Merge pull request #2997 from weaveworks/no-image-host-propagation

don't map image adjacencies to hosts

render/host.go

@@ -16,6 +16,10 @@ var HostRenderer = MakeReduce(
 	endpoints2Hosts{},
 )
 
+func newHostNode(id string) report.Node {
+	return report.MakeNode(id).WithTopology(report.Host)
+}
+
 // nodes2Hosts maps any Nodes to host Nodes.
 //
 // If this function is given a node without a hostname
@@ -32,11 +36,19 @@ func nodes2Hosts(nodes Nodes) Nodes {
 		if n.Topology == Pseudo {
 			continue // Don't propagate pseudo nodes - we do this in endpoints2Hosts
 		}
+		isImage := n.Topology == report.ContainerImage
 		hostIDs, _ := n.Parents.Lookup(report.Host)
 		for _, id := range hostIDs {
-			ret.addChild(n, id, func(id string) report.Node {
-				return report.MakeNode(id).WithTopology(report.Host)
-			})
+			if isImage {
+				// We need to treat image nodes specially because they
+				// aggregate adjacencies of containers across multiple
+				// hosts, and hence mapping these adjacencies to host
+				// adjacencies would produce edges that aren't present
+				// in reality.
+				ret.addUnmappedChild(n, id, newHostNode)
+			} else {
+				ret.addChild(n, id, newHostNode)
+			}
 		}
 	}
 	return ret.result(nodes)
@@ -64,7 +76,7 @@ func (e endpoints2Hosts) Render(rpt report.Report) Nodes {
 			ret.addChild(n, id, func(id string) report.Node {
 				// we have a hostNodeID, but no matching host node;
 				// create a new one rather than dropping the data
-				return report.MakeNode(id).WithTopology(report.Host).
+				return newHostNode(id).
 					WithLatest(report.HostNodeID, timestamp, hostNodeID)
 			})
 		}

render/render.go

@@ -176,18 +176,17 @@ func newJoinResults(inputNodes report.Nodes) joinResults {
 	return joinResults{nodes: nodes, mapped: map[string]string{}, multi: map[string][]string{}}
 }
 
-func (ret *joinResults) add(m report.Node, n report.Node) {
-	ret.nodes[n.ID] = n
-	if _, ok := ret.mapped[m.ID]; !ok {
-		ret.mapped[m.ID] = n.ID
+func (ret *joinResults) mapChild(from, to string) {
+	if _, ok := ret.mapped[from]; !ok {
+		ret.mapped[from] = to
 	} else {
-		ret.multi[m.ID] = append(ret.multi[m.ID], n.ID)
+		ret.multi[from] = append(ret.multi[from], to)
 	}
 }
 
 // Add m as a child of the node at id, creating a new result node if
-// not already there, and updating the mapping from old ID to new ID.
-func (ret *joinResults) addChild(m report.Node, id string, create func(string) report.Node) {
+// not already there.
+func (ret *joinResults) addUnmappedChild(m report.Node, id string, create func(string) report.Node) {
 	result, exists := ret.nodes[id]
 	if !exists {
 		result = create(id)
@@ -196,27 +195,30 @@ func (ret *joinResults) addChild(m report.Node, id string, create func(string) r
 	if m.Topology != report.Endpoint { // optimisation: we never look at endpoint counts
 		result.Counters = result.Counters.Add(m.Topology, 1)
 	}
-	ret.add(m, result)
+	ret.nodes[id] = result
+}
+
+// Add m as a child of the node at id, creating a new result node if
+// not already there, and updating the mapping from old ID to new ID.
+func (ret *joinResults) addChild(m report.Node, id string, create func(string) report.Node) {
+	ret.addUnmappedChild(m, id, create)
+	ret.mapChild(m.ID, id)
 }
 
 // Like addChild, but also add m's children.
 func (ret *joinResults) addChildAndChildren(m report.Node, id string, create func(string) report.Node) {
-	result, exists := ret.nodes[id]
-	if !exists {
-		result = create(id)
-	}
-	result.Children = result.Children.Add(m)
+	ret.addUnmappedChild(m, id, create)
+	result := ret.nodes[id]
 	result.Children = result.Children.Merge(m.Children)
-	if m.Topology != report.Endpoint { // optimisation: we never look at endpoint counts
-		result.Counters = result.Counters.Add(m.Topology, 1)
-	}
-	ret.add(m, result)
+	ret.nodes[id] = result
+	ret.mapChild(m.ID, id)
 }
 
 // Add a copy of n straight into the results
 func (ret *joinResults) passThrough(n report.Node) {
 	n.Adjacency = nil // result() assumes all nodes start with no adjacencies
-	ret.add(n, n)
+	ret.nodes[n.ID] = n
+	ret.mapChild(n.ID, n.ID)
 }
 
 // Rewrite Adjacency of nodes in ret mapped from original nodes in