Use Django models to store variables

- Remove dependency on withsqlite and use Django models.
  This avoids depending on a module that is not available in PyPi.
  Withsqlite does not have Python3 support. It does not work when
  we choose a different database backend. Atleast partly duplicates
  what Django models are meant for.

- Check and update database schema on every run so that
  newly added modules can add tables and old ones can update.

data/etc/plinth/plinth.config

@@ -13,7 +13,7 @@ actions_dir = /usr/share/plinth/actions
 doc_dir = /usr/share/doc/plinth
 
 # file locations
-store_file = %(data_dir)s/store.sqlite3
+store_file = %(data_dir)s/plinth.sqlite3
 status_log_file = %(log_dir)s/status.log
 access_log_file = %(log_dir)s/access.log
 pidfile = %(pid_dir)s/plinth.pid

plinth.config

@@ -13,7 +13,7 @@ actions_dir = %(file_root)s/actions
 doc_dir = %(file_root)s/doc
 
 # file locations
-store_file = %(data_dir)s/store.sqlite3
+store_file = %(data_dir)s/plinth.sqlite3
 status_log_file = %(log_dir)s/status.log
 access_log_file = %(log_dir)s/access.log
 pidfile = %(pid_dir)s/plinth.pid

plinth/__main__.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python
+#!/usr/bin/python
 
 import argparse
 import django.conf
@@ -160,8 +160,6 @@ def configure_django():
             }
         }
 
-    data_file = os.path.join(cfg.data_dir, 'plinth.sqlite3')
-
     template_directories = module_loader.get_template_directories()
     sessions_directory = os.path.join(cfg.data_dir, 'sessions')
     django.conf.settings.configure(
@@ -170,12 +168,13 @@ def configure_django():
                 {'BACKEND': 'django.core.cache.backends.dummy.DummyCache'}},
         DATABASES={'default':
                    {'ENGINE': 'django.db.backends.sqlite3',
-                    'NAME': data_file}},
+                    'NAME': cfg.store_file}},
         DEBUG=cfg.debug,
         INSTALLED_APPS=['bootstrapform',
                         'django.contrib.auth',
                         'django.contrib.contenttypes',
-                        'django.contrib.messages'],
+                        'django.contrib.messages',
+                        'plinth'],
         LOGGING=logging_configuration,
         LOGIN_URL='lib:login',
         LOGIN_REDIRECT_URL='apps:index',
@@ -199,10 +198,9 @@ def configure_django():
     LOGGER.info('Configured Django')
     LOGGER.info('Template directories - %s', template_directories)
 
-    if not os.path.isfile(data_file):
-        LOGGER.info('Creating and initializing data file')
-        django.core.management.call_command('syncdb', interactive=False)
-        os.chmod(data_file, stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP)
+    LOGGER.info('Creating or adding new tables to data file')
+    django.core.management.call_command('syncdb', interactive=False)
+    os.chmod(cfg.store_file, stat.S_IRUSR | stat.S_IWUSR | stat.S_IRGRP)
 
 
 def main():

plinth/cfg.py

@@ -70,7 +70,3 @@ def read():
 
     global port  # pylint: disable-msg=W0603
     port = int(port)
-
-    global store_file  # pylint: disable-msg=W0603
-    if store_file.endswith(".sqlite3"):
-        store_file = os.path.splitext(store_file)[0]

plinth/kvstore.py

@@ -0,0 +1,42 @@
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Simple key/value store using Django models
+"""
+
+from plinth.models import KVStore
+
+
+def get(key):
+    """Return the value of a key"""
+    # pylint: disable-msg=E1101
+    return KVStore.objects.get(pk=key).value
+
+
+def get_default(key, default_value):
+    """Return the value of the key if key exists else return default_value"""
+    try:
+        return get(key)
+    except Exception:
+        return default_value
+
+
+def set(key, value):  # pylint: disable-msg=W0622
+    """Store the value of a key"""
+    store = KVStore(key=key, value=value)
+    store.save()

plinth/models.py

@@ -0,0 +1,39 @@
+#
+# This file is part of Plinth.
+#
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as
+# published by the Free Software Foundation, either version 3 of the
+# License, or (at your option) any later version.
+#
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+#
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <http://www.gnu.org/licenses/>.
+#
+
+"""
+Django models for the main application
+"""
+
+from django.db import models
+import json
+
+
+class KVStore(models.Model):
+    """Model to store retrieve key/value configuration"""
+    key = models.TextField(primary_key=True)
+    value_json = models.TextField()
+
+    @property
+    def value(self):
+        """Return the JSON decoded value of the key/value pair"""
+        return json.loads(self.value_json)
+
+    @value.setter
+    def value(self, val):
+        """Store the value of the key/value pair by JSON encoding it"""
+        self.value_json = json.dumps(val)

plinth/modules/first_boot/first_boot.py

@@ -26,10 +26,9 @@ from django.http.response import HttpResponseRedirect
 from django.template.response import TemplateResponse
 from gettext import gettext as _
 
-from plinth import cfg
 from plinth.modules.config import config
 from plinth.modules.lib.auth import add_user
-from withsqlite.withsqlite import sqlite_db
+from plinth import kvstore
 
 
 ## TODO: flesh out these tests values
@@ -94,7 +93,7 @@ def state0(request):
     user. It's a good place to put error messages.
     """
     try:
-        if _read_state() >= 5:
+        if kvstore.get_default('firstboot_state', 0) >= 5:
             return HttpResponseRedirect(reverse('index'))
     except KeyError:
         pass
@@ -112,7 +111,7 @@ def state0(request):
 
             if success:
                 # Everything is good, permanently mark and move to page 2
-                _write_state(1)
+                kvstore.set('firstboot_state', 1)
                 return HttpResponseRedirect(reverse('first_boot:state1'))
     else:
         form = State0Form(initial=status, prefix='firstboot')
@@ -124,35 +123,29 @@ def state0(request):
 
 def get_state0():
     """Return the state for form state 0"""
-    with sqlite_db(cfg.store_file, table="thisbox", autocommit=True) as \
-            database:
-        return {'hostname': config.get_hostname(),
-                'box_key': database.get('box_key', None)}
+    return {'hostname': config.get_hostname(),
+            'box_key': kvstore.get_default('box_key', None)}
 
 
 def _apply_state0(request, old_state, new_state):
     """Apply changes in state 0 form"""
     success = True
-    with sqlite_db(cfg.store_file, table="thisbox", autocommit=True) as \
-            database:
-        database['about'] = 'Information about this FreedomBox'
 
-        if new_state['box_key']:
-            database['box_key'] = new_state['box_key']
-        elif not old_state['box_key']:
-            database['box_key'] = generate_box_key()
+    if new_state['box_key']:
+        kvstore.set('box_key', new_state['box_key'])
+    elif not old_state['box_key']:
+        kvstore.set('box_key', generate_box_key())
 
-        if old_state['hostname'] != new_state['hostname']:
-            config.set_hostname(new_state['hostname'])
+    if old_state['hostname'] != new_state['hostname']:
+        config.set_hostname(new_state['hostname'])
 
-        error = add_user(new_state['username'], new_state['password'],
-                         'First user, please change', '', True)
-        if error:
-            messages.error(
-                request, _('User account creation failed: %s') % error)
-            success = False
-        else:
-            messages.success(request, _('User account created'))
+    error = add_user(new_state['username'], new_state['password'],
+                     'First user, please change', '', True)
+    if error:
+        messages.error(request, _('User account creation failed: %s') % error)
+        success = False
+    else:
+        messages.success(request, _('User account created'))
 
     return success
 
@@ -168,21 +161,7 @@ def state1(request):
     """
     # TODO complete first_boot handling
     # Make sure the user is not stuck on a dead end for now.
-    _write_state(5)
+    kvstore.set('firstboot_state', 5)
 
     return TemplateResponse(request, 'firstboot_state1.html',
                             {'title': _('Installing the Certificate')})
-
-
-def _read_state():
-    """Read the current state from database"""
-    with sqlite_db(cfg.store_file, table='firstboot',
-                   autocommit=True) as database:
-        return database['state']
-
-
-def _write_state(state):
-    """Write state to database"""
-    with sqlite_db(cfg.store_file, table='firstboot',
-                   autocommit=True) as database:
-        database['state'] = state

plinth/modules/first_boot/middleware.py

@@ -24,8 +24,7 @@ from django.core.urlresolvers import reverse
 from django.http.response import HttpResponseRedirect
 import logging
 
-from plinth import cfg
-from withsqlite.withsqlite import sqlite_db
+from plinth import kvstore
 
 
 LOGGER = logging.getLogger(__name__)
@@ -42,14 +41,13 @@ class FirstBootMiddleware(object):
         if request.path.startswith(reverse('first_boot:index')):
             return
 
-        with sqlite_db(cfg.store_file, table='firstboot') as database:
-            if 'state' not in database:
-                # Permanent redirect causes the browser to cache the redirect,
-                # preventing the user from navigating to /plinth until the
-                # browser is restarted.
-                return HttpResponseRedirect(reverse('first_boot:index'))
+        state = kvstore.get_default('firstboot_state', 0)
+        if not state:
+            # Permanent redirect causes the browser to cache the redirect,
+            # preventing the user from navigating to /plinth until the
+            # browser is restarted.
+            return HttpResponseRedirect(reverse('first_boot:index'))
 
-            if database['state'] < 5:
-                LOGGER.info('First boot state - %d', database['state'])
-                return HttpResponseRedirect(reverse('first_boot:state%d' %
-                                                    database['state']))
+        if state < 5:
+            LOGGER.info('First boot state - %d', state)
+            return HttpResponseRedirect(reverse('first_boot:state%d' % state))