Initial work on a dynamic topology mapper

netbox/dcim/api/urls.py

@@ -1,7 +1,7 @@
 from django.conf.urls import url
 
 from extras.models import GRAPH_TYPE_INTERFACE, GRAPH_TYPE_SITE
-from extras.api.views import GraphListView
+from extras.api.views import GraphListView, TopologyMapperView
 
 from .views import *
 
@@ -62,5 +62,6 @@ urlpatterns = [
 
     # Miscellaneous
     url(r'^related-connections/$', RelatedConnectionsView.as_view(), name='related_connections'),
+    url(r'^topology-mapper/$', TopologyMapperView.as_view(), name='topology_mapper'),
 
 ]

netbox/extras/api/views.py

@@ -1,10 +1,15 @@
+import pydot
 from rest_framework import generics
+from rest_framework.views import APIView
+import tempfile
+from wsgiref.util import FileWrapper
 
-from django.http import Http404
+from django.db.models import Q
+from django.http import Http404, HttpResponse
 from django.shortcuts import get_object_or_404
 
 from circuits.models import Provider
-from dcim.models import Site, Interface
+from dcim.models import Site, Device, Interface, InterfaceConnection
 from extras.models import Graph, GRAPH_TYPE_INTERFACE, GRAPH_TYPE_PROVIDER, GRAPH_TYPE_SITE
 from .serializers import GraphSerializer
 
@@ -31,3 +36,60 @@ class GraphListView(generics.ListAPIView):
             raise Http404()
         queryset = Graph.objects.filter(type=graph_type)
         return queryset
+
+
+class TopologyMapperView(APIView):
+    """
+    Generate a topology diagram
+    """
+
+    def get(self, request):
+
+        # Glean device sets to map. Each set is represented as a hierarchical tier in the diagram.
+        device_sets = request.GET.getlist('devices', [])
+
+        # Construct the graph
+        graph = pydot.Dot(graph_type='graph', ranksep='1')
+        for i, device_set in enumerate(device_sets):
+
+            subgraph = pydot.Subgraph('sg{}'.format(i), rank='same')
+
+            # Add a pseudonode for each device_set to enforce hierarchical layout
+            subgraph.add_node(pydot.Node('set{}'.format(i), shape='none'))
+            if i:
+                graph.add_edge(pydot.Edge('set{}'.format(i - 1), 'set{}'.format(i), style='invis'))
+
+            # Add each device to the graph
+            devices = Device.objects.filter(name__regex=device_set)
+            for d in devices:
+                node = pydot.Node(d.name)
+                subgraph.add_node(node)
+
+            # Add an invisible connection to each successive device in a set to enforce horizontal order
+            for j in range(0, len(devices) - 1):
+                edge = pydot.Edge(devices[j].name, devices[j + 1].name)
+                # edge.set('style', 'invis') doesn't seem to work for some reason
+                edge.set_style('invis')
+                subgraph.add_edge(edge)
+
+            graph.add_subgraph(subgraph)
+
+        # Compile list of all devices
+        device_superset = Q()
+        for regex in device_sets:
+            device_superset = device_superset | Q(name__regex=regex)
+
+        # Add all connections to the graph
+        devices = Device.objects.filter(*(device_superset,))
+        connections = InterfaceConnection.objects.filter(interface_a__device__in=devices, interface_b__device__in=devices)
+        for c in connections:
+            edge = pydot.Edge(c.interface_a.device.name, c.interface_b.device.name)
+            graph.add_edge(edge)
+
+        # Write the image to disk and return
+        topo_file = tempfile.NamedTemporaryFile()
+        graph.write(topo_file.name, format='png')
+        response = HttpResponse(FileWrapper(topo_file), content_type='image/png')
+        topo_file.close()
+
+        return response