Task #8899: Added dbcredentials module to marshall database credentials from configuration files.

LCS/PyCommon/CMakeLists.txt

@@ -8,6 +8,7 @@ include(PythonInstall)
 #add_subdirectory(test)
 
 set(_py_files
+  dbcredentials.py
   factory.py
   util.py
   datetimeutils.py)

LCS/PyCommon/dbcredentials.py

+#!/usr/bin/python
+
+# Copyright (C) 2012-2015    ASTRON (Netherlands Institute for Radio Astronomy)
+# P.O. Box 2, 7990 AA Dwingeloo, The Netherlands
+#
+# This file is part of the LOFAR software suite.
+# The LOFAR software suite is free software: you can redistribute it and/or
+# modify it under the terms of the GNU General Public License as published
+# by the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# The LOFAR software suite 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with the LOFAR software suite. If not, see <http://www.gnu.org/licenses/>.
+
+# $Id$
+
+from glob import glob
+from os import environ
+from ConfigParser import SafeConfigParser, NoSectionError, DuplicateSectionError
+
+__all__ = ["DBCredentials"]
+
+def findfiles(pattern):
+  """ Returns a list of files matched by `pattern'.
+      The pattern can include environment variables using the
+      {VAR} notation.
+  """
+  try:
+    return glob(pattern.format(**environ))
+  except KeyError:
+    return []
+
+class DBCredentials:
+  defaults = {
+    # Flavour of database (postgres, mysql, oracle, sqlite)
+    "type": "postgres",
+
+    # Connection information
+    "host": "localhost",
+    "port": "",
+
+    # Authentication
+    "user": "{USER}".format(**environ),
+    "password": "",
+
+    # Database selection
+    "database": "",
+  }
+
+  def __init__(self, filepatterns=None):
+    """
+      Read database credentials from all configuration files matched by any of the patterns 
+    """
+    if filepatterns is None:
+      filepatterns = [
+        "{LOFARROOT}/etc/dbcredentials/*.ini",
+        "{HOME}/.lofar/dbcredentials/*.ini",
+        ]
+
+    self.config = SafeConfigParser(defaults=self.defaults)
+
+    self.files = sum([findfiles(p) for p in filepatterns],[])
+    self.config.read(self.files)
+
+
+  def get(self, database):
+    """
+      Return credentials for a given database.
+    """
+    try:
+      return dict(self.config.items(self._section(database)))
+    except NoSectionError:
+      return self.config.defaults()
+
+
+  def set(self, database, credentials):
+    """
+      Add or overwrite credentials for a given database.
+    """
+    section = self._section(database)
+
+    # create section if needed
+    try:
+      self.config.add_section(section)
+    except DuplicateSectionError:
+      pass
+
+    # set or override credentials
+    for k,v in credentials.iteritems():
+      self.config.set(section, k, v)
+
+
+  def list(self):
+    """
+      Return a list of databases for which credentials are available.
+    """
+    sections = self.config.sections()
+    return [s[9:] for s in sections if s.startsWith("database:")]
+
+
+  def _section(self, database):
+    return "database:%s" % (database,)
+
+if __name__ == "__main__":
+  import sys
+  from optparse import OptionParser
+
+  parser = OptionParser("%prog [options]")
+  parser.add_option("-D", "--database", dest="database", type="string", default="",
+                    help="Name of the database")
+  parser.add_option("-L", "--list", dest="list", action="store_true", default=False,
+                    help="List known databases")
+  parser.add_option("-F", "--files", dest="files", action="store_true", default=False,
+                    help="List names of parsed configuration files")
+  (options, args) = parser.parse_args()
+
+  if not options.database and not options.list and not options.files:
+    print "Missing database name"
+    parser.print_help()
+    sys.exit(1)
+
+  dbc = DBCredentials()
+
+  if options.files:
+    """ Print list of configuration files that we've read. """
+    if dbc.files:
+      print "\n".join(dbc.files)
+    sys.exit(0)
+
+  if options.list:
+    """ Print list of databases. """
+    databases = dbc.list()
+    if databases:
+      print "\n".join(databases)
+    sys.exit(0)
+
+  """ Print credentials of a specific database. """
+  print "\n".join(["%s %s" % (k,v) for k,v in dbc.get(options.database).iteritems()])
+