@ func (v *Viper) searchInPath(in string) (filename string) {
 func (v *Viper) findConfigFile() (string, error) {
 	jww.INFO.Println("Searching for config in ", v.configPaths)
 
+	var validFiles = v.findAllConfigFiles()
+
+	if len(validFiles) == 0 {
+		return "", fmt.Errorf("config file not found in: %s", v.configPaths)
+	}
+
+	return validFiles[0], nil
+}
+
+func (v *Viper) findAllConfigFiles() []string {
+
+	var validFiles []string
 	for _, cp := range v.configPaths {
 		file := v.searchInPath(cp)
 		if file != "" {
-			return file, nil
+			jww.TRACE.Println("Found config file in: %s", file)
+			validFiles = append(validFiles, file)
 		}
 	}
 
@@ -997,9 +1077,10 @@ func (v *Viper) findConfigFile() (string, error) {
 	wd, _ := os.Getwd()
 	file := v.searchInPath(wd)
 	if file != "" {
-		return file, nil
+		validFiles = append(validFiles, file)
 	}
-	return "", fmt.Errorf("config file not found in: %s", v.configPaths)
+
+	return validFiles
 }
 
 // Prints all configuration registries for debugging

viper_test.go

@@ -10,6 +10,8 @@ import (
 	"fmt"
 	"io/ioutil"
 	"os"
+	"os/exec"
+	"path"
 	"path/filepath"
 	"sort"
 	"strings"
@@ -587,3 +589,106 @@ func TestReadDir(t *testing.T) {
 	assert.Equal(t, "https://donuts/api/1/", v.Get("app.service.url"))
 	assert.Equal(t, "0123456789abcdef", v.Get("app.service.key"))
 }
+
+func TestCanCascadeConfigurationValues(t *testing.T) {
+
+	v2 := New()
+
+	generateCascadingTests(v2, "cascading")
+
+	v2.ReadInConfig()
+	v2.EnableCascading(true)
+
+	assert.Equal(t, "high", v2.GetString("0"), "Key 0 should be high")
+	assert.Equal(t, "med", v2.GetString("1"), "Key 1 should be med")
+	assert.Equal(t, "low", v2.GetString("2"), "key 2 should be low")
+
+	v2.EnableCascading(false)
+
+	assert.Nil(t, v2.Get("1"), "With enable cascading disabled, no value for 1 should exist")
+	assert.Nil(t, v2.Get("2"), "With enable cascading disabled, no value for 2 should exist")
+}
+
+func TestFindAllConfigPaths(t *testing.T) {
+
+	v2 := New()
+
+	file := "viper_test"
+
+	var expected = generateCascadingTests(v2, file)
+
+	found := v2.findAllConfigFiles()
+
+	for _, fp := range expected {
+		command := exec.Command("rm", fp)
+		command.Run()
+	}
+
+	assert.Equal(t, expected, removeDuplicates(found), "All files should exist")
+}
+
+func generateCascadingTests(v2 *Viper, file_name string) []string {
+
+	v2.SetConfigName(file_name)
+
+	tmp := os.Getenv("TMPDIR")
+	if tmp == "" {
+		tmp, _ = filepath.Abs(filepath.Dir("./"))
+	}
+	// $TMPDIR/a > $TMPDIR/b > %TMPDIR
+	paths := []string{path.Join(tmp, "a"), path.Join(tmp, "b"), tmp}
+
+	v2.SetConfigName(file_name)
+
+	var expected []string
+
+	for idx, fp := range paths {
+		v2.AddConfigPath(fp)
+
+		exec.Command("mkdir", "-m", "777", fp).Run()
+
+		full_path := path.Join(fp, file_name+".json")
+
+		var val string
+		switch idx {
+		case 0:
+			val = "high"
+			break
+		case 1:
+			val = "med"
+			break
+		case 2:
+			val = "low"
+		}
+
+		config := "{"
+		for i := 0; i <= idx; i++ {
+			config += fmt.Sprintf("\"%d\": \"%s\"", i, val)
+			if i == idx {
+				config += "\n"
+			} else {
+				config += ",\n"
+			}
+		}
+
+		config += "}"
+
+		ioutil.WriteFile(full_path, []byte(config), 0777)
+
+		expected = append(expected, full_path)
+	}
+
+	return expected
+}
+
+func removeDuplicates(a []string) []string {
+	result := []string{}
+	seen := map[string]string{}
+	for _, val := range a {
+		if _, ok := seen[val]; !ok {
+			result = append(result, val)
+			seen[val] = val
+		}
+	}
+	return result
+}