125 lines
3.2 KiB
Go
125 lines
3.2 KiB
Go
// Copyright (c) Tailscale Inc & AUTHORS
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// SPDX-License-Identifier: BSD-3-Clause
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package prober
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import (
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"embed"
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"fmt"
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"html/template"
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"net/http"
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"strings"
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"time"
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"tailscale.com/tsweb"
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"tailscale.com/util/mak"
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)
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//go:embed status.html
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var statusFiles embed.FS
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var statusTpl = template.Must(template.ParseFS(statusFiles, "status.html"))
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type statusHandlerOpt func(*statusHandlerParams)
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type statusHandlerParams struct {
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title string
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pageLinks map[string]string
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probeLinks map[string]string
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}
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// WithTitle sets the title of the status page.
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func WithTitle(title string) statusHandlerOpt {
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return func(opts *statusHandlerParams) {
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opts.title = title
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}
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}
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// WithPageLink adds a top-level link to the status page.
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func WithPageLink(text, url string) statusHandlerOpt {
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return func(opts *statusHandlerParams) {
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mak.Set(&opts.pageLinks, text, url)
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}
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}
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// WithProbeLink adds a link to each probe on the status page.
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// The textTpl and urlTpl are Go templates that will be rendered
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// with the respective ProbeInfo struct as the data.
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func WithProbeLink(textTpl, urlTpl string) statusHandlerOpt {
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return func(opts *statusHandlerParams) {
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mak.Set(&opts.probeLinks, textTpl, urlTpl)
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}
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}
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// StatusHandler is a handler for the probe overview HTTP endpoint.
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// It shows a list of probes and their current status.
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func (p *Prober) StatusHandler(opts ...statusHandlerOpt) tsweb.ReturnHandlerFunc {
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params := &statusHandlerParams{
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title: "Prober Status",
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}
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for _, opt := range opts {
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opt(params)
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}
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return func(w http.ResponseWriter, r *http.Request) error {
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type probeStatus struct {
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ProbeInfo
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TimeSinceLast time.Duration
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Links map[string]template.URL
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}
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vars := struct {
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Title string
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Links map[string]template.URL
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TotalProbes int64
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UnhealthyProbes int64
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Probes map[string]probeStatus
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}{
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Title: params.title,
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}
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for text, url := range params.pageLinks {
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mak.Set(&vars.Links, text, template.URL(url))
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}
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for name, info := range p.ProbeInfo() {
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vars.TotalProbes++
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if !info.Result {
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vars.UnhealthyProbes++
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}
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s := probeStatus{ProbeInfo: info}
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if !info.End.IsZero() {
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s.TimeSinceLast = time.Since(info.End).Truncate(time.Second)
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}
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for textTpl, urlTpl := range params.probeLinks {
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text, err := renderTemplate(textTpl, info)
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if err != nil {
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return tsweb.Error(500, err.Error(), err)
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}
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url, err := renderTemplate(urlTpl, info)
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if err != nil {
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return tsweb.Error(500, err.Error(), err)
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}
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mak.Set(&s.Links, text, template.URL(url))
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}
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mak.Set(&vars.Probes, name, s)
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}
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if err := statusTpl.ExecuteTemplate(w, "status", vars); err != nil {
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return tsweb.HTTPError{Code: 500, Err: err, Msg: "error rendering status page"}
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}
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return nil
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}
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}
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// renderTemplate renders the given Go template with the provided data
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// and returns the result as a string.
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func renderTemplate(tpl string, data any) (string, error) {
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t, err := template.New("").Parse(tpl)
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if err != nil {
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return "", fmt.Errorf("error parsing template %q: %w", tpl, err)
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}
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var buf strings.Builder
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if err := t.ExecuteTemplate(&buf, "", data); err != nil {
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return "", fmt.Errorf("error rendering template %q with data %v: %w", tpl, data, err)
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}
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return buf.String(), nil
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}
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