Converge etcd functionality as part of quick.Config

pkg/quick/quick.go

@@ -26,6 +26,7 @@ import (
 	"reflect"
 	"sync"
 
+	etcd "github.com/coreos/etcd/client"
 	"github.com/fatih/structs"
 	"github.com/minio/minio/pkg/safe"
 )
@@ -41,21 +42,22 @@ type Config interface {
 	DeepDiff(Config) ([]structs.Field, error)
 }
 
-// localConfig - implements quick.Config interface
-type localConfig struct {
+// config - implements quick.Config interface
+type config struct {
 	data interface{}
+	clnt etcd.Client
 	lock *sync.RWMutex
 }
 
 // Version returns the current config file format version
-func (d localConfig) Version() string {
+func (d config) Version() string {
 	st := structs.New(d.data)
 	f := st.Field("Version")
 	return f.Value().(string)
 }
 
 // String converts JSON config to printable string
-func (d localConfig) String() string {
+func (d config) String() string {
 	configBytes, _ := json.MarshalIndent(d.data, "", "\t")
 	return string(configBytes)
 }
@@ -63,10 +65,14 @@ func (d localConfig) String() string {
 // Save writes config data to a file. Data format
 // is selected based on file extension or JSON if
 // not provided.
-func (d localConfig) Save(filename string) error {
+func (d config) Save(filename string) error {
 	d.lock.Lock()
 	defer d.lock.Unlock()
 
+	if d.clnt != nil {
+		return saveFileConfigEtcd(filename, d.clnt, d.data)
+	}
+
 	// Backup if given file exists
 	oldData, err := ioutil.ReadFile(filename)
 	if err != nil {
@@ -89,19 +95,22 @@ func (d localConfig) Save(filename string) error {
 // Load - loads config from file and merge with currently set values
 // File content format is guessed from the file name extension, if not
 // available, consider that we have JSON.
-func (d localConfig) Load(filename string) error {
+func (d config) Load(filename string) error {
 	d.lock.Lock()
 	defer d.lock.Unlock()
+	if d.clnt != nil {
+		return loadFileConfigEtcd(filename, d.clnt, d.data)
+	}
 	return loadFileConfig(filename, d.data)
 }
 
 // Data - grab internal data map for reading
-func (d localConfig) Data() interface{} {
+func (d config) Data() interface{} {
 	return d.data
 }
 
 // Diff  - list fields that are in A but not in B
-func (d localConfig) Diff(c Config) ([]structs.Field, error) {
+func (d config) Diff(c Config) ([]structs.Field, error) {
 	var fields []structs.Field
 
 	currFields := structs.Fields(d.Data())
@@ -123,7 +132,7 @@ func (d localConfig) Diff(c Config) ([]structs.Field, error) {
 }
 
 // DeepDiff  - list fields in A that are missing or not equal to fields in B
-func (d localConfig) DeepDiff(c Config) ([]structs.Field, error) {
+func (d config) DeepDiff(c Config) ([]structs.Field, error) {
 	var fields []structs.Field
 
 	currFields := structs.Fields(d.Data())
@@ -179,43 +188,50 @@ func writeFile(filename string, data []byte) error {
 	return safeFile.Close()
 }
 
-// NewLocalConfig - instantiate a new config r/w configs from local files.
-func NewLocalConfig(data interface{}) (Config, error) {
+// GetVersion - extracts the version information.
+func GetVersion(filename string, clnt etcd.Client) (version string, err error) {
+	var qc Config
+	qc, err = LoadConfig(filename, clnt, &struct {
+		Version string
+	}{})
+	if err != nil {
+		return "", err
+	}
+	return qc.Version(), nil
+}
+
+// LoadConfig - loads json config from filename for the a given struct data
+func LoadConfig(filename string, clnt etcd.Client, data interface{}) (qc Config, err error) {
+	qc, err = NewConfig(data, clnt)
+	if err != nil {
+		return nil, err
+	}
+	return qc, qc.Load(filename)
+}
+
+// SaveConfig - saves given configuration data into given file as JSON.
+func SaveConfig(data interface{}, filename string, clnt etcd.Client) (err error) {
+	if err = checkData(data); err != nil {
+		return err
+	}
+	var qc Config
+	qc, err = NewConfig(data, clnt)
+	if err != nil {
+		return err
+	}
+	return qc.Save(filename)
+}
+
+// NewConfig loads config from etcd client if provided, otherwise loads from a local filename.
+// fails when all else fails.
+func NewConfig(data interface{}, clnt etcd.Client) (cfg Config, err error) {
 	if err := checkData(data); err != nil {
 		return nil, err
 	}
 
-	d := new(localConfig)
+	d := new(config)
 	d.data = data
+	d.clnt = clnt
 	d.lock = new(sync.RWMutex)
 	return d, nil
 }
-
-// GetLocalVersion - extracts the version information.
-func GetLocalVersion(filename string) (version string, err error) {
-	var qc Config
-	if qc, err = LoadLocalConfig(filename, &struct {
-		Version string
-	}{}); err != nil {
-		return "", err
-	}
-	return qc.Version(), err
-}
-
-// LoadLocalConfig - loads json config from filename for the a given struct data
-func LoadLocalConfig(filename string, data interface{}) (qc Config, err error) {
-	if qc, err = NewLocalConfig(data); err == nil {
-		err = qc.Load(filename)
-	}
-	return qc, err
-}
-
-// SaveLocalConfig - saves given configuration data into given file as JSON.
-func SaveLocalConfig(filename string, data interface{}) (err error) {
-	var qc Config
-	if qc, err = NewLocalConfig(data); err == nil {
-		err = qc.Save(filename)
-	}
-
-	return err
-}