add config

config/default.go

@@ -0,0 +1,253 @@
+package config
+
+import (
+	"bytes"
+	"sync"
+	"time"
+
+	"github.com/micro/go-micro/config/loader"
+	"github.com/micro/go-micro/config/loader/memory"
+	"github.com/micro/go-micro/config/reader"
+	"github.com/micro/go-micro/config/reader/json"
+	"github.com/micro/go-micro/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 {
+	options := Options{
+		Loader: memory.NewLoader(),
+		Reader: json.NewReader(),
+	}
+
+	for _, o := range opts {
+		o(&options)
+	}
+
+	options.Loader.Load(options.Source...)
+	snap, _ := options.Loader.Snapshot()
+	vals, _ := options.Reader.Values(snap.ChangeSet)
+
+	c := &config{
+		exit: make(chan bool),
+		opts: options,
+		snap: snap,
+		vals: vals,
+	}
+
+	go c.run()
+
+	return c
+}
+
+func (c *config) run() {
+	watch := func(w loader.Watcher) error {
+		for {
+			// get changeset
+			snap, err := w.Next()
+			if err != nil {
+				return err
+			}
+
+			c.Lock()
+
+			// 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 {
+	c.RLock()
+	defer c.RUnlock()
+
+	// did sync actually work?
+	if c.vals != nil {
+		return c.vals.Get(path...)
+	}
+
+	// no value
+	return newValue()
+}
+
+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 := c.Get(path...)
+
+	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
+		}
+
+		w.value = v.Get()
+		return w.value, nil
+	}
+}
+
+func (w *watcher) Stop() error {
+	return w.lw.Stop()
+}