WIP

andviro · andviro · commit dc43fa568949 · 2017-12-27T20:28:28.000+03:00
diff --git a/libkv/loader.go b/libkv/loader.go
@@ -0,0 +1,49 @@
+package libkv
+
+import (
+	"strings"
+
+	"github.com/docker/libkv/store"
+
+	"github.com/go-mixins/loader"
+)
+
+// Loader implements loader.Loader
+type Loader struct {
+	store   kvStore
+	prefix  string
+	changes chan struct{}
+}
+
+var _ loader.Loader = (*Loader)(nil)
+
+type kvStore interface {
+	// Get a value given its key
+	Get(key string) (*store.KVPair, error)
+	// List the content of a given prefix
+	List(directory string) ([]*store.KVPair, error)
+	// Close the store connection
+	Close()
+}
+
+// Close closes underlying changes channel
+func (l *Loader) Close() error {
+	l.store.Close()
+	close(l.changes)
+	return nil
+}
+
+// Changes provides source of config change events. For environment variables
+// there will never be any.
+func (l *Loader) Changes() <-chan struct{} {
+	return l.changes
+}
+
+// New creates loader initialized with KV store prefix
+func New(prefix string, store kvStore) *Loader {
+	return &Loader{
+		store:   store,
+		prefix:  strings.Trim(prefix, "/") + "/",
+		changes: make(chan struct{}),
+	}
+}
diff --git a/libkv/loader_test.go b/libkv/loader_test.go
@@ -0,0 +1,58 @@
+package libkv_test
+
+import (
+	"testing"
+
+	"github.com/docker/libkv/store"
+	"github.com/go-mixins/loader/libkv"
+)
+
+type kvMock struct{}
+
+func (kvm *kvMock) Close() {}
+
+func (kvm *kvMock) Get(key string) (res *store.KVPair, err error) {
+	switch key {
+	case "unknown":
+		err = store.ErrKeyNotFound
+	case "a/b/c/":
+		res = &store.KVPair{
+			Key:   key,
+			Value: []byte("1"),
+		}
+	}
+	return
+}
+
+func (kvm *kvMock) List(directory string) (res []*store.KVPair, err error) {
+	switch directory {
+	case "a/":
+		res = []*store.KVPair{
+			&store.KVPair{Key: "a/b/"},
+		}
+	case "a/b/":
+		res = []*store.KVPair{
+			&store.KVPair{Key: "a/b/c/"},
+		}
+	case "a/b/c/":
+		res = []*store.KVPair{}
+	default:
+		err = store.ErrKeyNotFound
+	}
+	return
+}
+
+func TestLoad(t *testing.T) {
+	loader := libkv.New("a", &kvMock{})
+	var dest struct {
+		B struct {
+			C int
+		}
+	}
+	defer loader.Close()
+	err := loader.Load(&dest)
+	if err != nil {
+		t.Fatalf("%+v", err)
+	}
+	t.Logf("%+v", dest)
+}
diff --git a/libkv/struct.go b/libkv/struct.go
@@ -0,0 +1,72 @@
+package libkv
+
+import (
+	"fmt"
+	"strings"
+
+	"github.com/docker/libkv/store"
+	"github.com/go-mixins/loader"
+	"github.com/mitchellh/mapstructure"
+)
+
+// Load loads the target from environment
+func (l *Loader) Load(dest interface{}) error {
+	cfg := &mapstructure.DecoderConfig{
+		Result:           dest,
+		WeaklyTypedInput: true,
+	}
+	decoder, err := mapstructure.NewDecoder(cfg)
+	if err != nil {
+		return loader.Errors.Wrap(err, "creating map decoder")
+	}
+	data, err := l.getRecursive(l.prefix)
+	if err != nil {
+		return err
+	}
+	fmt.Printf("*** %+v\n", data)
+	return loader.Errors.Wrap(decoder.Decode(data), "decoding values")
+}
+
+func put(dest map[string]interface{}, prefix string, val interface{}) {
+	path := strings.Split(strings.Trim(prefix, "/"), "/")
+	fmt.Printf("&&& %s %#v\n", prefix, path)
+	if len(path) == 0 {
+		return
+	}
+	for i := len(path) - 1; i >= 1; i-- {
+		val = map[string]interface{}{
+			path[i]: val,
+		}
+	}
+	dest[path[0]] = val
+}
+
+func (l *Loader) getRecursive(prefix string) (interface{}, error) {
+	fmt.Printf("### %s\n", prefix)
+	pairs, err := l.store.List(prefix)
+	if err == store.ErrKeyNotFound {
+		return nil, nil
+	}
+	if err != nil {
+		return nil, loader.Errors.Wrap(err, "getting KV list")
+	}
+	if len(pairs) == 0 {
+		val, err := l.store.Get(prefix)
+		if err != nil {
+			return nil, loader.Errors.Wrap(err, "getting key value")
+		}
+		if val != nil {
+			return string(val.Value), nil
+		}
+		return nil, nil
+	}
+	res := make(map[string]interface{})
+	for _, p := range pairs {
+		val, err := l.getRecursive(p.Key)
+		if err != nil {
+			return res, err
+		}
+		put(res, strings.TrimPrefix(p.Key, prefix), val)
+	}
+	return res, nil
+}
