Add warnings for env_file entries not copied

As 'env_file' entries are not taken in account,
we warn the user to copy that and fix it's
compose file.

Signed-off-by: Ulysses Souza <ulysses.souza@docker.com>

internal/packager/init.go

@@ -122,6 +122,45 @@ func checkComposeFileVersion(compose map[string]interface{}) error {
 	return schema.Validate(compose, fmt.Sprintf("%v", version))
 }
 
+func getEnvFiles(svcName string, envFileEntry interface{}) []string {
+	var envFiles []string
+	switch envFileEntry.(type) {
+	case string:
+		envFiles = append(envFiles, envFileEntry.(string))
+	case []string:
+		envFiles = append(envFiles, envFileEntry.([]string)...)
+	case []interface{}:
+		for _, env := range envFileEntry.([]interface{}) {
+			envFiles = append(envFiles, env.(string))
+		}
+	default:
+		logrus.Warnf("unknown entries in 'env_file' for service %s -> %v\n",
+			svcName, envFileEntry)
+		return envFiles
+	}
+	return envFiles
+}
+
+func checkEnvFiles(cfgMap map[string]interface{}) {
+	services, ok := cfgMap["services"]
+	if !ok {
+		return
+	}
+	servicesMap := services.(map[string]interface{})
+	for svcName, svc := range servicesMap {
+		svcContent := svc.(map[string]interface{})
+		envFileEntry, ok := svcContent["env_file"]
+		if !ok {
+			return
+		}
+		for _, envFilePath := range getEnvFiles(svcName, envFileEntry) {
+			logrus.Warnf("\"env_file: %s\" entry of service %q will NOT be copied automatically! "+
+				"Please, copy the file inside the application folder and update your compose file"+
+				" referring to it.", envFilePath, svcName)
+		}
+	}
+}
+
 func initFromComposeFile(name string, composeFile string) error {
 	logrus.Debugf("Initializing from compose file %s", composeFile)
 
@@ -138,6 +177,7 @@ func initFromComposeFile(name string, composeFile string) error {
 	if err := checkComposeFileVersion(cfgMap); err != nil {
 		return err
 	}
+	checkEnvFiles(cfgMap)
 	params := make(map[string]string)
 	envs, err := opts.ParseEnvFile(filepath.Join(filepath.Dir(composeFile), ".env"))
 	if err == nil {