Merge pull request #194 from grooverdan/defination-substitution

ENH: Allow recursive tag substitution in action files

ChangeLog

@@ -92,6 +92,8 @@ Borreli, blotus:
    * [c8c7b0b,23bbc60] Better logging of log file read errors.
    * [3665e6d] Added code coverage to development process.
    * [41b9f7b,32d10e9] More complete ssh filter rules to match openssh source.
+   * [1d9abd1] Action files can have tags in definition that refer to other
+     tags.
   Pascal Borreli
    * [a2b29b4] Fixed lots of typos in config files and documentation.
   hamilton5

server/action.py

@@ -28,7 +28,7 @@ __copyright__ = "Copyright (c) 2004 Cyril Jaquier"
 __license__ = "GPL"
 
 import logging, os
-import threading
+import threading, re
 #from subprocess import call
 
 # Gets the instance of the logger.
@@ -143,6 +143,10 @@ class Action:
 	# @return True if the command succeeded
 	
 	def execActionStart(self):
+		if self.__cInfo:
+			if not Action.substituteRecursiveTags(self.__cInfo):
+				logSys.error("Cinfo/definitions contain self referencing definitions and cannot be resolved")
+				return False
 		startCmd = Action.replaceTag(self.__actionStart, self.__cInfo)
 		return Action.executeCmd(startCmd)
 	
@@ -242,6 +246,38 @@ class Action:
 		stopCmd = Action.replaceTag(self.__actionStop, self.__cInfo)
 		return Action.executeCmd(stopCmd)
 
+	##
+	# Sort out tag definitions within other tags
+	#
+	# so:		becomes:
+	# a = 3		a = 3
+	# b = <a>_3	b = 3_3
+	# @param	tags, a dictionary
+	# @returns	tags altered or False if there is a recursive definition
+	#@staticmethod
+	def substituteRecursiveTags(tags):
+		t = re.compile(r'<([^ >]+)>')
+		for tag, value in tags.iteritems():
+			value = str(value)
+			m = t.search(value)
+			while m:
+				if m.group(1) == tag:
+					# recursive definitions are bad
+					return False
+				else:
+					if tags.has_key(m.group(1)):
+						value = value[0:m.start()] + tags[m.group(1)] + value[m.end():]
+						m = t.search(value, m.start())
+					else:
+						# Missing tags are ok so we just continue on searching.
+						# cInfo can contain aInfo elements like <HOST> and valid shell
+						# constructs like <STDIN>.
+						m = t.search(value, m.start() + 1)
+			tags[tag] = value
+		return tags
+	substituteRecursiveTags = staticmethod(substituteRecursiveTags)
+
+	#@staticmethod
 	def escapeTag(tag):
 		for c in '\\#&;`|*?~<>^()[]{}$\n\'"':
 			if c in tag:

testcases/actiontestcase.py

@@ -61,6 +61,27 @@ class ExecuteAction(unittest.TestCase):
 	def _is_logged(self, s):
 		return s in self._log.getvalue()
 
+	def testSubstituteRecursiveTags(self):
+		aInfo = {
+			'HOST': "192.0.2.0",
+			'ABC': "123 <HOST>",
+			'xyz': "890 <ABC>",
+		}
+		# Recursion is bad
+		self.assertFalse(Action.substituteRecursiveTags({'A': '<A>'}))
+		self.assertFalse(Action.substituteRecursiveTags({'A': '<B>', 'B': '<A>'}))
+		self.assertFalse(Action.substituteRecursiveTags({'A': '<B>', 'B': '<C>', 'C': '<A>'}))
+		# missing tags are ok
+		self.assertEquals(Action.substituteRecursiveTags({'A': '<C>'}), {'A': '<C>'})
+		self.assertEquals(Action.substituteRecursiveTags({'A': '<C> <D> <X>','X':'fun'}), {'A': '<C> <D> fun', 'X':'fun'})
+		self.assertEquals(Action.substituteRecursiveTags({'A': '<C> <B>', 'B': 'cool'}), {'A': '<C> cool', 'B': 'cool'})
+		# rest is just cool
+		self.assertEquals(Action.substituteRecursiveTags(aInfo),
+								{ 'HOST': "192.0.2.0",
+									'ABC': '123 192.0.2.0',
+									'xyz': '890 123 192.0.2.0',
+								})
+
 	def testReplaceTag(self):
 		aInfo = {
 			'HOST': "192.0.2.0",