prometheus/web/api/v1/api.go
Julius Volz 3bfec97d46 Make the storage interface higher-level.
See discussion in
https://groups.google.com/forum/#!topic/prometheus-developers/bkuGbVlvQ9g

The main idea is that the user of a storage shouldn't have to deal with
fingerprints anymore, and should not need to do an individual preload
call for each metric. The storage interface needs to be made more
high-level to not expose these details.

This also makes it easier to reuse the same storage interface for remote
storages later, as fewer roundtrips are required and the fingerprint
concept doesn't work well across the network.

NOTE: this deliberately gets rid of a small optimization in the old
query Analyzer, where we dedupe instants and ranges for the same series.
This should have a minor impact, as most queries do not have multiple
selectors loading the same series (and at the same offset).
2016-07-25 13:59:22 +02:00

371 lines
9.2 KiB
Go

// 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"
"net/http"
"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/promql"
"github.com/prometheus/prometheus/storage/local"
"github.com/prometheus/prometheus/storage/metric"
"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"
)
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 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
context func(r *http.Request) context.Context
now func() model.Time
}
// NewAPI returns an initialized API type.
func NewAPI(qe *promql.Engine, st local.Storage) *API {
return &API{
QueryEngine: qe,
Storage: st,
context: route.Context,
now: model.Now,
}
}
// 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 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))
}
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()
}
qry, err := api.QueryEngine.NewInstantQuery(r.FormValue("query"), ts)
if err != nil {
return nil, &apiError{errorBadData, err}
}
res := qry.Exec()
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) 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}
}
step, err := parseDuration(r.FormValue("step"))
if err != nil {
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}
}
qry, err := api.QueryEngine.NewRangeQuery(r.FormValue("query"), start, end, step)
if err != nil {
return nil, &apiError{errorBadData, err}
}
res := qry.Exec()
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(api.context(r), "name")
if !model.LabelNameRE.MatchString(name) {
return nil, &apiError{errorBadData, fmt.Errorf("invalid label name: %q", name)}
}
vals, err := api.Storage.LabelValuesForLabelName(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)
}
res, err := api.Storage.MetricsForLabelMatchers(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(matchers...)
if err != nil {
return nil, &apiError{errorExec, err}
}
numDeleted += n
}
res := struct {
NumDeleted int `json:"numDeleted"`
}{
NumDeleted: numDeleted,
}
return res, nil
}
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
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 := int64(t * float64(time.Second))
return model.TimeFromUnixNano(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 {
return time.Duration(d * float64(time.Second)), 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)
}