add module to deal with flat file dependencies

etc/shinken-specific.cfg

@@ -504,6 +504,17 @@ define module{
        # debug 	    1
 }
 
+# Another way to update dependencies is to update a flat file
+# See some examples to do that in the python script
+define module{
+      module_name      External_auto_linking
+      module_type      hot_dependencies
+      mapping_file     /tmp/external_mapping_file.json
+      mapping_command  /usr/local/shinken/libexec/external_mapping.py -i /tmp/shinken_flat_mapping -o /tmp/external_mapping_file.json
+      mapping_command_interval  60   ; optionnal
+      mapping_command_timeout   300 ; optionnal
+}
+
 # Arbiter module to change on the fly a poller tag of a 
 # command by another.
 # Useful when you use a fixed configuration tool that do not allow you

libexec/external_mapping.py

@@ -0,0 +1,84 @@
+#!/usr/bin/env python
+#
+#This file is part of Shinken.
+#
+#Shinken is free software: you can redistribute it and/or modify
+#it under the terms of the GNU Affero General Public License as published by
+#the Free Software Foundation, either version 3 of the License, or
+#(at your option) any later version.
+#
+#Shinken 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 Affero General Public License for more details.
+#
+#You should have received a copy of the GNU Affero General Public License
+#along with Shinken.  If not, see <http://www.gnu.org/licenses/>.
+
+# This program transforms a flat dependency file into a json one so it can be loaded in
+# hot_dependencies_arbiter module
+# The input file format is :
+# host1 : vm1
+# host2 : vm2
+# ...
+# You can now get a live update of your dependency tree in shinken for your xen/virtualbox/qemu 
+# All you have to do is finding a way to modify this flat file when you do a live migration
+# for example, you can use a script like this in your crontab
+# dsh -Mc -g mydom0group 'xm list | awk "/vm-/ { print \$1 }"' > /tmp/shinken_flat_mapping
+# 
+
+import os
+import sys
+import optparse
+
+# Try to load json (2.5 and higer) or simplejson if failed (python2.4)
+try:
+    import json
+except ImportError:
+    # For old Python version, load
+    # simple json (it can be hard json?! It's 2 functions guy!)
+    try:
+        import simplejson as json
+    except ImportError:
+        sys.exit("Error : you need the json or simplejson module for this script")
+
+VERSION = '0.1'
+
+def main(input_file, output_file):
+    #Check if input_file is newer than output_file
+    if os.path.exists(output_file):
+        if os.path.getmtime(output_file) >= os.path.getmtime(input_file):
+            print "Nothing to do"
+            return True
+    r = []
+    flatmappingfile = open(input_file,'rb')
+
+    for ligne in flatmappingfile:
+        ligne = ligne.rstrip('\n\r')
+        parts = ligne.split(':')
+        host = parts[0]
+        vm = parts[1]
+        v = (('host', host),('host', vm))
+        r.append(v)
+
+    flatmappingfile.close()
+
+    jsonmappingfile = open(output_file,'wb')
+    buf=json.dumps(r)
+    jsonmappingfile.write(buf)
+    jsonmappingfile.close()
+
+if __name__ == "__main__":
+    # Manage the options
+    parser = optparse.OptionParser(
+        version="Shinken external flat mapping file to json mapping %s" % VERSION)
+    parser.add_option("-o", "--output",dest='output_file',default='/tmp/external_mapping_file.json',
+                      help="Path of the generated json mapping file.")
+    parser.add_option("-i", "--input", dest='input_file', default='/tmp/shinken_flat_mapping',
+                      help="Path oh the flat mapping file")
+
+    opts, args = parser.parse_args()
+    if args:
+        parser.error("does not take any positional arguments")
+
+    main(**opts.__dict__)