apache-frontend: fix read of JSON file to not override current JSON

software/apache-frontend/instance-apache-replicate.cfg.in

@@ -77,7 +77,11 @@ sla-{{ parameter }} = {{ slapparameter_dict.pop( sla_key + parameter ) }}
 {% set slave_test_list = [] %}
 
 {% set slave_configuration_path = slave_list_parameter.get('configuration-path') %}
-{% set slave_configuration_json = builtin.open(slave_configuration_path, 'w+').read() %}
+{% if os.path.exists(slave_configuration_path) %}
+{%   set slave_configuration_json = builtin.open(slave_configuration_path, 'r').read() %}
+{% else %}
+{%   set slave_configuration_json = '' %}
+{% endif %}
 {% if slave_configuration_json == '' %}
 {%   set slave_configuration = {} %}
 {% else %}
@@ -86,7 +90,7 @@ sla-{{ parameter }} = {{ slapparameter_dict.pop( sla_key + parameter ) }}
 {% for slave in slave_instance_list %}
 {%   set slave_reference = slave.get('slave_reference') %}
 ## Update slave information if slave is new or have changed
-{%   if slave_configuration.has_key(slave_reference) %}
+{%   if slave_reference in slave_configuration %}
 {%     if slave.get('timestamp') != slave_configuration.get(slave_reference).get('timestamp') %}
 {%       do slave_configuration.get(slave_reference).__setitem__('timestamp', slave.get('timestamp')) %}
 {%       do slave_configuration.get(slave_reference).__setitem__('configuration', slave) %}

software/apache-frontend/instance.cfg

@@ -46,6 +46,7 @@ filename = instance-apache-replicate.cfg
 extensions = jinja2.ext.do
 extra-context =
     import builtin __builtin__
+    import os os
     key root_directory buildout:directory
     section slave_list_parameter slave-list-parameter
     raw template_publish_slave_information ${template-replicate-publish-slave-information:target}