forked from prometheus/prometheus
/
discovery.go
580 lines (497 loc) · 16.1 KB
/
discovery.go
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// Copyright 2015 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 kubernetes
import (
"crypto/tls"
"crypto/x509"
"encoding/json"
"fmt"
"io/ioutil"
"net"
"net/http"
"os"
"sync"
"time"
"github.com/prometheus/common/model"
"github.com/prometheus/log"
"github.com/prometheus/prometheus/config"
"github.com/prometheus/prometheus/util/httputil"
"github.com/prometheus/prometheus/util/strutil"
)
const (
sourceServicePrefix = "services"
// kubernetesMetaLabelPrefix is the meta prefix used for all meta labels.
// in this discovery.
metaLabelPrefix = model.MetaLabelPrefix + "kubernetes_"
// nodeLabel is the name for the label containing a target's node name.
nodeLabel = metaLabelPrefix + "node"
// serviceNamespaceLabel is the name for the label containing a target's service namespace.
serviceNamespaceLabel = metaLabelPrefix + "service_namespace"
// serviceNameLabel is the name for the label containing a target's service name.
serviceNameLabel = metaLabelPrefix + "service_name"
// nodeLabelPrefix is the prefix for the node labels.
nodeLabelPrefix = metaLabelPrefix + "node_label_"
// serviceLabelPrefix is the prefix for the service labels.
serviceLabelPrefix = metaLabelPrefix + "service_label_"
// serviceAnnotationPrefix is the prefix for the service annotations.
serviceAnnotationPrefix = metaLabelPrefix + "service_annotation_"
// nodesTargetGroupName is the name given to the target group for nodes.
nodesTargetGroupName = "nodes"
serviceAccountToken = "/var/run/secrets/kubernetes.io/serviceaccount/token"
serviceAccountCACert = "/var/run/secrets/kubernetes.io/serviceaccount/ca.crt"
apiVersion = "v1"
apiPrefix = "api/" + apiVersion
nodesURL = apiPrefix + "/nodes"
servicesURL = apiPrefix + "/services"
endpointsURL = apiPrefix + "/endpoints"
serviceEndpointsURL = apiPrefix + "/namespaces/%s/endpoints/%s"
)
// Discovery implements a TargetProvider for Kubernetes services.
type Discovery struct {
client *http.Client
Conf *config.KubernetesSDConfig
nodesResourceVersion string
servicesResourceVersion string
endpointsResourceVersion string
nodes map[string]*Node
services map[string]map[string]*Service
nodesMu sync.RWMutex
servicesMu sync.RWMutex
runDone chan struct{}
}
// Initialize sets up the discovery for usage.
func (kd *Discovery) Initialize() error {
client, err := newKubernetesHTTPClient(kd.Conf)
if err != nil {
return err
}
kd.client = client
kd.nodes = map[string]*Node{}
kd.services = map[string]map[string]*Service{}
kd.runDone = make(chan struct{})
return nil
}
// Sources implements the TargetProvider interface.
func (kd *Discovery) Sources() []string {
res, err := kd.client.Get(kd.Conf.Server + nodesURL)
if err != nil {
// If we can't list nodes then we can't watch them. Assume this is a misconfiguration
// & log & return empty.
log.Errorf("Unable to list Kubernetes nodes: %s", err)
return []string{}
}
if res.StatusCode != http.StatusOK {
log.Errorf("Unable to list Kubernetes nodes. Unexpected response: %d %s", res.StatusCode, res.Status)
return []string{}
}
var nodes NodeList
if err := json.NewDecoder(res.Body).Decode(&nodes); err != nil {
body, _ := ioutil.ReadAll(res.Body)
log.Errorf("Unable to list Kubernetes nodes. Unexpected response body: %s", string(body))
return []string{}
}
kd.nodesMu.Lock()
defer kd.nodesMu.Unlock()
sourceNames := make([]string, 0, len(nodes.Items))
kd.nodesResourceVersion = nodes.ResourceVersion
for idx, node := range nodes.Items {
sourceNames = append(sourceNames, nodesTargetGroupName+":"+node.ObjectMeta.Name)
kd.nodes[node.ObjectMeta.Name] = &nodes.Items[idx]
}
res, err = kd.client.Get(kd.Conf.Server + servicesURL)
if err != nil {
// If we can't list services then we can't watch them. Assume this is a misconfiguration
// & log & return empty.
log.Errorf("Unable to list Kubernetes services: %s", err)
return []string{}
}
if res.StatusCode != http.StatusOK {
log.Errorf("Unable to list Kubernetes services. Unexpected response: %d %s", res.StatusCode, res.Status)
return []string{}
}
var services ServiceList
if err := json.NewDecoder(res.Body).Decode(&services); err != nil {
body, _ := ioutil.ReadAll(res.Body)
log.Errorf("Unable to list Kubernetes services. Unexpected response body: %s", string(body))
return []string{}
}
kd.servicesMu.Lock()
defer kd.servicesMu.Unlock()
kd.servicesResourceVersion = services.ResourceVersion
for idx, service := range services.Items {
sourceNames = append(sourceNames, serviceSource(&service))
namespace, ok := kd.services[service.ObjectMeta.Namespace]
if !ok {
namespace = map[string]*Service{}
kd.services[service.ObjectMeta.Namespace] = namespace
}
namespace[service.ObjectMeta.Name] = &services.Items[idx]
}
return sourceNames
}
// Run implements the TargetProvider interface.
func (kd *Discovery) Run(ch chan<- *config.TargetGroup, done <-chan struct{}) {
defer close(ch)
select {
case ch <- kd.updateNodesTargetGroup():
case <-done:
return
}
for _, ns := range kd.services {
for _, service := range ns {
select {
case ch <- kd.addService(service):
case <-done:
return
}
}
}
retryInterval := time.Duration(kd.Conf.RetryInterval)
update := make(chan interface{}, 10)
go kd.watchNodes(update, done, retryInterval)
go kd.watchServices(update, done, retryInterval)
go kd.watchServiceEndpoints(update, done, retryInterval)
var tg *config.TargetGroup
for {
select {
case <-done:
return
case event := <-update:
switch obj := event.(type) {
case *nodeEvent:
kd.updateNode(obj.Node, obj.EventType)
tg = kd.updateNodesTargetGroup()
case *serviceEvent:
tg = kd.updateService(obj.Service, obj.EventType)
case *endpointsEvent:
tg = kd.updateServiceEndpoints(obj.Endpoints, obj.EventType)
}
}
select {
case ch <- tg:
case <-done:
return
}
}
}
func (kd *Discovery) updateNodesTargetGroup() *config.TargetGroup {
kd.nodesMu.Lock()
defer kd.nodesMu.Unlock()
tg := &config.TargetGroup{Source: nodesTargetGroupName}
// Now let's loop through the nodes & add them to the target group with appropriate labels.
for nodeName, node := range kd.nodes {
address := fmt.Sprintf("%s:%d", node.Status.Addresses[0].Address, kd.Conf.KubeletPort)
t := model.LabelSet{
model.AddressLabel: model.LabelValue(address),
nodeLabel: model.LabelValue(nodeName),
}
for k, v := range node.ObjectMeta.Labels {
labelName := strutil.SanitizeLabelName(nodeLabelPrefix + k)
t[model.LabelName(labelName)] = model.LabelValue(v)
}
tg.Targets = append(tg.Targets, t)
}
return tg
}
func (kd *Discovery) updateNode(node *Node, eventType EventType) {
kd.nodesMu.Lock()
defer kd.nodesMu.Unlock()
updatedNodeName := node.ObjectMeta.Name
switch eventType {
case deleted:
// Deleted - remove from nodes map.
delete(kd.nodes, updatedNodeName)
case added, modified:
// Added/Modified - update the node in the nodes map.
kd.nodes[updatedNodeName] = node
}
}
// watchNodes watches nodes as they come & go.
func (kd *Discovery) watchNodes(events chan interface{}, done <-chan struct{}, retryInterval time.Duration) {
until(func() {
req, err := http.NewRequest("GET", kd.Conf.Server+nodesURL, nil)
if err != nil {
log.Errorf("Failed to watch nodes: %s", err)
return
}
values := req.URL.Query()
values.Add("watch", "true")
values.Add("resourceVersion", kd.nodesResourceVersion)
req.URL.RawQuery = values.Encode()
res, err := kd.client.Do(req)
if err != nil {
log.Errorf("Failed to watch nodes: %s", err)
return
}
if res.StatusCode != http.StatusOK {
log.Errorf("Failed to watch nodes: %d", res.StatusCode)
return
}
d := json.NewDecoder(res.Body)
for {
var event nodeEvent
if err := d.Decode(&event); err != nil {
log.Errorf("Failed to watch nodes: %s", err)
return
}
kd.nodesResourceVersion = event.Node.ObjectMeta.ResourceVersion
select {
case events <- &event:
case <-done:
}
}
}, retryInterval, done)
}
// watchServices watches services as they come & go.
func (kd *Discovery) watchServices(events chan interface{}, done <-chan struct{}, retryInterval time.Duration) {
until(func() {
req, err := http.NewRequest("GET", kd.Conf.Server+servicesURL, nil)
if err != nil {
log.Errorf("Failed to watch services: %s", err)
return
}
values := req.URL.Query()
values.Add("watch", "true")
values.Add("resourceVersion", kd.servicesResourceVersion)
req.URL.RawQuery = values.Encode()
res, err := kd.client.Do(req)
if err != nil {
log.Errorf("Failed to watch services: %s", err)
return
}
if res.StatusCode != http.StatusOK {
log.Errorf("Failed to watch services: %d", res.StatusCode)
return
}
d := json.NewDecoder(res.Body)
for {
var event serviceEvent
if err := d.Decode(&event); err != nil {
log.Errorf("Unable to watch services: %s", err)
return
}
kd.servicesResourceVersion = event.Service.ObjectMeta.ResourceVersion
select {
case events <- &event:
case <-done:
}
}
}, retryInterval, done)
}
func (kd *Discovery) updateService(service *Service, eventType EventType) *config.TargetGroup {
kd.servicesMu.Lock()
defer kd.servicesMu.Unlock()
var (
name = service.ObjectMeta.Name
namespace = service.ObjectMeta.Namespace
_, exists = kd.services[namespace][name]
)
switch eventType {
case deleted:
if exists {
return kd.deleteService(service)
}
case added, modified:
return kd.addService(service)
}
return nil
}
func (kd *Discovery) deleteService(service *Service) *config.TargetGroup {
tg := &config.TargetGroup{Source: serviceSource(service)}
delete(kd.services[service.ObjectMeta.Namespace], service.ObjectMeta.Name)
if len(kd.services[service.ObjectMeta.Namespace]) == 0 {
delete(kd.services, service.ObjectMeta.Namespace)
}
return tg
}
func (kd *Discovery) addService(service *Service) *config.TargetGroup {
namespace, ok := kd.services[service.ObjectMeta.Namespace]
if !ok {
namespace = map[string]*Service{}
kd.services[service.ObjectMeta.Namespace] = namespace
}
namespace[service.ObjectMeta.Name] = service
endpointURL := fmt.Sprintf(serviceEndpointsURL, service.ObjectMeta.Namespace, service.ObjectMeta.Name)
res, err := kd.client.Get(kd.Conf.Server + endpointURL)
if err != nil {
log.Errorf("Error getting service endpoints: %s", err)
return nil
}
if res.StatusCode != http.StatusOK {
log.Errorf("Failed to get service endpoints: %d", res.StatusCode)
return nil
}
var eps Endpoints
if err := json.NewDecoder(res.Body).Decode(&eps); err != nil {
log.Errorf("Error getting service endpoints: %s", err)
return nil
}
return kd.updateServiceTargetGroup(service, &eps)
}
func (kd *Discovery) updateServiceTargetGroup(service *Service, eps *Endpoints) *config.TargetGroup {
tg := &config.TargetGroup{
Source: serviceSource(service),
Labels: model.LabelSet{
serviceNamespaceLabel: model.LabelValue(service.ObjectMeta.Namespace),
serviceNameLabel: model.LabelValue(service.ObjectMeta.Name),
},
}
for k, v := range service.ObjectMeta.Labels {
labelName := strutil.SanitizeLabelName(serviceLabelPrefix + k)
tg.Labels[model.LabelName(labelName)] = model.LabelValue(v)
}
for k, v := range service.ObjectMeta.Annotations {
labelName := strutil.SanitizeLabelName(serviceAnnotationPrefix + k)
tg.Labels[model.LabelName(labelName)] = model.LabelValue(v)
}
// Now let's loop through the endpoints & add them to the target group with appropriate labels.
for _, ss := range eps.Subsets {
epPort := ss.Ports[0].Port
for _, addr := range ss.Addresses {
ipAddr := addr.IP
if len(ipAddr) == net.IPv6len {
ipAddr = "[" + ipAddr + "]"
}
address := fmt.Sprintf("%s:%d", ipAddr, epPort)
t := model.LabelSet{model.AddressLabel: model.LabelValue(address)}
tg.Targets = append(tg.Targets, t)
}
}
return tg
}
// watchServiceEndpoints watches service endpoints as they come & go.
func (kd *Discovery) watchServiceEndpoints(events chan interface{}, done <-chan struct{}, retryInterval time.Duration) {
until(func() {
req, err := http.NewRequest("GET", kd.Conf.Server+endpointsURL, nil)
if err != nil {
log.Errorf("Failed to watch service endpoints: %s", err)
return
}
values := req.URL.Query()
values.Add("watch", "true")
values.Add("resourceVersion", kd.servicesResourceVersion)
req.URL.RawQuery = values.Encode()
res, err := kd.client.Do(req)
if err != nil {
log.Errorf("Failed to watch service endpoints: %s", err)
return
}
if res.StatusCode != http.StatusOK {
log.Errorf("Failed to watch service endpoints: %d", res.StatusCode)
return
}
d := json.NewDecoder(res.Body)
for {
var event endpointsEvent
if err := d.Decode(&event); err != nil {
log.Errorf("Unable to watch service endpoints: %s", err)
return
}
kd.servicesResourceVersion = event.Endpoints.ObjectMeta.ResourceVersion
select {
case events <- &event:
case <-done:
}
}
}, retryInterval, done)
}
func (kd *Discovery) updateServiceEndpoints(endpoints *Endpoints, eventType EventType) *config.TargetGroup {
kd.servicesMu.Lock()
defer kd.servicesMu.Unlock()
serviceNamespace := endpoints.ObjectMeta.Namespace
serviceName := endpoints.ObjectMeta.Name
if service, ok := kd.services[serviceNamespace][serviceName]; ok {
return kd.updateServiceTargetGroup(service, endpoints)
}
return nil
}
func newKubernetesHTTPClient(conf *config.KubernetesSDConfig) (*http.Client, error) {
bearerTokenFile := conf.BearerTokenFile
caFile := conf.CAFile
if conf.InCluster {
if len(bearerTokenFile) == 0 {
bearerTokenFile = serviceAccountToken
}
if len(caFile) == 0 {
// With recent versions, the CA certificate is provided as a token
// but we need to handle older versions too. In this case, don't
// set the CAFile & the configuration will have to use Insecure.
if _, err := os.Stat(serviceAccountCACert); err == nil {
caFile = serviceAccountCACert
}
}
}
tlsConfig := &tls.Config{InsecureSkipVerify: conf.Insecure}
// Load client cert if specified.
if len(conf.CertFile) > 0 && len(conf.KeyFile) > 0 {
cert, err := tls.LoadX509KeyPair(conf.CertFile, conf.KeyFile)
if err != nil {
return nil, err
}
tlsConfig.Certificates = []tls.Certificate{cert}
}
caCertPool := x509.NewCertPool()
if len(caFile) > 0 {
// Load CA cert.
caCert, err := ioutil.ReadFile(caFile)
if err != nil {
return nil, err
}
caCertPool.AppendCertsFromPEM(caCert)
}
tlsConfig.RootCAs = caCertPool
tlsConfig.BuildNameToCertificate()
tr := &http.Transport{
Dial: func(netw, addr string) (c net.Conn, err error) {
c, err = net.DialTimeout(netw, addr, time.Duration(conf.RequestTimeout))
return
},
}
tr.TLSClientConfig = tlsConfig
var rt http.RoundTripper
rt = tr
bearerToken, err := ioutil.ReadFile(bearerTokenFile)
if err != nil {
return nil, err
}
if len(bearerToken) > 0 {
rt = httputil.NewBearerAuthRoundTripper(string(bearerToken), rt)
}
if len(conf.Username) > 0 && len(conf.Password) > 0 {
rt = httputil.NewBasicAuthRoundTripper(conf.Username, conf.Password, rt)
}
return &http.Client{
Transport: rt,
}, nil
}
func serviceSource(service *Service) string {
return sourceServicePrefix + ":" + service.ObjectMeta.Namespace + "/" + service.ObjectMeta.Name
}
// Until loops until stop channel is closed, running f every period.
// f may not be invoked if stop channel is already closed.
func until(f func(), period time.Duration, stopCh <-chan struct{}) {
select {
case <-stopCh:
return
default:
f()
}
for {
select {
case <-stopCh:
return
case <-time.After(period):
f()
}
}
}