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Merge pull request #214 from stv0g/graph-handler
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kg: add new handler for rendering the topology graph via the metrics webserver
leonnicolas authored Aug 18, 2021

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2 parents ee5300d + b34e7f6 commit ce8b76d
Showing 5 changed files with 175 additions and 5 deletions.
2 changes: 1 addition & 1 deletion Dockerfile
Original file line number Diff line number Diff line change
@@ -11,7 +11,7 @@ ARG GOARCH
ARG ALPINE_VERSION=v3.12
LABEL maintainer="squat <lserven@gmail.com>"
RUN echo -e "https://alpine.global.ssl.fastly.net/alpine/$ALPINE_VERSION/main\nhttps://alpine.global.ssl.fastly.net/alpine/$ALPINE_VERSION/community" > /etc/apk/repositories && \
apk add --no-cache ipset iptables ip6tables wireguard-tools
apk add --no-cache ipset iptables ip6tables wireguard-tools graphviz font-noto
COPY --from=cni bridge host-local loopback portmap /opt/cni/bin/
COPY bin/linux/$GOARCH/kg /opt/bin/
ENTRYPOINT ["/opt/bin/kg"]
2 changes: 1 addition & 1 deletion Makefile
Original file line number Diff line number Diff line change
@@ -209,7 +209,7 @@ $(BASH_UNIT):
chmod +x $@

e2e: container $(KIND_BINARY) $(KUBECTL_BINARY) $(BASH_UNIT) bin/$(OS)/$(ARCH)/kgctl
KILO_IMAGE=$(IMAGE):$(ARCH)-$(VERSION) KIND_BINARY=$(KIND_BINARY) KUBECTL_BINARY=$(KUBECTL_BINARY) KGCTL_BINARY=$(shell pwd)/bin/$(OS)/$(ARCH)/kgctl $(BASH_UNIT) $(BASH_UNIT_FLAGS) ./e2e/setup.sh ./e2e/full-mesh.sh ./e2e/location-mesh.sh ./e2e/multi-cluster.sh ./e2e/teardown.sh
KILO_IMAGE=$(IMAGE):$(ARCH)-$(VERSION) KIND_BINARY=$(KIND_BINARY) KUBECTL_BINARY=$(KUBECTL_BINARY) KGCTL_BINARY=$(shell pwd)/bin/$(OS)/$(ARCH)/kgctl $(BASH_UNIT) $(BASH_UNIT_FLAGS) ./e2e/setup.sh ./e2e/full-mesh.sh ./e2e/location-mesh.sh ./e2e/multi-cluster.sh ./e2e/handlers.sh ./e2e/teardown.sh

header: .header
@HEADER=$$(cat .header); \
145 changes: 145 additions & 0 deletions cmd/kg/handlers.go
Original file line number Diff line number Diff line change
@@ -0,0 +1,145 @@
// 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 main

import (
"bytes"
"fmt"
"io"
"mime"
"net"
"net/http"
"os"
"os/exec"

"github.com/squat/kilo/pkg/mesh"
)

type graphHandler struct {
mesh *mesh.Mesh
granularity mesh.Granularity
hostname *string
subnet *net.IPNet
}

func (h *graphHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
ns, err := h.mesh.Nodes().List()
if err != nil {
http.Error(w, fmt.Sprintf("failed to list nodes: %v", err), http.StatusInternalServerError)
return
}
ps, err := h.mesh.Peers().List()
if err != nil {
http.Error(w, fmt.Sprintf("failed to list peers: %v", err), http.StatusInternalServerError)
return
}

nodes := make(map[string]*mesh.Node)
for _, n := range ns {
if n.Ready() {
nodes[n.Name] = n
}
}
if len(nodes) == 0 {
http.Error(w, "did not find any valid Kilo nodes in the cluster", http.StatusInternalServerError)
return
}
peers := make(map[string]*mesh.Peer)
for _, p := range ps {
if p.Ready() {
peers[p.Name] = p
}
}
topo, err := mesh.NewTopology(nodes, peers, h.granularity, *h.hostname, 0, []byte{}, h.subnet, nodes[*h.hostname].PersistentKeepalive, nil)
if err != nil {
http.Error(w, fmt.Sprintf("failed to create topology: %v", err), http.StatusInternalServerError)
return
}

dot, err := topo.Dot()
if err != nil {
http.Error(w, fmt.Sprintf("failed to generate graph: %v", err), http.StatusInternalServerError)
}

buf := bytes.NewBufferString(dot)

format := r.URL.Query().Get("format")
switch format {
case "":
format = "svg"
case "dot", "gv":
// If the raw dot data is requested, return it as string.
// This allows client-side rendering rather than server-side.
w.Write(buf.Bytes())
return

case "svg", "png", "bmp", "fig", "gif", "json", "ps":
// Accepted format

default:
http.Error(w, "unsupported format", http.StatusInternalServerError)
return
}

layout := r.URL.Query().Get("layout")
switch layout {
case "":
layout = "circo"

case "circo", "dot", "neato", "twopi", "fdp":
// Accepted layout

default:
http.Error(w, "unsupported layout", http.StatusInternalServerError)
return
}

command := exec.Command("dot", "-K"+layout, "-T"+format)
command.Stderr = os.Stderr

stdin, err := command.StdinPipe()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}

if _, err = io.Copy(stdin, buf); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}

if err = stdin.Close(); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}

output, err := command.Output()
if err != nil {
http.Error(w, "unable to render graph", http.StatusInternalServerError)
return
}

mimeType := mime.TypeByExtension("." + format)
if mimeType == "" {
mimeType = "application/octet-stream"
}

w.Header().Add("content-type", mimeType)
w.Write(output)
}

func healthHandler(w http.ResponseWriter, _ *http.Request) {
w.WriteHeader(http.StatusOK)
}
5 changes: 2 additions & 3 deletions cmd/kg/main.go
Original file line number Diff line number Diff line change
@@ -198,9 +198,8 @@ func Main() error {
{
// Run the HTTP server.
mux := http.NewServeMux()
mux.HandleFunc("/health", func(w http.ResponseWriter, _ *http.Request) {
w.WriteHeader(http.StatusOK)
})
mux.HandleFunc("/health", healthHandler)
mux.Handle("/graph", &graphHandler{m, gr, hostname, s})
mux.Handle("/metrics", promhttp.HandlerFor(r, promhttp.HandlerOpts{}))
l, err := net.Listen("tcp", *listen)
if err != nil {
26 changes: 26 additions & 0 deletions e2e/handlers.sh
Original file line number Diff line number Diff line change
@@ -0,0 +1,26 @@
#!/usr/bin/env bash
# shellcheck disable=SC1091
. lib.sh

setup_suite() {
# shellcheck disable=SC2016
block_until_ready_by_name kube-system kilo-userspace
_kubectl wait pod -l app.kubernetes.io/name=adjacency --for=condition=Ready --timeout 3m
}

test_graph_handler() {
assert "curl_pod 'http://10.4.0.1:1107/graph?format=svg&layout=circo' | grep -q '<svg'" "graph handler should produce SVG output"
assert "curl_pod http://10.4.0.1:1107/graph?layout=circo | grep -q '<svg'" "graph handler should default to SVG output"
assert "curl_pod http://10.4.0.1:1107/graph | grep -q '<svg'" "graph handler should default to SVG output"
assert_fail "curl_pod http://10.4.0.1:1107/graph?layout=fake | grep -q '<svg'" "graph handler should reject invalid layout"
assert_fail "curl_pod http://10.4.0.1:1107/graph?format=fake | grep -q '<svg'" "graph handler should reject invalid format"
}

test_health_handler() {
assert "curl_pod http://10.4.0.1:1107/health" "health handler should return a status code of 200"
}

test_metrics_handler() {
assert "curl_pod http://10.4.0.1:1107/metrics" "metrics handler should return a status code of 200"
assert "(( $(curl_pod http://10.4.0.1:1107/metrics | grep -E ^kilo_nodes | cut -d " " -f 2) > 0 ))" "metrics handler should provide metric: kilo_nodes > 0"
}

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