VictoriaMetrics/app/vmalert/datasource/vm.go
Roman Khavronenko d111969d39 vmalert: add support for datasource.lookback flag (#779)
New datasource flag `datasource.lookback` defines how far to look into
past when evaluating queries.

Address https://github.com/VictoriaMetrics/VictoriaMetrics/issues/668
2020-09-21 15:56:47 +03:00

113 lines
3.1 KiB
Go

package datasource
import (
"context"
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"net/url"
"strconv"
"strings"
"time"
)
type response struct {
Status string `json:"status"`
Data struct {
ResultType string `json:"resultType"`
Result []struct {
Labels map[string]string `json:"metric"`
TV [2]interface{} `json:"value"`
} `json:"result"`
} `json:"data"`
ErrorType string `json:"errorType"`
Error string `json:"error"`
}
func (r response) metrics() ([]Metric, error) {
var ms []Metric
var m Metric
var f float64
var err error
for i, res := range r.Data.Result {
f, err = strconv.ParseFloat(res.TV[1].(string), 64)
if err != nil {
return nil, fmt.Errorf("metric %v, unable to parse float64 from %s: %w", res, res.TV[1], err)
}
m.Labels = nil
for k, v := range r.Data.Result[i].Labels {
m.Labels = append(m.Labels, Label{Name: k, Value: v})
}
m.Timestamp = int64(res.TV[0].(float64))
m.Value = f
ms = append(ms, m)
}
return ms, nil
}
// VMStorage represents vmstorage entity with ability to read and write metrics
type VMStorage struct {
c *http.Client
queryURL string
basicAuthUser string
basicAuthPass string
lookBack time.Duration
}
const queryPath = "/api/v1/query?query="
// NewVMStorage is a constructor for VMStorage
func NewVMStorage(baseURL, basicAuthUser, basicAuthPass string, lookBack time.Duration, c *http.Client) *VMStorage {
return &VMStorage{
c: c,
basicAuthUser: basicAuthUser,
basicAuthPass: basicAuthPass,
queryURL: strings.TrimSuffix(baseURL, "/") + queryPath,
lookBack: lookBack,
}
}
// Query reads metrics from datasource by given query
func (s *VMStorage) Query(ctx context.Context, query string) ([]Metric, error) {
const (
statusSuccess, statusError, rtVector = "success", "error", "vector"
)
q := s.queryURL + url.QueryEscape(query)
if s.lookBack > 0 {
lookBack := time.Now().UTC().Add(-s.lookBack)
q += fmt.Sprintf("&time=%d", lookBack.Unix())
}
req, err := http.NewRequest("POST", q, nil)
if err != nil {
return nil, err
}
req.Header.Set("Content-Type", "application/json")
if s.basicAuthPass != "" {
req.SetBasicAuth(s.basicAuthUser, s.basicAuthPass)
}
resp, err := s.c.Do(req.WithContext(ctx))
if err != nil {
return nil, fmt.Errorf("error getting response from %s: %w", req.URL, err)
}
defer func() { _ = resp.Body.Close() }()
if resp.StatusCode != http.StatusOK {
body, _ := ioutil.ReadAll(resp.Body)
return nil, fmt.Errorf("datasource returns unexpected response code %d for %s. Reponse body %s", resp.StatusCode, req.URL, body)
}
r := &response{}
if err := json.NewDecoder(resp.Body).Decode(r); err != nil {
return nil, fmt.Errorf("error parsing metrics for %s: %w", req.URL, err)
}
if r.Status == statusError {
return nil, fmt.Errorf("response error, query: %s, errorType: %s, error: %s", req.URL, r.ErrorType, r.Error)
}
if r.Status != statusSuccess {
return nil, fmt.Errorf("unknown status: %s, Expected success or error ", r.Status)
}
if r.Data.ResultType != rtVector {
return nil, fmt.Errorf("unknown restul type:%s. Expected vector", r.Data.ResultType)
}
return r.metrics()
}