prometheus/discovery/hetzner/robot.go

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// Copyright 2020 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 hetzner
import (
"context"
"encoding/json"
"fmt"
"io"
"net"
"net/http"
"strconv"
"strings"
"time"
"github.com/go-kit/log"
"github.com/prometheus/common/config"
"github.com/prometheus/common/model"
"github.com/prometheus/common/version"
"github.com/prometheus/prometheus/discovery/refresh"
"github.com/prometheus/prometheus/discovery/targetgroup"
)
const (
hetznerRobotLabelPrefix = hetznerLabelPrefix + "robot_"
hetznerLabelRobotProduct = hetznerRobotLabelPrefix + "product"
hetznerLabelRobotCancelled = hetznerRobotLabelPrefix + "cancelled"
)
var userAgent = fmt.Sprintf("Prometheus/%s", version.Version)
// Discovery periodically performs Hetzner Robot requests. It implements
// the Discoverer interface.
type robotDiscovery struct {
*refresh.Discovery
client *http.Client
port int
endpoint string
}
// newRobotDiscovery returns a new robotDiscovery which periodically refreshes its targets.
func newRobotDiscovery(conf *SDConfig, logger log.Logger) (*robotDiscovery, error) {
d := &robotDiscovery{
port: conf.Port,
endpoint: conf.robotEndpoint,
}
rt, err := config.NewRoundTripperFromConfig(conf.HTTPClientConfig, "hetzner_sd")
if err != nil {
return nil, err
}
d.client = &http.Client{
Transport: rt,
Timeout: time.Duration(conf.RefreshInterval),
}
return d, nil
}
func (d *robotDiscovery) refresh(ctx context.Context) ([]*targetgroup.Group, error) {
req, err := http.NewRequest("GET", d.endpoint+"/server", nil)
if err != nil {
return nil, err
}
req.Header.Add("User-Agent", userAgent)
resp, err := d.client.Do(req)
if err != nil {
return nil, err
}
defer func() {
io.Copy(io.Discard, resp.Body)
resp.Body.Close()
}()
if resp.StatusCode/100 != 2 {
return nil, fmt.Errorf("non 2xx status '%d' response during hetzner service discovery with role robot", resp.StatusCode)
}
b, err := io.ReadAll(resp.Body)
if err != nil {
return nil, err
}
var servers serversList
err = json.Unmarshal(b, &servers)
if err != nil {
return nil, err
}
targets := make([]model.LabelSet, len(servers))
for i, server := range servers {
labels := model.LabelSet{
hetznerLabelRole: model.LabelValue(hetznerRoleRobot),
hetznerLabelServerID: model.LabelValue(strconv.Itoa(server.Server.ServerNumber)),
hetznerLabelServerName: model.LabelValue(server.Server.ServerName),
hetznerLabelDatacenter: model.LabelValue(strings.ToLower(server.Server.Dc)),
hetznerLabelPublicIPv4: model.LabelValue(server.Server.ServerIP),
hetznerLabelServerStatus: model.LabelValue(server.Server.Status),
hetznerLabelRobotProduct: model.LabelValue(server.Server.Product),
hetznerLabelRobotCancelled: model.LabelValue(fmt.Sprintf("%t", server.Server.Canceled)),
model.AddressLabel: model.LabelValue(net.JoinHostPort(server.Server.ServerIP, strconv.FormatUint(uint64(d.port), 10))),
}
for _, subnet := range server.Server.Subnet {
ip := net.ParseIP(subnet.IP)
if ip.To4() == nil {
labels[hetznerLabelPublicIPv6Network] = model.LabelValue(fmt.Sprintf("%s/%s", subnet.IP, subnet.Mask))
break
}
}
targets[i] = labels
}
return []*targetgroup.Group{{Source: "hetzner", Targets: targets}}, nil
}
type serversList []struct {
Server struct {
ServerIP string `json:"server_ip"`
ServerNumber int `json:"server_number"`
ServerName string `json:"server_name"`
Dc string `json:"dc"`
Status string `json:"status"`
Product string `json:"product"`
Canceled bool `json:"cancelled"`
Subnet []struct {
IP string `json:"ip"`
Mask string `json:"mask"`
} `json:"subnet"`
} `json:"server"`
}