yaml/json file backend support

backends/client.go

@@ -12,6 +12,7 @@ import (
 	"github.com/kelseyhightower/confd/backends/redis"
 	"github.com/kelseyhightower/confd/backends/stackengine"
 	"github.com/kelseyhightower/confd/backends/vault"
+	"github.com/kelseyhightower/confd/backends/yaml"
 	"github.com/kelseyhightower/confd/backends/zookeeper"
 	"github.com/kelseyhightower/confd/log"
 )
@@ -47,6 +48,8 @@ func New(config Config) (StoreClient, error) {
 		return redis.NewRedisClient(backendNodes)
 	case "env":
 		return env.NewEnvClient()
+	case "yaml":
+		return yaml.NewYamlClient(config.YAMLFile)
 	case "vault":
 		vaultConfig := map[string]string{
 			"app-id":   config.AppID,

backends/config.go

@@ -15,4 +15,5 @@ type Config struct {
 	Username     string
 	AppID        string
 	UserID       string
+	YAMLFile     string
 }

backends/yaml/client.go

@@ -0,0 +1,91 @@
+package yaml
+
+import (
+	"fmt"
+	"io/ioutil"
+	"strings"
+
+	"github.com/fsnotify/fsnotify"
+	"github.com/kelseyhightower/confd/log"
+	"gopkg.in/yaml.v2"
+)
+
+var replacer = strings.NewReplacer("/", "_")
+
+// Client provides a shell for the yaml client
+type Client struct {
+	filepath string
+}
+
+func NewYamlClient(filepath string) (*Client, error) {
+	return &Client{filepath}, nil
+}
+
+func (c *Client) GetValues(keys []string) (map[string]string, error) {
+	yamlMap := make(map[string]string)
+	vars := make(map[string]string)
+
+	data, err := ioutil.ReadFile(c.filepath)
+	if err != nil {
+		return vars, err
+	}
+	err = yaml.Unmarshal(data, &yamlMap)
+	if err != nil {
+		return vars, err
+	}
+
+	for _, key := range keys {
+		k := transform(key)
+		for yamlKey, yamlValue := range yamlMap {
+			if strings.HasPrefix(yamlKey, k) {
+				vars[clean(yamlKey)] = yamlValue
+			}
+		}
+	}
+	log.Debug(fmt.Sprintf("Key Map: %#v", vars))
+
+	return vars, nil
+}
+
+func transform(key string) string {
+	k := strings.TrimPrefix(key, "/")
+	return strings.ToUpper(replacer.Replace(k))
+}
+
+var cleanReplacer = strings.NewReplacer("_", "/")
+
+func clean(key string) string {
+	newKey := "/" + key
+	return cleanReplacer.Replace(strings.ToLower(newKey))
+}
+
+func (c *Client) WatchPrefix(prefix string, waitIndex uint64, stopChan chan bool) (uint64, error) {
+	if waitIndex == 0 {
+		return 1, nil
+	}
+
+	watcher, err := fsnotify.NewWatcher()
+	if err != nil {
+		return 0, err
+	}
+	defer watcher.Close()
+
+	err = watcher.Add(c.filepath)
+	if err != nil {
+		return 0, err
+	}
+
+	for {
+		select {
+		case event := <-watcher.Events:
+			if event.Op&fsnotify.Write == fsnotify.Write {
+				return 0, nil
+			}
+		case err := <-watcher.Errors:
+			return 0, err
+		case <-stopChan:
+			return 0, nil
+		}
+	}
+	return waitIndex, nil
+}

config.go

@@ -49,6 +49,7 @@ var (
 	watch             bool
 	appID             string
 	userID            string
+	yamlFile          string
 )
 
 // A Config structure is used to configure confd.
@@ -76,6 +77,7 @@ type Config struct {
 	Watch        bool     `toml:"watch"`
 	AppID        string   `toml:"app_id"`
 	UserID       string   `toml:"user_id"`
+	YAMLFile     string   `toml:"yaml_file"`
 }
 
 func init() {
@@ -87,6 +89,7 @@ func init() {
 	flag.StringVar(&clientKey, "client-key", "", "the client key")
 	flag.StringVar(&confdir, "confdir", "/etc/confd", "confd conf directory")
 	flag.StringVar(&configFile, "config-file", "", "the confd config file")
+	flag.StringVar(&yamlFile, "yaml-file", "", "yaml file")
 	flag.IntVar(&interval, "interval", 600, "backend polling interval")
 	flag.BoolVar(&keepStageFile, "keep-stage-file", false, "keep staged files")
 	flag.StringVar(&logLevel, "log-level", "", "level which confd should log messages")
@@ -218,6 +221,7 @@ func initConfig() error {
 		Username:     config.Username,
 		AppID:        config.AppID,
 		UserID:       config.UserID,
+		YAMLFile:     config.YAMLFile,
 	}
 	// Template configuration.
 	templateConfig = template.Config{
@@ -319,5 +323,7 @@ func setConfigFromFlag(f *flag.Flag) {
 		config.AppID = appID
 	case "user-id":
 		config.UserID = userID
+	case "yaml-file":
+		config.YAMLFile = yamlFile
 	}
 }