diff --git a/runner/logger.go b/runner/logger.go
index ae2f3b1..da075f8 100644
--- a/runner/logger.go
+++ b/runner/logger.go
@@ -4,6 +4,7 @@ import (
 	"fmt"
 	logPkg "log"
 	"time"
+	"strings"
 
 	"github.com/mattn/go-colorable"
 )
@@ -35,7 +36,7 @@ func fatal(err error) {
 type appLogWriter struct{}
 
 func (a appLogWriter) Write(p []byte) (n int, err error) {
-	appLog(string(p))
+	appLog(strings.Replace(string(p), "%", "%%", -1))
 
 	return len(p), nil
 }
diff --git a/runner/settings.go b/runner/settings.go
index 10117ec..3304e3f 100644
--- a/runner/settings.go
+++ b/runner/settings.go
@@ -20,6 +20,7 @@ const (
 var settings = map[string]string{
 	"config_path":       "./runner.conf",
 	"root":              ".",
+	"env":               ".env",
 	"tmp_path":          "./tmp",
 	"build_name":        "runner-build",
 	"build_log":         "runner-build-errors.log",
@@ -112,6 +113,10 @@ func root() string {
 	return settings["root"]
 }
 
+func envFile() string {
+	return settings["env"]
+}
+
 func tmpPath() string {
 	return settings["tmp_path"]
 }
diff --git a/runner/start.go b/runner/start.go
index e22923a..fab9fb4 100644
--- a/runner/start.go
+++ b/runner/start.go
@@ -6,6 +6,7 @@ import (
 	"runtime"
 	"strings"
 	"time"
+	"github.com/joho/godotenv"
 )
 
 var (
@@ -73,6 +74,7 @@ func start() {
 				}
 				run()
 			}
+			watch()
 
 			started = true
 			mainLog(strings.Repeat("-", 20))
@@ -94,6 +96,12 @@ func initLogFuncs() {
 }
 
 func setEnvVars() {
+	if _, err := os.Stat(envFile()); !os.IsNotExist(err) {
+                err := godotenv.Load(envFile())
+                if err != nil {
+                        fatal(err)
+                }
+        }
 	os.Setenv("DEV_RUNNER", "1")
 	wd, err := os.Getwd()
 	if err == nil {
@@ -113,8 +121,8 @@ func Start() {
 	initSettings()
 	initLogFuncs()
 	initFolders()
+	initWatcher()
 	setEnvVars()
-	watch()
 	start()
 	startChannel <- "/"
 
diff --git a/runner/watcher.go b/runner/watcher.go
index 1f3f1ac..96818ec 100644
--- a/runner/watcher.go
+++ b/runner/watcher.go
@@ -2,18 +2,60 @@ package runner
 
 import (
 	"os"
-	"path/filepath"
 	"strings"
-
+	"fmt"
 	"github.com/howeyc/fsnotify"
+	"io"
+	"io/ioutil"
+	"os/exec"
+	"runtime"
 )
 
-func watchFolder(path string) {
-	watcher, err := fsnotify.NewWatcher()
+var watchedFolders = map[string]struct{}{}
+var pkgName = ""
+var pkgPath = ""
+var goPaths = []string{}
+var watcher *fsnotify.Watcher
+
+func initWatcher() {
+	// parse running package name
+	separator := ":"
+	if runtime.GOOS == "windows" {
+		separator = ";"
+	}
+	goPaths = strings.Split(os.Getenv("GOPATH"), separator)
+	root := root()
+	dir, err := os.Getwd()
 	if err != nil {
 		fatal(err)
 	}
+	if root != "." {
+		pkgName = root
+		for _, gopath := range goPaths {
+			pkgPath = gopath + "/src/" + pkgName
+			e, err := exists(pkgPath)
+			if err != nil {
+				fatal(err)
+			}
+			if e {
+				break
+			}
+		}
+	} else {
+		for _, gopath := range goPaths {
+			if strings.HasPrefix(dir, gopath) && len(dir) > len(gopath)+5 {
+				pkgName = dir[len(gopath)+5:]
+				pkgPath = dir
+				break
+			}
+		}
+	}
 
+	// init watcher
+	watcher, err = fsnotify.NewWatcher()
+	if err != nil {
+		fatal(err)
+	}
 	go func() {
 		for {
 			select {
@@ -27,31 +69,90 @@ func watchFolder(path string) {
 			}
 		}
 	}()
+}
+
+// exists returns whether the given file or directory exists or not
+func exists(path string) (bool, error) {
+	_, err := os.Stat(path)
+	if err == nil {
+		return true, nil
+	}
+	if os.IsNotExist(err) {
+		return false, nil
+	}
+	return true, err
+}
 
-	watcherLog("Watching %s", path)
-	err = watcher.Watch(path)
+func getFolders() map[string]struct{} {
+	cmd := exec.Command("go", "list", "-f", `{{ join .Deps "\n" }}`, pkgName)
 
+	stderr, err := cmd.StderrPipe()
 	if err != nil {
 		fatal(err)
 	}
+
+	stdout, err := cmd.StdoutPipe()
+	if err != nil {
+		fatal(err)
+	}
+
+	err = cmd.Start()
+	if err != nil {
+		fatal(err)
+	}
+
+	imps, _ := ioutil.ReadAll(stdout)
+	io.Copy(os.Stderr, stderr)
+
+	err = cmd.Wait()
+	if err != nil {
+		fatal(err)
+	}
+
+	_imps := strings.Split(strings.Trim(string(imps), "\n"), "\n")
+	_watchedFolders := map[string]struct{}{pkgPath: struct{}{}}
+	for _, imp := range _imps {
+		for _, gopath := range goPaths {
+			path := fmt.Sprintf("%s/src/%s", gopath, imp)
+			e, err := exists(path)
+			if err != nil {
+				fatal(err)
+			}
+			if e {
+				_watchedFolders[path] = struct{}{}
+				break
+			}
+		}
+	}
+
+	return _watchedFolders
 }
 
 func watch() {
-	root := root()
-	filepath.Walk(root, func(path string, info os.FileInfo, err error) error {
-		if info.IsDir() && !isTmpDir(path) {
-			if len(path) > 1 && strings.HasPrefix(filepath.Base(path), ".") {
-				return filepath.SkipDir
+	_watchedFolders := getFolders()
+	for folder, _ := range watchedFolders {
+		_, ok := _watchedFolders[folder]
+		if !ok {
+			watcherLog("remove watch %s", folder)
+			err := watcher.RemoveWatch(folder)
+			if err != nil {
+				fatal(err)
 			}
-
-			if isIgnoredFolder(path) {
-				watcherLog("Ignoring %s", path)
-				return filepath.SkipDir
+		}
+	}
+	for folder, _ := range _watchedFolders {
+		_, ok := watchedFolders[folder]
+		if !ok && !isTmpDir(folder) {
+			if isIgnoredFolder(folder) {
+				watcherLog("Ignoring %s", folder)
+				continue
+			}
+			watcherLog("add watch %s", folder)
+			err := watcher.Watch(folder)
+			if err != nil {
+				fatal(err)
 			}
-
-			watchFolder(path)
 		}
-
-		return err
-	})
+	}
+	watchedFolders = _watchedFolders
 }