add a timestamp to deployment json (#5114)

hobo/environment/models.py

@@ -16,6 +16,7 @@ class Variable(models.Model):
     value = models.TextField(verbose_name=_('value'),
             blank=True,
             help_text=_('start with [ or { for a JSON document'))
+    last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
 
     @property
     def json(self):
@@ -42,6 +43,7 @@ class ServiceBase(models.Model):
 
     last_operational_check_timestamp = models.DateTimeField(null=True)
     last_operational_success_timestamp = models.DateTimeField(null=True)
+    last_update_timestamp = models.DateTimeField(auto_now=True, null=True)
 
     def is_operational(self):
         return (self.last_operational_success_timestamp is not None and
@@ -56,7 +58,7 @@ class ServiceBase(models.Model):
             self.last_operational_success_timestamp = once_now
         except (urllib2.URLError, urllib2.HTTPError):
             pass
-        self.save()
+        self.save(update_fields=('last_operational_check_timestamp', 'last_operational_success_timestamp'))
 
     def wants_frequent_checks(self):
         if self.last_operational_check_timestamp is None:

hobo/environment/views.py

@@ -1,3 +1,5 @@
+import calendar
+import datetime
 import json
 import string
 
@@ -6,6 +8,7 @@ from django.core.urlresolvers import reverse_lazy
 from django.http import HttpResponse
 from django.views.generic.base import TemplateView
 from django.views.generic.edit import CreateView, UpdateView, DeleteView
+from django.db.models import Max
 
 from .models import Variable, Authentic, Wcs, AVAILABLE_SERVICES
 from . import forms, utils
@@ -134,7 +137,18 @@ def operational_check_view(request, service, slug, **kwargs):
 
 def installed_services_json_view(request, **kwargs):
     response = HttpResponse(content_type='application/json')
+
+    timestamp = None
+    for klass in [Variable] + AVAILABLE_SERVICES:
+        ts = klass.objects.all().aggregate(Max('last_update_timestamp')
+                ).get('last_update_timestamp__max')
+        if timestamp is None or (ts and ts > timestamp):
+            timestamp = ts
+    if timestamp is None:
+        timestamp = datetime.datetime.now()
+
     json.dump({
+        'timestamp': calendar.timegm(timestamp.timetuple()),
         'services': [x.as_dict() for x in utils.get_installed_services()],
         'variables': dict(((v.name, v.json)
             for v in Variable.objects.all())),