Add connection error handling

hosting/templates/hosting/create_virtual_machine.html

@@ -5,9 +5,19 @@
     <div class="container dashboard-container">
         <div class="row">
             <div class="col-md-8 col-md-offset-2">
+                <div class="col-md-12">
+                    <br/>
+                    {% if messages %}
+                        <div class="alert alert-warning">
+                            {% for message in messages %}
+                            <span>{{ message }}</span>
+                            {% endfor %}
+                        </div>
+                    {% endif %}
+                </div>
+                {% if not error %}
                 <h3><i class="fa fa-server" aria-hidden="true"></i> {% trans "New Virtual Machine"%} </h3>
                 <hr/>
-                
                 <form  method="POST" action="">
                     {% csrf_token %}
                     <div class="form-group">
@@ -34,6 +44,7 @@
                         <button class="btn btn-success" >{% trans "Start VM"%} </button>                         
                     </div>
                 </form>
+                {% endif %}
 
             </div>
 

hosting/templates/hosting/virtual_machines.html

@@ -7,10 +7,6 @@
 			<div class="col-md-8 col-md-offset-2" style="margin-top: 35px;">
 				<table class="table borderless table-hover"> 
 				<h3 class="pull-left"><i class="fa fa-server" aria-hidden="true"></i> {% trans "Virtual Machines"%} </h3>
-                <p class="pull-right">
-                    <a class="btn btn-success" href="{% url 'hosting:create-virtual-machine' %}" >{% trans "Create VM"%} </a>                    
-                </p>
-				<br/>
                 <div class="col-md-12">
                     <br/>
                     {% if messages %}
@@ -21,6 +17,12 @@
                         </div>
                     {% endif %}
                 </div>
+                {% if not error %}
+                <p class="pull-right">
+                    <a class="btn btn-success" href="{% url 'hosting:create-virtual-machine' %}" >{% trans "Create VM"%} </a>                    
+                </p>
+				<br/>
+                
 				<thead> 
 				<tr> 
 					<th>{% trans "ID"%}</th>
@@ -53,6 +55,7 @@
 					{% endfor %}
 				</tbody> 
 				</table>
+                {% endif %}
 
 			    {% if is_paginated %}
 			        <div class="pagination">

hosting/views.py

@@ -37,6 +37,8 @@ from opennebula_api.serializers import VirtualMachineSerializer,\
 from oca.exceptions import OpenNebulaException
 from oca.pool import WrongNameError
 
+CONNECTION_ERROR = "Your VMs cannot be displayed at the moment due to a backend \
+                    connection error. please try again in a few minutes."
 
 class DjangoHostingView(ProcessVMSelectionMixin, View):
     template_name = "hosting/django.html"
@@ -528,8 +530,13 @@ class OrdersHostingDetailView(PermissionRequiredMixin, LoginRequiredMixin, Detai
         owner = self.request.user
         manager = OpenNebulaManager(email=owner.email,
                                     password=owner.password)
+        try:
             vm = manager.get_vm(obj.vm_id)
             context['vm'] = VirtualMachineSerializer(vm).data
+        except ConnectionRefusedError:
+            messages.error( request,
+                'In order to create a VM, you need to create/upload your SSH KEY first.'
+                )
         return context
 
 
@@ -564,9 +571,28 @@ class VirtualMachinesPlanListView(LoginRequiredMixin, ListView):
         owner = self.request.user
         manager = OpenNebulaManager(email=owner.email,
                                     password=owner.password)
+        try:
             queryset = manager.get_vms()
             serializer = VirtualMachineSerializer(queryset, many=True)
             return serializer.data
+        except ConnectionRefusedError:
+            messages.error( self.request,
+                'We could not load your VMs due to a backend connection \
+                error. Please try again in a few minutes'
+                )
+
+            self.kwargs['error'] = 'connection'
+            return []
+
+    
+    def get_context_data(self, **kwargs):
+        error = self.kwargs.get('error')
+        if error is not None:
+            print(error)
+            context = { 'error' : 'connection' }
+        else:
+            context = super(ListView, self).get_context_data(**kwargs)
+        return context
 
 
 class CreateVirtualMachinesView(LoginRequiredMixin, View):
@@ -586,6 +612,7 @@ class CreateVirtualMachinesView(LoginRequiredMixin, View):
             )
             return HttpResponseRedirect(reverse('hosting:key_pair'))
 
+        try:
             manager = OpenNebulaManager()
             templates = manager.get_templates()
             configuration_options = HostingPlan.get_serialized_configs()
@@ -594,6 +621,15 @@ class CreateVirtualMachinesView(LoginRequiredMixin, View):
                 'templates': VirtualMachineTemplateSerializer(templates, many=True).data,
                 'configuration_options' : configuration_options,
             }
+        except:
+            messages.error( request,
+                'We could not load the VM templates due to a backend connection \
+                error. Please try again in a few minutes'
+                )
+            context = {
+                'error' : 'connection'
+                    }
+
         return render(request, self.template_name, context)
 
     def post(self, request):
@@ -622,10 +658,16 @@ class VirtualMachineView(LoginRequiredMixin, View):
         vm_id = self.kwargs.get('pk')
         try:
             vm = manager.get_vm(vm_id)
+            return vm
+        except ConnectionRefusedError:
+            messages.error( self.request,
+                'We could not load your VM due to a backend connection \
+                error. Please try again in a few minutes'
+                )
+            return None
         except Exception as error:
             print(error)
             raise Http404()
-        return vm
 
     def get_success_url(self):
         final_url = reverse('hosting:virtual_machines')
@@ -633,10 +675,14 @@ class VirtualMachineView(LoginRequiredMixin, View):
 
     def get(self, request, *args, **kwargs):
         vm = self.get_object()
+        try: 
             serializer = VirtualMachineSerializer(vm)
             context = {
                 'virtual_machine': serializer.data,
             }
+        except:
+            pass
+
         return render(request, self.template_name, context)
 
     def post(self, request, *args, **kwargs):

opennebula_api/models.py

@@ -86,6 +86,7 @@ class OpenNebulaManager():
             logger.info('Could not connect via client, using oneadmin instead') 
             vm_pool = oca.VirtualMachinePool(self.oneadmin_client)
             vm_pool.info(filter=-2)
+            return vm_pool
 
         except ConnectionRefusedError:
             logger.info('Could not connect to host: {host} via protocol {protocol}'.format(
@@ -93,13 +94,16 @@ class OpenNebulaManager():
                     protocol=settings.OPENNEBULA_PROTOCOL)
                 )
             raise ConnectionRefusedError
-        return vm_pool
+        # For now we'll just handle all other errors as connection errors
+        except:
+            raise ConnectionRefusedError
 
     def get_vms(self):
         try:
             return self._get_vm_pool()
         except ConnectionRefusedError:
-            return []
+            raise ConnectionRefusedError
+            
    
     def get_vm(self, vm_id):
         vm_id = int(vm_id)
@@ -107,7 +111,7 @@ class OpenNebulaManager():
             vm_pool = self._get_vm_pool()
             return vm_pool.get_by_id(vm_id)
         except:
-            return None
+            raise ConnectionRefusedError
 
     def create_template(self, name, cores, memory, disk_size, core_price, memory_price,
                         disk_size_price, ssh='' ):
@@ -233,13 +237,16 @@ class OpenNebulaManager():
         try:
            template_pool = oca.VmTemplatePool(self.oneadmin_client)
            template_pool.info()
+           return template_pool
         except ConnectionRefusedError:
             logger.info('Could not connect to host: {host} via protocol {protocol}'.format(
                     host=settings.OPENNEBULA_DOMAIN,
                     protocol=settings.OPENNEBULA_PROTOCOL)
                 )
             raise ConnectionRefusedError
-        return template_pool
+        except:
+            raise ConnectionRefusedError
+        
 
     def get_templates(self):
         try:
@@ -250,6 +257,14 @@ class OpenNebulaManager():
                     ]
             return public_templates 
         except ConnectionRefusedError:
+            raise ConnectionRefusedError
+        except:
+            raise ConnectionRefusedError
+
+    def try_get_templates(self):
+        try:
+            return self.get_templates()
+        except:
             return []
 
     def get_template(self, template_id):
@@ -258,7 +273,7 @@ class OpenNebulaManager():
             template_pool = self._get_template_pool()
             return template_pool.get_by_id(template_id)
         except:
-            return None
+            raise ConnectionRefusedError
 
     
     

opennebula_api/serializers.py

@@ -92,9 +92,11 @@ class VirtualMachineSerializer(serializers.Serializer):
 
     template_id = serializers.ChoiceField(
                 choices=[(key.id, key.name) for key in
-                    OpenNebulaManager().get_templates()],
+                        OpenNebulaManager().try_get_templates()
+                        ],
                 source='template.template_id',
-                write_only=True
+                write_only=True,
+                default=[]
             )
 
     def create(self, validated_data):