Merge from trunk

[plcapi.git] / trunk / PLC / Config.py

diff --git a/trunk/PLC/Config.py b/trunk/PLC/Config.py
new file mode 100644 (file)
index 0000000..6a4a7e2
--- /dev/null
+++ b/trunk/PLC/Config.py
@@ -0,0 +1,96 @@
+#!/usr/bin/python
+#
+# PLCAPI configuration store. Supports XML-based configuration file
+# format exported by MyPLC.
+#
+# Mark Huang <mlhuang@cs.princeton.edu>
+# Copyright (C) 2004-2006 The Trustees of Princeton University
+#
+# $Id$
+#
+
+import os
+import sys
+
+from PLC.Faults import *
+from PLC.Debug import profile
+
+# If we have been checked out into a directory at the same
+# level as myplc, where plc_config.py lives. If we are in a
+# MyPLC environment, plc_config.py has already been installed
+# in site-packages.
+myplc = os.path.dirname(os.path.dirname(os.path.dirname(os.path.abspath(__file__)))) + \
+        os.sep + "myplc"
+
+class Config:
+    """
+    Parse the bash/Python/PHP version of the configuration file. Very
+    fast but no type conversions.
+    """
+
+    def __init__(self, file = "/etc/planetlab/plc_config"):
+        # Load plc_config
+        try:
+            execfile(file, self.__dict__)
+        except:
+            # Try myplc directory
+            try:
+                execfile(myplc + os.sep + "plc_config", self.__dict__)
+            except:
+                raise PLCAPIError("Could not find plc_config in " + \
+                                  file + ", " + \
+                                  myplc + os.sep + "plc_config")
+
+class XMLConfig:
+    """
+    Parse the XML configuration file directly. Takes longer but is
+    presumably more accurate.
+    """
+
+    def __init__(self, file = "/etc/planetlab/plc_config.xml"):
+        try:
+            from plc_config import PLCConfiguration
+        except:
+            sys.path.append(myplc)
+            from plc_config import PLCConfiguration
+
+        # Load plc_config.xml
+        try:
+            cfg = PLCConfiguration(file)
+        except:
+            # Try myplc directory
+            try:
+                cfg = PLCConfiguration(myplc + os.sep + "plc_config.xml")
+            except:
+                raise PLCAPIError("Could not find plc_config.xml in " + \
+                                  file + ", " + \
+                                  myplc + os.sep + "plc_config.xml")
+
+        for (category, variablelist) in cfg.variables().values():
+            for variable in variablelist.values():
+                # Try to cast each variable to an appropriate Python
+                # type.
+                if variable['type'] == "int":
+                    value = int(variable['value'])
+                elif variable['type'] == "double":
+                    value = float(variable['value'])
+                elif variable['type'] == "boolean":
+                    if variable['value'] == "true":
+                        value = True
+                    else:
+                        value = False
+                else:
+                    value = variable['value']
+
+                # Variables are split into categories such as
+                # "plc_api", "plc_db", etc. Within each category are
+                # variables such as "host", "port", etc. For backward
+                # compatibility, refer to variables by their shell
+                # names.
+                shell_name = category['id'].upper() + "_" + variable['id'].upper()
+                setattr(self, shell_name, value)
+
+if __name__ == '__main__':
+    import pprint
+    pprint = pprint.PrettyPrinter()
+    pprint.pprint(Config().__dict__.items())