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prometheus/scrape/manager.go

325 lines
8.5 KiB

// Copyright 2013 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 scrape
import (
"fmt"
"hash/fnv"
"reflect"
"sync"
"time"
"github.com/go-kit/log"
"github.com/go-kit/log/level"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
config_util "github.com/prometheus/common/config"
"github.com/prometheus/common/model"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/discovery/targetgroup"
"github.com/prometheus/prometheus/model/labels"
"github.com/prometheus/prometheus/storage"
"github.com/prometheus/prometheus/util/osutil"
)
// NewManager is the Manager constructor.
func NewManager(o *Options, logger log.Logger, app storage.Appendable, registerer prometheus.Registerer) (*Manager, error) {
if o == nil {
o = &Options{}
}
if logger == nil {
logger = log.NewNopLogger()
}
sm, err := newScrapeMetrics(registerer)
if err != nil {
return nil, fmt.Errorf("failed to create scrape manager due to error: %w", err)
}
m := &Manager{
append: app,
opts: o,
logger: logger,
scrapeConfigs: make(map[string]*config.ScrapeConfig),
scrapePools: make(map[string]*scrapePool),
graceShut: make(chan struct{}),
triggerReload: make(chan struct{}, 1),
metrics: sm,
}
m.metrics.setTargetMetadataCacheGatherer(m)
return m, nil
}
// Options are the configuration parameters to the scrape manager.
type Options struct {
ExtraMetrics bool
NoDefaultPort bool
// Option used by downstream scraper users like OpenTelemetry Collector
// to help lookup metric metadata. Should be false for Prometheus.
PassMetadataInContext bool
// Option to enable the experimental in-memory metadata storage and append
// metadata to the WAL.
EnableMetadataStorage bool
// Option to increase the interval used by scrape manager to throttle target groups updates.
DiscoveryReloadInterval model.Duration
// Optional HTTP client options to use when scraping.
HTTPClientOptions []config_util.HTTPClientOption
}
// Manager maintains a set of scrape pools and manages start/stop cycles
// when receiving new target groups from the discovery manager.
type Manager struct {
opts *Options
logger log.Logger
append storage.Appendable
graceShut chan struct{}
offsetSeed uint64 // Global offsetSeed seed is used to spread scrape workload across HA setup.
mtxScrape sync.Mutex // Guards the fields below.
scrapeConfigs map[string]*config.ScrapeConfig
scrapePools map[string]*scrapePool
targetSets map[string][]*targetgroup.Group
triggerReload chan struct{}
metrics *scrapeMetrics
}
// Run receives and saves target set updates and triggers the scraping loops reloading.
// Reloading happens in the background so that it doesn't block receiving targets updates.
func (m *Manager) Run(tsets <-chan map[string][]*targetgroup.Group) error {
go m.reloader()
for {
select {
case ts := <-tsets:
m.updateTsets(ts)
select {
case m.triggerReload <- struct{}{}:
default:
}
case <-m.graceShut:
return nil
}
}
}
func (m *Manager) reloader() {
reloadIntervalDuration := m.opts.DiscoveryReloadInterval
if reloadIntervalDuration < model.Duration(5*time.Second) {
reloadIntervalDuration = model.Duration(5 * time.Second)
}
ticker := time.NewTicker(time.Duration(reloadIntervalDuration))
defer ticker.Stop()
for {
select {
case <-m.graceShut:
return
case <-ticker.C:
select {
case <-m.triggerReload:
m.reload()
case <-m.graceShut:
return
}
}
}
}
func (m *Manager) reload() {
m.mtxScrape.Lock()
var wg sync.WaitGroup
for setName, groups := range m.targetSets {
if _, ok := m.scrapePools[setName]; !ok {
scrapeConfig, ok := m.scrapeConfigs[setName]
if !ok {
level.Error(m.logger).Log("msg", "error reloading target set", "err", "invalid config id:"+setName)
continue
}
m.metrics.targetScrapePools.Inc()
sp, err := newScrapePool(scrapeConfig, m.append, m.offsetSeed, log.With(m.logger, "scrape_pool", setName), m.opts, m.metrics)
if err != nil {
m.metrics.targetScrapePoolsFailed.Inc()
level.Error(m.logger).Log("msg", "error creating new scrape pool", "err", err, "scrape_pool", setName)
continue
}
m.scrapePools[setName] = sp
}
wg.Add(1)
// Run the sync in parallel as these take a while and at high load can't catch up.
go func(sp *scrapePool, groups []*targetgroup.Group) {
sp.Sync(groups)
wg.Done()
}(m.scrapePools[setName], groups)
}
m.mtxScrape.Unlock()
wg.Wait()
}
// setOffsetSeed calculates a global offsetSeed per server relying on extra label set.
func (m *Manager) setOffsetSeed(labels labels.Labels) error {
h := fnv.New64a()
hostname, err := osutil.GetFQDN()
if err != nil {
return err
}
if _, err := fmt.Fprintf(h, "%s%s", hostname, labels.String()); err != nil {
return err
}
m.offsetSeed = h.Sum64()
return nil
}
// Stop cancels all running scrape pools and blocks until all have exited.
func (m *Manager) Stop() {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
for _, sp := range m.scrapePools {
sp.stop()
}
close(m.graceShut)
}
func (m *Manager) updateTsets(tsets map[string][]*targetgroup.Group) {
m.mtxScrape.Lock()
m.targetSets = tsets
m.mtxScrape.Unlock()
}
// ApplyConfig resets the manager's target providers and job configurations as defined by the new cfg.
func (m *Manager) ApplyConfig(cfg *config.Config) error {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
scfgs, err := cfg.GetScrapeConfigs()
if err != nil {
return err
}
c := make(map[string]*config.ScrapeConfig)
for _, scfg := range scfgs {
c[scfg.JobName] = scfg
}
m.scrapeConfigs = c
if err := m.setOffsetSeed(cfg.GlobalConfig.ExternalLabels); err != nil {
return err
}
// Cleanup and reload pool if the configuration has changed.
var failed bool
for name, sp := range m.scrapePools {
switch cfg, ok := m.scrapeConfigs[name]; {
case !ok:
sp.stop()
delete(m.scrapePools, name)
case !reflect.DeepEqual(sp.config, cfg):
err := sp.reload(cfg)
if err != nil {
level.Error(m.logger).Log("msg", "error reloading scrape pool", "err", err, "scrape_pool", name)
failed = true
}
}
}
if failed {
return errors.New("failed to apply the new configuration")
}
return nil
}
// TargetsAll returns active and dropped targets grouped by job_name.
func (m *Manager) TargetsAll() map[string][]*Target {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
targets := make(map[string][]*Target, len(m.scrapePools))
for tset, sp := range m.scrapePools {
targets[tset] = append(sp.ActiveTargets(), sp.DroppedTargets()...)
}
return targets
}
// ScrapePools returns the list of all scrape pool names.
func (m *Manager) ScrapePools() []string {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
names := make([]string, 0, len(m.scrapePools))
for name := range m.scrapePools {
names = append(names, name)
}
return names
}
// TargetsActive returns the active targets currently being scraped.
func (m *Manager) TargetsActive() map[string][]*Target {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
var (
wg sync.WaitGroup
mtx sync.Mutex
)
targets := make(map[string][]*Target, len(m.scrapePools))
wg.Add(len(m.scrapePools))
for tset, sp := range m.scrapePools {
// Running in parallel limits the blocking time of scrapePool to scrape
// interval when there's an update from SD.
go func(tset string, sp *scrapePool) {
mtx.Lock()
targets[tset] = sp.ActiveTargets()
mtx.Unlock()
wg.Done()
}(tset, sp)
}
wg.Wait()
return targets
}
// TargetsDropped returns the dropped targets during relabelling, subject to KeepDroppedTargets limit.
func (m *Manager) TargetsDropped() map[string][]*Target {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
targets := make(map[string][]*Target, len(m.scrapePools))
for tset, sp := range m.scrapePools {
targets[tset] = sp.DroppedTargets()
}
return targets
}
func (m *Manager) TargetsDroppedCounts() map[string]int {
m.mtxScrape.Lock()
defer m.mtxScrape.Unlock()
counts := make(map[string]int, len(m.scrapePools))
for tset, sp := range m.scrapePools {
counts[tset] = sp.droppedTargetsCount
}
return counts
}