traefik/provider/kubernetes/kubernetes.go
Timo Reimann 91ce78da46 [k8s] Tell glog to log everything into STDERR.
Logging errors into a file inside a minimalistic container might not be
possible, and glog bails out with an exit code > 0 if it fails.
2017-07-04 17:11:50 +02:00

393 lines
12 KiB
Go

package kubernetes
import (
"bufio"
"bytes"
"errors"
"flag"
"fmt"
"os"
"reflect"
"strconv"
"strings"
"text/template"
"time"
"github.com/cenk/backoff"
"github.com/containous/traefik/job"
"github.com/containous/traefik/log"
"github.com/containous/traefik/provider"
"github.com/containous/traefik/safe"
"github.com/containous/traefik/types"
"k8s.io/client-go/pkg/api/v1"
"k8s.io/client-go/pkg/apis/extensions/v1beta1"
"k8s.io/client-go/pkg/util/intstr"
)
var _ provider.Provider = (*Provider)(nil)
const (
annotationFrontendRuleType = "traefik.frontend.rule.type"
ruleTypePathPrefix = "PathPrefix"
)
const traefikDefaultRealm = "traefik"
// Provider holds configurations of the provider.
type Provider struct {
provider.BaseProvider `mapstructure:",squash"`
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"`
Namespaces Namespaces `description:"Kubernetes namespaces"`
LabelSelector string `description:"Kubernetes api label selector to use"`
lastConfiguration safe.Safe
}
func (p *Provider) newK8sClient() (Client, error) {
withEndpoint := ""
if p.Endpoint != "" {
withEndpoint = fmt.Sprintf(" with endpoint %v", p.Endpoint)
}
if os.Getenv("KUBERNETES_SERVICE_HOST") != "" && os.Getenv("KUBERNETES_SERVICE_PORT") != "" {
log.Infof("Creating in-cluster Provider client%s\n", withEndpoint)
return NewInClusterClient(p.Endpoint)
}
log.Infof("Creating cluster-external Provider client%s\n", withEndpoint)
return NewExternalClusterClient(p.Endpoint, p.Token, p.CertAuthFilePath)
}
// Provide allows the k8s provider to provide configurations to traefik
// using the given configuration channel.
func (p *Provider) Provide(configurationChan chan<- types.ConfigMessage, pool *safe.Pool, constraints types.Constraints) error {
// 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.
flag.Set("logtostderr", "true")
k8sClient, err := p.newK8sClient()
if err != nil {
return err
}
p.Constraints = append(p.Constraints, constraints...)
pool.Go(func(stop chan bool) {
operation := func() error {
for {
stopWatch := make(chan struct{}, 1)
defer close(stopWatch)
log.Debugf("Using label selector: '%s'", p.LabelSelector)
eventsChan, err := k8sClient.WatchAll(p.LabelSelector, stopWatch)
if err != nil {
log.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:
log.Debugf("Received event from kubernetes %+v", event)
templateObjects, err := p.loadIngresses(k8sClient)
if err != nil {
return err
}
if reflect.DeepEqual(p.lastConfiguration.Get(), templateObjects) {
log.Debugf("Skipping event from kubernetes %+v", event)
} else {
p.lastConfiguration.Set(templateObjects)
configurationChan <- types.ConfigMessage{
ProviderName: "kubernetes",
Configuration: p.loadConfig(*templateObjects),
}
}
}
}
}
}
notify := func(err error, time time.Duration) {
log.Errorf("Provider connection error: %s; retrying in %s", err, time)
}
err := backoff.RetryNotify(safe.OperationWithRecover(operation), job.NewBackOff(backoff.NewExponentialBackOff()), notify)
if err != nil {
log.Errorf("Cannot connect to Provider: %s", err)
}
})
return nil
}
func (p *Provider) loadIngresses(k8sClient Client) (*types.Configuration, error) {
ingresses := k8sClient.GetIngresses(p.Namespaces)
templateObjects := types.Configuration{
map[string]*types.Backend{},
map[string]*types.Frontend{},
}
for _, i := range ingresses {
ingressClass := i.Annotations["kubernetes.io/ingress.class"]
if !shouldProcessIngress(ingressClass) {
continue
}
for _, r := range i.Spec.Rules {
if r.HTTP == nil {
log.Warnf("Error in ingress: HTTP is nil")
continue
}
for _, pa := range r.HTTP.Paths {
if _, exists := templateObjects.Backends[r.Host+pa.Path]; !exists {
templateObjects.Backends[r.Host+pa.Path] = &types.Backend{
Servers: make(map[string]types.Server),
LoadBalancer: &types.LoadBalancer{
Sticky: false,
Method: "wrr",
},
}
}
PassHostHeader := p.getPassHostHeader()
passHostHeaderAnnotation, ok := i.Annotations["traefik.frontend.passHostHeader"]
switch {
case !ok:
// No op.
case passHostHeaderAnnotation == "false":
PassHostHeader = false
case passHostHeaderAnnotation == "true":
PassHostHeader = true
default:
log.Warnf("Unknown value '%s' for traefik.frontend.passHostHeader, falling back to %s", passHostHeaderAnnotation, PassHostHeader)
}
if realm := i.Annotations["ingress.kubernetes.io/auth-realm"]; realm != "" && realm != traefikDefaultRealm {
return nil, errors.New("no realm customization supported")
}
if _, exists := templateObjects.Frontends[r.Host+pa.Path]; !exists {
basicAuthCreds, err := handleBasicAuthConfig(i, k8sClient)
if err != nil {
log.Errorf("Failed to retrieve basic auth configuration for ingress %s/%s: %s", i.ObjectMeta.Namespace, i.ObjectMeta.Name, err)
continue
}
templateObjects.Frontends[r.Host+pa.Path] = &types.Frontend{
Backend: r.Host + pa.Path,
PassHostHeader: PassHostHeader,
Routes: make(map[string]types.Route),
Priority: len(pa.Path),
BasicAuth: basicAuthCreds,
}
}
if len(r.Host) > 0 {
rule := "Host:" + r.Host
if strings.Contains(r.Host, "*") {
rule = "HostRegexp:" + strings.Replace(r.Host, "*", "{subdomain:[A-Za-z0-9-_]+}", 1)
}
if _, exists := templateObjects.Frontends[r.Host+pa.Path].Routes[r.Host]; !exists {
templateObjects.Frontends[r.Host+pa.Path].Routes[r.Host] = types.Route{
Rule: rule,
}
}
}
if len(pa.Path) > 0 {
ruleType := i.Annotations[annotationFrontendRuleType]
if ruleType == "" {
ruleType = ruleTypePathPrefix
}
templateObjects.Frontends[r.Host+pa.Path].Routes[pa.Path] = types.Route{
Rule: ruleType + ":" + pa.Path,
}
}
service, exists, err := k8sClient.GetService(i.ObjectMeta.Namespace, pa.Backend.ServiceName)
if err != nil {
log.Errorf("Error while retrieving service information from k8s API %s/%s: %v", i.ObjectMeta.Namespace, pa.Backend.ServiceName, err)
return nil, err
}
if !exists {
log.Errorf("Service not found for %s/%s", i.ObjectMeta.Namespace, pa.Backend.ServiceName)
delete(templateObjects.Frontends, r.Host+pa.Path)
continue
}
if expression := service.Annotations["traefik.backend.circuitbreaker"]; expression != "" {
templateObjects.Backends[r.Host+pa.Path].CircuitBreaker = &types.CircuitBreaker{
Expression: expression,
}
}
if service.Annotations["traefik.backend.loadbalancer.method"] == "drr" {
templateObjects.Backends[r.Host+pa.Path].LoadBalancer.Method = "drr"
}
if service.Annotations["traefik.backend.loadbalancer.sticky"] == "true" {
templateObjects.Backends[r.Host+pa.Path].LoadBalancer.Sticky = true
}
protocol := "http"
for _, port := range service.Spec.Ports {
if equalPorts(port, pa.Backend.ServicePort) {
if port.Port == 443 {
protocol = "https"
}
if service.Spec.Type == "ExternalName" {
url := protocol + "://" + service.Spec.ExternalName
name := url
templateObjects.Backends[r.Host+pa.Path].Servers[name] = types.Server{
URL: url,
Weight: 1,
}
} else {
endpoints, exists, err := k8sClient.GetEndpoints(service.ObjectMeta.Namespace, service.ObjectMeta.Name)
if err != nil {
log.Errorf("Error retrieving endpoints %s/%s: %v", service.ObjectMeta.Namespace, service.ObjectMeta.Name, err)
return nil, err
}
if !exists {
log.Warnf("Endpoints not found for %s/%s", service.ObjectMeta.Namespace, service.ObjectMeta.Name)
break
}
if len(endpoints.Subsets) == 0 {
log.Warnf("Endpoints not available for %s/%s", service.ObjectMeta.Namespace, service.ObjectMeta.Name)
break
}
for _, subset := range endpoints.Subsets {
for _, address := range subset.Addresses {
url := protocol + "://" + address.IP + ":" + strconv.Itoa(endpointPortNumber(port, subset.Ports))
name := url
if address.TargetRef != nil && address.TargetRef.Name != "" {
name = address.TargetRef.Name
}
templateObjects.Backends[r.Host+pa.Path].Servers[name] = types.Server{
URL: url,
Weight: 1,
}
}
}
}
break
}
}
}
}
}
return &templateObjects, nil
}
func handleBasicAuthConfig(i *v1beta1.Ingress, k8sClient Client) ([]string, error) {
authType, exists := i.Annotations["ingress.kubernetes.io/auth-type"]
if !exists {
return nil, nil
}
if strings.ToLower(authType) != "basic" {
return nil, fmt.Errorf("unsupported auth-type on annotation ingress.kubernetes.io/auth-type: %q", authType)
}
authSecret := i.Annotations["ingress.kubernetes.io/auth-secret"]
if authSecret == "" {
return nil, errors.New("auth-secret annotation ingress.kubernetes.io/auth-secret must be set")
}
basicAuthCreds, err := loadAuthCredentials(i.Namespace, authSecret, k8sClient)
if err != nil {
return nil, fmt.Errorf("failed to load auth credentials: %s", err)
}
return basicAuthCreds, nil
}
func loadAuthCredentials(namespace, secretName string, k8sClient Client) ([]string, error) {
secret, ok, err := k8sClient.GetSecret(namespace, secretName)
switch { // keep order of case conditions
case err != nil:
return nil, fmt.Errorf("failed to fetch secret %q/%q: %s", namespace, secretName, err)
case !ok:
return nil, fmt.Errorf("secret %q/%q not found", namespace, secretName)
case secret == nil:
return nil, fmt.Errorf("data for secret %q/%q must not be nil", namespace, secretName)
case len(secret.Data) != 1:
return nil, fmt.Errorf("found %d elements for secret %q/%q, must be single element exactly", len(secret.Data), namespace, secretName)
default:
}
var firstSecret []byte
for _, v := range secret.Data {
firstSecret = v
break
}
creds := make([]string, 0)
scanner := bufio.NewScanner(bytes.NewReader(firstSecret))
for scanner.Scan() {
if cred := scanner.Text(); cred != "" {
creds = append(creds, cred)
}
}
if len(creds) == 0 {
return nil, fmt.Errorf("secret %q/%q does not contain any credentials", namespace, secretName)
}
return creds, nil
}
func endpointPortNumber(servicePort v1.ServicePort, endpointPorts []v1.EndpointPort) int {
if len(endpointPorts) > 0 {
//name is optional if there is only one port
port := endpointPorts[0]
for _, endpointPort := range endpointPorts {
if servicePort.Name == endpointPort.Name {
port = endpointPort
}
}
return int(port.Port)
}
return int(servicePort.Port)
}
func equalPorts(servicePort v1.ServicePort, ingressPort intstr.IntOrString) bool {
if int(servicePort.Port) == ingressPort.IntValue() {
return true
}
if servicePort.Name != "" && servicePort.Name == ingressPort.String() {
return true
}
return false
}
func shouldProcessIngress(ingressClass string) bool {
switch ingressClass {
case "", "traefik":
return true
default:
return false
}
}
func (p *Provider) getPassHostHeader() bool {
if p.DisablePassHostHeaders {
return false
}
return true
}
func (p *Provider) loadConfig(templateObjects types.Configuration) *types.Configuration {
var FuncMap = template.FuncMap{}
configuration, err := p.GetConfiguration("templates/kubernetes.tmpl", FuncMap, templateObjects)
if err != nil {
log.Error(err)
}
return configuration
}