init

pkg/mesh/graph.go

@@ -0,0 +1,101 @@
+// Copyright 2019 the Kilo authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package mesh
+
+import (
+	"fmt"
+	"net"
+
+	"github.com/awalterschulze/gographviz"
+)
+
+// Dot generates a Graphviz graph of the Topology in DOT fomat.
+func (t *Topology) Dot() (string, error) {
+	g := gographviz.NewGraph()
+	g.Name = "kilo"
+	if err := g.AddAttr("kilo", string(gographviz.Label), graphEscape(t.subnet.String())); err != nil {
+		return "", fmt.Errorf("failed to add label to graph")
+	}
+	if err := g.AddAttr("kilo", string(gographviz.LabelLOC), "t"); err != nil {
+		return "", fmt.Errorf("failed to add label location to graph")
+	}
+	if err := g.AddAttr("kilo", string(gographviz.Overlap), "false"); err != nil {
+		return "", fmt.Errorf("failed to disable graph overlap")
+	}
+	if err := g.SetDir(true); err != nil {
+		return "", fmt.Errorf("failed to set direction")
+	}
+	leaders := make([]string, len(t.Segments))
+	nodeAttrs := map[string]string{
+		string(gographviz.Shape): "ellipse",
+	}
+	for i, s := range t.Segments {
+		if err := g.AddSubGraph("kilo", subGraphName(s.Location), nil); err != nil {
+			return "", fmt.Errorf("failed to add subgraph")
+		}
+		if err := g.AddAttr(subGraphName(s.Location), string(gographviz.Label), graphEscape(s.Location)); err != nil {
+			return "", fmt.Errorf("failed to add label to subgraph")
+		}
+		if err := g.AddAttr(subGraphName(s.Location), string(gographviz.Style), `"dashed,rounded"`); err != nil {
+			return "", fmt.Errorf("failed to add style to subgraph")
+		}
+		for j := range s.cidrs {
+			if err := g.AddNode(subGraphName(s.Location), graphEscape(s.hostnames[j]), nodeAttrs); err != nil {
+				return "", fmt.Errorf("failed to add node to subgraph")
+			}
+			var wg net.IP
+			if j == s.leader {
+				wg = s.wireGuardIP
+				if err := g.Nodes.Lookup[graphEscape(s.hostnames[j])].Attrs.Add(string(gographviz.Rank), "1"); err != nil {
+					return "", fmt.Errorf("failed to add rank to node")
+				}
+			}
+			if err := g.Nodes.Lookup[graphEscape(s.hostnames[j])].Attrs.Add(string(gographviz.Label), nodeLabel(s.Location, s.hostnames[j], s.cidrs[j], s.privateIPs[j], wg)); err != nil {
+				return "", fmt.Errorf("failed to add label to node")
+			}
+		}
+		meshSubGraph(g, g.Relations.SortedChildren(subGraphName(s.Location)), s.leader)
+		leaders[i] = graphEscape(s.hostnames[s.leader])
+	}
+	meshSubGraph(g, leaders, 0)
+	return g.String(), nil
+}
+
+func meshSubGraph(g *gographviz.Graph, nodes []string, leader int) {
+	for i := range nodes {
+		if i == leader {
+			continue
+		}
+		a := make(gographviz.Attrs)
+		a[gographviz.Dir] = "both"
+		g.Edges.Add(&gographviz.Edge{Src: nodes[leader], Dst: nodes[i], Dir: true, Attrs: a})
+	}
+}
+
+func graphEscape(s string) string {
+	return fmt.Sprintf("\"%s\"", s)
+}
+
+func subGraphName(name string) string {
+	return graphEscape(fmt.Sprintf("cluster_%s", name))
+}
+
+func nodeLabel(location, name string, cidr *net.IPNet, priv, wgIP net.IP) string {
+	var wg string
+	if wgIP != nil {
+		wg = wgIP.String()
+	}
+	return graphEscape(fmt.Sprintf("%s\n%s\n%s\n%s\n%s", location, name, cidr.String(), priv.String(), wg))
+}