prometheus/discovery/triton/triton.go

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2016-12-27 18:16:47 -08:00
// 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 triton
import (
"encoding/json"
"fmt"
"io/ioutil"
"net/http"
"time"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/common/log"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/util/httputil"
"golang.org/x/net/context"
)
const (
tritonLabel = model.MetaLabelPrefix + "triton_"
tritonLabelMachineId = tritonLabel + "machine_id"
tritonLabelMachineAlias = tritonLabel + "machine_alias"
tritonLabelMachineImage = tritonLabel + "machine_image"
tritonLabelServerId = tritonLabel + "server_id"
namespace = "prometheus"
)
var (
refreshFailuresCount = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_sd_triton_refresh_failures_total",
Help: "The number of Triton-SD scrape failures.",
})
refreshDuration = prometheus.NewSummary(
prometheus.SummaryOpts{
Name: "prometheus_sd_triton_refresh_duration_seconds",
Help: "The duration of a Triton-SD refresh in seconds.",
})
)
func init() {
prometheus.MustRegister(refreshFailuresCount)
prometheus.MustRegister(refreshDuration)
}
type DiscoveryResponse struct {
Containers []struct {
ServerUUID string `json:"server_uuid"`
VMAlias string `json:"vm_alias"`
VMImageUUID string `json:"vm_image_uuid"`
VMUUID string `json:"vm_uuid"`
} `json:"containers"`
}
// Discovery periodically performs Triton-SD requests. It implements
// the TargetProvider interface.
type Discovery struct {
client *http.Client
interval time.Duration
logger log.Logger
sdConfig *config.TritonSDConfig
}
// New returns a new Discovery which periodically refreshes its targets.
func New(logger log.Logger, conf *config.TritonSDConfig) (*Discovery, error) {
tls, err := httputil.NewTLSConfig(conf.TLSConfig)
if err != nil {
return nil, err
}
transport := &http.Transport{TLSClientConfig: tls}
client := &http.Client{Transport: transport}
return &Discovery{
client: client,
interval: time.Duration(conf.RefreshInterval),
logger: logger,
sdConfig: conf,
}, nil
}
// Run implements the TargetProvider interface.
func (d *Discovery) Run(ctx context.Context, ch chan<- []*config.TargetGroup) {
defer close(ch)
ticker := time.NewTicker(d.interval)
defer ticker.Stop()
// Get an initial set right away.
tg, err := d.refresh()
if err != nil {
d.logger.With("err", err).Error("Refreshing targets failed")
} else {
ch <- []*config.TargetGroup{tg}
}
for {
select {
case <-ticker.C:
tg, err := d.refresh()
if err != nil {
d.logger.With("err", err).Error("Refreshing targets failed")
} else {
ch <- []*config.TargetGroup{tg}
}
case <-ctx.Done():
return
}
}
}
func (d *Discovery) refresh() (tg *config.TargetGroup, err error) {
t0 := time.Now()
defer func() {
refreshDuration.Observe(time.Since(t0).Seconds())
if err != nil {
refreshFailuresCount.Inc()
}
}()
var endpoint = fmt.Sprintf("https://%s:%d/v%d/discover", d.sdConfig.Endpoint, d.sdConfig.Port, d.sdConfig.Version)
tg = &config.TargetGroup{
Source: endpoint,
}
resp, err := d.client.Get(endpoint)
if err != nil {
return tg, fmt.Errorf("an error occurred when requesting targets from the discovery endpoint. %s", err)
}
defer resp.Body.Close()
data, err := ioutil.ReadAll(resp.Body)
if err != nil {
return tg, fmt.Errorf("an error occurred when reading the response body. %s", err)
}
dr := DiscoveryResponse{}
err = json.Unmarshal(data, &dr)
if err != nil {
return tg, fmt.Errorf("an error occurred unmarshaling the disovery response json. %s", err)
}
for _, container := range dr.Containers {
labels := model.LabelSet{
tritonLabelMachineId: model.LabelValue(container.VMUUID),
tritonLabelMachineAlias: model.LabelValue(container.VMAlias),
tritonLabelMachineImage: model.LabelValue(container.VMImageUUID),
tritonLabelServerId: model.LabelValue(container.ServerUUID),
}
addr := fmt.Sprintf("%s.%s:%d", container.VMUUID, d.sdConfig.DNSSuffix, d.sdConfig.Port)
labels[model.AddressLabel] = model.LabelValue(addr)
tg.Targets = append(tg.Targets, labels)
}
return tg, nil
}