client_golang/api/prometheus/v1/api.go

260 lines
6.1 KiB
Go

// Copyright 2017 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 provides bindings to the Prometheus HTTP API v1:
// http://prometheus.io/docs/querying/api/
package v1
import (
"context"
"encoding/json"
"fmt"
"net/http"
"strconv"
"time"
"github.com/prometheus/client_golang/api"
"github.com/prometheus/common/model"
)
const (
statusAPIError = 422
apiPrefix = "/api/v1"
epQuery = apiPrefix + "/query"
epQueryRange = apiPrefix + "/query_range"
epLabelValues = apiPrefix + "/label/:name/values"
epSeries = apiPrefix + "/series"
)
// ErrorType models the different API error types.
type ErrorType string
// Possible values for ErrorType.
const (
ErrBadData ErrorType = "bad_data"
ErrTimeout = "timeout"
ErrCanceled = "canceled"
ErrExec = "execution"
ErrBadResponse = "bad_response"
)
// Error is an error returned by the API.
type Error struct {
Type ErrorType
Msg string
}
func (e *Error) Error() string {
return fmt.Sprintf("%s: %s", e.Type, e.Msg)
}
// Range represents a sliced time range.
type Range struct {
// The boundaries of the time range.
Start, End time.Time
// The maximum time between two slices within the boundaries.
Step time.Duration
}
// API provides bindings the Prometheus's v1 API.
type API interface {
// Query performs a query for the given time.
Query(ctx context.Context, query string, ts time.Time) (model.Value, error)
// QueryRange performs a query for the given range.
QueryRange(ctx context.Context, query string, r Range) (model.Value, error)
// LabelValues performs a query for the values of the given label.
LabelValues(ctx context.Context, label string) (model.LabelValues, error)
}
// queryResult contains result data for a query.
type queryResult struct {
Type model.ValueType `json:"resultType"`
Result interface{} `json:"result"`
// The decoded value.
v model.Value
}
func (qr *queryResult) UnmarshalJSON(b []byte) error {
v := struct {
Type model.ValueType `json:"resultType"`
Result json.RawMessage `json:"result"`
}{}
err := json.Unmarshal(b, &v)
if err != nil {
return err
}
switch v.Type {
case model.ValScalar:
var sv model.Scalar
err = json.Unmarshal(v.Result, &sv)
qr.v = &sv
case model.ValVector:
var vv model.Vector
err = json.Unmarshal(v.Result, &vv)
qr.v = vv
case model.ValMatrix:
var mv model.Matrix
err = json.Unmarshal(v.Result, &mv)
qr.v = mv
default:
err = fmt.Errorf("unexpected value type %q", v.Type)
}
return err
}
// NewAPI returns a new API for the client.
//
// It is safe to use the returned API from multiple goroutines.
func NewAPI(c api.Client) API {
return &httpAPI{client: apiClient{c}}
}
type httpAPI struct {
client api.Client
}
func (h *httpAPI) Query(ctx context.Context, query string, ts time.Time) (model.Value, error) {
u := h.client.URL(epQuery, nil)
q := u.Query()
q.Set("query", query)
q.Set("time", ts.Format(time.RFC3339Nano))
u.RawQuery = q.Encode()
req, err := http.NewRequest("GET", u.String(), nil)
if err != nil {
return nil, err
}
_, body, err := h.client.Do(ctx, req)
if err != nil {
return nil, err
}
var qres queryResult
err = json.Unmarshal(body, &qres)
return model.Value(qres.v), err
}
func (h *httpAPI) QueryRange(ctx context.Context, query string, r Range) (model.Value, error) {
u := h.client.URL(epQueryRange, nil)
q := u.Query()
var (
start = r.Start.Format(time.RFC3339Nano)
end = r.End.Format(time.RFC3339Nano)
step = strconv.FormatFloat(r.Step.Seconds(), 'f', 3, 64)
)
q.Set("query", query)
q.Set("start", start)
q.Set("end", end)
q.Set("step", step)
u.RawQuery = q.Encode()
req, err := http.NewRequest("GET", u.String(), nil)
if err != nil {
return nil, err
}
_, body, err := h.client.Do(ctx, req)
if err != nil {
return nil, err
}
var qres queryResult
err = json.Unmarshal(body, &qres)
return model.Value(qres.v), err
}
func (h *httpAPI) LabelValues(ctx context.Context, label string) (model.LabelValues, error) {
u := h.client.URL(epLabelValues, map[string]string{"name": label})
req, err := http.NewRequest(http.MethodGet, u.String(), nil)
if err != nil {
return nil, err
}
_, body, err := h.client.Do(ctx, req)
if err != nil {
return nil, err
}
var labelValues model.LabelValues
err = json.Unmarshal(body, &labelValues)
return labelValues, err
}
// apiClient wraps a regular client and processes successful API responses.
// Successful also includes responses that errored at the API level.
type apiClient struct {
api.Client
}
type apiResponse struct {
Status string `json:"status"`
Data json.RawMessage `json:"data"`
ErrorType ErrorType `json:"errorType"`
Error string `json:"error"`
}
func (c apiClient) Do(ctx context.Context, req *http.Request) (*http.Response, []byte, error) {
resp, body, err := c.Client.Do(ctx, req)
if err != nil {
return resp, body, err
}
code := resp.StatusCode
if code/100 != 2 && code != statusAPIError {
return resp, body, &Error{
Type: ErrBadResponse,
Msg: fmt.Sprintf("bad response code %d", resp.StatusCode),
}
}
var result apiResponse
if err = json.Unmarshal(body, &result); err != nil {
return resp, body, &Error{
Type: ErrBadResponse,
Msg: err.Error(),
}
}
if (code == statusAPIError) != (result.Status == "error") {
err = &Error{
Type: ErrBadResponse,
Msg: "inconsistent body for response code",
}
}
if code == statusAPIError && result.Status == "error" {
err = &Error{
Type: result.ErrorType,
Msg: result.Error,
}
}
return resp, []byte(result.Data), err
}