Merge pull request #519 from weaveworks/509-filtered-stats

Report number of filtered nodes in topology stats.

app/api_topologies.go

@@ -4,6 +4,7 @@ import (
 	"net/http"
 
 	"github.com/weaveworks/scope/render"
+	"github.com/weaveworks/scope/report"
 	"github.com/weaveworks/scope/xfer"
 )
 
@@ -27,6 +28,7 @@ type topologyStats struct {
 	NodeCount          int `json:"node_count"`
 	NonpseudoNodeCount int `json:"nonpseudo_node_count"`
 	EdgeCount          int `json:"edge_count"`
+	FilteredNodes      int `json:"filtered_nodes"`
 }
 
 // makeTopologyList returns a handler that yields an APITopologyList.
@@ -41,16 +43,18 @@ func makeTopologyList(rep xfer.Reporter) func(w http.ResponseWriter, r *http.Req
 			if def.parent != "" {
 				continue
 			}
+			decorateTopologyForRequest(r, &def)
 
 			// Collect all sub-topologies of this one, depth=1 only.
 			subTopologies := []APITopologyDesc{}
 			for subName, subDef := range topologyRegistry {
 				if subDef.parent == name {
+					decorateTopologyForRequest(r, &subDef)
 					subTopologies = append(subTopologies, APITopologyDesc{
 						Name:    subDef.human,
 						URL:     "/api/topology/" + subName,
 						Options: makeTopologyOptions(subDef),
-						Stats:   stats(subDef.renderer.Render(rpt)),
+						Stats:   stats(subDef.renderer, rpt),
 					})
 				}
 			}
@@ -61,7 +65,7 @@ func makeTopologyList(rep xfer.Reporter) func(w http.ResponseWriter, r *http.Req
 				URL:           "/api/topology/" + name,
 				SubTopologies: subTopologies,
 				Options:       makeTopologyOptions(def),
-				Stats:         stats(def.renderer.Render(rpt)),
+				Stats:         stats(def.renderer, rpt),
 			})
 		}
 		respondWith(w, http.StatusOK, topologies)
@@ -82,14 +86,14 @@ func makeTopologyOptions(view topologyView) map[string][]APITopologyOption {
 	return options
 }
 
-func stats(r render.RenderableNodes) *topologyStats {
+func stats(renderer render.Renderer, rpt report.Report) *topologyStats {
 	var (
 		nodes     int
 		realNodes int
 		edges     int
 	)
 
-	for _, n := range r {
+	for _, n := range renderer.Render(rpt) {
 		nodes++
 		if !n.Pseudo {
 			realNodes++
@@ -97,9 +101,12 @@ func stats(r render.RenderableNodes) *topologyStats {
 		edges += len(n.Adjacency)
 	}
 
+	renderStats := renderer.Stats(rpt)
+
 	return &topologyStats{
 		NodeCount:          nodes,
 		NonpseudoNodeCount: realNodes,
 		EdgeCount:          edges,
+		FilteredNodes:      renderStats.FilteredNodes,
 	}
 }

app/router.go

@@ -100,6 +100,17 @@ func makeReportPostHandler(a xfer.Adder) http.HandlerFunc {
 	}
 }
 
+func decorateTopologyForRequest(r *http.Request, topology *topologyView) {
+	for param, opts := range topology.options {
+		value := r.FormValue(param)
+		for _, opt := range opts {
+			if (value == "" && opt.def) || (opt.value != "" && opt.value == value) {
+				topology.renderer = opt.decorator(topology.renderer)
+			}
+		}
+	}
+}
+
 func captureTopology(rep xfer.Reporter, f func(xfer.Reporter, topologyView, http.ResponseWriter, *http.Request)) http.HandlerFunc {
 	return func(w http.ResponseWriter, r *http.Request) {
 		topology, ok := topologyRegistry[mux.Vars(r)["topology"]]
@@ -107,14 +118,7 @@ func captureTopology(rep xfer.Reporter, f func(xfer.Reporter, topologyView, http
 			http.NotFound(w, r)
 			return
 		}
-		for param, opts := range topology.options {
-			value := r.FormValue(param)
-			for _, opt := range opts {
-				if (value == "" && opt.def) || (opt.value != "" && opt.value == value) {
-					topology.renderer = opt.decorator(topology.renderer)
-				}
-			}
-		}
+		decorateTopologyForRequest(r, &topology)
 		f(rep, topology, w, r)
 	}
 }
@@ -135,7 +139,7 @@ var topologyRegistry = map[string]topologyView{
 	"applications": {
 		human:    "Applications",
 		parent:   "",
-		renderer: render.FilterUnconnected(render.ProcessWithContainerNameRenderer{}),
+		renderer: render.FilterUnconnected(render.ProcessWithContainerNameRenderer),
 	},
 	"applications-by-name": {
 		human:    "by name",
@@ -145,7 +149,7 @@ var topologyRegistry = map[string]topologyView{
 	"containers": {
 		human:    "Containers",
 		parent:   "",
-		renderer: render.ContainerWithImageNameRenderer{},
+		renderer: render.ContainerWithImageNameRenderer,
 		options: optionParams{"system": {
 			{"show", "System containers shown", false, nop},
 			{"hide", "System containers hidden", true, render.FilterSystem},

client/app/scripts/actions/app-actions.js

@@ -5,17 +5,27 @@ let RouterUtils;
 let WebapiUtils;
 
 module.exports = {
-  changeTopologyOption: function(option, value) {
+  changeTopologyOption: function(option, value, topologyId) {
     AppDispatcher.dispatch({
       type: ActionTypes.CHANGE_TOPOLOGY_OPTION,
+      topologyId: topologyId,
       option: option,
       value: value
     });
     RouterUtils.updateRoute();
+    // update all request workers with new options
+    WebapiUtils.getTopologies(
+      AppStore.getActiveTopologyOptions()
+    );
     WebapiUtils.getNodesDelta(
       AppStore.getCurrentTopologyUrl(),
       AppStore.getActiveTopologyOptions()
     );
+    WebapiUtils.getNodeDetails(
+      AppStore.getCurrentTopologyUrl(),
+      AppStore.getSelectedNodeId(),
+      AppStore.getActiveTopologyOptions()
+    );
   },
 
   clickCloseDetails: function() {
@@ -146,6 +156,9 @@ module.exports = {
       state: state,
       type: ActionTypes.ROUTE_TOPOLOGY
     });
+    WebapiUtils.getTopologies(
+      AppStore.getActiveTopologyOptions()
+    );
     WebapiUtils.getNodesDelta(
       AppStore.getCurrentTopologyUrl(),
       AppStore.getActiveTopologyOptions()

client/app/scripts/charts/nodes-chart.js

@@ -394,7 +394,10 @@ const NodesChart = React.createClass({
     const n = props.nodes.size;
 
     if (n === 0) {
-      return {};
+      return {
+        nodes: {},
+        edges: {}
+      };
     }
 
     const nodes = this.initNodes(props.nodes, state.nodes);

client/app/scripts/components/app.js

@@ -48,7 +48,10 @@ const App = React.createClass({
     window.addEventListener('keyup', this.onKeyPress);
 
     RouterUtils.getRouter().start({hashbang: true});
-    WebapiUtils.getTopologies();
+    if (!AppStore.isRouteSet()) {
+      // dont request topologies when already done via router
+      WebapiUtils.getTopologies(AppStore.getActiveTopologyOptions());
+    }
     WebapiUtils.getApiDetails();
   },
 
@@ -93,6 +96,7 @@ const App = React.createClass({
 
         <Sidebar>
           <TopologyOptions options={this.state.currentTopologyOptions}
+            topologyId={this.state.currentTopologyId}
             activeOptions={this.state.activeTopologyOptions} />
           <Status errorUrl={this.state.errorUrl} topology={this.state.currentTopology}
             topologiesLoaded={this.state.topologiesLoaded}

client/app/scripts/components/status.js

@@ -21,7 +21,10 @@ const Status = React.createClass({
       showWarningIcon = true;
     } else if (this.props.topology) {
       const stats = this.props.topology.stats;
-      text = `${stats.node_count} nodes, ${stats.edge_count} connections`;
+      text = `${stats.node_count} nodes`;
+      if (stats.filtered_nodes) {
+        text = `${text} (${stats.filtered_nodes} filtered)`;
+      }
       classNames += ' status-stats';
       showWarningIcon = false;
     }

client/app/scripts/components/topologies.js

@@ -2,7 +2,6 @@ const React = require('react');
 const _ = require('lodash');
 
 const AppActions = require('../actions/app-actions');
-const AppStore = require('../stores/app-store');
 
 const Topologies = React.createClass({
 
@@ -13,7 +12,7 @@ const Topologies = React.createClass({
 
   renderSubTopology: function(subTopology) {
     const isActive = subTopology.name === this.props.currentTopology.name;
-    const topologyId = AppStore.getTopologyIdForUrl(subTopology.url);
+    const topologyId = subTopology.id;
     const title = this.renderTitle(subTopology);
     const className = isActive ? 'topologies-sub-item topologies-sub-item-active' : 'topologies-sub-item';
 
@@ -35,7 +34,7 @@ const Topologies = React.createClass({
   renderTopology: function(topology) {
     const isActive = topology.name === this.props.currentTopology.name;
     const className = isActive ? 'topologies-item-main topologies-item-main-active' : 'topologies-item-main';
-    const topologyId = AppStore.getTopologyIdForUrl(topology.url);
+    const topologyId = topology.id;
     const title = this.renderTitle(topology);
 
     return (

client/app/scripts/components/topology-option-action.js

@@ -6,7 +6,7 @@ const TopologyOptionAction = React.createClass({
 
   onClick: function(ev) {
     ev.preventDefault();
-    AppActions.changeTopologyOption(this.props.option, this.props.value);
+    AppActions.changeTopologyOption(this.props.option, this.props.value, this.props.topologyId);
   },
 
   render: function() {

client/app/scripts/components/topology-options.js

@@ -5,9 +5,9 @@ const TopologyOptionAction = require('./topology-option-action');
 
 const TopologyOptions = React.createClass({
 
-  renderAction: function(action, option) {
+  renderAction: function(action, option, topologyId) {
     return (
-      <TopologyOptionAction option={option} value={action} />
+      <TopologyOptionAction option={option} value={action} topologyId={topologyId} />
     );
   },
 
@@ -15,11 +15,12 @@ const TopologyOptions = React.createClass({
     let activeText;
     const actions = [];
     const activeOptions = this.props.activeOptions;
+    const topologyId = this.props.topologyId;
     items.forEach(function(item) {
-      if (activeOptions[item.option] && activeOptions[item.option] === item.value) {
+      if (activeOptions && activeOptions.has(item.option) && activeOptions.get(item.option) === item.value) {
         activeText = item.display;
       } else {
-        actions.push(this.renderAction(item.value, item.option));
+        actions.push(this.renderAction(item.value, item.option, topologyId));
       }
     }, this);
 

client/app/scripts/stores/__tests__/app-store-test.js

@@ -1,4 +1,4 @@
-
+// Appstore test suite using Jasmine matchers
 
 describe('AppStore', function() {
   const ActionTypes = require('../../constants/action-types');
@@ -30,12 +30,14 @@ describe('AppStore', function() {
 
   const ChangeTopologyOptionAction = {
     type: ActionTypes.CHANGE_TOPOLOGY_OPTION,
+    topologyId: 'topo1',
     option: 'option1',
     value: 'on'
   };
 
   const ChangeTopologyOptionAction2 = {
     type: ActionTypes.CHANGE_TOPOLOGY_OPTION,
+    topologyId: 'topo1',
     option: 'option1',
     value: 'off'
   };
@@ -159,39 +161,40 @@ describe('AppStore', function() {
     // default options
     registeredCallback(ReceiveTopologiesAction);
     registeredCallback(ClickTopologyAction);
-    expect(AppStore.getActiveTopologyOptions().option1).toBe('off');
-    expect(AppStore.getAppState().topologyOptions.option1).toBe('off');
+    expect(AppStore.getActiveTopologyOptions().has('option1')).toBeTruthy();
+    expect(AppStore.getActiveTopologyOptions().get('option1')).toBe('off');
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('off');
 
     // turn on
     registeredCallback(ChangeTopologyOptionAction);
-    expect(AppStore.getActiveTopologyOptions().option1).toBe('on');
-    expect(AppStore.getAppState().topologyOptions.option1).toBe('on');
+    expect(AppStore.getActiveTopologyOptions().get('option1')).toBe('on');
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('on');
 
     // turn off
     registeredCallback(ChangeTopologyOptionAction2);
-    expect(AppStore.getActiveTopologyOptions().option1).toBe('off');
-    expect(AppStore.getAppState().topologyOptions.option1).toBe('off');
+    expect(AppStore.getActiveTopologyOptions().get('option1')).toBe('off');
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('off');
 
-    // other topology w/o options
+    // other topology w/o options dont return options, but keep in app state
     registeredCallback(ClickSubTopologyAction);
-    expect(AppStore.getActiveTopologyOptions().option1).toBeUndefined();
-    expect(AppStore.getAppState().topologyOptions.option1).toBeUndefined();
+    expect(AppStore.getActiveTopologyOptions()).toBeUndefined();
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('off');
   });
 
   it('sets topology options from route', function() {
     RouteAction.state = {
       "topologyId":"topo1",
       "selectedNodeId": null,
-      "topologyOptions": {'option1': 'on'}};
+      "topologyOptions": {'topo1':{'option1': 'on'}}};
     registeredCallback(RouteAction);
-    expect(AppStore.getActiveTopologyOptions().option1).toBe('on');
-    expect(AppStore.getAppState().topologyOptions.option1).toBe('on');
+    expect(AppStore.getActiveTopologyOptions().get('option1')).toBe('on');
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('on');
 
     // stay same after topos have been received
     registeredCallback(ReceiveTopologiesAction);
     registeredCallback(ClickTopologyAction);
-    expect(AppStore.getActiveTopologyOptions().option1).toBe('on');
-    expect(AppStore.getAppState().topologyOptions.option1).toBe('on');
+    expect(AppStore.getActiveTopologyOptions().get('option1')).toBe('on');
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('on');
   });
 
   it('uses default topology options from route', function() {
@@ -202,8 +205,8 @@ describe('AppStore', function() {
     registeredCallback(RouteAction);
     registeredCallback(ReceiveTopologiesAction);
     registeredCallback(ClickTopologyAction);
-    expect(AppStore.getActiveTopologyOptions().option1).toBe('off');
-    expect(AppStore.getAppState().topologyOptions.option1).toBe('off');
+    expect(AppStore.getActiveTopologyOptions().get('option1')).toBe('off');
+    expect(AppStore.getAppState().topologyOptions.topo1.option1).toBe('off');
   });
 
   // nodes delta
@@ -222,6 +225,12 @@ describe('AppStore', function() {
     expect(AppStore.getNodes().toJS()).toEqual(NODE_SET);
   });
 
+  it('knows a route was set', function() {
+    expect(AppStore.isRouteSet()).toBeFalsy();
+    registeredCallback(RouteAction);
+    expect(AppStore.isRouteSet()).toBeTruthy();
+  });
+
   it('gets selected node after click', function() {
     registeredCallback(ReceiveNodesDeltaAction);
 

client/app/scripts/stores/app-store.js

@@ -44,7 +44,7 @@ function makeNode(node) {
 
 // Initial values
 
-let activeTopologyOptions = null;
+let topologyOptions = makeOrderedMap();
 let adjacentNodes = makeSet();
 let currentTopology = null;
 let currentTopologyId = 'containers';
@@ -57,24 +57,43 @@ let nodeDetails = null;
 let selectedNodeId = null;
 let topologies = [];
 let topologiesLoaded = false;
+let routeSet = false;
 let websocketClosed = true;
 
+function processTopologies(topologyList) {
+  // adds ID field to topology, based on last part of URL path
+  _.each(topologyList, function(topology) {
+    topology.id = topology.url.split('/').pop();
+    processTopologies(topology.sub_topologies);
+  });
+  return topologyList;
+}
+
 function setTopology(topologyId) {
   currentTopologyId = topologyId;
   currentTopology = findCurrentTopology(topologies, topologyId);
 }
 
-function setDefaultTopologyOptions() {
-  if (currentTopology) {
-    activeTopologyOptions = {};
-    _.each(currentTopology.options, function(items, option) {
+function setDefaultTopologyOptions(topologyList) {
+  _.each(topologyList, function(topology) {
+    let defaultOptions = makeOrderedMap();
+    _.each(topology.options, function(items, option) {
       _.each(items, function(item) {
         if (item.default === true) {
-          activeTopologyOptions[option] = item.value;
+          defaultOptions = defaultOptions.set(option, item.value);
         }
       });
     });
-  }
+
+    if (defaultOptions.size) {
+      topologyOptions = topologyOptions.set(
+        topology.id,
+        defaultOptions
+      );
+    }
+
+    setDefaultTopologyOptions(topology.sub_topologies);
+  });
 }
 
 // Store API
@@ -88,12 +107,13 @@ const AppStore = assign({}, EventEmitter.prototype, {
     return {
       topologyId: currentTopologyId,
       selectedNodeId: this.getSelectedNodeId(),
-      topologyOptions: this.getActiveTopologyOptions()
+      topologyOptions: topologyOptions.toJS() // all options
     };
   },
 
   getActiveTopologyOptions: function() {
-    return activeTopologyOptions;
+    // options for current topology
+    return topologyOptions.get(currentTopologyId);
   },
 
   getAdjacentNodes: function(nodeId) {
@@ -136,7 +156,7 @@ const AppStore = assign({}, EventEmitter.prototype, {
   },
 
   getHighlightedEdgeIds: function() {
-    if (mouseOverNodeId) {
+    if (mouseOverNodeId && nodes.has(mouseOverNodeId)) {
       // all neighbour combinations because we dont know which direction exists
       const adjacency = nodes.get(mouseOverNodeId).get('adjacency');
       if (adjacency) {
@@ -185,14 +205,14 @@ const AppStore = assign({}, EventEmitter.prototype, {
     return topologies;
   },
 
-  getTopologyIdForUrl: function(url) {
-    return url.split('/').pop();
-  },
-
   getVersion: function() {
     return version;
   },
 
+  isRouteSet: function() {
+    return routeSet;
+  },
+
   isTopologiesLoaded: function() {
     return topologiesLoaded;
   },
@@ -209,10 +229,14 @@ AppStore.registeredCallback = function(payload) {
   switch (payload.type) {
 
     case ActionTypes.CHANGE_TOPOLOGY_OPTION:
-      if (activeTopologyOptions[payload.option] !== payload.value) {
+      if (topologyOptions.getIn([payload.topologyId, payload.option])
+        !== payload.value) {
         nodes = nodes.clear();
       }
-      activeTopologyOptions[payload.option] = payload.value;
+      topologyOptions = topologyOptions.setIn(
+        [payload.topologyId, payload.option],
+        payload.value
+      );
       AppStore.emit(AppStore.CHANGE_EVENT);
       break;
 
@@ -230,7 +254,6 @@ AppStore.registeredCallback = function(payload) {
       selectedNodeId = null;
       if (payload.topologyId !== currentTopologyId) {
         setTopology(payload.topologyId);
-        setDefaultTopologyOptions();
         nodes = nodes.clear();
       }
       AppStore.emit(AppStore.CHANGE_EVENT);
@@ -321,15 +344,13 @@ AppStore.registeredCallback = function(payload) {
 
     case ActionTypes.RECEIVE_TOPOLOGIES:
       errorUrl = null;
-      topologiesLoaded = true;
-      topologies = payload.topologies;
-      if (!currentTopology) {
-        setTopology(currentTopologyId);
-        // only set on first load
-        if (activeTopologyOptions === null) {
-          setDefaultTopologyOptions();
-        }
+      topologies = processTopologies(payload.topologies);
+      setTopology(currentTopologyId);
+      // only set on first load, if options are not already set via route
+      if (!topologiesLoaded && topologyOptions.size === 0) {
+        setDefaultTopologyOptions(topologies);
       }
+      topologiesLoaded = true;
       AppStore.emit(AppStore.CHANGE_EVENT);
       break;
 
@@ -340,13 +361,15 @@ AppStore.registeredCallback = function(payload) {
       break;
 
     case ActionTypes.ROUTE_TOPOLOGY:
+      routeSet = true;
       if (currentTopologyId !== payload.state.topologyId) {
         nodes = nodes.clear();
       }
       setTopology(payload.state.topologyId);
-      setDefaultTopologyOptions();
+      setDefaultTopologyOptions(topologies);
       selectedNodeId = payload.state.selectedNodeId;
-      activeTopologyOptions = payload.state.topologyOptions || activeTopologyOptions;
+      topologyOptions = Immutable.fromJS(payload.state.topologyOptions)
+        || topologyOptions;
       AppStore.emit(AppStore.CHANGE_EVENT);
       break;
 

client/app/scripts/utils/web-api-utils.js

@@ -1,4 +1,3 @@
-const _ = require('lodash');
 const debug = require('debug')('scope:web-api-utils');
 const reqwest = require('reqwest');
 
@@ -21,9 +20,12 @@ let apiDetailsTimer = 0;
 
 
 function buildOptionsQuery(options) {
-  return _.map(options, function(value, param) {
-    return param + '=' + value;
-  }).join('&');
+  if (options) {
+    return options.reduce(function(query, value, param) {
+      return `${query}&${param}=${value}`;
+    }, '');
+  }
+  return '';
 }
 
 function createWebsocket(topologyUrl, optionsQuery) {
@@ -66,19 +68,24 @@ function createWebsocket(topologyUrl, optionsQuery) {
 
 /* keep URLs relative */
 
-function getTopologies() {
+function getTopologies(options) {
   clearTimeout(topologyTimer);
-  const url = 'api/topology';
+  const optionsQuery = buildOptionsQuery(options);
+  const url = `api/topology?${optionsQuery}`;
   reqwest({
     url: url,
     success: function(res) {
       AppActions.receiveTopologies(res);
-      topologyTimer = setTimeout(getTopologies, topologyTimerInterval);
+      topologyTimer = setTimeout(function() {
+        getTopologies(options);
+      }, topologyTimerInterval / 2);
     },
     error: function(err) {
       debug('Error in topology request: ' + err);
       AppActions.receiveError(url);
-      topologyTimer = setTimeout(getTopologies, topologyTimerInterval / 2);
+      topologyTimer = setTimeout(function() {
+        getTopologies(options);
+      }, topologyTimerInterval / 2);
     }
   });
 }

render/render.go

@@ -11,6 +11,18 @@ import (
 type Renderer interface {
 	Render(report.Report) RenderableNodes
 	EdgeMetadata(rpt report.Report, localID, remoteID string) report.EdgeMetadata
+	Stats(report.Report) Stats
+}
+
+// Stats is the type returned by Renderer.Stats
+type Stats struct {
+	FilteredNodes int
+}
+
+func (s Stats) merge(other Stats) Stats {
+	return Stats{
+		FilteredNodes: s.FilteredNodes + other.FilteredNodes,
+	}
 }
 
 // Reduce renderer is a Renderer which merges together the output of several
@@ -40,6 +52,15 @@ func (r Reduce) EdgeMetadata(rpt report.Report, localID, remoteID string) report
 	return metadata
 }
 
+// Stats implements Renderer
+func (r Reduce) Stats(rpt report.Report) Stats {
+	var result Stats
+	for _, renderer := range r {
+		result = result.merge(renderer.Stats(rpt))
+	}
+	return result
+}
+
 // Map is a Renderer which produces a set of RenderableNodes from the set of
 // RenderableNodes produced by another Renderer.
 type Map struct {
@@ -54,6 +75,14 @@ func (m Map) Render(rpt report.Report) RenderableNodes {
 	return output
 }
 
+// Stats implements Renderer
+func (m Map) Stats(rpt report.Report) Stats {
+	// There doesn't seem to be an instance where we want stats to recurse
+	// through Maps - for instance we don't want to see the number of filtered
+	// processes in the container renderer.
+	return Stats{}
+}
+
 func (m Map) render(rpt report.Report) (RenderableNodes, map[string]report.IDList) {
 	var (
 		input         = m.Renderer.Render(rpt)
@@ -177,13 +206,21 @@ type Filter struct {
 
 // Render implements Renderer
 func (f Filter) Render(rpt report.Report) RenderableNodes {
+	nodes, _ := f.render(rpt)
+	return nodes
+}
+
+func (f Filter) render(rpt report.Report) (RenderableNodes, int) {
 	output := RenderableNodes{}
 	inDegrees := map[string]int{}
+	filtered := 0
 	for id, node := range f.Renderer.Render(rpt) {
 		if f.FilterFunc(node) {
 			output[id] = node
+			inDegrees[id] = 0
+		} else {
+			filtered++
 		}
-		inDegrees[id] = 0
 	}
 
 	// Deleted nodes also need to be cut as destinations in adjacency lists.
@@ -209,8 +246,17 @@ func (f Filter) Render(rpt report.Report) RenderableNodes {
 			continue
 		}
 		delete(output, id)
+		filtered++
 	}
-	return output
+	return output, filtered
+}
+
+// Stats implements Renderer
+func (f Filter) Stats(rpt report.Report) Stats {
+	_, filtered := f.render(rpt)
+	var upstream = f.Renderer.Stats(rpt)
+	upstream.FilteredNodes += filtered
+	return upstream
 }
 
 // IsConnected is the key added to Node.Metadata by ColorConnected

render/render_test.go

@@ -20,6 +20,9 @@ func (m mockRenderer) Render(rpt report.Report) render.RenderableNodes {
 func (m mockRenderer) EdgeMetadata(rpt report.Report, localID, remoteID string) report.EdgeMetadata {
 	return m.edgeMetadata
 }
+func (m mockRenderer) Stats(rpt report.Report) render.Stats {
+	return render.Stats{}
+}
 
 func TestReduceRender(t *testing.T) {
 	renderer := render.Reduce([]render.Renderer{

render/selectors.go

@@ -29,6 +29,11 @@ func (t TopologySelector) EdgeMetadata(rpt report.Report, srcID, dstID string) r
 	return metadata
 }
 
+// Stats implements Renderer
+func (t TopologySelector) Stats(r report.Report) Stats {
+	return Stats{}
+}
+
 // MakeRenderableNodes converts a topology to a set of RenderableNodes
 func MakeRenderableNodes(t report.Topology) RenderableNodes {
 	result := RenderableNodes{}

render/topologies.go

@@ -27,14 +27,14 @@ var ProcessRenderer = MakeReduce(
 	},
 )
 
-// ProcessWithContainerNameRenderer is a Renderer which produces a process
+// processWithContainerNameRenderer is a Renderer which produces a process
 // graph enriched with container names where appropriate
-type ProcessWithContainerNameRenderer struct{}
+type processWithContainerNameRenderer struct {
+	Renderer
+}
 
-// Render produces a process graph where the minor labels contain the
-// container name, if found.
-func (r ProcessWithContainerNameRenderer) Render(rpt report.Report) RenderableNodes {
-	processes := ProcessRenderer.Render(rpt)
+func (r processWithContainerNameRenderer) Render(rpt report.Report) RenderableNodes {
+	processes := r.Renderer.Render(rpt)
 	containers := Map{
 		MapFunc:  MapContainerIdentity,
 		Renderer: SelectContainer,
@@ -60,10 +60,9 @@ func (r ProcessWithContainerNameRenderer) Render(rpt report.Report) RenderableNo
 	return processes
 }
 
-// EdgeMetadata produces an EdgeMetadata for a given edge.
-func (r ProcessWithContainerNameRenderer) EdgeMetadata(rpt report.Report, localID, remoteID string) report.EdgeMetadata {
-	return ProcessRenderer.EdgeMetadata(rpt, localID, remoteID)
-}
+// ProcessWithContainerNameRenderer is a Renderer which produces a process
+// graph enriched with container names where appropriate
+var ProcessWithContainerNameRenderer = processWithContainerNameRenderer{ProcessRenderer}
 
 // ProcessRenderer is a Renderer which produces a renderable process
 // name graph by munging the progess graph.
@@ -120,14 +119,14 @@ var ContainerRenderer = MakeReduce(
 	},
 )
 
-// ContainerWithImageNameRenderer is a Renderer which produces a container
-// graph where the ranks are the image names, not their IDs
-type ContainerWithImageNameRenderer struct{}
+type containerWithImageNameRenderer struct {
+	Renderer
+}
 
 // Render produces a process graph where the minor labels contain the
 // container name, if found.
-func (r ContainerWithImageNameRenderer) Render(rpt report.Report) RenderableNodes {
-	containers := ContainerRenderer.Render(rpt)
+func (r containerWithImageNameRenderer) Render(rpt report.Report) RenderableNodes {
+	containers := r.Renderer.Render(rpt)
 	images := Map{
 		MapFunc:  MapContainerImageIdentity,
 		Renderer: SelectContainerImage,
@@ -149,10 +148,9 @@ func (r ContainerWithImageNameRenderer) Render(rpt report.Report) RenderableNode
 	return containers
 }
 
-// EdgeMetadata produces an EdgeMetadata for a given edge.
-func (r ContainerWithImageNameRenderer) EdgeMetadata(rpt report.Report, localID, remoteID string) report.EdgeMetadata {
-	return ContainerRenderer.EdgeMetadata(rpt, localID, remoteID)
-}
+// ContainerWithImageNameRenderer is a Renderer which produces a container
+// graph where the ranks are the image names, not their IDs
+var ContainerWithImageNameRenderer = containerWithImageNameRenderer{ContainerRenderer}
 
 // ContainerImageRenderer is a Renderer which produces a renderable container
 // image graph by merging the container graph and the container image topology.

render/topologies_test.go

@@ -27,7 +27,7 @@ func TestProcessNameRenderer(t *testing.T) {
 }
 
 func TestContainerRenderer(t *testing.T) {
-	have := (render.ContainerWithImageNameRenderer{}.Render(test.Report)).Prune()
+	have := (render.ContainerWithImageNameRenderer.Render(test.Report)).Prune()
 	want := expected.RenderedContainers
 	if !reflect.DeepEqual(want, have) {
 		t.Error(test.Diff(want, have))
@@ -39,7 +39,7 @@ func TestContainerFilterRenderer(t *testing.T) {
 	// it is filtered out correctly.
 	input := test.Report.Copy()
 	input.Container.Nodes[test.ClientContainerNodeID].Metadata[docker.LabelPrefix+"works.weave.role"] = "system"
-	have := render.FilterSystem(render.ContainerWithImageNameRenderer{}).Render(input).Prune()
+	have := render.FilterSystem(render.ContainerWithImageNameRenderer).Render(input).Prune()
 	want := expected.RenderedContainers.Copy()
 	delete(want, test.ClientContainerID)
 	if !reflect.DeepEqual(want, have) {