config package rework (#9)

* change config interface
* reuse codec
* allow to modify next config based on values in current config via BeforeLoad

Signed-off-by: Vasiliy Tolstov <v.tolstov@unistack.org>

config/default.go

@@ -1,294 +0,0 @@
-package config
-
-import (
-	"bytes"
-	"fmt"
-	"sync"
-	"time"
-
-	"github.com/unistack-org/micro/v3/config/loader"
-	"github.com/unistack-org/micro/v3/config/reader"
-	"github.com/unistack-org/micro/v3/config/source"
-)
-
-type config struct {
-	exit chan bool
-	opts Options
-
-	sync.RWMutex
-	// the current snapshot
-	snap *loader.Snapshot
-	// the current values
-	vals reader.Values
-}
-
-type watcher struct {
-	lw    loader.Watcher
-	rd    reader.Reader
-	path  []string
-	value reader.Value
-}
-
-func newConfig(opts ...Option) (Config, error) {
-	var c config
-
-	if err := c.Init(opts...); err != nil {
-		return nil, err
-	}
-
-	go c.run()
-	return &c, nil
-}
-
-func (c *config) Init(opts ...Option) error {
-	c.opts = Options{}
-	c.exit = make(chan bool)
-	for _, o := range opts {
-		o(&c.opts)
-	}
-
-	err := c.opts.Loader.Load(c.opts.Source...)
-	if err != nil {
-		return err
-	}
-
-	c.snap, err = c.opts.Loader.Snapshot()
-	if err != nil {
-		return err
-	}
-
-	c.vals, err = c.opts.Reader.Values(c.snap.ChangeSet)
-	if err != nil {
-		return err
-	}
-
-	return nil
-}
-
-func (c *config) Options() Options {
-	return c.opts
-}
-
-func (c *config) run() {
-	watch := func(w loader.Watcher) error {
-		for {
-			// get changeset
-			snap, err := w.Next()
-			if err != nil {
-				return err
-			}
-
-			c.Lock()
-
-			if c.snap != nil && c.snap.Version >= snap.Version {
-				c.Unlock()
-				continue
-			}
-
-			// save
-			c.snap = snap
-
-			// set values
-			c.vals, _ = c.opts.Reader.Values(snap.ChangeSet)
-
-			c.Unlock()
-		}
-	}
-
-	for {
-		w, err := c.opts.Loader.Watch()
-		if err != nil {
-			time.Sleep(time.Second)
-			continue
-		}
-
-		done := make(chan bool)
-
-		// the stop watch func
-		go func() {
-			select {
-			case <-done:
-			case <-c.exit:
-			}
-			w.Stop()
-		}()
-
-		// block watch
-		if err := watch(w); err != nil {
-			// do something better
-			time.Sleep(time.Second)
-		}
-
-		// close done chan
-		close(done)
-
-		// if the config is closed exit
-		select {
-		case <-c.exit:
-			return
-		default:
-		}
-	}
-}
-
-func (c *config) Map() map[string]interface{} {
-	c.RLock()
-	defer c.RUnlock()
-	return c.vals.Map()
-}
-
-func (c *config) Scan(v interface{}) error {
-	c.RLock()
-	defer c.RUnlock()
-	return c.vals.Scan(v)
-}
-
-// sync loads all the sources, calls the parser and updates the config
-func (c *config) Sync() error {
-	if err := c.opts.Loader.Sync(); err != nil {
-		return err
-	}
-
-	snap, err := c.opts.Loader.Snapshot()
-	if err != nil {
-		return err
-	}
-
-	c.Lock()
-	defer c.Unlock()
-
-	c.snap = snap
-	vals, err := c.opts.Reader.Values(snap.ChangeSet)
-	if err != nil {
-		return err
-	}
-	c.vals = vals
-
-	return nil
-}
-
-func (c *config) Close() error {
-	select {
-	case <-c.exit:
-		return nil
-	default:
-		close(c.exit)
-	}
-	return nil
-}
-
-func (c *config) Get(path ...string) (reader.Value, error) {
-	c.RLock()
-	defer c.RUnlock()
-
-	// did sync actually work?
-	if c.vals != nil {
-		return c.vals.Get(path...)
-	}
-
-	// no value
-	return nil, fmt.Errorf("no value")
-}
-
-func (c *config) Set(val interface{}, path ...string) error {
-	c.Lock()
-	defer c.Unlock()
-
-	if c.vals != nil {
-		c.vals.Set(val, path...)
-	}
-	return nil
-}
-
-func (c *config) Del(path ...string) error {
-	c.Lock()
-	defer c.Unlock()
-
-	if c.vals != nil {
-		c.vals.Del(path...)
-	}
-
-	return nil
-}
-
-func (c *config) Bytes() []byte {
-	c.RLock()
-	defer c.RUnlock()
-
-	if c.vals == nil {
-		return []byte{}
-	}
-
-	return c.vals.Bytes()
-}
-
-func (c *config) Load(sources ...source.Source) error {
-	if err := c.opts.Loader.Load(sources...); err != nil {
-		return err
-	}
-
-	snap, err := c.opts.Loader.Snapshot()
-	if err != nil {
-		return err
-	}
-
-	c.Lock()
-	defer c.Unlock()
-
-	c.snap = snap
-	vals, err := c.opts.Reader.Values(snap.ChangeSet)
-	if err != nil {
-		return err
-	}
-	c.vals = vals
-
-	return nil
-}
-
-func (c *config) Watch(path ...string) (Watcher, error) {
-	value, err := c.Get(path...)
-	if err != nil {
-		return nil, err
-	}
-
-	w, err := c.opts.Loader.Watch(path...)
-	if err != nil {
-		return nil, err
-	}
-
-	return &watcher{
-		lw:    w,
-		rd:    c.opts.Reader,
-		path:  path,
-		value: value,
-	}, nil
-}
-
-func (c *config) String() string {
-	return "config"
-}
-
-func (w *watcher) Next() (reader.Value, error) {
-	for {
-		s, err := w.lw.Next()
-		if err != nil {
-			return nil, err
-		}
-
-		// only process changes
-		if bytes.Equal(w.value.Bytes(), s.ChangeSet.Data) {
-			continue
-		}
-
-		v, err := w.rd.Values(s.ChangeSet)
-		if err != nil {
-			return nil, err
-		}
-
-		return v.Get()
-	}
-}
-
-func (w *watcher) Stop() error {
-	return w.lw.Stop()
-}