allow object overrides with CDIST_ALLOW_OVERRIDE=true

cdist/core/cdist_object.py

@@ -2,6 +2,7 @@
 #
 # 2011 Steven Armstrong (steven-cdist at armstrong.cc)
 # 2011-2013 Nico Schottelius (nico-cdist at schottelius.org)
+# 2014 Daniel Heule (hda at sfs.biz)
 #
 # This file is part of cdist.
 #
@@ -215,9 +216,10 @@ class CdistObject(object):
         """Create this cdist object on the filesystem.
         """
         try:
-            os.makedirs(self.absolute_path, exist_ok=False)
+            cdexist_ok = True if os.environ.get('CDIST_ALLOW_OVERRIDE',"false") == 'true' else False
+            os.makedirs(self.absolute_path, exist_ok=cdexist_ok)
             absolute_parameter_path = os.path.join(self.base_path, self.parameter_path)
-            os.makedirs(absolute_parameter_path, exist_ok=False)
+            os.makedirs(absolute_parameter_path, exist_ok=cdexist_ok)
         except EnvironmentError as error:
             raise cdist.Error('Error creating directories for cdist object: %s: %s' % (self, error))
 

cdist/emulator.py

@@ -2,6 +2,7 @@
 #
 # 2011-2013 Nico Schottelius (nico-cdist at schottelius.org)
 # 2012 Steven Armstrong (steven-cdist at armstrong.cc)
+# 2014 Daniel Heule (hda at sfs.biz)
 #
 # This file is part of cdist.
 #
@@ -144,12 +145,14 @@ class Emulator(object):
             if value is not None:
                 self.parameters[key] = value
 
-        if self.cdist_object.exists:
+        if self.cdist_object.exists and os.environ.get('CDIST_ALLOW_OVERRIDE',"false") != 'true':
             if self.cdist_object.parameters != self.parameters:
                 raise cdist.Error("Object %s already exists with conflicting parameters:\n%s: %s\n%s: %s"
                     % (self.cdist_object.name, " ".join(self.cdist_object.source), self.cdist_object.parameters, self.object_source, self.parameters)
             )
         else:
+            if self.cdist_object.exists:
+                self.log.debug('Object %s override forced with CDIST_ALLOW_OVERRIDE=true',self.cdist_object.name)
             self.cdist_object.create()
             self.cdist_object.parameters = self.parameters
 

docs/man/man7/cdist-manifest.text

@@ -161,6 +161,30 @@ __package lighttpd --state present
 require="__package/lighttpd" __package munin --state present
 --------------------------------------------------------------------------------
 
+OVERRIDES
+---------
+In some special cases, you would like to create an allready defined object 
+with different parameters. In normal situations this leads to an error in cdist.
+If you whish, you can mark this second definition of an object with 
+CDIST_ALLOW_OVERRIDE=true to tell cdist, that this object override is 
+wanted and should be accepted.
+
+--------------------------------------------------------------------------------
+# for example in the inial manifest
+
+# reate user account foobar with some hash for password
+__user foobar --password 'some_fancy_hash'
+
+# ... many statements and includes in the manifest later ...
+# somewhere in a conditionaly sourced manifest 
+# (e.g. for example only sourced if a special application is on the target host)
+
+# this leads to an error ...
+__user foobar --password 'some_other_hash' 
+
+# this tells cdist, that you know that this is an override and should be accepted
+CDIST_ALLOW_OVERRIDE=true __user foobar --password 'some_other_hash'
+--------------------------------------------------------------------------------
 
 
 SEE ALSO