Add new recipe : generate output if input is not null

setup.py

@@ -58,6 +58,7 @@ setup(name=name,
           'erp5scalabilitytestbed = slapos.recipe.erp5scalabilitytestbed:Recipe',
           'equeue = slapos.recipe.equeue:Recipe',
           'erp5testnode = slapos.recipe.erp5testnode:Recipe',
+          'generate_output_if_input_not_null = slapos.recipe.generate_output_if_input_not_null:Recipe',
           'generate.mac = slapos.recipe.generatemac:Recipe',
           'nbdserver = slapos.recipe.nbdserver:Recipe',
           'generic.onetimeupload = slapos.recipe.generic_onetimeupload:Recipe',

slapos/recipe/generate_output_if_input_not_null.py

+##############################################################################
+#
+# Copyright (c) 2010 Vifib SARL and Contributors. All Rights Reserved.
+#
+# WARNING: This program as such is intended to be used by professional
+# programmers who take the whole responsibility of assessing all potential
+# consequences resulting from its eventual inadequacies and bugs
+# End users who are looking for a ready-to-use solution with commercial
+# guarantees and support are strongly adviced to contract a Free Software
+# Service Company
+#
+# This program 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.
+#
+# This program 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 this program; if not, write to the Free Software
+# Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
+#
+##############################################################################
+from slapos.recipe.librecipe import GenericBaseRecipe
+
+class Recipe(GenericBaseRecipe):
+  """Generate an output from one or several input and a template.
+  
+  Take "input-list" buildout parameter as input.
+  Each input of the list is separated by \n
+  Each input contains :
+    1/ The parameter to use (like mybuildoutpart:myparameter)
+    2/ The name of the input to use as key.
+
+  If all parameters in input are found, create an "output" parameter from a
+  "template" parameter. The "template" parameter is just a string containing
+  python parameters (like %(mykey)s).
+
+  Will produce nothing if one element of "input_list" doesn't exist.
+  Will raise if any input reference non-existent buildout part.
+
+  Example : 
+  [get-output]
+  recipe = slapos.cookbook:generate_output_if_input_not_null
+  input-list =
+    firstkey mybuildoutpart:myparameter
+    otherkey myotherbuildoutpart:myotherparameter
+  template = I want to get %(key)s and %(otherkey)s
+
+  This example will produce an "output" parameter if myparameter and
+  myotherparameter are defined.
+  """
+  def __init__(self, buildout, name, options):
+    # Get all inputs
+    input_dict = {}
+    for line in options['input-list'].strip().split('\n'):
+      key, buildout_parameter = line.split(' ')
+      buildout_part, parameter_name = buildout_parameter.split(':')
+      parameter_value = buildout[buildout_part].get(parameter_name)
+      # If any parameter is not defined, don't do anything
+      if not parameter_value:
+        return
+      input_dict[key] = parameter_value
+    # Generate output
+    options['output'] = options['template'] % input_dict
+
+  def install(self):
+    return []