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web.go
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web.go
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package main
import (
"encoding/json"
"fmt"
"net/http"
"sort"
"strconv"
"strings"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/httpserver"
)
// APIAlert has info for an alert.
type APIAlert struct {
ID uint64 `json:"id"`
Name string `json:"name"`
Group string `json:"group"`
Expression string `json:"expression"`
State string `json:"state"`
Value string `json:"value"`
Labels map[string]string `json:"labels"`
Annotations map[string]string `json:"annotations"`
ActiveAt time.Time `json:"activeAt"`
}
type requestHandler struct {
groups []Group
}
var pathList = [][]string{
{"/api/v1/alerts", "list all active alerts"},
{"/api/v1/groupName/alertID/status", "get alert status by ID"},
// /metrics is served by httpserver by default
{"/metrics", "list of application metrics"},
}
func (rh *requestHandler) handler(w http.ResponseWriter, r *http.Request) bool {
resph := responseHandler{w}
switch r.URL.Path {
case "/":
for _, path := range pathList {
p, doc := path[0], path[1]
fmt.Fprintf(w, "<a href='%s'>%q</a> - %s<br/>", p, p, doc)
}
return true
case "/api/v1/alerts":
resph.handle(rh.list())
return true
default:
// /api/v1/<groupName>/<alertID>/status
if strings.HasSuffix(r.URL.Path, "/status") {
resph.handle(rh.alert(r.URL.Path))
return true
}
return false
}
}
type listAlertsResponse struct {
Data struct {
Alerts []*APIAlert `json:"alerts"`
} `json:"data"`
Status string `json:"status"`
}
func (rh *requestHandler) list() ([]byte, error) {
lr := listAlertsResponse{Status: "success"}
for _, g := range rh.groups {
for _, r := range g.Rules {
lr.Data.Alerts = append(lr.Data.Alerts, r.AlertsAPI()...)
}
}
// sort list of alerts for deterministic output
sort.Slice(lr.Data.Alerts, func(i, j int) bool {
return lr.Data.Alerts[i].Name < lr.Data.Alerts[j].Name
})
b, err := json.Marshal(lr)
if err != nil {
return nil, &httpserver.ErrorWithStatusCode{
Err: fmt.Errorf(`error encoding list of active alerts: %s`, err),
StatusCode: http.StatusInternalServerError,
}
}
return b, nil
}
func (rh *requestHandler) alert(path string) ([]byte, error) {
parts := strings.SplitN(strings.TrimPrefix(path, "/api/v1/"), "/", 3)
if len(parts) != 3 {
return nil, &httpserver.ErrorWithStatusCode{
Err: fmt.Errorf(`path %q cointains /status suffix but doesn't match pattern "/group/alert/status"`, path),
StatusCode: http.StatusBadRequest,
}
}
group := strings.TrimRight(parts[0], "/")
idStr := strings.TrimRight(parts[1], "/")
id, err := strconv.ParseUint(idStr, 10, 0)
if err != nil {
return nil, &httpserver.ErrorWithStatusCode{
Err: fmt.Errorf(`cannot parse int from %q`, idStr),
StatusCode: http.StatusBadRequest,
}
}
for _, g := range rh.groups {
if g.Name != group {
continue
}
for i := range g.Rules {
if apiAlert := g.Rules[i].AlertAPI(id); apiAlert != nil {
return json.Marshal(apiAlert)
}
}
}
return nil, &httpserver.ErrorWithStatusCode{
Err: fmt.Errorf(`cannot find alert %s in %q`, idStr, group),
StatusCode: http.StatusNotFound,
}
}
// responseHandler wrapper on http.ResponseWriter with sugar
type responseHandler struct{ http.ResponseWriter }
func (w responseHandler) handle(b []byte, err error) {
if err != nil {
httpserver.Errorf(w, "%s", err)
return
}
w.Header().Set("Content-Type", "application/json")
w.Write(b)
}