[utils][commands] Add command to change databases root path

The file in parameter follows the same logic as with the
install command.

beat/web/utils/management/commands/change_databases_root_folder.py

+#!/usr/bin/env python
+# vim: set fileencoding=utf-8 :
+
+###############################################################################
+#                                                                             #
+# Copyright (c) 2018 Idiap Research Institute, http://www.idiap.ch/           #
+# Contact: beat.support@idiap.ch                                              #
+#                                                                             #
+# This file is part of the beat.web module of the BEAT platform.              #
+#                                                                             #
+# Commercial License Usage                                                    #
+# Licensees holding valid commercial BEAT licenses may use this file in       #
+# accordance with the terms contained in a written agreement between you      #
+# and Idiap. For further information contact tto@idiap.ch                     #
+#                                                                             #
+# Alternatively, this file may be used under the terms of the GNU Affero      #
+# Public License version 3 as published by the Free Software and appearing    #
+# in the file LICENSE.AGPL included in the packaging of this file.            #
+# The BEAT platform 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.                                        #
+#                                                                             #
+# You should have received a copy of the GNU Affero Public License along      #
+# with the BEAT platform. If not, see http://www.gnu.org/licenses/.           #
+#                                                                             #
+###############################################################################
+
+
+"""
+Examples:
+
+  To change the root path of installed databases:
+
+    $ manage.py change_databases_root_folder -v1 db_root_paths.json
+
+  Note: The format is::
+
+    {
+      "atnt/1": "/remote/databases/atnt",
+      "banca/2": "file:///remote/databases/banca"
+      "foo/3": "nfs://myhost.db/databases/foo"
+    }
+
+  It's also possible to do a dry-run to just determine what would be installed
+  using the option ``--dry-run``::
+
+      $ manage.py update_installed_databases -v1 --dry-run
+"""
+
+import os
+import sys
+import logging
+
+from django.core.management.base import BaseCommand
+from django.conf import settings
+
+from beat.web.databases.models import Database
+
+from .install import load_database_folders
+
+
+logger = logging.getLogger(__name__)
+
+
+class Command(BaseCommand):
+
+    help = 'Change the root path of the databases listed in the given conf file'
+
+
+    def add_arguments(self, parser):
+
+        from argparse import RawDescriptionHelpFormatter
+        parser.epilog = __doc__
+        parser.formatter_class = RawDescriptionHelpFormatter
+
+
+        parser.add_argument('database_root_file', type=str,
+                            help='The JSON file containing ' \
+                            'the root directories of the databases installed ' \
+                            'on the platform.')
+
+        parser.add_argument('--dry-run', '-d', action='store_true',
+                            dest='dry_run', default=False, help='Set this flag to ' \
+                            'simulate a run.')
+
+
+    def handle(self, *ignored, **arguments):
+        # Setup this command's logging level
+        global logger
+        arguments['verbosity'] = int(arguments['verbosity'])
+        if arguments['verbosity'] >= 1:
+            if arguments['verbosity'] == 1:
+                logger.setLevel(logging.INFO)
+            elif arguments['verbosity'] >= 2:
+                logger.setLevel(logging.DEBUG)
+
+        dry_run = arguments['dry_run']
+
+        # Reads database root file, if provided
+        db_root_file = arguments['database_root_file']
+        db_root = load_database_folders(db_root_file)
+
+        for db, path in db_root.items():
+            name, version = db.split('/')
+            try:
+                database = Database.objects.get(name=name, version=int(version))
+            except Database.DoesNotExist:
+                logger.error("Failed to find %s", db)
+            else:
+                if dry_run:
+                    logger.info("Would change %s for %s" %(database.declaration['root_folder'],
+                                                           path))
+                else:
+                    logger.info("Changing %s path for %s" %(db, path))
+                    declaration = database.declaration
+                    declaration['root_folder'] = path
+                    database.declaration = declaration
+                    database.save()