mirror of
https://github.com/tailscale/tailscale.git
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8a11a43c28
To make it easier for people to monitor their custom DERP fleet. Updates tailscale/corp#20654 Change-Id: Id8af22936a6d893cc7b6186d298ab794a2672524 Signed-off-by: Brad Fitzpatrick <bradfitz@tailscale.com>
131 lines
3.7 KiB
Go
131 lines
3.7 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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// The derpprobe binary probes derpers.
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package main
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import (
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"flag"
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"fmt"
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"html"
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"io"
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"log"
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"net/http"
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"sort"
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"time"
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"tailscale.com/prober"
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"tailscale.com/tsweb"
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"tailscale.com/version"
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)
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var (
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derpMapURL = flag.String("derp-map", "https://login.tailscale.com/derpmap/default", "URL to DERP map (https:// or file://) or 'local' to use the local tailscaled's DERP map")
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versionFlag = flag.Bool("version", false, "print version and exit")
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listen = flag.String("listen", ":8030", "HTTP listen address")
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probeOnce = flag.Bool("once", false, "probe once and print results, then exit; ignores the listen flag")
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spread = flag.Bool("spread", true, "whether to spread probing over time")
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interval = flag.Duration("interval", 15*time.Second, "probe interval")
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meshInterval = flag.Duration("mesh-interval", 15*time.Second, "mesh probe interval")
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stunInterval = flag.Duration("stun-interval", 15*time.Second, "STUN probe interval")
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tlsInterval = flag.Duration("tls-interval", 15*time.Second, "TLS probe interval")
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bwInterval = flag.Duration("bw-interval", 0, "bandwidth probe interval (0 = no bandwidth probing)")
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bwSize = flag.Int64("bw-probe-size-bytes", 1_000_000, "bandwidth probe size")
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)
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func main() {
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flag.Parse()
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if *versionFlag {
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fmt.Println(version.Long())
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return
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}
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p := prober.New().WithSpread(*spread).WithOnce(*probeOnce).WithMetricNamespace("derpprobe")
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opts := []prober.DERPOpt{
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prober.WithMeshProbing(*meshInterval),
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prober.WithSTUNProbing(*stunInterval),
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prober.WithTLSProbing(*tlsInterval),
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}
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if *bwInterval > 0 {
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opts = append(opts, prober.WithBandwidthProbing(*bwInterval, *bwSize))
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}
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dp, err := prober.DERP(p, *derpMapURL, opts...)
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if err != nil {
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log.Fatal(err)
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}
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p.Run("derpmap-probe", *interval, nil, dp.ProbeMap)
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if *probeOnce {
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log.Printf("Waiting for all probes (may take up to 1m)")
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p.Wait()
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st := getOverallStatus(p)
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for _, s := range st.good {
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log.Printf("good: %s", s)
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}
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for _, s := range st.bad {
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log.Printf("bad: %s", s)
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}
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return
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}
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mux := http.NewServeMux()
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tsweb.Debugger(mux)
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mux.HandleFunc("/", http.HandlerFunc(serveFunc(p)))
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log.Printf("Listening on %s", *listen)
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log.Fatal(http.ListenAndServe(*listen, mux))
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}
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type overallStatus struct {
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good, bad []string
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}
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func (st *overallStatus) addBadf(format string, a ...any) {
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st.bad = append(st.bad, fmt.Sprintf(format, a...))
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}
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func (st *overallStatus) addGoodf(format string, a ...any) {
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st.good = append(st.good, fmt.Sprintf(format, a...))
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}
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func getOverallStatus(p *prober.Prober) (o overallStatus) {
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for p, i := range p.ProbeInfo() {
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if i.End.IsZero() {
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// Do not show probes that have not finished yet.
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continue
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}
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if i.Result {
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o.addGoodf("%s: %s", p, i.Latency)
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} else {
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o.addBadf("%s: %s", p, i.Error)
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}
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}
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sort.Strings(o.bad)
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sort.Strings(o.good)
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return
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}
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func serveFunc(p *prober.Prober) func(w http.ResponseWriter, r *http.Request) {
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return func(w http.ResponseWriter, r *http.Request) {
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st := getOverallStatus(p)
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summary := "All good"
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if (float64(len(st.bad)) / float64(len(st.bad)+len(st.good))) > 0.25 {
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// Returning a 500 allows monitoring this server externally and configuring
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// an alert on HTTP response code.
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w.WriteHeader(500)
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summary = fmt.Sprintf("%d problems", len(st.bad))
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}
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io.WriteString(w, "<html><head><style>.bad { font-weight: bold; color: #700; }</style></head>\n")
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fmt.Fprintf(w, "<body><h1>derp probe</h1>\n%s:<ul>", summary)
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for _, s := range st.bad {
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fmt.Fprintf(w, "<li class=bad>%s</li>\n", html.EscapeString(s))
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}
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for _, s := range st.good {
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fmt.Fprintf(w, "<li>%s</li>\n", html.EscapeString(s))
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}
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io.WriteString(w, "</ul></body></html>\n")
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}
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}
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