func (h *Handler) executeTemplate(w http.ResponseWriter, name string, data interface{}) {
	text, err := h.getTemplate(name)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}

	tmpl := template.NewTemplateExpander(text, name, data, clientmodel.Now(), h.queryEngine, h.options.PathPrefix)
	tmpl.Funcs(template_text.FuncMap{
		"since":       time.Since,
		"getConsoles": h.getConsoles,
		"pathPrefix":  func() string { return h.options.PathPrefix },
		"stripLabels": func(lset clientmodel.LabelSet, labels ...clientmodel.LabelName) clientmodel.LabelSet {
			for _, ln := range labels {
				delete(lset, ln)
			}
			return lset
		},
		"globalURL": func(u *url.URL) *url.URL {
			for _, lhr := range localhostRepresentations {
				if strings.HasPrefix(u.Host, lhr+":") {
					u.Host = strings.Replace(u.Host, lhr+":", h.options.Hostname+":", 1)
				}
			}
			return u
		},
		"healthToClass": func(th retrieval.TargetHealth) string {
			switch th {
			case retrieval.HealthUnknown:
				return "warning"
			case retrieval.HealthGood:
				return "success"
			default:
				return "danger"
			}
		},
		"alertStateToClass": func(as rules.AlertState) string {
			switch as {
			case rules.StateInactive:
				return "success"
			case rules.StatePending:
				return "warning"
			case rules.StateFiring:
				return "danger"
			default:
				panic("unknown alert state")
			}
		},
	})

	result, err := tmpl.ExpandHTML(nil)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	io.WriteString(w, result)
}

func (m *Manager) queueAlertNotifications(rule *AlertingRule, timestamp clientmodel.Timestamp) {
	activeAlerts := rule.ActiveAlerts()
	if len(activeAlerts) == 0 {
		return
	}

	notifications := make(notification.NotificationReqs, 0, len(activeAlerts))
	for _, aa := range activeAlerts {
		if aa.State != StateFiring {
			// BUG: In the future, make AlertManager support pending alerts?
			continue
		}

		// Provide the alert information to the template.
		l := map[string]string{}
		for k, v := range aa.Labels {
			l[string(k)] = string(v)
		}
		tmplData := struct {
			Labels map[string]string
			Value  clientmodel.SampleValue
		}{
			Labels: l,
			Value:  aa.Value,
		}
		// Inject some convenience variables that are easier to remember for users
		// who are not used to Go's templating system.
		defs := "{{$labels := .Labels}}{{$value := .Value}}"

		expand := func(text string) string {
			tmpl := template.NewTemplateExpander(defs+text, "__alert_"+rule.Name(), tmplData, timestamp, m.queryEngine, m.externalURL.Path)
			result, err := tmpl.Expand()
			if err != nil {
				result = err.Error()
				log.Warnf("Error expanding alert template %v with data '%v': %v", rule.Name(), tmplData, err)
			}
			return result
		}

		notifications = append(notifications, &notification.NotificationReq{
			Summary:     expand(rule.summary),
			Description: expand(rule.description),
			Runbook:     rule.runbook,
			Labels: aa.Labels.Merge(clientmodel.LabelSet{
				alertNameLabel: clientmodel.LabelValue(rule.Name()),
			}),
			Value:        aa.Value,
			ActiveSince:  aa.ActiveSince.Time(),
			RuleString:   rule.String(),
			GeneratorURL: m.externalURL.String() + strutil.GraphLinkForExpression(rule.vector.String()),
		})
	}
	m.notificationHandler.SubmitReqs(notifications)
}

func (h *Handler) consoles(w http.ResponseWriter, r *http.Request) {
	ctx := route.Context(r)
	name := route.Param(ctx, "filepath")

	file, err := http.Dir(h.options.ConsoleTemplatesPath).Open(name)
	if err != nil {
		http.Error(w, err.Error(), http.StatusNotFound)
		return
	}
	text, err := ioutil.ReadAll(file)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}

	// Provide URL parameters as a map for easy use. Advanced users may have need for
	// parameters beyond the first, so provide RawParams.
	rawParams, err := url.ParseQuery(r.URL.RawQuery)
	if err != nil {
		http.Error(w, err.Error(), http.StatusBadRequest)
		return
	}
	params := map[string]string{}
	for k, v := range rawParams {
		params[k] = v[0]
	}
	data := struct {
		RawParams url.Values
		Params    map[string]string
		Path      string
	}{
		RawParams: rawParams,
		Params:    params,
		Path:      strings.TrimLeft(name, "/"),
	}

	tmpl := template.NewTemplateExpander(string(text), "__console_"+name, data, model.Now(), h.queryEngine, h.options.ExternalURL.Path)
	filenames, err := filepath.Glob(h.options.ConsoleLibrariesPath + "/*.lib")
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	result, err := tmpl.ExpandHTML(filenames)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	io.WriteString(w, result)
}

func (h *Handler) executeTemplate(w http.ResponseWriter, name string, data interface{}) {
	text, err := h.getTemplate(name)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
	}

	tmpl := template.NewTemplateExpander(text, name, data, model.Now(), h.queryEngine, h.options.ExternalURL.Path)
	tmpl.Funcs(tmplFuncs(h.consolesPath(), h.options))

	result, err := tmpl.ExpandHTML(nil)
	if err != nil {
		http.Error(w, err.Error(), http.StatusInternalServerError)
		return
	}
	io.WriteString(w, result)
}

// eval evaluates the rule expression and then creates pending alerts and fires
// or removes previously pending alerts accordingly.
func (r *AlertingRule) eval(ts model.Time, engine *promql.Engine, externalURLPath string) (model.Vector, error) {
	query, err := engine.NewInstantQuery(r.vector.String(), ts)
	if err != nil {
		return nil, err
	}
	res, err := query.Exec().Vector()
	if err != nil {
		return nil, err
	}

	r.mtx.Lock()
	defer r.mtx.Unlock()

	// Create pending alerts for any new vector elements in the alert expression
	// or update the expression value for existing elements.
	resultFPs := map[model.Fingerprint]struct{}{}

	for _, smpl := range res {
		// Provide the alert information to the template.
		l := make(map[string]string, len(smpl.Metric))
		for k, v := range smpl.Metric {
			l[string(k)] = string(v)
		}

		tmplData := struct {
			Labels map[string]string
			Value  float64
		}{
			Labels: l,
			Value:  float64(smpl.Value),
		}
		// Inject some convenience variables that are easier to remember for users
		// who are not used to Go's templating system.
		defs := "{{$labels := .Labels}}{{$value := .Value}}"

		expand := func(text model.LabelValue) model.LabelValue {
			tmpl := template.NewTemplateExpander(
				defs+string(text),
				"__alert_"+r.Name(),
				tmplData,
				ts,
				engine,
				externalURLPath,
			)
			result, err := tmpl.Expand()
			if err != nil {
				result = fmt.Sprintf("<error expanding template: %s>", err)
				log.Warnf("Error expanding alert template %v with data '%v': %s", r.Name(), tmplData, err)
			}
			return model.LabelValue(result)
		}

		labels := make(model.LabelSet, len(smpl.Metric)+len(r.labels)+1)
		for ln, lv := range smpl.Metric {
			labels[ln] = lv
		}
		for ln, lv := range r.labels {
			labels[ln] = expand(lv)
		}
		labels[model.AlertNameLabel] = model.LabelValue(r.Name())

		annotations := make(model.LabelSet, len(r.annotations))
		for an, av := range r.annotations {
			annotations[an] = expand(av)
		}
		fp := smpl.Metric.Fingerprint()
		resultFPs[fp] = struct{}{}

		if alert, ok := r.active[fp]; ok && alert.State != StateInactive {
			alert.Value = smpl.Value
			continue
		}

		delete(smpl.Metric, model.MetricNameLabel)

		r.active[fp] = &Alert{
			Labels:      labels,
			Annotations: annotations,
			ActiveAt:    ts,
			State:       StatePending,
			Value:       smpl.Value,
		}
	}

	var vec model.Vector
	// Check if any pending alerts should be removed or fire now. Write out alert timeseries.
	for fp, a := range r.active {
		if _, ok := resultFPs[fp]; !ok {
			if a.State != StateInactive {
				vec = append(vec, r.sample(a, ts, false))
			}
			// If the alert was previously firing, keep it around for a given
			// retention time so it is reported as resolved to the AlertManager.
			if a.State == StatePending || (a.ResolvedAt != 0 && ts.Sub(a.ResolvedAt) > resolvedRetention) {
				delete(r.active, fp)
			}
			if a.State != StateInactive {
				a.State = StateInactive
//.........这里部分代码省略.........

// sendAlerts sends alert notifications for the given rule.
func (g *Group) sendAlerts(rule *AlertingRule, timestamp model.Time) error {
	var alerts model.Alerts

	for _, alert := range rule.currentAlerts() {
		// Only send actually firing alerts.
		if alert.State == StatePending {
			continue
		}

		// Provide the alert information to the template.
		l := make(map[string]string, len(alert.Labels))
		for k, v := range alert.Labels {
			l[string(k)] = string(v)
		}

		tmplData := struct {
			Labels map[string]string
			Value  float64
		}{
			Labels: l,
			Value:  float64(alert.Value),
		}
		// Inject some convenience variables that are easier to remember for users
		// who are not used to Go's templating system.
		defs := "{{$labels := .Labels}}{{$value := .Value}}"

		expand := func(text model.LabelValue) model.LabelValue {
			tmpl := template.NewTemplateExpander(
				defs+string(text),
				"__alert_"+rule.Name(),
				tmplData,
				timestamp,
				g.opts.QueryEngine,
				g.opts.ExternalURL.Path,
			)
			result, err := tmpl.Expand()
			if err != nil {
				result = fmt.Sprintf("<error expanding template: %s>", err)
				log.Warnf("Error expanding alert template %v with data '%v': %s", rule.Name(), tmplData, err)
			}
			return model.LabelValue(result)
		}

		labels := make(model.LabelSet, len(alert.Labels)+1)
		for ln, lv := range alert.Labels {
			labels[ln] = expand(lv)
		}
		labels[model.AlertNameLabel] = model.LabelValue(rule.Name())

		annotations := make(model.LabelSet, len(rule.annotations))
		for an, av := range rule.annotations {
			annotations[an] = expand(av)
		}

		a := &model.Alert{
			StartsAt:     alert.ActiveAt.Add(rule.holdDuration).Time(),
			Labels:       labels,
			Annotations:  annotations,
			GeneratorURL: g.opts.ExternalURL.String() + strutil.GraphLinkForExpression(rule.vector.String()),
		}
		if alert.ResolvedAt != 0 {
			a.EndsAt = alert.ResolvedAt.Time()
		}

		alerts = append(alerts, a)
	}

	if len(alerts) > 0 {
		g.opts.NotificationHandler.Send(alerts...)
	}

	return nil
}