prometheus/web/web.go

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// Copyright 2013 The Prometheus 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 web
import (
"encoding/json"
"fmt"
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"io"
"io/ioutil"
"net"
"net/http"
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"net/url"
"os"
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"path/filepath"
"sort"
"strings"
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"sync"
"time"
pprof_runtime "runtime/pprof"
template_text "text/template"
clientmodel "github.com/prometheus/client_golang/model"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/log"
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"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/retrieval"
"github.com/prometheus/prometheus/rules"
"github.com/prometheus/prometheus/storage/local"
"github.com/prometheus/prometheus/template"
"github.com/prometheus/prometheus/util/route"
"github.com/prometheus/prometheus/version"
"github.com/prometheus/prometheus/web/api/legacy"
"github.com/prometheus/prometheus/web/api/v1"
"github.com/prometheus/prometheus/web/blob"
)
var localhostRepresentations = []string{"127.0.0.1", "localhost"}
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// Handler serves various HTTP endpoints of the Prometheus server
type Handler struct {
ruleManager *rules.Manager
queryEngine *promql.Engine
apiV1 *v1.API
apiLegacy *legacy.API
federation *Federation
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router *route.Router
quitCh chan struct{}
options *Options
statusInfo *PrometheusStatus
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muAlerts sync.Mutex
}
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// PrometheusStatus contains various information about the status
// of the running Prometheus process.
type PrometheusStatus struct {
Birth time.Time
Flags map[string]string
Config string
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// A function that returns the current scrape targets pooled
// by their job name.
TargetPools func() map[string][]*retrieval.Target
// A function that returns all loaded rules.
Rules func() []rules.Rule
mu sync.RWMutex
}
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// ApplyConfig updates the status state as the new config requires.
// Returns true on success.
func (s *PrometheusStatus) ApplyConfig(conf *config.Config) bool {
s.mu.Lock()
s.Config = conf.String()
s.mu.Unlock()
return true
}
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// Options for the web Handler.
type Options struct {
ListenAddress string
ExternalURL *url.URL
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MetricsPath string
UseLocalAssets bool
UserAssetsPath string
ConsoleTemplatesPath string
ConsoleLibrariesPath string
EnableQuit bool
}
// New initializes a new web Handler.
func New(st local.Storage, qe *promql.Engine, rm *rules.Manager, status *PrometheusStatus, o *Options) *Handler {
router := route.New()
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h := &Handler{
router: router,
quitCh: make(chan struct{}),
options: o,
statusInfo: status,
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ruleManager: rm,
queryEngine: qe,
apiV1: &v1.API{
QueryEngine: qe,
Storage: st,
},
apiLegacy: &legacy.API{
QueryEngine: qe,
Storage: st,
Now: clientmodel.Now,
},
federation: &Federation{
Storage: st,
},
}
if o.ExternalURL.Path != "" {
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// If the prefix is missing for the root path, prepend it.
router.Get("/", func(w http.ResponseWriter, r *http.Request) {
http.Redirect(w, r, o.ExternalURL.Path, http.StatusFound)
})
router = router.WithPrefix(o.ExternalURL.Path)
}
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instrf := prometheus.InstrumentHandlerFunc
instrh := prometheus.InstrumentHandler
router.Get("/", instrf("status", h.status))
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router.Get("/alerts", instrf("alerts", h.alerts))
router.Get("/graph", instrf("graph", h.graph))
router.Get("/version", instrf("version", h.version))
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router.Get("/heap", instrf("heap", dumpHeap))
router.Get("/federate", instrh("federate", h.federation))
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router.Get(o.MetricsPath, prometheus.Handler().ServeHTTP)
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h.apiLegacy.Register(router.WithPrefix("/api"))
h.apiV1.Register(router.WithPrefix("/api/v1"))
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router.Get("/consoles/*filepath", instrf("consoles", h.consoles))
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if o.UseLocalAssets {
router.Get("/static/*filepath", instrf("static", route.FileServe("web/blob/static")))
} else {
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router.Get("/static/*filepath", instrh("static", blob.Handler{}))
}
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if o.UserAssetsPath != "" {
router.Get("/user/*filepath", instrf("user", route.FileServe(o.UserAssetsPath)))
}
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if o.EnableQuit {
router.Post("/-/quit", h.quit)
}
router.Get("/debug/*subpath", http.DefaultServeMux.ServeHTTP)
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return h
}
// Quit returns the receive-only quit channel.
func (h *Handler) Quit() <-chan struct{} {
return h.quitCh
}
// Run serves the HTTP endpoints.
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func (h *Handler) Run() {
log.Infof("Listening on %s", h.options.ListenAddress)
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// If we cannot bind to a port, retry after 30 seconds.
for {
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err := http.ListenAndServe(h.options.ListenAddress, h.router)
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if err != nil {
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log.Errorf("Could not listen on %s: %s", h.options.ListenAddress, err)
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}
time.Sleep(30 * time.Second)
}
}
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func (h *Handler) alerts(w http.ResponseWriter, r *http.Request) {
h.muAlerts.Lock()
defer h.muAlerts.Unlock()
alerts := h.ruleManager.AlertingRules()
alertsSorter := byAlertStateSorter{alerts: alerts}
sort.Sort(alertsSorter)
alertStatus := AlertStatus{
AlertingRules: alertsSorter.alerts,
AlertStateToRowClass: map[rules.AlertState]string{
rules.StateInactive: "success",
rules.StatePending: "warning",
rules.StateFiring: "danger",
},
}
h.executeTemplate(w, "alerts", alertStatus)
}
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, "/"),
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}
tmpl := template.NewTemplateExpander(string(text), "__console_"+name, data, clientmodel.Now(), h.queryEngine, h.options.ExternalURL.Path)
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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) graph(w http.ResponseWriter, r *http.Request) {
h.executeTemplate(w, "graph", nil)
}
func (h *Handler) status(w http.ResponseWriter, r *http.Request) {
h.statusInfo.mu.RLock()
defer h.statusInfo.mu.RUnlock()
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h.executeTemplate(w, "status", struct {
Status *PrometheusStatus
Info map[string]string
}{
Status: h.statusInfo,
Info: version.Map,
})
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}
func (h *Handler) version(w http.ResponseWriter, r *http.Request) {
dec := json.NewEncoder(w)
if err := dec.Encode(version.Map); err != nil {
http.Error(w, fmt.Sprintf("error encoding JSON: %s", err), http.StatusInternalServerError)
}
}
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func (h *Handler) quit(w http.ResponseWriter, r *http.Request) {
fmt.Fprintf(w, "Requesting termination... Goodbye!")
close(h.quitCh)
}
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func (h *Handler) getTemplateFile(name string) (string, error) {
if h.options.UseLocalAssets {
file, err := ioutil.ReadFile(fmt.Sprintf("web/blob/templates/%s.html", name))
if err != nil {
log.Errorf("Could not read %s template: %s", name, err)
return "", err
}
return string(file), nil
}
file, err := blob.GetFile(blob.TemplateFiles, name+".html")
if err != nil {
log.Errorf("Could not read %s template: %s", name, err)
return "", err
}
return string(file), nil
}
func (h *Handler) consolesPath() string {
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if _, err := os.Stat(h.options.ConsoleTemplatesPath + "/index.html"); !os.IsNotExist(err) {
return h.options.ExternalURL.Path + "/consoles/index.html"
}
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if h.options.UserAssetsPath != "" {
if _, err := os.Stat(h.options.UserAssetsPath + "/index.html"); !os.IsNotExist(err) {
return h.options.ExternalURL.Path + "/user/index.html"
}
}
return ""
}
func (h *Handler) getTemplate(name string) (string, error) {
baseTmpl, err := h.getTemplateFile("_base")
if err != nil {
return "", fmt.Errorf("Error reading base template: %s", err)
}
pageTmpl, err := h.getTemplateFile(name)
if err != nil {
return "", fmt.Errorf("Error reading page template %s: %s", name, err)
}
return baseTmpl + pageTmpl, nil
}
func tmplFuncs(consolesPath string, opts *Options) template_text.FuncMap {
return template_text.FuncMap{
"since": time.Since,
"consolesPath": func() string { return consolesPath },
"pathPrefix": func() string { return opts.ExternalURL.Path },
"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 {
host, port, err := net.SplitHostPort(u.Host)
if err != nil {
return u
}
for _, lhr := range localhostRepresentations {
if host == lhr {
_, ownPort, err := net.SplitHostPort(opts.ListenAddress)
if err != nil {
return u
}
if port == ownPort {
// Only in the case where the target is on localhost and its port is
// the same as the one we're listening on, we know for sure that
// we're monitoring our own process and that we need to change the
// scheme, hostname, and port to the externally reachable ones as
// well. We shouldn't need to touch the path at all, since if a
// path prefix is defined, the path under which we scrape ourselves
// should already contain the prefix.
u.Scheme = opts.ExternalURL.Scheme
u.Host = opts.ExternalURL.Host
} else {
// Otherwise, we only know that localhost is not reachable
// externally, so we replace only the hostname by the one in the
// external URL. It could be the wrong hostname for the service on
// this port, but it's still the best possible guess.
host, _, err := net.SplitHostPort(opts.ExternalURL.Host)
if err != nil {
return u
}
u.Host = host + ":" + port
}
break
}
}
return u
},
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"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")
}
},
}
}
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.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)
}
func dumpHeap(w http.ResponseWriter, r *http.Request) {
target := fmt.Sprintf("/tmp/%d.heap", time.Now().Unix())
f, err := os.Create(target)
if err != nil {
log.Error("Could not dump heap: ", err)
}
fmt.Fprintf(w, "Writing to %s...", target)
defer f.Close()
pprof_runtime.WriteHeapProfile(f)
fmt.Fprintf(w, "Done")
}
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// AlertStatus bundles alerting rules and the mapping of alert states to row classes.
type AlertStatus struct {
AlertingRules []*rules.AlertingRule
AlertStateToRowClass map[rules.AlertState]string
}
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type byAlertStateSorter struct {
alerts []*rules.AlertingRule
}
func (s byAlertStateSorter) Len() int {
return len(s.alerts)
}
func (s byAlertStateSorter) Less(i, j int) bool {
return s.alerts[i].State() > s.alerts[j].State()
}
func (s byAlertStateSorter) Swap(i, j int) {
s.alerts[i], s.alerts[j] = s.alerts[j], s.alerts[i]
}