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Throttle Kubernetes config refresh

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This commit is contained in:
Ben Weissmann 2019-08-30 06:16:04 -04:00 • committed by Traefiker Bot
parent 6e8138e19b
commit 43af0b051f
8 changed files with 169 additions and 13 deletions
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66
pkg/provider/kubernetes/crd/kubernetes.go
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@ -20,6 +20,7 @@ import (
"github.com/containous/traefik/v2/pkg/provider/kubernetes/crd/traefik/v1alpha1"
"github.com/containous/traefik/v2/pkg/safe"
"github.com/containous/traefik/v2/pkg/tls"
"github.com/containous/traefik/v2/pkg/types"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/labels"
)
@ -31,13 +32,14 @@ const (
// Provider holds configurations of the provider.
type Provider struct {
Endpoint string `description:"Kubernetes server endpoint (required for external cluster client)." json:"endpoint,omitempty" toml:"endpoint,omitempty" yaml:"endpoint,omitempty"`
Token string `description:"Kubernetes bearer token (not needed for in-cluster client)." json:"token,omitempty" toml:"token,omitempty" yaml:"token,omitempty"`
CertAuthFilePath string `description:"Kubernetes certificate authority file path (not needed for in-cluster client)." json:"certAuthFilePath,omitempty" toml:"certAuthFilePath,omitempty" yaml:"certAuthFilePath,omitempty"`
DisablePassHostHeaders bool `description:"Kubernetes disable PassHost Headers." json:"disablePassHostHeaders,omitempty" toml:"disablePassHostHeaders,omitempty" yaml:"disablePassHostHeaders,omitempty" export:"true"`
Namespaces []string `description:"Kubernetes namespaces." json:"namespaces,omitempty" toml:"namespaces,omitempty" yaml:"namespaces,omitempty" export:"true"`
LabelSelector string `description:"Kubernetes label selector to use." json:"labelSelector,omitempty" toml:"labelSelector,omitempty" yaml:"labelSelector,omitempty" export:"true"`
IngressClass string `description:"Value of kubernetes.io/ingress.class annotation to watch for." json:"ingressClass,omitempty" toml:"ingressClass,omitempty" yaml:"ingressClass,omitempty" export:"true"`
Endpoint string `description:"Kubernetes server endpoint (required for external cluster client)." json:"endpoint,omitempty" toml:"endpoint,omitempty" yaml:"endpoint,omitempty"`
Token string `description:"Kubernetes bearer token (not needed for in-cluster client)." json:"token,omitempty" toml:"token,omitempty" yaml:"token,omitempty"`
CertAuthFilePath string `description:"Kubernetes certificate authority file path (not needed for in-cluster client)." json:"certAuthFilePath,omitempty" toml:"certAuthFilePath,omitempty" yaml:"certAuthFilePath,omitempty"`
DisablePassHostHeaders bool `description:"Kubernetes disable PassHost Headers." json:"disablePassHostHeaders,omitempty" toml:"disablePassHostHeaders,omitempty" yaml:"disablePassHostHeaders,omitempty" export:"true"`
Namespaces []string `description:"Kubernetes namespaces." json:"namespaces,omitempty" toml:"namespaces,omitempty" yaml:"namespaces,omitempty" export:"true"`
LabelSelector string `description:"Kubernetes label selector to use." json:"labelSelector,omitempty" toml:"labelSelector,omitempty" yaml:"labelSelector,omitempty" export:"true"`
IngressClass string `description:"Value of kubernetes.io/ingress.class annotation to watch for." json:"ingressClass,omitempty" toml:"ingressClass,omitempty" yaml:"ingressClass,omitempty" export:"true"`
ThrottleDuration types.Duration `description:"Ingress refresh throttle duration" json:"throttleDuration,omitempty" toml:"throttleDuration,omitempty" yaml:"throttleDuration,omitempty"`
lastConfiguration safe.Safe
}
@ -95,6 +97,7 @@ func (p *Provider) Provide(configurationChan chan<- dynamic.Message, pool *safe.
stopWatch := make(chan struct{}, 1)
defer close(stopWatch)
eventsChan, err := k8sClient.WatchAll(p.Namespaces, stopWatch)
if err != nil {
logger.Errorf("Error watching kubernetes events: %v", err)
timer := time.NewTimer(1 * time.Second)
@ -105,11 +108,20 @@ func (p *Provider) Provide(configurationChan chan<- dynamic.Message, pool *safe.
return nil
}
}
throttleDuration := time.Duration(p.ThrottleDuration)
eventsChanToRead := throttleEvents(ctxLog, throttleDuration, stop, eventsChan)
for {
select {
case <-stop:
return nil
case event := <-eventsChan:
case event := <-eventsChanToRead:
// Note that event is the *first* event that came in during this
// throttling interval -- if we're hitting our throttle, we may have
// dropped events. This is fine, because we don't treat different
// event types differently. But if we do in the future, we'll need to
// track more information about the dropped events.
conf := p.loadConfigurationFromCRD(ctxLog, k8sClient)
if reflect.DeepEqual(p.lastConfiguration.Get(), conf) {
@ -121,6 +133,11 @@ func (p *Provider) Provide(configurationChan chan<- dynamic.Message, pool *safe.
Configuration: conf,
}
}
// If we're throttling, we sleep here for the throttle duration to
// enforce that we don't refresh faster than our throttle. time.Sleep
// returns immediately if p.ThrottleDuration is 0 (no throttle).
time.Sleep(throttleDuration)
}
}
}
@ -587,3 +604,36 @@ func getCABlocks(secret *corev1.Secret, namespace, secretName string) (string, e
return cert, nil
}
func throttleEvents(ctx context.Context, throttleDuration time.Duration, stop chan bool, eventsChan <-chan interface{}) chan interface{} {
if throttleDuration == 0 {
return nil
}
// Create a buffered channel to hold the pending event (if we're delaying processing the event due to throttling)
eventsChanBuffered := make(chan interface{}, 1)
// Run a goroutine that reads events from eventChan and does a
// non-blocking write to pendingEvent. This guarantees that writing to
// eventChan will never block, and that pendingEvent will have
// something in it if there's been an event since we read from that channel.
go func() {
for {
select {
case <-stop:
return
case nextEvent := <-eventsChan:
select {
case eventsChanBuffered <- nextEvent:
default:
// We already have an event in eventsChanBuffered, so we'll
// do a refresh as soon as our throttle allows us to. It's fine
// to drop the event and keep whatever's in the buffer -- we
// don't do different things for different events
log.FromContext(ctx).Debugf("Dropping event kind %T due to throttling", nextEvent)
}
}
}
}()
return eventsChanBuffered
}