traefik/provider/kubernetes/kubernetes.go

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package kubernetes
import (
"context"
"flag"
"fmt"
"math"
"os"
"reflect"
"sort"
"strconv"
"strings"
"time"
"github.com/cenkalti/backoff"
"github.com/containous/traefik/config"
"github.com/containous/traefik/job"
"github.com/containous/traefik/log"
"github.com/containous/traefik/provider"
"github.com/containous/traefik/safe"
"github.com/containous/traefik/tls"
"github.com/pkg/errors"
corev1 "k8s.io/api/core/v1"
"k8s.io/api/extensions/v1beta1"
"k8s.io/apimachinery/pkg/labels"
"k8s.io/apimachinery/pkg/util/intstr"
)
var _ provider.Provider = (*Provider)(nil)
const (
annotationKubernetesIngressClass = "kubernetes.io/ingress.class"
traefikDefaultIngressClass = "traefik"
)
// IngressEndpoint holds the endpoint information for the Kubernetes provider.
type IngressEndpoint struct {
IP string `description:"IP used for Kubernetes Ingress endpoints"`
Hostname string `description:"Hostname used for Kubernetes Ingress endpoints"`
PublishedService string `description:"Published Kubernetes Service to copy status from"`
}
// Provider holds configurations of the provider.
type Provider struct {
provider.BaseProvider `mapstructure:",squash" export:"true"`
Endpoint string `description:"Kubernetes server endpoint (required for external cluster client)"`
Token string `description:"Kubernetes bearer token (not needed for in-cluster client)"`
CertAuthFilePath string `description:"Kubernetes certificate authority file path (not needed for in-cluster client)"`
DisablePassHostHeaders bool `description:"Kubernetes disable PassHost Headers" export:"true"`
EnablePassTLSCert bool `description:"Kubernetes enable Pass TLS Client Certs" export:"true"` // Deprecated
Namespaces Namespaces `description:"Kubernetes namespaces" export:"true"`
LabelSelector string `description:"Kubernetes Ingress label selector to use" export:"true"`
IngressClass string `description:"Value of kubernetes.io/ingress.class annotation to watch for" export:"true"`
IngressEndpoint *IngressEndpoint `description:"Kubernetes Ingress Endpoint"`
lastConfiguration safe.Safe
}
func (p *Provider) newK8sClient(ctx context.Context, ingressLabelSelector string) (Client, error) {
ingLabelSel, err := labels.Parse(ingressLabelSelector)
if err != nil {
return nil, fmt.Errorf("invalid ingress label selector: %q", ingressLabelSelector)
}
log.FromContext(ctx).Infof("ingress label selector is: %q", ingLabelSel)
withEndpoint := ""
if p.Endpoint != "" {
withEndpoint = fmt.Sprintf(" with endpoint %v", p.Endpoint)
}
var cl *clientImpl
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switch {
case os.Getenv("KUBERNETES_SERVICE_HOST") != "" && os.Getenv("KUBERNETES_SERVICE_PORT") != "":
log.FromContext(ctx).Infof("Creating in-cluster Provider client%s", withEndpoint)
cl, err = newInClusterClient(p.Endpoint)
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case os.Getenv("KUBECONFIG") != "":
log.FromContext(ctx).Infof("Creating cluster-external Provider client from KUBECONFIG %s", os.Getenv("KUBECONFIG"))
cl, err = newExternalClusterClientFromFile(os.Getenv("KUBECONFIG"))
default:
log.FromContext(ctx).Infof("Creating cluster-external Provider client%s", withEndpoint)
cl, err = newExternalClusterClient(p.Endpoint, p.Token, p.CertAuthFilePath)
}
if err == nil {
cl.ingressLabelSelector = ingLabelSel
}
return cl, err
}
// Init the provider.
func (p *Provider) Init() error {
return p.BaseProvider.Init()
}
// Provide allows the k8s provider to provide configurations to traefik
// using the given configuration channel.
func (p *Provider) Provide(configurationChan chan<- config.Message, pool *safe.Pool) error {
ctxLog := log.With(context.Background(), log.Str(log.ProviderName, "docker"))
logger := log.FromContext(ctxLog)
// Tell glog (used by client-go) to log into STDERR. Otherwise, we risk
// certain kinds of API errors getting logged into a directory not
// available in a `FROM scratch` Docker container, causing glog to abort
// hard with an exit code > 0.
err := flag.Set("logtostderr", "true")
if err != nil {
return err
}
logger.Debugf("Using Ingress label selector: %q", p.LabelSelector)
k8sClient, err := p.newK8sClient(ctxLog, p.LabelSelector)
if err != nil {
return err
}
pool.Go(func(stop chan bool) {
operation := func() error {
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)
select {
case <-timer.C:
return err
case <-stop:
return nil
}
}
for {
select {
case <-stop:
return nil
case event := <-eventsChan:
conf := p.loadConfigurationFromIngresses(ctxLog, k8sClient)
if reflect.DeepEqual(p.lastConfiguration.Get(), conf) {
logger.Debugf("Skipping Kubernetes event kind %T", event)
} else {
p.lastConfiguration.Set(conf)
configurationChan <- config.Message{
ProviderName: "kubernetes",
Configuration: conf,
}
}
}
}
}
notify := func(err error, time time.Duration) {
logger.Errorf("Provider connection error: %s; retrying in %s", err, time)
}
err := backoff.RetryNotify(safe.OperationWithRecover(operation), job.NewBackOff(backoff.NewExponentialBackOff()), notify)
if err != nil {
logger.Errorf("Cannot connect to Provider: %s", err)
}
})
return nil
}
func checkStringQuoteValidity(value string) error {
_, err := strconv.Unquote(`"` + value + `"`)
return err
}
func loadService(client Client, namespace string, backend v1beta1.IngressBackend) (*config.Service, error) {
service, exists, err := client.GetService(namespace, backend.ServiceName)
if err != nil {
return nil, err
}
if !exists {
return nil, errors.New("service not found")
}
var servers []config.Server
var portName string
var portSpec corev1.ServicePort
var match bool
for _, p := range service.Spec.Ports {
if (backend.ServicePort.Type == intstr.Int && backend.ServicePort.IntVal == p.Port) ||
(backend.ServicePort.Type == intstr.String && backend.ServicePort.StrVal == p.Name) {
portName = p.Name
portSpec = p
match = true
break
}
}
if !match {
return nil, errors.New("service port not found")
}
if service.Spec.Type == corev1.ServiceTypeExternalName {
servers = append(servers, config.Server{
URL: fmt.Sprintf("http://%s:%d", service.Spec.ExternalName, portSpec.Port),
Weight: 1,
})
} else {
endpoints, endpointsExists, endpointsErr := client.GetEndpoints(namespace, backend.ServiceName)
if endpointsErr != nil {
return nil, endpointsErr
}
if !endpointsExists {
return nil, errors.New("endpoints not found")
}
if len(endpoints.Subsets) == 0 {
return nil, errors.New("subset not found")
}
var port int32
for _, subset := range endpoints.Subsets {
for _, p := range subset.Ports {
if portName == p.Name {
port = p.Port
break
}
}
if port == 0 {
return nil, errors.New("cannot define a port")
}
protocol := "http"
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if port == 443 || strings.HasPrefix(portName, "https") {
protocol = "https"
}
for _, addr := range subset.Addresses {
servers = append(servers, config.Server{
URL: fmt.Sprintf("%s://%s:%d", protocol, addr.IP, port),
Weight: 1,
})
}
}
}
return &config.Service{
LoadBalancer: &config.LoadBalancerService{
Servers: servers,
Method: "wrr",
PassHostHeader: true,
},
}, nil
}
func (p *Provider) loadConfigurationFromIngresses(ctx context.Context, client Client) *config.Configuration {
conf := &config.Configuration{
Routers: map[string]*config.Router{},
Middlewares: map[string]*config.Middleware{},
Services: map[string]*config.Service{},
}
ingresses := client.GetIngresses()
tlsConfigs := make(map[string]*tls.Configuration)
for _, ingress := range ingresses {
ctx = log.With(ctx, log.Str("ingress", ingress.Name), log.Str("namespace", ingress.Namespace))
if !shouldProcessIngress(p.IngressClass, ingress.Annotations[annotationKubernetesIngressClass]) {
continue
}
err := getTLS(ctx, ingress, client, tlsConfigs)
if err != nil {
log.FromContext(ctx).Errorf("Error configuring TLS: %v", err)
}
if len(ingress.Spec.Rules) == 0 {
if ingress.Spec.Backend != nil {
if _, ok := conf.Services["default-backend"]; ok {
log.FromContext(ctx).Error("The default backend already exists.")
continue
}
service, err := loadService(client, ingress.Namespace, *ingress.Spec.Backend)
if err != nil {
log.FromContext(ctx).
WithField("serviceName", ingress.Spec.Backend.ServiceName).
WithField("servicePort", ingress.Spec.Backend.ServicePort.String()).
Errorf("Cannot create service: %v", err)
continue
}
conf.Routers["/"] = &config.Router{
Rule: "PathPrefix(`/`)",
Priority: math.MinInt32,
Service: "default-backend",
}
conf.Services["default-backend"] = service
}
}
for _, rule := range ingress.Spec.Rules {
if err := checkStringQuoteValidity(rule.Host); err != nil {
log.FromContext(ctx).Errorf("Invalid syntax for host: %s", rule.Host)
continue
}
for _, p := range rule.HTTP.Paths {
service, err := loadService(client, ingress.Namespace, p.Backend)
if err != nil {
log.FromContext(ctx).
WithField("serviceName", p.Backend.ServiceName).
WithField("servicePort", p.Backend.ServicePort.String()).
Errorf("Cannot create service: %v", err)
continue
}
if err = checkStringQuoteValidity(p.Path); err != nil {
log.FromContext(ctx).Errorf("Invalid syntax for path: %s", p.Path)
continue
}
serviceName := ingress.Namespace + "/" + p.Backend.ServiceName + "/" + p.Backend.ServicePort.String()
var rules []string
if len(rule.Host) > 0 {
rules = []string{"Host(`" + rule.Host + "`)"}
}
if len(p.Path) > 0 {
rules = append(rules, "PathPrefix(`"+p.Path+"`)")
}
conf.Routers[strings.Replace(rule.Host, ".", "-", -1)+p.Path] = &config.Router{
Rule: strings.Join(rules, " && "),
Service: serviceName,
}
conf.Services[serviceName] = service
}
}
}
conf.TLS = getTLSConfig(tlsConfigs)
return conf
}
func shouldProcessIngress(ingressClass string, ingressClassAnnotation string) bool {
return ingressClass == ingressClassAnnotation ||
(len(ingressClass) == 0 && ingressClassAnnotation == traefikDefaultIngressClass)
}
func getTLS(ctx context.Context, ingress *v1beta1.Ingress, k8sClient Client, tlsConfigs map[string]*tls.Configuration) error {
for _, t := range ingress.Spec.TLS {
if t.SecretName == "" {
log.FromContext(ctx).Debugf("Skipping TLS sub-section: No secret name provided")
continue
}
configKey := ingress.Namespace + "/" + t.SecretName
if _, tlsExists := tlsConfigs[configKey]; !tlsExists {
secret, exists, err := k8sClient.GetSecret(ingress.Namespace, t.SecretName)
if err != nil {
return fmt.Errorf("failed to fetch secret %s/%s: %v", ingress.Namespace, t.SecretName, err)
}
if !exists {
return fmt.Errorf("secret %s/%s does not exist", ingress.Namespace, t.SecretName)
}
cert, key, err := getCertificateBlocks(secret, ingress.Namespace, t.SecretName)
if err != nil {
return err
}
tlsConfigs[configKey] = &tls.Configuration{
Certificate: &tls.Certificate{
CertFile: tls.FileOrContent(cert),
KeyFile: tls.FileOrContent(key),
},
}
}
}
return nil
}
func getTLSConfig(tlsConfigs map[string]*tls.Configuration) []*tls.Configuration {
var secretNames []string
for secretName := range tlsConfigs {
secretNames = append(secretNames, secretName)
}
sort.Strings(secretNames)
var configs []*tls.Configuration
for _, secretName := range secretNames {
configs = append(configs, tlsConfigs[secretName])
}
return configs
}
func getCertificateBlocks(secret *corev1.Secret, namespace, secretName string) (string, string, error) {
var missingEntries []string
tlsCrtData, tlsCrtExists := secret.Data["tls.crt"]
if !tlsCrtExists {
missingEntries = append(missingEntries, "tls.crt")
}
tlsKeyData, tlsKeyExists := secret.Data["tls.key"]
if !tlsKeyExists {
missingEntries = append(missingEntries, "tls.key")
}
if len(missingEntries) > 0 {
return "", "", fmt.Errorf("secret %s/%s is missing the following TLS data entries: %s",
namespace, secretName, strings.Join(missingEntries, ", "))
}
cert := string(tlsCrtData)
if cert == "" {
missingEntries = append(missingEntries, "tls.crt")
}
key := string(tlsKeyData)
if key == "" {
missingEntries = append(missingEntries, "tls.key")
}
if len(missingEntries) > 0 {
return "", "", fmt.Errorf("secret %s/%s contains the following empty TLS data entries: %s",
namespace, secretName, strings.Join(missingEntries, ", "))
}
return cert, key, nil
}