kilo/pkg/mesh/graph.go
Lucas Servén Marín aa376ff0d1
pkg/mesh,pkg/wireguard: allow DNS name endpoints
This commit allows DNS names to be used when specifying the endpoint
for a node in the WireGuard mesh. This is useful in many scenarios, in
particular when operating an IoT device whose public IP is dynamic. This
change allows the administrator to use a dynamic DNS name in the node's
endpoint.

One of the side-effects of this change is that the WireGuard port can
now be specified individually for each node in the mesh, if the
administrator wishes to do so.

*Note*: this commit introduces a breaking change; the
`force-external-ip` node annotation has been removed; its functionality
has been ported over to the `force-endpoint` annotation. This annotation
is documented in the annotations.md file. The expected content of this
annotation is no longer a CIDR but rather a host:port. The host can be
either a DNS name or an IP.

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>
2020-02-22 17:17:13 +01:00

172 lines
5.7 KiB
Go

// 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"
"strings"
"github.com/awalterschulze/gographviz"
"github.com/squat/kilo/pkg/wireguard"
)
// 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.OutputOrder), "nodesfirst"); err != nil {
return "", fmt.Errorf("failed to set output ordering")
}
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
var endpoint *wireguard.Endpoint
if j == s.leader {
wg = s.wireGuardIP
endpoint = s.endpoint
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, endpoint)); err != nil {
return "", fmt.Errorf("failed to add label to node")
}
}
meshSubGraph(g, g.Relations.SortedChildren(subGraphName(s.location)), s.leader, nil)
leaders[i] = graphEscape(s.hostnames[s.leader])
}
meshGraph(g, leaders, nil)
if err := g.AddSubGraph("kilo", graphEscape("cluster_peers"), nil); err != nil {
return "", fmt.Errorf("failed to add peer subgraph")
}
if err := g.AddAttr(graphEscape("cluster_peers"), string(gographviz.Label), graphEscape("peers")); err != nil {
return "", fmt.Errorf("failed to add label to peer subgraph")
}
if err := g.AddAttr(graphEscape("cluster_peers"), string(gographviz.Style), `"dashed,rounded"`); err != nil {
return "", fmt.Errorf("failed to add style to peer subgraph")
}
for j := range t.peers {
if err := g.AddNode(graphEscape("cluster_peers"), graphEscape(t.peers[j].Name), nodeAttrs); err != nil {
return "", fmt.Errorf("failed to add peer node to peer subgraph")
}
if err := g.Nodes.Lookup[graphEscape(t.peers[j].Name)].Attrs.Add(string(gographviz.Label), peerLabel(t.peers[j])); err != nil {
return "", fmt.Errorf("failed to add label to peer node")
}
}
meshPeers(g, leaders, g.Relations.SortedChildren(graphEscape("cluster_peers")), nil)
return g.String(), nil
}
func meshGraph(g *gographviz.Graph, nodes []string, attrs gographviz.Attrs) {
if attrs == nil {
attrs = make(gographviz.Attrs)
attrs[gographviz.Dir] = "both"
}
for i := range nodes {
for j := i + 1; j < len(nodes); j++ {
if i == j {
continue
}
g.Edges.Add(&gographviz.Edge{Src: nodes[i], Dst: nodes[j], Dir: true, Attrs: attrs})
}
}
}
func meshSubGraph(g *gographviz.Graph, nodes []string, leader int, attrs gographviz.Attrs) {
if attrs == nil {
attrs = make(gographviz.Attrs)
attrs[gographviz.Dir] = "both"
}
for i := range nodes {
if i == leader {
continue
}
g.Edges.Add(&gographviz.Edge{Src: nodes[leader], Dst: nodes[i], Dir: true, Attrs: attrs})
}
}
func meshPeers(g *gographviz.Graph, nodes, peers []string, attrs gographviz.Attrs) {
if attrs == nil {
attrs = make(gographviz.Attrs)
attrs[gographviz.Dir] = "both"
attrs[gographviz.Style] = "dashed"
}
for i := range nodes {
for j := range peers {
g.Edges.Add(&gographviz.Edge{Src: nodes[i], Dst: peers[j], Dir: true, Attrs: attrs})
}
}
}
func graphEscape(s string) string {
return fmt.Sprintf("\"%s\"", s)
}
func subGraphName(name string) string {
return graphEscape(fmt.Sprintf("cluster_location_%s", name))
}
func nodeLabel(location, name string, cidr *net.IPNet, priv, wgIP net.IP, endpoint *wireguard.Endpoint) string {
label := []string{
location,
name,
cidr.String(),
priv.String(),
}
if wgIP != nil {
label = append(label, wgIP.String())
}
if endpoint != nil {
label = append(label, endpoint.String())
}
return graphEscape(strings.Join(label, "\n"))
}
func peerLabel(peer *Peer) string {
return graphEscape(fmt.Sprintf("%s\n%s\n", peer.Name, peer.Endpoint.String()))
}