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api.go
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// Copyright 2016 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 v1
import (
"encoding/json"
"errors"
"fmt"
"math"
"net/http"
"net/url"
"sort"
"strconv"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/model"
"github.com/prometheus/common/route"
"golang.org/x/net/context"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/promql"
"github.com/prometheus/prometheus/retrieval"
"github.com/prometheus/prometheus/storage/local"
"github.com/prometheus/prometheus/storage/metric"
"github.com/prometheus/prometheus/storage/remote"
"github.com/prometheus/prometheus/util/httputil"
)
type status string
const (
statusSuccess status = "success"
statusError = "error"
)
type errorType string
const (
errorNone errorType = ""
errorTimeout = "timeout"
errorCanceled = "canceled"
errorExec = "execution"
errorBadData = "bad_data"
errorInternal = "internal"
)
var corsHeaders = map[string]string{
"Access-Control-Allow-Headers": "Accept, Authorization, Content-Type, Origin",
"Access-Control-Allow-Methods": "GET, OPTIONS",
"Access-Control-Allow-Origin": "*",
"Access-Control-Expose-Headers": "Date",
}
type apiError struct {
typ errorType
err error
}
func (e *apiError) Error() string {
return fmt.Sprintf("%s: %s", e.typ, e.err)
}
type targetRetriever interface {
Targets() []*retrieval.Target
}
type alertmanagerRetriever interface {
Alertmanagers() []*url.URL
}
type response struct {
Status status `json:"status"`
Data interface{} `json:"data,omitempty"`
ErrorType errorType `json:"errorType,omitempty"`
Error string `json:"error,omitempty"`
}
// Enables cross-site script calls.
func setCORS(w http.ResponseWriter) {
for h, v := range corsHeaders {
w.Header().Set(h, v)
}
}
type apiFunc func(r *http.Request) (interface{}, *apiError)
// API can register a set of endpoints in a router and handle
// them using the provided storage and query engine.
type API struct {
Storage local.Storage
QueryEngine *promql.Engine
targetRetriever targetRetriever
alertmanagerRetriever alertmanagerRetriever
now func() model.Time
config func() config.Config
ready func(http.HandlerFunc) http.HandlerFunc
}
// NewAPI returns an initialized API type.
func NewAPI(
qe *promql.Engine,
st local.Storage,
tr targetRetriever,
ar alertmanagerRetriever,
configFunc func() config.Config,
readyFunc func(http.HandlerFunc) http.HandlerFunc,
) *API {
return &API{
QueryEngine: qe,
Storage: st,
targetRetriever: tr,
alertmanagerRetriever: ar,
now: model.Now,
config: configFunc,
ready: readyFunc,
}
}
// Register the API's endpoints in the given router.
func (api *API) Register(r *route.Router) {
instr := func(name string, f apiFunc) http.HandlerFunc {
hf := http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
setCORS(w)
if data, err := f(r); err != nil {
respondError(w, err, data)
} else if data != nil {
respond(w, data)
} else {
w.WriteHeader(http.StatusNoContent)
}
})
return api.ready(prometheus.InstrumentHandler(name, httputil.CompressionHandler{
Handler: hf,
}))
}
r.Options("/*path", instr("options", api.options))
r.Get("/query", instr("query", api.query))
r.Get("/query_range", instr("query_range", api.queryRange))
r.Get("/label/:name/values", instr("label_values", api.labelValues))
r.Get("/series", instr("series", api.series))
r.Del("/series", instr("drop_series", api.dropSeries))
r.Get("/targets", instr("targets", api.targets))
r.Get("/alertmanagers", instr("alertmanagers", api.alertmanagers))
r.Get("/status/config", instr("config", api.serveConfig))
r.Post("/read", api.ready(prometheus.InstrumentHandler("read", http.HandlerFunc(api.remoteRead))))
}
type queryData struct {
ResultType model.ValueType `json:"resultType"`
Result model.Value `json:"result"`
}
func (api *API) options(r *http.Request) (interface{}, *apiError) {
return nil, nil
}
func (api *API) query(r *http.Request) (interface{}, *apiError) {
var ts model.Time
if t := r.FormValue("time"); t != "" {
var err error
ts, err = parseTime(t)
if err != nil {
return nil, &apiError{errorBadData, err}
}
} else {
ts = api.now()
}
ctx := r.Context()
if to := r.FormValue("timeout"); to != "" {
var cancel context.CancelFunc
timeout, err := parseDuration(to)
if err != nil {
return nil, &apiError{errorBadData, err}
}
ctx, cancel = context.WithTimeout(ctx, timeout)
defer cancel()
}
qry, err := api.QueryEngine.NewInstantQuery(r.FormValue("query"), ts)
if err != nil {
return nil, &apiError{errorBadData, err}
}
res := qry.Exec(ctx)
if res.Err != nil {
switch res.Err.(type) {
case promql.ErrQueryCanceled:
return nil, &apiError{errorCanceled, res.Err}
case promql.ErrQueryTimeout:
return nil, &apiError{errorTimeout, res.Err}
case promql.ErrStorage:
return nil, &apiError{errorInternal, res.Err}
}
return nil, &apiError{errorExec, res.Err}
}
return &queryData{
ResultType: res.Value.Type(),
Result: res.Value,
}, nil
}
func (api *API) queryRange(r *http.Request) (interface{}, *apiError) {
start, err := parseTime(r.FormValue("start"))
if err != nil {
return nil, &apiError{errorBadData, err}
}
end, err := parseTime(r.FormValue("end"))
if err != nil {
return nil, &apiError{errorBadData, err}
}
if end.Before(start) {
err := errors.New("end timestamp must not be before start time")
return nil, &apiError{errorBadData, err}
}
step, err := parseDuration(r.FormValue("step"))
if err != nil {
return nil, &apiError{errorBadData, err}
}
if step <= 0 {
err := errors.New("zero or negative query resolution step widths are not accepted. Try a positive integer")
return nil, &apiError{errorBadData, err}
}
// For safety, limit the number of returned points per timeseries.
// This is sufficient for 60s resolution for a week or 1h resolution for a year.
if end.Sub(start)/step > 11000 {
err := errors.New("exceeded maximum resolution of 11,000 points per timeseries. Try decreasing the query resolution (?step=XX)")
return nil, &apiError{errorBadData, err}
}
ctx := r.Context()
if to := r.FormValue("timeout"); to != "" {
var cancel context.CancelFunc
timeout, err := parseDuration(to)
if err != nil {
return nil, &apiError{errorBadData, err}
}
ctx, cancel = context.WithTimeout(ctx, timeout)
defer cancel()
}
qry, err := api.QueryEngine.NewRangeQuery(r.FormValue("query"), start, end, step)
if err != nil {
return nil, &apiError{errorBadData, err}
}
res := qry.Exec(ctx)
if res.Err != nil {
switch res.Err.(type) {
case promql.ErrQueryCanceled:
return nil, &apiError{errorCanceled, res.Err}
case promql.ErrQueryTimeout:
return nil, &apiError{errorTimeout, res.Err}
}
return nil, &apiError{errorExec, res.Err}
}
return &queryData{
ResultType: res.Value.Type(),
Result: res.Value,
}, nil
}
func (api *API) labelValues(r *http.Request) (interface{}, *apiError) {
name := route.Param(r.Context(), "name")
if !model.LabelNameRE.MatchString(name) {
return nil, &apiError{errorBadData, fmt.Errorf("invalid label name: %q", name)}
}
q, err := api.Storage.Querier()
if err != nil {
return nil, &apiError{errorExec, err}
}
defer q.Close()
vals, err := q.LabelValuesForLabelName(r.Context(), model.LabelName(name))
if err != nil {
return nil, &apiError{errorExec, err}
}
sort.Sort(vals)
return vals, nil
}
func (api *API) series(r *http.Request) (interface{}, *apiError) {
r.ParseForm()
if len(r.Form["match[]"]) == 0 {
return nil, &apiError{errorBadData, fmt.Errorf("no match[] parameter provided")}
}
var start model.Time
if t := r.FormValue("start"); t != "" {
var err error
start, err = parseTime(t)
if err != nil {
return nil, &apiError{errorBadData, err}
}
} else {
start = model.Earliest
}
var end model.Time
if t := r.FormValue("end"); t != "" {
var err error
end, err = parseTime(t)
if err != nil {
return nil, &apiError{errorBadData, err}
}
} else {
end = model.Latest
}
var matcherSets []metric.LabelMatchers
for _, s := range r.Form["match[]"] {
matchers, err := promql.ParseMetricSelector(s)
if err != nil {
return nil, &apiError{errorBadData, err}
}
matcherSets = append(matcherSets, matchers)
}
q, err := api.Storage.Querier()
if err != nil {
return nil, &apiError{errorExec, err}
}
defer q.Close()
res, err := q.MetricsForLabelMatchers(r.Context(), start, end, matcherSets...)
if err != nil {
return nil, &apiError{errorExec, err}
}
metrics := make([]model.Metric, 0, len(res))
for _, met := range res {
metrics = append(metrics, met.Metric)
}
return metrics, nil
}
func (api *API) dropSeries(r *http.Request) (interface{}, *apiError) {
r.ParseForm()
if len(r.Form["match[]"]) == 0 {
return nil, &apiError{errorBadData, fmt.Errorf("no match[] parameter provided")}
}
numDeleted := 0
for _, s := range r.Form["match[]"] {
matchers, err := promql.ParseMetricSelector(s)
if err != nil {
return nil, &apiError{errorBadData, err}
}
n, err := api.Storage.DropMetricsForLabelMatchers(context.TODO(), matchers...)
if err != nil {
return nil, &apiError{errorExec, err}
}
numDeleted += n
}
res := struct {
NumDeleted int `json:"numDeleted"`
}{
NumDeleted: numDeleted,
}
return res, nil
}
// Target has the information for one target.
type Target struct {
// Labels before any processing.
DiscoveredLabels model.LabelSet `json:"discoveredLabels"`
// Any labels that are added to this target and its metrics.
Labels model.LabelSet `json:"labels"`
ScrapeURL string `json:"scrapeUrl"`
LastError string `json:"lastError"`
LastScrape time.Time `json:"lastScrape"`
Health retrieval.TargetHealth `json:"health"`
}
// TargetDiscovery has all the active targets.
type TargetDiscovery struct {
ActiveTargets []*Target `json:"activeTargets"`
}
func (api *API) targets(r *http.Request) (interface{}, *apiError) {
targets := api.targetRetriever.Targets()
res := &TargetDiscovery{ActiveTargets: make([]*Target, len(targets))}
for i, t := range targets {
lastErrStr := ""
lastErr := t.LastError()
if lastErr != nil {
lastErrStr = lastErr.Error()
}
res.ActiveTargets[i] = &Target{
DiscoveredLabels: t.DiscoveredLabels(),
Labels: t.Labels(),
ScrapeURL: t.URL().String(),
LastError: lastErrStr,
LastScrape: t.LastScrape(),
Health: t.Health(),
}
}
return res, nil
}
// AlertmanagerDiscovery has all the active Alertmanagers.
type AlertmanagerDiscovery struct {
ActiveAlertmanagers []*AlertmanagerTarget `json:"activeAlertmanagers"`
}
// AlertmanagerTarget has info on one AM.
type AlertmanagerTarget struct {
URL string `json:"url"`
}
func (api *API) alertmanagers(r *http.Request) (interface{}, *apiError) {
urls := api.alertmanagerRetriever.Alertmanagers()
ams := &AlertmanagerDiscovery{ActiveAlertmanagers: make([]*AlertmanagerTarget, len(urls))}
for i, url := range urls {
ams.ActiveAlertmanagers[i] = &AlertmanagerTarget{URL: url.String()}
}
return ams, nil
}
type prometheusConfig struct {
YAML string `json:"yaml"`
}
func (api *API) serveConfig(r *http.Request) (interface{}, *apiError) {
cfg := &prometheusConfig{
YAML: api.config().String(),
}
return cfg, nil
}
func (api *API) remoteRead(w http.ResponseWriter, r *http.Request) {
req, err := remote.DecodeReadRequest(r)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
resp := remote.ReadResponse{
Results: make([]*remote.QueryResult, len(req.Queries)),
}
for i, query := range req.Queries {
querier, err := api.Storage.Querier()
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
defer querier.Close()
from, through, matchers, err := remote.FromQuery(query)
if err != nil {
http.Error(w, err.Error(), http.StatusBadRequest)
return
}
iters, err := querier.QueryRange(r.Context(), from, through, matchers...)
if err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
resp.Results[i] = remote.ToQueryResult(remote.IteratorsToMatrix(iters, metric.Interval{
OldestInclusive: from,
NewestInclusive: through,
}))
}
if err := remote.EncodeReadResponse(&resp, w); err != nil {
http.Error(w, err.Error(), http.StatusInternalServerError)
return
}
}
func respond(w http.ResponseWriter, data interface{}) {
w.Header().Set("Content-Type", "application/json")
w.WriteHeader(http.StatusOK)
b, err := json.Marshal(&response{
Status: statusSuccess,
Data: data,
})
if err != nil {
return
}
w.Write(b)
}
func respondError(w http.ResponseWriter, apiErr *apiError, data interface{}) {
w.Header().Set("Content-Type", "application/json")
var code int
switch apiErr.typ {
case errorBadData:
code = http.StatusBadRequest
case errorExec:
code = 422
case errorCanceled, errorTimeout:
code = http.StatusServiceUnavailable
case errorInternal:
code = http.StatusInternalServerError
default:
code = http.StatusInternalServerError
}
w.WriteHeader(code)
b, err := json.Marshal(&response{
Status: statusError,
ErrorType: apiErr.typ,
Error: apiErr.err.Error(),
Data: data,
})
if err != nil {
return
}
w.Write(b)
}
func parseTime(s string) (model.Time, error) {
if t, err := strconv.ParseFloat(s, 64); err == nil {
ts := t * float64(time.Second)
if ts > float64(math.MaxInt64) || ts < float64(math.MinInt64) {
return 0, fmt.Errorf("cannot parse %q to a valid timestamp. It overflows int64", s)
}
return model.TimeFromUnixNano(int64(ts)), nil
}
if t, err := time.Parse(time.RFC3339Nano, s); err == nil {
return model.TimeFromUnixNano(t.UnixNano()), nil
}
return 0, fmt.Errorf("cannot parse %q to a valid timestamp", s)
}
func parseDuration(s string) (time.Duration, error) {
if d, err := strconv.ParseFloat(s, 64); err == nil {
ts := d * float64(time.Second)
if ts > float64(math.MaxInt64) || ts < float64(math.MinInt64) {
return 0, fmt.Errorf("cannot parse %q to a valid duration. It overflows int64", s)
}
return time.Duration(ts), nil
}
if d, err := model.ParseDuration(s); err == nil {
return time.Duration(d), nil
}
return 0, fmt.Errorf("cannot parse %q to a valid duration", s)
}