From 19375c42643b2c5ca2c494c760d7cc7887b95608 Mon Sep 17 00:00:00 2001
From: Edoardo Putti <edoardo.putti@gmail.com>
Date: Fri, 20 Jul 2018 12:24:34 +0200
Subject: [PATCH] draft for loading external converters, references #112

---
 netjsonconfig/backends/base/backend.py    | 16 ++++++++++++++++
 netjsonconfig/backends/openvpn/openvpn.py |  2 +-
 netjsonconfig/backends/openwrt/openwrt.py |  2 +-
 3 files changed, 18 insertions(+), 2 deletions(-)

diff --git a/netjsonconfig/backends/base/backend.py b/netjsonconfig/backends/base/backend.py
index 892c67cba..cbf120c51 100644
--- a/netjsonconfig/backends/base/backend.py
+++ b/netjsonconfig/backends/base/backend.py
@@ -4,6 +4,7 @@
 from collections import OrderedDict
 from copy import deepcopy
 from io import BytesIO
+from pkg_resources import iter_entry_points
 
 import six
 from jsonschema import FormatChecker, validate
@@ -21,6 +22,7 @@ class BaseBackend(object):
     schema = None
     FILE_SECTION_DELIMITER = '# ---------- files ---------- #'
     list_identifiers = []
+    _converters = []
 
     def __init__(self, config=None, native=None, templates=None, context=None):
         """
@@ -49,6 +51,20 @@ def __init__(self, config=None, native=None, templates=None, context=None):
             raise ValueError('Expecting either config or native argument to be '
                              'passed during the initialization of the backend')
 
+    @property
+    def converters(self):
+        converters = []
+        entry_key = 'netjsonconfig.{}.converter'.format(self.__class__.__name__)
+        for entry_point in iter_entry_points(entry_key):
+            try:
+                converters.append(entry_point.load())
+            except ImportError as e:  # noqa
+                # TODO: some error handling here
+                continue
+
+        return self._converters + converters
+
+
     def _load(self, config):
         """
         Loads config from string or dict
diff --git a/netjsonconfig/backends/openvpn/openvpn.py b/netjsonconfig/backends/openvpn/openvpn.py
index 4145ce5e9..46a1b9b6e 100644
--- a/netjsonconfig/backends/openvpn/openvpn.py
+++ b/netjsonconfig/backends/openvpn/openvpn.py
@@ -11,7 +11,7 @@ class OpenVpn(BaseBackend):
     OpenVPN 2.x Configuration Backend
     """
     schema = schema
-    converters = [converters.OpenVpn]
+    _converters = [converters.OpenVpn]
     parser = OpenVpnParser
     renderer = OpenVpnRenderer
     list_identifiers = ['name']
diff --git a/netjsonconfig/backends/openwrt/openwrt.py b/netjsonconfig/backends/openwrt/openwrt.py
index 0d18d91ff..01e66e798 100644
--- a/netjsonconfig/backends/openwrt/openwrt.py
+++ b/netjsonconfig/backends/openwrt/openwrt.py
@@ -10,7 +10,7 @@ class OpenWrt(BaseBackend):
     OpenWRT / LEDE Configuration Backend
     """
     schema = schema
-    converters = [
+    _converters = [
         converters.General,
         converters.Ntp,
         converters.Led,