prometheus/scrape/manager.go

365 lines
9.0 KiB
Go

// 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 (
"encoding"
"fmt"
"hash/fnv"
"net"
"os"
"reflect"
"sync"
"time"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
"github.com/pkg/errors"
"github.com/prometheus/client_golang/prometheus"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/discovery/targetgroup"
"github.com/prometheus/prometheus/pkg/labels"
"github.com/prometheus/prometheus/storage"
)
var targetMetadataCache = newMetadataMetricsCollector()
// MetadataMetricsCollector is a Custom Collector for the metadata cache metrics.
type MetadataMetricsCollector struct {
CacheEntries *prometheus.Desc
CacheBytes *prometheus.Desc
scrapeManager *Manager
}
func newMetadataMetricsCollector() *MetadataMetricsCollector {
return &MetadataMetricsCollector{
CacheEntries: prometheus.NewDesc(
"prometheus_target_metadata_cache_entries",
"Total number of metric metadata entries in the cache",
[]string{"scrape_job"},
nil,
),
CacheBytes: prometheus.NewDesc(
"prometheus_target_metadata_cache_bytes",
"The number of bytes that are currently used for storing metric metadata in the cache",
[]string{"scrape_job"},
nil,
),
}
}
func (mc *MetadataMetricsCollector) registerManager(m *Manager) {
mc.scrapeManager = m
}
// Describe sends the metrics descriptions to the channel.
func (mc *MetadataMetricsCollector) Describe(ch chan<- *prometheus.Desc) {
ch <- mc.CacheEntries
ch <- mc.CacheBytes
}
// Collect creates and sends the metrics for the metadata cache.
func (mc *MetadataMetricsCollector) Collect(ch chan<- prometheus.Metric) {
if mc.scrapeManager == nil {
return
}
for tset, targets := range mc.scrapeManager.TargetsActive() {
var size, length int
for _, t := range targets {
size += t.MetadataSize()
length += t.MetadataLength()
}
ch <- prometheus.MustNewConstMetric(
mc.CacheEntries,
prometheus.GaugeValue,
float64(length),
tset,
)
ch <- prometheus.MustNewConstMetric(
mc.CacheBytes,
prometheus.GaugeValue,
float64(size),
tset,
)
}
}
// NewManager is the Manager constructor
func NewManager(logger log.Logger, app storage.Appendable) *Manager {
if logger == nil {
logger = log.NewNopLogger()
}
m := &Manager{
append: app,
logger: logger,
scrapeConfigs: make(map[string]*config.ScrapeConfig),
scrapePools: make(map[string]*scrapePool),
graceShut: make(chan struct{}),
triggerReload: make(chan struct{}, 1),
}
targetMetadataCache.registerManager(m)
return m
}
// Manager maintains a set of scrape pools and manages start/stop cycles
// when receiving new target groups form the discovery manager.
type Manager struct {
logger log.Logger
append storage.Appendable
graceShut chan struct{}
jitterSeed uint64 // Global jitterSeed 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{}
}
// 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() {
ticker := time.NewTicker(5 * time.Second)
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
}
sp, err := newScrapePool(scrapeConfig, m.append, m.jitterSeed, log.With(m.logger, "scrape_pool", setName))
if err != nil {
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()
}
// setJitterSeed calculates a global jitterSeed per server relying on extra label set.
func (m *Manager) setJitterSeed(labels labels.Labels) error {
h := fnv.New64a()
hostname, err := getFqdn()
if err != nil {
return err
}
if _, err := fmt.Fprintf(h, "%s%s", hostname, labels.String()); err != nil {
return err
}
m.jitterSeed = 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()
c := make(map[string]*config.ScrapeConfig)
for _, scfg := range cfg.ScrapeConfigs {
c[scfg.JobName] = scfg
}
m.scrapeConfigs = c
if err := m.setJitterSeed(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 {
if cfg, ok := m.scrapeConfigs[name]; !ok {
sp.stop()
delete(m.scrapePools, name)
} else if !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
}
// 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.
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
}
// getFqdn returns a FQDN if it's possible, otherwise falls back to hostname.
func getFqdn() (string, error) {
hostname, err := os.Hostname()
if err != nil {
return "", err
}
ips, err := net.LookupIP(hostname)
if err != nil {
// Return the system hostname if we can't look up the IP address.
return hostname, nil
}
lookup := func(ipStr encoding.TextMarshaler) (string, error) {
ip, err := ipStr.MarshalText()
if err != nil {
return "", err
}
hosts, err := net.LookupAddr(string(ip))
if err != nil || len(hosts) == 0 {
return "", err
}
return hosts[0], nil
}
for _, addr := range ips {
if ip := addr.To4(); ip != nil {
if fqdn, err := lookup(ip); err == nil {
return fqdn, nil
}
}
if ip := addr.To16(); ip != nil {
if fqdn, err := lookup(ip); err == nil {
return fqdn, nil
}
}
}
return hostname, nil
}