occi: handle storagelink errors

detect if the target storage and source vm exists

circle/occi/occi.py

 import re
 
-from django.shortcuts import get_object_or_404
 from django.contrib.auth.models import User
 from django.template.loader import render_to_string
 from django.utils import timezone
@@ -428,17 +427,24 @@ class StorageLink(Link):
         g = re.match(occi_attribute_link_regex % "vm", source)
         vm_pk = g.group("id")
 
-        disk = get_object_or_404(Disk, pk=disk_pk)
-        vm = get_object_or_404(Instance, pk=vm_pk)
-
+        try:
+            vm = Instance.objects.filter(destroyed_at=None).get(pk=vm_pk)
+            disk = Disk.objects.filter(destroyed=None).get(pk=disk_pk)
+        except (Instance.DoesNotExist, Disk.DoesNotExist):
+            return None
 
+        try:
             vm.attach_disk(user=user, disk=disk)
+        except:
+            pass
+
         cls.location = "%sstoragelink/%svm_%sdisk" % (OCCI_ADDR, vm_pk,
                                                       disk_pk)
         return cls
 
     def render_location(self):
-        return "/link/storagelink/vm%d_disk%d" % (instance.pk, disk.pk)
+        return "/link/storagelink/vm%d_disk%d" % (self.instance.pk,
+                                                  self.disk.pk)
 
     def render_as_link(self):
         kind = STORAGE_LINK_KIND

circle/occi/views.py

-from django.http import HttpResponse
-from django.shortcuts import get_object_or_404
+from django.http import HttpResponse, Http404
 from django.utils.decorators import method_decorator
 from django.views.decorators.csrf import csrf_exempt
 from django.views.generic import View, DetailView
@@ -191,9 +190,14 @@ class DiskInterface(DetailView):
 class StorageLinkInterface(View):
 
     def get_vm_and_disk(self):
-        vm = get_object_or_404(Instance, pk=self.kwargs['vm_pk'])
-        disk = get_object_or_404(Disk, pk=self.kwargs['disk_pk'])
+        try:
+            vm = Instance.objects.filter(destroyed=None
+                                         ).get(pk=self.kwargs['vm_pk'])
+            disk = Disk.objects.filter(destroyed=None
+                                       ).get(pk=self.kwargs['disk_pk'])
             return vm, disk
+        except (Instance.DoesNotExist, Disk.DoesNotExist):
+            raise Http404
 
     def get(self, request, *args, **kwargs):
         vm, disk = self.get_vm_and_disk()
@@ -208,17 +212,18 @@ class StorageLinkInterface(View):
         # (they don't even exist in the model)
         if request.GET.get("action"):
             return HttpResponse("", status=500)
-        else:
+
         data = get_post_data_from_request(request)
         sl = StorageLink.create_object(data=data)
+        if sl:
             response = HttpResponse(
                 "X-OCCI-Location: %s" % sl.location,
                 status=201,
                 content_type="text/plain",
             )
             return response
-
-        return HttpResponse()
+        else:
+            return HttpResponse("VM or Storage does not exist.", status=500)
 
     @method_decorator(csrf_exempt)
     def dispatch(self, *args, **kwargs):

circle/vm/operations.py

@@ -1295,6 +1295,12 @@ class AttachDiskOperation(InstanceOperation):
     accept_states = ('STOPPED', 'PENDING', 'RUNNING')
 
     def _operation(self, user, activity, disk):
+        if disk in self.instance.disks.all():
+            raise humanize_exception(ugettext_noop(
+                "Disk (#%d) is already attached to this virtual machine."
+            ) % disk.pk,
+                Exception())
+
         devnums = list(ascii_lowercase)
         for d in self.instance.disks.all():
             devnums.remove(d.dev_num)