Add a listening port promise recipe.

setup.py

@@ -41,6 +41,7 @@ setup(name=name,
         'zc.buildout': [
           'certificate_authority = slapos.recipe.certificate_authority:Recipe',
           'certificate_authority.request = slapos.recipe.certificate_authority:Request',
+          'check_port_listening = slapos.recipe.check_port_listening:Recipe',
           'cron = slapos.recipe.dcron:Recipe',
           'cron.d = slapos.recipe.dcron:Part',
           'davstorage = slapos.recipe.davstorage:Recipe',

slapos/recipe/check_port_listening/__init__.py

+##############################################################################
+#
+# Copyright (c) 2011 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
+import sys
+
+class Recipe(GenericBaseRecipe):
+  """
+  Check listening port promise
+  """
+
+  def install(self):
+    config = dict(
+      hostname=self.options['hostname'],
+      port=self.options['port'],
+      python_path=sys.executable,
+    )
+
+    vnc_promise = self.createExecutable(
+      self.options['path'],
+      self.substituteTemplate(
+        self.getTemplateFilename('socket_connection_attempt.py.in'),
+        config))
+
+    return [vnc_promise]

slapos/recipe/check_port_listening/template/socket_connection_attempt.py.in

+#!%(python_path)s
+# BEWARE: This file is operated by slapgrid
+# BEWARE: It will be overwritten automatically
+import socket
+import sys
+
+hostname = "%(hostname)s"
+port = %(port)s
+
+connection_okay = False
+
+try:
+  s = socket.create_connection((hostname, port))
+  connection_okay = True
+  s.close()
+except (socket.error, socket.timeout):
+  connection_okay = False
+
+if not connection_okay:
+  print >> sys.stderr, "%(port)s on %(hostname)s isn't listening"
+  sys.exit(127)