add file change watch

registry/file/backend.go

@@ -1,30 +1,133 @@
 // Package file implements a simple file based registry
-// backend which reads the routes from a file once.
+// backend which reads the routes from a file.
+//file content like registry.static.routes = route add web-svc /test http://127.0.0.1:8082
+//registry.file.path = /home/zjj/fabio.txt
+//registry.file.noroutehtmlpath = /home/zjj/404.html
 package file
 
 import (
 	"io/ioutil"
 	"log"
+	"os"
+	"time"
 
 	"github.com/fabiolb/fabio/config"
 	"github.com/fabiolb/fabio/registry"
-	"github.com/fabiolb/fabio/registry/static"
+)
+
+type be struct {
+	cfg          *config.File
+	routeMtime   time.Time
+	norouteMtime time.Time
+	Routes       string
+	NoRouteHTML  string
+	Interval     time.Duration
+}
+
+var (
+	zero time.Time
 )
 
 func NewBackend(cfg *config.File) (registry.Backend, error) {
-	routes, err := ioutil.ReadFile(cfg.RoutesPath)
-	if err != nil {
-		log.Println("[ERROR] Cannot read routes from ", cfg.RoutesPath)
+	b := &be{cfg: cfg, Interval: 2 * time.Second}
+	if err := b.readRoute(); err != nil {
 		return nil, err
 	}
-	noroutehtml, err := ioutil.ReadFile(cfg.NoRouteHTMLPath)
-	if err != nil {
-		log.Println("[ERROR] Cannot read no route HTML from ", cfg.NoRouteHTMLPath)
+	if err := b.readNoRouteHtml(); err != nil {
 		return nil, err
 	}
-	staticCfg := &config.Static{
-		NoRouteHTML: string(noroutehtml),
-		Routes:      string(routes),
+	return b, nil
+}
+
+func (b *be) readRoute() error {
+	finfo, err := os.Stat(b.cfg.RoutesPath)
+	if err != nil {
+		log.Println("[ERROR] Cannot read routes stat from ", b.cfg.RoutesPath)
+		return err
+	}
+
+	if b.routeMtime == zero || b.routeMtime != finfo.ModTime() {
+		b.routeMtime = finfo.ModTime()
+		routes, err := ioutil.ReadFile(b.cfg.RoutesPath)
+		if err != nil {
+			log.Println("[ERROR] Cannot read routes from ", b.cfg.RoutesPath)
+			return err
+		}
+		b.Routes = string(routes)
+	}
+	return nil
+}
+
+func (b *be) readNoRouteHtml() error {
+	if b.cfg.NoRouteHTMLPath != "" {
+		finfo, err := os.Stat(b.cfg.NoRouteHTMLPath)
+		if err != nil {
+			log.Println("[ERROR] Cannot read no route HTML stat from ", b.cfg.NoRouteHTMLPath)
+			return err
+		}
+		if b.norouteMtime == zero || b.norouteMtime != finfo.ModTime() {
+			b.norouteMtime = finfo.ModTime()
+			noroutehtml, err := ioutil.ReadFile(b.cfg.NoRouteHTMLPath)
+			if err != nil {
+				log.Println("[ERROR] Cannot read no route HTML from ", b.cfg.NoRouteHTMLPath)
+				return err
+			}
+			b.NoRouteHTML = string(noroutehtml)
+		}
 	}
-	return static.NewBackend(staticCfg)
+	return nil
+}
+
+func (b *be) Register(services []string) error {
+	return nil
+}
+
+func (b *be) Deregister(serviceName string) error {
+	return nil
+}
+
+func (b *be) DeregisterAll() error {
+	return nil
+}
+
+func (b *be) ManualPaths() ([]string, error) {
+	return nil, nil
+}
+
+func (b *be) ReadManual(string) (value string, version uint64, err error) {
+	return "", 0, nil
+}
+
+func (b *be) WriteManual(path string, value string, version uint64) (ok bool, err error) {
+	return false, nil
+}
+
+func (b *be) WatchServices() chan string {
+	ch := make(chan string, 1)
+	ch <- b.Routes
+	go func() {
+		for {
+			b.readRoute()
+			ch <- b.Routes
+			time.Sleep(b.Interval)
+		}
+	}()
+	return ch
+}
+
+func (b *be) WatchManual() chan string {
+	return make(chan string)
+}
+
+func (b *be) WatchNoRouteHTML() chan string {
+	ch := make(chan string, 1)
+	ch <- b.NoRouteHTML
+	go func() {
+		for {
+			b.readNoRouteHtml()
+			ch <- b.NoRouteHTML
+			time.Sleep(b.Interval)
+		}
+	}()
+	return ch
 }