json_db.py: Adds JSON databasing support to layman

2 files changed, 144 insertions, 0 deletions

diff --git a/layman/db_modules/json_db/__init__.py b/layman/db_modules/json_db/__init__.py
new file mode 100644
index 0000000..e095f4f
--- /dev/null
+++ b/layman/db_modules/json_db/__init__.py
@@ -0,0 +1,24 @@
+# Copyright 2015 Gentoo Foundation
+# Distributed under the terms of the GNU General Public License v2
+
+'''
+JSON database plug-in module for layman.
+'''
+
+module_spec = {
+    'name': 'json_db',
+    'description': __doc__,
+    'provides':{
+        'json-module': {
+            'name': 'json_db',
+            'class': 'DBHandler',
+            'description': __doc__,
+            'functions': ['add_new', 'read_db', 'write'],
+            'func_desc': {
+                'add_new': 'Adds overlay from provided document text',
+                'read_db': 'Reads the list of overlays from database file',
+                'write': 'Writes the list of overlays to database file',
+            },
+        }
+    }
+}
diff --git a/layman/db_modules/json_db/json_db.py b/layman/db_modules/json_db/json_db.py
new file mode 100644
index 0000000..47413c6
--- /dev/null
+++ b/layman/db_modules/json_db/json_db.py
@@ -0,0 +1,120 @@
+#!/usr/bin/python
+# -*- coding: utf-8 -*-
+#################################################################################
+# LAYMAN JSON DB
+#################################################################################
+# File:       json_db.py
+#
+#             Access JSON overlay database(s).
+#
+# Copyright:
+#             (c) 2015        Devan Franchini
+#             Distributed under the terms of the GNU General Public License v2
+#
+# Author(s):
+#             Devan Franchini <twitch153@gentoo.org>
+#
+'''Handler for json overlay databases.'''
+
+from __future__ import unicode_literals
+
+__version__ = "$Id: json.py 273 2015-07-10 10:10:49Z twitch153 $"
+
+#===============================================================================
+#
+# Dependencies
+#
+#-------------------------------------------------------------------------------
+
+import json
+import sys
+
+from   layman.compatibility      import fileopen
+from   layman.overlays.overlay   import Overlay
+
+
+#py3.2+
+if sys.hexversion >= 0x30200f0:
+    _UNICODE = 'unicode'
+else:
+    _UNICODE = 'UTF-8'
+
+
+
+#===============================================================================
+#
+# Class DBHandler
+#
+#-------------------------------------------------------------------------------
+
+class DBHandler(object):
+    '''
+    Handle a json overlay database.
+    '''
+
+    def __init__(self, config, overlays, paths=None, ignore=0,
+                 ignore_init_read_errors=False):
+
+        self.config = config
+        self.ignore = ignore
+        self.overlays = overlays
+        self.paths = paths
+        self.output = config['output']
+        self.ignore_init_read_errors = ignore_init_read_errors
+
+        self.output.debug('Initializing JSON overlay list handler', 8)
+
+
+    def read_db(self, path, text=None):
+        '''
+        Read the overlay definition file.
+        '''
+        document = text
+
+        if not document:
+            try:
+                with fileopen(path, 'r') as df:
+                    document = df.read()
+            except Exception as error:
+                if not self.ignore_init_read_errors:
+                    msg = 'JSON DBHandler - Failed to read the overlay list at'\
+                      '("%(path)s")' % {'path': path}
+                self.output.error(msg)
+                raise error
+
+        self.add_new(document, origin=path)
+
+
+    def add_new(self, document=None, origin=None):
+        '''
+        Reads in provided json text and generates overlays to populate database.
+        '''
+        if not document:
+            msg = 'JSON DBHandler - add_new() failed: JSON text cannot be none'\
+                  '.\nOrigin: %(path)s' % {'path': origin}
+            self.output.warn(msg)
+            return False
+
+        load = json.loads(document)['repo']
+
+        for ovl in load:
+            overlay = Overlay(self.config, json=ovl, ignore=self.ignore)
+            self.overlays[overlay.name] = overlay
+
+        return True
+
+
+    def write(self, path):
+        '''
+        Write the list of overlays to a file.
+        '''
+        try:
+            repo = {'@encoding': 'unicode', '@version': '1.0', 'repo': []}
+            repo['repo'] = [self.overlays[key].to_json() for key in self.overlays]
+            with fileopen(path, 'w') as df:
+                df.write(json.dumps(repo, sort_keys=True, indent=2))
+        except Exception as err:
+            msg = 'Failed to write to local overlays file: %(path)s\nError was'\
+                  ': %(err)s' % {'path': path, 'err': err}
+            self.output.error(msg)
+            raise err