diff --git a/auth/jwt_auth.go b/auth/jwt_auth.go
index 2d059f0..6fcbbc5 100644
--- a/auth/jwt_auth.go
+++ b/auth/jwt_auth.go
@@ -14,12 +14,9 @@ import (
 )
 
 // GetSignedJwtToken get a tokens signed with private key
-func GetSignedJwtToken(appID string, privateKeyPath string) (string, error) {
+func GetSignedJwtToken(appID string, privateKey string) (string, error) {
 
-	keyBytes, err := ioutil.ReadFile(privateKeyPath)
-	if err != nil {
-		return "", fmt.Errorf("unable to read private key path: %s, error: %s", privateKeyPath, err)
-	}
+	keyBytes := []byte(privateKey)
 
 	key, keyErr := jwt.ParseRSAPrivateKeyFromPEM(keyBytes)
 	if keyErr != nil {
@@ -50,8 +47,8 @@ type JWTAuth struct {
 }
 
 // MakeAccessTokenForInstallation makes an access token for an installation / private key
-func MakeAccessTokenForInstallation(appID string, installation int, privateKeyPath string) (string, error) {
-	signed, err := GetSignedJwtToken(appID, privateKeyPath)
+func MakeAccessTokenForInstallation(appID string, installation int, privateKey string) (string, error) {
+	signed, err := GetSignedJwtToken(appID, privateKey)
 
 	if err == nil {
 		c := http.Client{}
diff --git a/config/config.go b/config/config.go
index c781abe..76ae1e5 100644
--- a/config/config.go
+++ b/config/config.go
@@ -54,8 +54,13 @@ func NewConfig() (Config, error) {
 
 	if val, ok := os.LookupEnv("application_id"); ok && len(val) > 0 {
 		config.ApplicationID = val
+	} else {
+		return config, fmt.Errorf("application_id must be given")
 	}
 
+	// debug, _ := json.Marshal(config)
+	// fmt.Printf("Config:\n%s\n", debug)
+
 	return config, nil
 }
 
diff --git a/derek.yml b/derek.yml
index fb47008..125607f 100644
--- a/derek.yml
+++ b/derek.yml
@@ -5,7 +5,7 @@ provider:
 functions:
   derek:
     handler: ./
-    image: alexellis/derek:0.6.3-rc1
+    image: alexellis/derek:0.6.3-rc2
     lang: dockerfile
     environment:
       debug: true