kilo/cmd/kg/handlers.go
Steffen Vogel 1b5ad035d9
kg: add new handler for rendering the topology graph
docker: add missing fonts for rasterized graphviz  output formats

add missing license header

kg: do not export handlers

use http package for status codes

keep checks for errors in a single line

simplify error message about failed invocation of dot

pass node hostname and subnet to graph handler

use SVG as default format for graph handler

register health handler with HandleFunc

add option for selecting layout to graph handler and using circo as new default

e2e: add tests for HTTP handlers

e2e: fix and simplify handler tests

add should comments to assertions

e2s: use assert_fail instead of assert _not

add missing mime-type header for graph handler

use switch/case statements for validating formats / layouts

e2e: fix handlers tests

Co-authored-by: leonnicolas <60091705+leonnicolas@users.noreply.github.com>

graph-handler: add missing font to Dockerfile

Dockerfile: remove unnecessary font

This commit leaves Noto as the only font package, as one font package is
sufficient for the container.

Signed-off-by: Lucas Servén Marín <lserven@gmail.com>
2021-08-18 14:04:44 +02:00

146 lines
3.5 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 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)
}