prometheus/discovery/manager.go

424 lines
12 KiB
Go

// Copyright 2016 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 discovery
import (
"context"
"fmt"
"reflect"
"sync"
"time"
"github.com/go-kit/kit/log"
"github.com/go-kit/kit/log/level"
"github.com/prometheus/client_golang/prometheus"
sd_config "github.com/prometheus/prometheus/discovery/config"
"github.com/prometheus/prometheus/discovery/targetgroup"
"github.com/prometheus/prometheus/discovery/azure"
"github.com/prometheus/prometheus/discovery/consul"
"github.com/prometheus/prometheus/discovery/dns"
"github.com/prometheus/prometheus/discovery/ec2"
"github.com/prometheus/prometheus/discovery/file"
"github.com/prometheus/prometheus/discovery/gce"
"github.com/prometheus/prometheus/discovery/kubernetes"
"github.com/prometheus/prometheus/discovery/marathon"
"github.com/prometheus/prometheus/discovery/openstack"
"github.com/prometheus/prometheus/discovery/triton"
"github.com/prometheus/prometheus/discovery/zookeeper"
)
var (
failedConfigs = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_sd_configs_failed_total",
Help: "Total number of service discovery configurations that failed to load.",
},
)
discoveredTargets = prometheus.NewGaugeVec(
prometheus.GaugeOpts{
Name: "prometheus_sd_discovered_targets",
Help: "Current number of discovered targets.",
},
[]string{"name", "config"},
)
receivedUpdates = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_sd_received_updates_total",
Help: "Total number of update events received from the SD providers.",
},
)
delayedUpdates = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_sd_updates_delayed_total",
Help: "Total number of update events that couldn't be sent immediately.",
},
)
sentUpdates = prometheus.NewCounter(
prometheus.CounterOpts{
Name: "prometheus_sd_updates_total",
Help: "Total number of update events sent to the SD consumers.",
},
)
)
func init() {
prometheus.MustRegister(failedConfigs, discoveredTargets, receivedUpdates, delayedUpdates, sentUpdates)
}
// Discoverer provides information about target groups. It maintains a set
// of sources from which TargetGroups can originate. Whenever a discovery provider
// detects a potential change, it sends the TargetGroup through its channel.
//
// Discoverer does not know if an actual change happened.
// It does guarantee that it sends the new TargetGroup whenever a change happens.
//
// Discoverers should initially send a full set of all discoverable TargetGroups.
type Discoverer interface {
// Run hands a channel to the discovery provider (Consul, DNS etc) through which it can send
// updated target groups.
// Must returns if the context gets canceled. It should not close the update
// channel on returning.
Run(ctx context.Context, up chan<- []*targetgroup.Group)
}
type poolKey struct {
setName string
provider string
}
// provider holds a Discoverer instance, its configuration and its subscribers.
type provider struct {
name string
d Discoverer
subs []string
config interface{}
}
// NewManager is the Discovery Manager constructor.
func NewManager(ctx context.Context, logger log.Logger, options ...func(*Manager)) *Manager {
if logger == nil {
logger = log.NewNopLogger()
}
mgr := &Manager{
logger: logger,
syncCh: make(chan map[string][]*targetgroup.Group),
targets: make(map[poolKey]map[string]*targetgroup.Group),
discoverCancel: []context.CancelFunc{},
ctx: ctx,
updatert: 5 * time.Second,
triggerSend: make(chan struct{}, 1),
}
for _, option := range options {
option(mgr)
}
return mgr
}
// Name sets the name of the manager.
func Name(n string) func(*Manager) {
return func(m *Manager) {
m.mtx.Lock()
defer m.mtx.Unlock()
m.name = n
}
}
// Manager maintains a set of discovery providers and sends each update to a map channel.
// Targets are grouped by the target set name.
type Manager struct {
logger log.Logger
name string
mtx sync.RWMutex
ctx context.Context
discoverCancel []context.CancelFunc
// Some Discoverers(eg. k8s) send only the updates for a given target group
// so we use map[tg.Source]*targetgroup.Group to know which group to update.
targets map[poolKey]map[string]*targetgroup.Group
// providers keeps track of SD providers.
providers []*provider
// The sync channel sends the updates as a map where the key is the job value from the scrape config.
syncCh chan map[string][]*targetgroup.Group
// How long to wait before sending updates to the channel. The variable
// should only be modified in unit tests.
updatert time.Duration
// The triggerSend channel signals to the manager that new updates have been received from providers.
triggerSend chan struct{}
}
// Run starts the background processing
func (m *Manager) Run() error {
go m.sender()
for range m.ctx.Done() {
m.cancelDiscoverers()
return m.ctx.Err()
}
return nil
}
// SyncCh returns a read only channel used by all the clients to receive target updates.
func (m *Manager) SyncCh() <-chan map[string][]*targetgroup.Group {
return m.syncCh
}
// ApplyConfig removes all running discovery providers and starts new ones using the provided config.
func (m *Manager) ApplyConfig(cfg map[string]sd_config.ServiceDiscoveryConfig) error {
m.mtx.Lock()
defer m.mtx.Unlock()
for pk := range m.targets {
if _, ok := cfg[pk.setName]; !ok {
discoveredTargets.DeleteLabelValues(m.name, pk.setName)
}
}
m.cancelDiscoverers()
for name, scfg := range cfg {
m.registerProviders(scfg, name)
discoveredTargets.WithLabelValues(m.name, name).Set(0)
}
for _, prov := range m.providers {
m.startProvider(m.ctx, prov)
}
return nil
}
// StartCustomProvider is used for sdtool. Only use this if you know what you're doing.
func (m *Manager) StartCustomProvider(ctx context.Context, name string, worker Discoverer) {
p := &provider{
name: name,
d: worker,
subs: []string{name},
}
m.providers = append(m.providers, p)
m.startProvider(ctx, p)
}
func (m *Manager) startProvider(ctx context.Context, p *provider) {
level.Debug(m.logger).Log("msg", "Starting provider", "provider", p.name, "subs", fmt.Sprintf("%v", p.subs))
ctx, cancel := context.WithCancel(ctx)
updates := make(chan []*targetgroup.Group)
m.discoverCancel = append(m.discoverCancel, cancel)
go p.d.Run(ctx, updates)
go m.updater(ctx, p, updates)
}
func (m *Manager) updater(ctx context.Context, p *provider, updates chan []*targetgroup.Group) {
for {
select {
case <-ctx.Done():
return
case tgs, ok := <-updates:
receivedUpdates.Inc()
if !ok {
level.Debug(m.logger).Log("msg", "discoverer channel closed", "provider", p.name)
return
}
for _, s := range p.subs {
m.updateGroup(poolKey{setName: s, provider: p.name}, tgs)
}
select {
case m.triggerSend <- struct{}{}:
default:
}
}
}
}
func (m *Manager) sender() {
ticker := time.NewTicker(m.updatert)
defer ticker.Stop()
for {
select {
case <-m.ctx.Done():
return
case <-ticker.C: // Some discoverers send updates too often so we throttle these with the ticker.
select {
case <-m.triggerSend:
sentUpdates.Inc()
select {
case m.syncCh <- m.allGroups():
default:
delayedUpdates.Inc()
level.Debug(m.logger).Log("msg", "discovery receiver's channel was full so will retry the next cycle")
select {
case m.triggerSend <- struct{}{}:
default:
}
}
default:
}
}
}
}
func (m *Manager) cancelDiscoverers() {
for _, c := range m.discoverCancel {
c()
}
m.targets = make(map[poolKey]map[string]*targetgroup.Group)
m.providers = nil
m.discoverCancel = nil
}
func (m *Manager) updateGroup(poolKey poolKey, tgs []*targetgroup.Group) {
m.mtx.Lock()
defer m.mtx.Unlock()
for _, tg := range tgs {
if tg != nil { // Some Discoverers send nil target group so need to check for it to avoid panics.
if _, ok := m.targets[poolKey]; !ok {
m.targets[poolKey] = make(map[string]*targetgroup.Group)
}
m.targets[poolKey][tg.Source] = tg
}
}
}
func (m *Manager) allGroups() map[string][]*targetgroup.Group {
m.mtx.Lock()
defer m.mtx.Unlock()
tSets := map[string][]*targetgroup.Group{}
for pkey, tsets := range m.targets {
var n int
for _, tg := range tsets {
// Even if the target group 'tg' is empty we still need to send it to the 'Scrape manager'
// to signal that it needs to stop all scrape loops for this target set.
tSets[pkey.setName] = append(tSets[pkey.setName], tg)
n += len(tg.Targets)
}
discoveredTargets.WithLabelValues(m.name, pkey.setName).Set(float64(n))
}
return tSets
}
func (m *Manager) registerProviders(cfg sd_config.ServiceDiscoveryConfig, setName string) {
add := func(cfg interface{}, newDiscoverer func() (Discoverer, error)) {
t := reflect.TypeOf(cfg).String()
for _, p := range m.providers {
if reflect.DeepEqual(cfg, p.config) {
p.subs = append(p.subs, setName)
return
}
}
d, err := newDiscoverer()
if err != nil {
level.Error(m.logger).Log("msg", "Cannot create service discovery", "err", err, "type", t)
failedConfigs.Inc()
return
}
provider := provider{
name: fmt.Sprintf("%s/%d", t, len(m.providers)),
d: d,
config: cfg,
subs: []string{setName},
}
m.providers = append(m.providers, &provider)
}
for _, c := range cfg.DNSSDConfigs {
add(c, func() (Discoverer, error) {
return dns.NewDiscovery(*c, log.With(m.logger, "discovery", "dns")), nil
})
}
for _, c := range cfg.FileSDConfigs {
add(c, func() (Discoverer, error) {
return file.NewDiscovery(c, log.With(m.logger, "discovery", "file")), nil
})
}
for _, c := range cfg.ConsulSDConfigs {
add(c, func() (Discoverer, error) {
return consul.NewDiscovery(c, log.With(m.logger, "discovery", "consul"))
})
}
for _, c := range cfg.MarathonSDConfigs {
add(c, func() (Discoverer, error) {
return marathon.NewDiscovery(*c, log.With(m.logger, "discovery", "marathon"))
})
}
for _, c := range cfg.KubernetesSDConfigs {
add(c, func() (Discoverer, error) {
return kubernetes.New(log.With(m.logger, "discovery", "k8s"), c)
})
}
for _, c := range cfg.ServersetSDConfigs {
add(c, func() (Discoverer, error) {
return zookeeper.NewServersetDiscovery(c, log.With(m.logger, "discovery", "zookeeper"))
})
}
for _, c := range cfg.NerveSDConfigs {
add(c, func() (Discoverer, error) {
return zookeeper.NewNerveDiscovery(c, log.With(m.logger, "discovery", "nerve"))
})
}
for _, c := range cfg.EC2SDConfigs {
add(c, func() (Discoverer, error) {
return ec2.NewDiscovery(c, log.With(m.logger, "discovery", "ec2")), nil
})
}
for _, c := range cfg.OpenstackSDConfigs {
add(c, func() (Discoverer, error) {
return openstack.NewDiscovery(c, log.With(m.logger, "discovery", "openstack"))
})
}
for _, c := range cfg.GCESDConfigs {
add(c, func() (Discoverer, error) {
return gce.NewDiscovery(*c, log.With(m.logger, "discovery", "gce"))
})
}
for _, c := range cfg.AzureSDConfigs {
add(c, func() (Discoverer, error) {
return azure.NewDiscovery(c, log.With(m.logger, "discovery", "azure")), nil
})
}
for _, c := range cfg.TritonSDConfigs {
add(c, func() (Discoverer, error) {
return triton.New(log.With(m.logger, "discovery", "triton"), c)
})
}
if len(cfg.StaticConfigs) > 0 {
add(setName, func() (Discoverer, error) {
return &StaticProvider{cfg.StaticConfigs}, nil
})
}
}
// StaticProvider holds a list of target groups that never change.
type StaticProvider struct {
TargetGroups []*targetgroup.Group
}
// Run implements the Worker interface.
func (sd *StaticProvider) Run(ctx context.Context, ch chan<- []*targetgroup.Group) {
// We still have to consider that the consumer exits right away in which case
// the context will be canceled.
select {
case ch <- sd.TargetGroups:
case <-ctx.Done():
}
close(ch)
}