adding cascading file support, off by default

.gitignore

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

viper.go

@@ -77,11 +77,13 @@ type viper struct {
 	envPrefix  string
 
 	automaticEnvApplied bool
+	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
@@ -98,6 +100,7 @@ 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
 }
@@ -136,6 +139,12 @@ func (v *viper) SetEnvPrefix(in string) {
 	}
 }
 
+// Enable cascading configuration values for files. Will traverse down
+// ConfigPaths in an attempt to find keys
+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)
@@ -389,6 +398,7 @@ 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)
@@ -434,6 +444,15 @@ 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)
@@ -449,6 +468,49 @@ func (v *viper) find(key string) interface{} {
 	return nil
 }
 
+func (v *viper) findCascading(key string) (interface{}, bool, string) {
+
+	if( v.cascadingConfigs != nil ){
+		for file,config := range v.cascadingConfigs {
+			result := config[key]
+			if( result != nil ){
+				return result,true,file
+			}
+		}
+	}
+
+	v.cascadingConfigs = make(map[string]map[string]interface{})
+
+	configFiles := v.findAllConfigFiles()
+	for _, configFile := range configFiles {
+
+		if(v.cascadingConfigs[configFile] != nil){
+			//already cached
+			continue
+		}
+
+		jww.TRACE.Printf("Looking in %s for key %s",configFile,key)
+		file, err := ioutil.ReadFile(configFile)
+		if err != nil {
+			jww.ERROR.Print(err)
+			continue
+		}
+
+		jww.TRACE.Printf("marshalling %s for cascading",configFile)
+		var config = make(map[string]interface{})
+
+		marshallConfigReader(bytes.NewReader(file), config, filepath.Ext(configFile)[1:])
+		v.cascadingConfigs[configFile] = config
+
+		result := config[key]
+
+		if( result != nil){
+			return result,true,configFile
+		}
+	}
+	return "", false, ""
+}
+
 // 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 {
@@ -733,26 +795,41 @@ 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)
 		}
 	}
 
 	cwd, _ := findCWD()
 	file := v.searchInPath(cwd)
 	if file != "" {
-		return file, nil
+		validFiles = append(validFiles, file)
 	}
 
 	// try the current working directory
 	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
 }
 
 func Debug() { v.Debug() }

viper_test.go

@@ -12,6 +12,9 @@ import (
 	"sort"
 	"testing"
 	"time"
+	"os/exec"
+	"path"
+	"io/ioutil"
 
 	"github.com/spf13/pflag"
 	"github.com/stretchr/testify/assert"
@@ -352,3 +355,91 @@ func TestBoundCaseSensitivity(t *testing.T) {
 	assert.Equal(t, "green", Get("eyes"))
 
 }
+
+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,found,"All files should exist")
+}
+
+func generateCascadingTests(v2 *viper, file_name string) []string {
+
+	v2.SetConfigName(file_name)
+
+	tmp := os.Getenv("TMPDIR")
+	// $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
+}