traefik/pkg/server/configurationwatcher.go

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package server
import (
"context"
"encoding/json"
"reflect"
"time"
"github.com/containous/traefik/v2/pkg/config/dynamic"
"github.com/containous/traefik/v2/pkg/log"
"github.com/containous/traefik/v2/pkg/provider"
"github.com/containous/traefik/v2/pkg/safe"
"github.com/eapache/channels"
"github.com/sirupsen/logrus"
)
// ConfigurationWatcher watches configuration changes.
type ConfigurationWatcher struct {
provider provider.Provider
providersThrottleDuration time.Duration
currentConfigurations safe.Safe
configurationChan chan dynamic.Message
configurationValidatedChan chan dynamic.Message
providerConfigUpdateMap map[string]chan dynamic.Message
configurationListeners []func(dynamic.Configuration)
routinesPool *safe.Pool
}
// NewConfigurationWatcher creates a new ConfigurationWatcher.
func NewConfigurationWatcher(routinesPool *safe.Pool, pvd provider.Provider, providersThrottleDuration time.Duration) *ConfigurationWatcher {
watcher := &ConfigurationWatcher{
provider: pvd,
configurationChan: make(chan dynamic.Message, 100),
configurationValidatedChan: make(chan dynamic.Message, 100),
providerConfigUpdateMap: make(map[string]chan dynamic.Message),
providersThrottleDuration: providersThrottleDuration,
routinesPool: routinesPool,
}
currentConfigurations := make(dynamic.Configurations)
watcher.currentConfigurations.Set(currentConfigurations)
return watcher
}
// Start the configuration watcher.
func (c *ConfigurationWatcher) Start() {
c.routinesPool.GoCtx(c.listenProviders)
c.routinesPool.GoCtx(c.listenConfigurations)
c.startProvider()
}
// Stop the configuration watcher.
func (c *ConfigurationWatcher) Stop() {
close(c.configurationChan)
close(c.configurationValidatedChan)
}
// AddListener adds a new listener function used when new configuration is provided
func (c *ConfigurationWatcher) AddListener(listener func(dynamic.Configuration)) {
if c.configurationListeners == nil {
c.configurationListeners = make([]func(dynamic.Configuration), 0)
}
c.configurationListeners = append(c.configurationListeners, listener)
}
func (c *ConfigurationWatcher) startProvider() {
logger := log.WithoutContext()
jsonConf, err := json.Marshal(c.provider)
if err != nil {
logger.Debugf("Unable to marshal provider configuration %T: %v", c.provider, err)
}
logger.Infof("Starting provider %T %s", c.provider, jsonConf)
currentProvider := c.provider
safe.Go(func() {
err := currentProvider.Provide(c.configurationChan, c.routinesPool)
if err != nil {
logger.Errorf("Error starting provider %T: %s", currentProvider, err)
}
})
}
// listenProviders receives configuration changes from the providers.
// The configuration message then gets passed along a series of check
// to finally end up in a throttler that sends it to listenConfigurations (through c. configurationValidatedChan).
func (c *ConfigurationWatcher) listenProviders(ctx context.Context) {
for {
select {
case <-ctx.Done():
return
case configMsg, ok := <-c.configurationChan:
if !ok {
return
}
if configMsg.Configuration == nil {
log.WithoutContext().WithField(log.ProviderName, configMsg.ProviderName).
Debug("Received nil configuration from provider, skipping.")
return
}
c.preLoadConfiguration(configMsg)
}
}
}
func (c *ConfigurationWatcher) listenConfigurations(ctx context.Context) {
for {
select {
case <-ctx.Done():
return
case configMsg, ok := <-c.configurationValidatedChan:
if !ok || configMsg.Configuration == nil {
return
}
c.loadMessage(configMsg)
}
}
}
func (c *ConfigurationWatcher) loadMessage(configMsg dynamic.Message) {
currentConfigurations := c.currentConfigurations.Get().(dynamic.Configurations)
// Copy configurations to new map so we don't change current if LoadConfig fails
newConfigurations := currentConfigurations.DeepCopy()
newConfigurations[configMsg.ProviderName] = configMsg.Configuration
c.currentConfigurations.Set(newConfigurations)
conf := mergeConfiguration(newConfigurations)
for _, listener := range c.configurationListeners {
listener(conf)
}
}
func (c *ConfigurationWatcher) preLoadConfiguration(configMsg dynamic.Message) {
logger := log.WithoutContext().WithField(log.ProviderName, configMsg.ProviderName)
if log.GetLevel() == logrus.DebugLevel {
copyConf := configMsg.Configuration.DeepCopy()
if copyConf.TLS != nil {
copyConf.TLS.Certificates = nil
for k := range copyConf.TLS.Stores {
st := copyConf.TLS.Stores[k]
st.DefaultCertificate = nil
copyConf.TLS.Stores[k] = st
}
}
jsonConf, err := json.Marshal(copyConf)
if err != nil {
logger.Errorf("Could not marshal dynamic configuration: %v", err)
logger.Debugf("Configuration received from provider %s: [struct] %#v", configMsg.ProviderName, copyConf)
} else {
logger.Debugf("Configuration received from provider %s: %s", configMsg.ProviderName, string(jsonConf))
}
}
if isEmptyConfiguration(configMsg.Configuration) {
logger.Infof("Skipping empty Configuration for provider %s", configMsg.ProviderName)
return
}
providerConfigUpdateCh, ok := c.providerConfigUpdateMap[configMsg.ProviderName]
if !ok {
providerConfigUpdateCh = make(chan dynamic.Message)
c.providerConfigUpdateMap[configMsg.ProviderName] = providerConfigUpdateCh
c.routinesPool.GoCtx(func(ctxPool context.Context) {
c.throttleProviderConfigReload(ctxPool, c.providersThrottleDuration, c.configurationValidatedChan, providerConfigUpdateCh)
})
}
providerConfigUpdateCh <- configMsg
}
// throttleProviderConfigReload throttles the configuration reload speed for a single provider.
// It will immediately publish a new configuration and then only publish the next configuration after the throttle duration.
// Note that in the case it receives N new configs in the timeframe of the throttle duration after publishing,
// it will publish the last of the newly received configurations.
func (c *ConfigurationWatcher) throttleProviderConfigReload(ctx context.Context, throttle time.Duration, publish chan<- dynamic.Message, in <-chan dynamic.Message) {
ring := channels.NewRingChannel(1)
defer ring.Close()
c.routinesPool.GoCtx(func(ctxPool context.Context) {
for {
select {
case <-ctxPool.Done():
return
case nextConfig := <-ring.Out():
if config, ok := nextConfig.(dynamic.Message); ok {
publish <- config
time.Sleep(throttle)
}
}
}
})
var previousConfig dynamic.Message
for {
select {
case <-ctx.Done():
return
case nextConfig := <-in:
if reflect.DeepEqual(previousConfig, nextConfig) {
logger := log.WithoutContext().WithField(log.ProviderName, nextConfig.ProviderName)
logger.Info("Skipping same configuration")
continue
}
previousConfig = nextConfig
ring.In() <- nextConfig
}
}
}
func isEmptyConfiguration(conf *dynamic.Configuration) bool {
if conf == nil {
return true
}
if conf.TCP == nil {
conf.TCP = &dynamic.TCPConfiguration{}
}
if conf.HTTP == nil {
conf.HTTP = &dynamic.HTTPConfiguration{}
}
httpEmpty := conf.HTTP.Routers == nil && conf.HTTP.Services == nil && conf.HTTP.Middlewares == nil
tlsEmpty := conf.TLS == nil || conf.TLS.Certificates == nil && conf.TLS.Stores == nil && conf.TLS.Options == nil
tcpEmpty := conf.TCP.Routers == nil && conf.TCP.Services == nil
return httpEmpty && tlsEmpty && tcpEmpty
}