[enhancement] Enable validation of context variables in templates #175

Fixed the issue by removing uneccessary work which @okraits began by
doing after he extracted the gsoc2019 branch.

Fixes #175

.gitignore

@@ -62,3 +62,4 @@ target/
 local_settings.py
 *.db
 *.tar.gz
+Pipfile

.travis.yml

@@ -13,7 +13,6 @@ env:
 branches:
   only:
     - master
-    - gsoc2019
 
 before_install:
   - pip install -U pip wheel setuptools
@@ -27,9 +26,9 @@ install:
 
 script:
   - |
-      openwisp-utils-qa-checks \
-        --migration-path ./django_netjsonconfig/migrations/ \
-        --migration-module django_netjsonconfig
+    openwisp-utils-qa-checks \
+      --migration-path ./django_netjsonconfig/migrations/ \
+      --migration-module django_netjsonconfig
   - coverage run --source=django_netjsonconfig runtests.py
 
 after_success:

django_netjsonconfig/base/admin.py

@@ -347,6 +347,7 @@ class AbstractTemplateAdmin(BaseConfigAdmin):
               'vpn',
               'auto_cert',
               'tags',
+              'default_values',
               'default',
               'config',
               'created',

django_netjsonconfig/base/base.py

@@ -138,15 +138,21 @@ def get_backend_instance(self, template_instances=None):
         """
         backend = self.backend_class
         kwargs = {'config': self.get_config()}
+        context = {}
         # determine if we can pass templates
         # expecting a many2many relationship
         if hasattr(self, 'templates'):
             if template_instances is None:
                 template_instances = self.templates.all()
-            kwargs['templates'] = [t.config for t in template_instances]
+            templates_list = list()
+            for t in template_instances:
+                templates_list.append(t.config)
+                context.update(t.get_context())
+            kwargs['templates'] = templates_list
         # pass context to backend if get_context method is defined
         if hasattr(self, 'get_context'):
-            kwargs['context'] = self.get_context()
+            context.update(self.get_context())
+            kwargs['context'] = context
         backend_instance = backend(**kwargs)
         # remove accidentally duplicated files when combining config and templates
         # this may happen if a device uses multiple VPN client templates

django_netjsonconfig/base/template.py

@@ -1,10 +1,12 @@
+from collections import OrderedDict
 from copy import copy
 
 from django.contrib.admin.models import ADDITION, LogEntry
 from django.contrib.contenttypes.models import ContentType
 from django.core.exceptions import ValidationError
 from django.db import models
 from django.utils.translation import ugettext_lazy as _
+from jsonfield import JSONField
 from taggit.managers import TaggableManager
 
 from ..settings import DEFAULT_AUTO_CERT
@@ -57,6 +59,15 @@ class AbstractTemplate(BaseConfig):
                                                 'be automatically managed behind the scenes '
                                                 'for each configuration using this template, '
                                                 'valid only for the VPN type'))
+    default_values = JSONField(_('Default Values'),
+                               default=dict,
+                               blank=True,
+                               help_text=_('A dictionary containing the default '
+                                           'values for the variables used by this '
+                                           'template; these default variables will '
+                                           'be used during schema validation.'),
+                               load_kwargs={'object_pairs_hook': OrderedDict},
+                               dump_kwargs={'indent': 4})
     __template__ = True
 
     class Meta:
@@ -110,12 +121,9 @@ def clean(self, *args, **kwargs):
             self.config = self.vpn.auto_client(auto_cert=self.auto_cert)
 
     def get_context(self):
-        c = {
-            'id': str(self.id),
-            'name': self.name,
-        }
-        c.update(super().get_context())
-        return c
+        context = self.default_values or {}
+        context.update(super().get_context())
+        return context
 
     def clone(self, user):
         clone = copy(self)

django_netjsonconfig/migrations/0044_template_default_values.py

@@ -0,0 +1,20 @@
+# Generated by Django 3.0.6 on 2020-05-15 15:18
+
+import collections
+from django.db import migrations
+import jsonfield.fields
+
+
+class Migration(migrations.Migration):
+
+    dependencies = [
+        ('django_netjsonconfig', '0043_add_indexes_on_ip_fields'),
+    ]
+
+    operations = [
+        migrations.AddField(
+            model_name='template',
+            name='default_values',
+            field=jsonfield.fields.JSONField(blank=True, default=dict, dump_kwargs={'ensure_ascii': False, 'indent': 4}, help_text='A dictionary containing the default values for the variables used by this template; these default variables will be used during schema validation.', load_kwargs={'object_pairs_hook': collections.OrderedDict}, verbose_name='Default Values'),
+        ),
+    ]