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lib/promscrape/discovery/kubernetes: move apiWatcher code to a separate file

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This commit is contained in:
Aliaksandr Valialkin 2021-03-05 12:36:05 +02:00
parent 1c3c844b38
commit 92ddb8f197
3 changed files with 515 additions and 505 deletions
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505
lib/promscrape/discovery/kubernetes/api.go
View file

@ -1,27 +1,17 @@
package kubernetes
import (
"context"
"encoding/json"
"errors"
"flag"
"fmt"
"io"
"io/ioutil"
"net"
"net/http"
"net/url"
"os"
"reflect"
"strconv"
"strings"
"sync"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promauth"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/promscrape/discoveryutils"
"github.com/VictoriaMetrics/metrics"
)
var apiServerTimeout = flag.Duration("promscrape.kubernetes.apiServerTimeout", 30*time.Minute, "How frequently to reload the full state from Kuberntes API server")
@ -104,498 +94,3 @@ func newAPIConfig(sdc *SDConfig, baseDir string, swcFunc ScrapeWorkConstructorFu
}
return cfg, nil
}
// WatchEvent is a watch event returned from API server endpoints if `watch=1` query arg is set.
//
// See https://kubernetes.io/docs/reference/using-api/api-concepts/#efficient-detection-of-changes
type WatchEvent struct {
Type string
Object json.RawMessage
}
// object is any Kubernetes object.
type object interface {
key() string
getTargetLabels(aw *apiWatcher) []map[string]string
}
// parseObjectFunc must parse object from the given data.
type parseObjectFunc func(data []byte) (object, error)
// parseObjectListFunc must parse objectList from the given data.
type parseObjectListFunc func(data []byte) (map[string]object, ListMeta, error)
// apiWatcher is used for watching for Kuberntes object changes and caching their latest states.
type apiWatcher struct {
// The client used for watching for object changes
client *http.Client
// Kubenetes API server address in the form http://api-server
apiServer string
// The contents for `Authorization` HTTP request header
authorization string
// Namespaces to watch
namespaces []string
// Selectors to apply during watch
selectors []Selector
// Constructor for creating ScrapeWork objects from labels.
swcFunc ScrapeWorkConstructorFunc
// mu protects watchersByURL
mu sync.Mutex
// a map of watchers keyed by request urls
watchersByURL map[string]*urlWatcher
stopFunc func()
stopCtx context.Context
wg sync.WaitGroup
}
func (aw *apiWatcher) mustStop() {
aw.stopFunc()
aw.wg.Wait()
}
func newAPIWatcher(client *http.Client, apiServer, authorization string, namespaces []string, selectors []Selector, swcFunc ScrapeWorkConstructorFunc) *apiWatcher {
stopCtx, stopFunc := context.WithCancel(context.Background())
return &apiWatcher{
apiServer: apiServer,
authorization: authorization,
client: client,
namespaces: namespaces,
selectors: selectors,
swcFunc: swcFunc,
watchersByURL: make(map[string]*urlWatcher),
stopFunc: stopFunc,
stopCtx: stopCtx,
}
}
// getScrapeWorkObjectsForRole returns all the ScrapeWork objects for the given role.
func (aw *apiWatcher) getScrapeWorkObjectsForRole(role string) []interface{} {
aw.startWatchersForRole(role)
var swos []interface{}
aw.mu.Lock()
for _, uw := range aw.watchersByURL {
if uw.role != role {
continue
}
uw.mu.Lock()
for _, swosLocal := range uw.swosByKey {
swos = append(swos, swosLocal...)
}
uw.mu.Unlock()
}
aw.mu.Unlock()
return swos
}
// getObjectByRole returns an object with the given (namespace, name) key and the given role.
func (aw *apiWatcher) getObjectByRole(role, namespace, name string) object {
if aw == nil {
return nil
}
key := namespace + "/" + name
aw.startWatchersForRole(role)
var o object
aw.mu.Lock()
for _, uw := range aw.watchersByURL {
if uw.role != role {
continue
}
uw.mu.Lock()
o = uw.objectsByKey[key]
uw.mu.Unlock()
if o != nil {
break
}
}
aw.mu.Unlock()
return o
}
func (aw *apiWatcher) startWatchersForRole(role string) {
parseObject, parseObjectList := getObjectParsersForRole(role)
paths := getAPIPaths(role, aw.namespaces, aw.selectors)
for _, path := range paths {
apiURL := aw.apiServer + path
aw.startWatcherForURL(role, apiURL, parseObject, parseObjectList)
}
}
func (aw *apiWatcher) startWatcherForURL(role, apiURL string, parseObject parseObjectFunc, parseObjectList parseObjectListFunc) {
aw.mu.Lock()
if aw.watchersByURL[apiURL] != nil {
// Watcher for the given path already exists.
aw.mu.Unlock()
return
}
uw := aw.newURLWatcher(role, apiURL, parseObject, parseObjectList)
aw.watchersByURL[apiURL] = uw
aw.mu.Unlock()
uw.watchersCount.Inc()
uw.watchersCreated.Inc()
resourceVersion := uw.reloadObjects()
aw.wg.Add(1)
go func() {
defer aw.wg.Done()
logger.Infof("started watcher for %q", apiURL)
uw.watchForUpdates(resourceVersion)
logger.Infof("stopped watcher for %q", apiURL)
uw.mu.Lock()
uw.objectsCount.Add(-len(uw.objectsByKey))
uw.objectsRemoved.Add(len(uw.objectsByKey))
uw.mu.Unlock()
aw.mu.Lock()
delete(aw.watchersByURL, apiURL)
aw.mu.Unlock()
uw.watchersCount.Dec()
uw.watchersStopped.Inc()
}()
}
// needStop returns true if aw must be stopped.
func (aw *apiWatcher) needStop() bool {
select {
case <-aw.stopCtx.Done():
return true
default:
return false
}
}
// doRequest performs http request to the given requestURL.
func (aw *apiWatcher) doRequest(requestURL string) (*http.Response, error) {
req, err := http.NewRequestWithContext(aw.stopCtx, "GET", requestURL, nil)
if err != nil {
logger.Fatalf("cannot create a request for %q: %s", requestURL, err)
}
if aw.authorization != "" {
req.Header.Set("Authorization", aw.authorization)
}
return aw.client.Do(req)
}
// urlWatcher watches for an apiURL and updates object states in objectsByKey.
type urlWatcher struct {
role string
apiURL string
parseObject parseObjectFunc
parseObjectList parseObjectListFunc
// mu protects objectsByKey and swosByKey
mu sync.Mutex
// objectsByKey contains the latest state for objects obtained from apiURL
objectsByKey map[string]object
swosByKey map[string][]interface{}
// the parent apiWatcher
aw *apiWatcher
watchersCount *metrics.Counter
watchersCreated *metrics.Counter
watchersStopped *metrics.Counter
objectsCount *metrics.Counter
objectsAdded *metrics.Counter
objectsRemoved *metrics.Counter
}
func (aw *apiWatcher) newURLWatcher(role, apiURL string, parseObject parseObjectFunc, parseObjectList parseObjectListFunc) *urlWatcher {
return &urlWatcher{
role: role,
apiURL: apiURL,
parseObject: parseObject,
parseObjectList: parseObjectList,
objectsByKey: make(map[string]object),
swosByKey: make(map[string][]interface{}),
aw: aw,
watchersCount: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_url_watchers{role=%q}`, role)),
watchersCreated: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_url_watchers_created_total{role=%q}`, role)),
watchersStopped: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_url_watchers_stopped_total{role=%q}`, role)),
objectsCount: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_objects{role=%q}`, role)),
objectsAdded: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_objects_added_total{role=%q}`, role)),
objectsRemoved: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_objects_removed_total{role=%q}`, role)),
}
}
// reloadObjects reloads objects to the latest state and returns resourceVersion for the latest state.
func (uw *urlWatcher) reloadObjects() string {
aw := uw.aw
requestURL := uw.apiURL
resp, err := aw.doRequest(requestURL)
if err != nil {
if !aw.needStop() {
logger.Errorf("error when performing a request to %q: %s", requestURL, err)
}
return ""
}
body, _ := ioutil.ReadAll(resp.Body)
_ = resp.Body.Close()
if resp.StatusCode != http.StatusOK {
logger.Errorf("unexpected status code for request to %q: %d; want %d; response: %q", requestURL, resp.StatusCode, http.StatusOK, body)
return ""
}
objectsByKey, metadata, err := uw.parseObjectList(body)
if err != nil {
if !aw.needStop() {
logger.Errorf("cannot parse response from %q: %s", requestURL, err)
}
return ""
}
swosByKey := make(map[string][]interface{}, len(objectsByKey))
for k, o := range objectsByKey {
labels := o.getTargetLabels(aw)
swos := getScrapeWorkObjectsForLabels(aw.swcFunc, labels)
if len(swos) > 0 {
swosByKey[k] = swos
}
}
uw.mu.Lock()
uw.objectsAdded.Add(len(objectsByKey))
uw.objectsRemoved.Add(len(uw.objectsByKey))
uw.objectsCount.Add(len(objectsByKey) - len(uw.objectsByKey))
uw.objectsByKey = objectsByKey
uw.swosByKey = swosByKey
uw.mu.Unlock()
return metadata.ResourceVersion
}
func getScrapeWorkObjectsForLabels(swcFunc ScrapeWorkConstructorFunc, labelss []map[string]string) []interface{} {
swos := make([]interface{}, 0, len(labelss))
for _, labels := range labelss {
swo := swcFunc(labels)
// The reflect check is needed because of https://mangatmodi.medium.com/go-check-nil-interface-the-right-way-d142776edef1
if swo != nil && !reflect.ValueOf(swo).IsNil() {
swos = append(swos, swo)
}
}
return swos
}
// watchForUpdates watches for object updates starting from resourceVersion and updates the corresponding objects to the latest state.
//
// See https://kubernetes.io/docs/reference/using-api/api-concepts/#efficient-detection-of-changes
func (uw *urlWatcher) watchForUpdates(resourceVersion string) {
aw := uw.aw
backoffDelay := time.Second
maxBackoffDelay := 30 * time.Second
backoffSleep := func() {
time.Sleep(backoffDelay)
backoffDelay *= 2
if backoffDelay > maxBackoffDelay {
backoffDelay = maxBackoffDelay
}
}
apiURL := uw.apiURL
delimiter := "?"
if strings.Contains(apiURL, "?") {
delimiter = "&"
}
timeoutSeconds := time.Duration(0.9 * float64(aw.client.Timeout)).Seconds()
apiURL += delimiter + "watch=1&timeoutSeconds=" + strconv.Itoa(int(timeoutSeconds))
for {
if aw.needStop() {
return
}
requestURL := apiURL
if resourceVersion != "" {
requestURL += "&resourceVersion=" + url.QueryEscape(resourceVersion)
}
resp, err := aw.doRequest(requestURL)
if err != nil {
if aw.needStop() {
return
}
logger.Errorf("error when performing a request to %q: %s", requestURL, err)
backoffSleep()
resourceVersion = uw.reloadObjects()
continue
}
if resp.StatusCode != http.StatusOK {
body, _ := ioutil.ReadAll(resp.Body)
_ = resp.Body.Close()
logger.Errorf("unexpected status code for request to %q: %d; want %d; response: %q", requestURL, resp.StatusCode, http.StatusOK, body)
if resp.StatusCode == 410 {
// There is no need for sleep on 410 error. See https://kubernetes.io/docs/reference/using-api/api-concepts/#410-gone-responses
backoffDelay = time.Second
} else {
backoffSleep()
}
resourceVersion = uw.reloadObjects()
continue
}
backoffDelay = time.Second
err = uw.readObjectUpdateStream(resp.Body)
_ = resp.Body.Close()
if err != nil {
if aw.needStop() {
return
}
if !errors.Is(err, io.EOF) {
logger.Errorf("error when reading WatchEvent stream from %q: %s", requestURL, err)
}
backoffSleep()
resourceVersion = uw.reloadObjects()
continue
}
}
}
// readObjectUpdateStream reads Kuberntes watch events from r and updates locally cached objects according to the received events.
func (uw *urlWatcher) readObjectUpdateStream(r io.Reader) error {
aw := uw.aw
d := json.NewDecoder(r)
var we WatchEvent
for {
if err := d.Decode(&we); err != nil {
return err
}
o, err := uw.parseObject(we.Object)
if err != nil {
return err
}
key := o.key()
switch we.Type {
case "ADDED", "MODIFIED":
uw.mu.Lock()
if uw.objectsByKey[key] == nil {
uw.objectsAdded.Inc()
uw.objectsCount.Inc()
}
uw.objectsByKey[key] = o
uw.mu.Unlock()
labels := o.getTargetLabels(aw)
swos := getScrapeWorkObjectsForLabels(aw.swcFunc, labels)
uw.mu.Lock()
if len(swos) > 0 {
uw.swosByKey[key] = swos
} else {
delete(uw.swosByKey, key)
}
uw.mu.Unlock()
case "DELETED":
uw.mu.Lock()
if uw.objectsByKey[key] != nil {
uw.objectsRemoved.Inc()
uw.objectsCount.Dec()
}
delete(uw.objectsByKey, key)
delete(uw.swosByKey, key)
uw.mu.Unlock()
default:
return fmt.Errorf("unexpected WatchEvent type %q for role %q", we.Type, uw.role)
}
}
}
func getAPIPaths(role string, namespaces []string, selectors []Selector) []string {
objectName := getObjectNameByRole(role)
if objectName == "nodes" || len(namespaces) == 0 {
query := joinSelectors(role, selectors)
path := getAPIPath(objectName, "", query)
return []string{path}
}
query := joinSelectors(role, selectors)
paths := make([]string, len(namespaces))
for i, namespace := range namespaces {
paths[i] = getAPIPath(objectName, namespace, query)
}
return paths
}
func getAPIPath(objectName, namespace, query string) string {
suffix := objectName
if namespace != "" {
suffix = "namespaces/" + namespace + "/" + objectName
}
if len(query) > 0 {
suffix += "?" + query
}
if objectName == "ingresses" {
return "/apis/networking.k8s.io/v1beta1/" + suffix
}
if objectName == "endpointslices" {
return "/apis/discovery.k8s.io/v1beta1/" + suffix
}
return "/api/v1/" + suffix
}
func joinSelectors(role string, selectors []Selector) string {
var labelSelectors, fieldSelectors []string
for _, s := range selectors {
if s.Role != role {
continue
}
if s.Label != "" {
labelSelectors = append(labelSelectors, s.Label)
}
if s.Field != "" {
fieldSelectors = append(fieldSelectors, s.Field)
}
}
var args []string
if len(labelSelectors) > 0 {
args = append(args, "labelSelector="+url.QueryEscape(strings.Join(labelSelectors, ",")))
}
if len(fieldSelectors) > 0 {
args = append(args, "fieldSelector="+url.QueryEscape(strings.Join(fieldSelectors, ",")))
}
return strings.Join(args, "&")
}
func getObjectNameByRole(role string) string {
switch role {
case "node":
return "nodes"
case "pod":
return "pods"
case "service":
return "services"
case "endpoints":
return "endpoints"
case "endpointslices":
return "endpointslices"
case "ingress":
return "ingresses"
default:
logger.Panicf("BUG: unknonw role=%q", role)
return ""
}
}
func getObjectParsersForRole(role string) (parseObjectFunc, parseObjectListFunc) {
switch role {
case "node":
return parseNode, parseNodeList
case "pod":
return parsePod, parsePodList
case "service":
return parseService, parseServiceList
case "endpoints":
return parseEndpoints, parseEndpointsList
case "endpointslices":
return parseEndpointSlice, parseEndpointSliceList
case "ingress":
return parseIngress, parseIngressList
default:
logger.Panicf("BUG: unsupported role=%q", role)
return nil, nil
}
}

515
lib/promscrape/discovery/kubernetes/api_watcher.go Normal file
View file

@ -0,0 +1,515 @@
package kubernetes
import (
"context"
"encoding/json"
"errors"
"fmt"
"io"
"io/ioutil"
"net/http"
"net/url"
"reflect"
"strconv"
"strings"
"sync"
"time"
"github.com/VictoriaMetrics/VictoriaMetrics/lib/logger"
"github.com/VictoriaMetrics/metrics"
)
// WatchEvent is a watch event returned from API server endpoints if `watch=1` query arg is set.
//
// See https://kubernetes.io/docs/reference/using-api/api-concepts/#efficient-detection-of-changes
type WatchEvent struct {
Type string
Object json.RawMessage
}
// object is any Kubernetes object.
type object interface {
key() string
getTargetLabels(aw *apiWatcher) []map[string]string
}
// parseObjectFunc must parse object from the given data.
type parseObjectFunc func(data []byte) (object, error)
// parseObjectListFunc must parse objectList from the given data.
type parseObjectListFunc func(data []byte) (map[string]object, ListMeta, error)
// apiWatcher is used for watching for Kuberntes object changes and caching their latest states.
type apiWatcher struct {
// The client used for watching for object changes
client *http.Client
// Kubenetes API server address in the form http://api-server
apiServer string
// The contents for `Authorization` HTTP request header
authorization string
// Namespaces to watch
namespaces []string
// Selectors to apply during watch
selectors []Selector
// Constructor for creating ScrapeWork objects from labels.
swcFunc ScrapeWorkConstructorFunc
// mu protects watchersByURL
mu sync.Mutex
// a map of watchers keyed by request urls
watchersByURL map[string]*urlWatcher
stopFunc func()
stopCtx context.Context
wg sync.WaitGroup
}
func (aw *apiWatcher) mustStop() {
aw.stopFunc()
aw.wg.Wait()
}
func newAPIWatcher(client *http.Client, apiServer, authorization string, namespaces []string, selectors []Selector, swcFunc ScrapeWorkConstructorFunc) *apiWatcher {
stopCtx, stopFunc := context.WithCancel(context.Background())
return &apiWatcher{
apiServer: apiServer,
authorization: authorization,
client: client,
namespaces: namespaces,
selectors: selectors,
swcFunc: swcFunc,
watchersByURL: make(map[string]*urlWatcher),
stopFunc: stopFunc,
stopCtx: stopCtx,
}
}
// getScrapeWorkObjectsForRole returns all the ScrapeWork objects for the given role.
func (aw *apiWatcher) getScrapeWorkObjectsForRole(role string) []interface{} {
aw.startWatchersForRole(role)
var swos []interface{}
aw.mu.Lock()
for _, uw := range aw.watchersByURL {
if uw.role != role {
continue
}
uw.mu.Lock()
for _, swosLocal := range uw.swosByKey {
swos = append(swos, swosLocal...)
}
uw.mu.Unlock()
}
aw.mu.Unlock()
return swos
}
// getObjectByRole returns an object with the given (namespace, name) key and the given role.
func (aw *apiWatcher) getObjectByRole(role, namespace, name string) object {
if aw == nil {
return nil
}
key := namespace + "/" + name
aw.startWatchersForRole(role)
var o object
aw.mu.Lock()
for _, uw := range aw.watchersByURL {
if uw.role != role {
continue
}
uw.mu.Lock()
o = uw.objectsByKey[key]
uw.mu.Unlock()
if o != nil {
break
}
}
aw.mu.Unlock()
return o
}
func (aw *apiWatcher) startWatchersForRole(role string) {
parseObject, parseObjectList := getObjectParsersForRole(role)
paths := getAPIPaths(role, aw.namespaces, aw.selectors)
for _, path := range paths {
apiURL := aw.apiServer + path
aw.startWatcherForURL(role, apiURL, parseObject, parseObjectList)
}
}
func (aw *apiWatcher) startWatcherForURL(role, apiURL string, parseObject parseObjectFunc, parseObjectList parseObjectListFunc) {
aw.mu.Lock()
if aw.watchersByURL[apiURL] != nil {
// Watcher for the given path already exists.
aw.mu.Unlock()
return
}
uw := aw.newURLWatcher(role, apiURL, parseObject, parseObjectList)
aw.watchersByURL[apiURL] = uw
aw.mu.Unlock()
uw.watchersCount.Inc()
uw.watchersCreated.Inc()
resourceVersion := uw.reloadObjects()
aw.wg.Add(1)
go func() {
defer aw.wg.Done()
logger.Infof("started watcher for %q", apiURL)
uw.watchForUpdates(resourceVersion)
logger.Infof("stopped watcher for %q", apiURL)
uw.mu.Lock()
uw.objectsCount.Add(-len(uw.objectsByKey))
uw.objectsRemoved.Add(len(uw.objectsByKey))
uw.mu.Unlock()
aw.mu.Lock()
delete(aw.watchersByURL, apiURL)
aw.mu.Unlock()
uw.watchersCount.Dec()
uw.watchersStopped.Inc()
}()
}
// needStop returns true if aw must be stopped.
func (aw *apiWatcher) needStop() bool {
select {
case <-aw.stopCtx.Done():
return true
default:
return false
}
}
// doRequest performs http request to the given requestURL.
func (aw *apiWatcher) doRequest(requestURL string) (*http.Response, error) {
req, err := http.NewRequestWithContext(aw.stopCtx, "GET", requestURL, nil)
if err != nil {
logger.Fatalf("cannot create a request for %q: %s", requestURL, err)
}
if aw.authorization != "" {
req.Header.Set("Authorization", aw.authorization)
}
return aw.client.Do(req)
}
// urlWatcher watches for an apiURL and updates object states in objectsByKey.
type urlWatcher struct {
role string
apiURL string
parseObject parseObjectFunc
parseObjectList parseObjectListFunc
// mu protects objectsByKey and swosByKey
mu sync.Mutex
// objectsByKey contains the latest state for objects obtained from apiURL
objectsByKey map[string]object
swosByKey map[string][]interface{}
// the parent apiWatcher
aw *apiWatcher
watchersCount *metrics.Counter
watchersCreated *metrics.Counter
watchersStopped *metrics.Counter
objectsCount *metrics.Counter
objectsAdded *metrics.Counter
objectsRemoved *metrics.Counter
}
func (aw *apiWatcher) newURLWatcher(role, apiURL string, parseObject parseObjectFunc, parseObjectList parseObjectListFunc) *urlWatcher {
return &urlWatcher{
role: role,
apiURL: apiURL,
parseObject: parseObject,
parseObjectList: parseObjectList,
objectsByKey: make(map[string]object),
swosByKey: make(map[string][]interface{}),
aw: aw,
watchersCount: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_url_watchers{role=%q}`, role)),
watchersCreated: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_url_watchers_created_total{role=%q}`, role)),
watchersStopped: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_url_watchers_stopped_total{role=%q}`, role)),
objectsCount: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_objects{role=%q}`, role)),
objectsAdded: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_objects_added_total{role=%q}`, role)),
objectsRemoved: metrics.GetOrCreateCounter(fmt.Sprintf(`vm_promscrape_discovery_kubernetes_objects_removed_total{role=%q}`, role)),
}
}
// reloadObjects reloads objects to the latest state and returns resourceVersion for the latest state.
func (uw *urlWatcher) reloadObjects() string {
aw := uw.aw
requestURL := uw.apiURL
resp, err := aw.doRequest(requestURL)
if err != nil {
if !aw.needStop() {
logger.Errorf("error when performing a request to %q: %s", requestURL, err)
}
return ""
}
body, _ := ioutil.ReadAll(resp.Body)
_ = resp.Body.Close()
if resp.StatusCode != http.StatusOK {
logger.Errorf("unexpected status code for request to %q: %d; want %d; response: %q", requestURL, resp.StatusCode, http.StatusOK, body)
return ""
}
objectsByKey, metadata, err := uw.parseObjectList(body)
if err != nil {
if !aw.needStop() {
logger.Errorf("cannot parse response from %q: %s", requestURL, err)
}
return ""
}
swosByKey := make(map[string][]interface{}, len(objectsByKey))
for k, o := range objectsByKey {
labels := o.getTargetLabels(aw)
swos := getScrapeWorkObjectsForLabels(aw.swcFunc, labels)
if len(swos) > 0 {
swosByKey[k] = swos
}
}
uw.mu.Lock()
uw.objectsAdded.Add(len(objectsByKey))
uw.objectsRemoved.Add(len(uw.objectsByKey))
uw.objectsCount.Add(len(objectsByKey) - len(uw.objectsByKey))
uw.objectsByKey = objectsByKey
uw.swosByKey = swosByKey
uw.mu.Unlock()
return metadata.ResourceVersion
}
func getScrapeWorkObjectsForLabels(swcFunc ScrapeWorkConstructorFunc, labelss []map[string]string) []interface{} {
swos := make([]interface{}, 0, len(labelss))
for _, labels := range labelss {
swo := swcFunc(labels)
// The reflect check is needed because of https://mangatmodi.medium.com/go-check-nil-interface-the-right-way-d142776edef1
if swo != nil && !reflect.ValueOf(swo).IsNil() {
swos = append(swos, swo)
}
}
return swos
}
// watchForUpdates watches for object updates starting from resourceVersion and updates the corresponding objects to the latest state.
//
// See https://kubernetes.io/docs/reference/using-api/api-concepts/#efficient-detection-of-changes
func (uw *urlWatcher) watchForUpdates(resourceVersion string) {
aw := uw.aw
backoffDelay := time.Second
maxBackoffDelay := 30 * time.Second
backoffSleep := func() {
time.Sleep(backoffDelay)
backoffDelay *= 2
if backoffDelay > maxBackoffDelay {
backoffDelay = maxBackoffDelay
}
}
apiURL := uw.apiURL
delimiter := "?"
if strings.Contains(apiURL, "?") {
delimiter = "&"
}
timeoutSeconds := time.Duration(0.9 * float64(aw.client.Timeout)).Seconds()
apiURL += delimiter + "watch=1&timeoutSeconds=" + strconv.Itoa(int(timeoutSeconds))
for {
if aw.needStop() {
return
}
requestURL := apiURL
if resourceVersion != "" {
requestURL += "&resourceVersion=" + url.QueryEscape(resourceVersion)
}
resp, err := aw.doRequest(requestURL)
if err != nil {
if aw.needStop() {
return
}
logger.Errorf("error when performing a request to %q: %s", requestURL, err)
backoffSleep()
resourceVersion = uw.reloadObjects()
continue
}
if resp.StatusCode != http.StatusOK {
body, _ := ioutil.ReadAll(resp.Body)
_ = resp.Body.Close()
logger.Errorf("unexpected status code for request to %q: %d; want %d; response: %q", requestURL, resp.StatusCode, http.StatusOK, body)
if resp.StatusCode == 410 {
// There is no need for sleep on 410 error. See https://kubernetes.io/docs/reference/using-api/api-concepts/#410-gone-responses
backoffDelay = time.Second
} else {
backoffSleep()
}
resourceVersion = uw.reloadObjects()
continue
}
backoffDelay = time.Second
err = uw.readObjectUpdateStream(resp.Body)
_ = resp.Body.Close()
if err != nil {
if aw.needStop() {
return
}
if !errors.Is(err, io.EOF) {
logger.Errorf("error when reading WatchEvent stream from %q: %s", requestURL, err)
}
backoffSleep()
resourceVersion = uw.reloadObjects()
continue
}
}
}
// readObjectUpdateStream reads Kuberntes watch events from r and updates locally cached objects according to the received events.
func (uw *urlWatcher) readObjectUpdateStream(r io.Reader) error {
aw := uw.aw
d := json.NewDecoder(r)
var we WatchEvent
for {
if err := d.Decode(&we); err != nil {
return err
}
o, err := uw.parseObject(we.Object)
if err != nil {
return err
}
key := o.key()
switch we.Type {
case "ADDED", "MODIFIED":
uw.mu.Lock()
if uw.objectsByKey[key] == nil {
uw.objectsAdded.Inc()
uw.objectsCount.Inc()
}
uw.objectsByKey[key] = o
uw.mu.Unlock()
labels := o.getTargetLabels(aw)
swos := getScrapeWorkObjectsForLabels(aw.swcFunc, labels)
uw.mu.Lock()
if len(swos) > 0 {
uw.swosByKey[key] = swos
} else {
delete(uw.swosByKey, key)
}
uw.mu.Unlock()
case "DELETED":
uw.mu.Lock()
if uw.objectsByKey[key] != nil {
uw.objectsRemoved.Inc()
uw.objectsCount.Dec()
}
delete(uw.objectsByKey, key)
delete(uw.swosByKey, key)
uw.mu.Unlock()
default:
return fmt.Errorf("unexpected WatchEvent type %q for role %q", we.Type, uw.role)
}
}
}
func getAPIPaths(role string, namespaces []string, selectors []Selector) []string {
objectName := getObjectNameByRole(role)
if objectName == "nodes" || len(namespaces) == 0 {
query := joinSelectors(role, selectors)
path := getAPIPath(objectName, "", query)
return []string{path}
}
query := joinSelectors(role, selectors)
paths := make([]string, len(namespaces))
for i, namespace := range namespaces {
paths[i] = getAPIPath(objectName, namespace, query)
}
return paths
}
func getAPIPath(objectName, namespace, query string) string {
suffix := objectName
if namespace != "" {
suffix = "namespaces/" + namespace + "/" + objectName
}
if len(query) > 0 {
suffix += "?" + query
}
if objectName == "ingresses" {
return "/apis/networking.k8s.io/v1beta1/" + suffix
}
if objectName == "endpointslices" {
return "/apis/discovery.k8s.io/v1beta1/" + suffix
}
return "/api/v1/" + suffix
}
func joinSelectors(role string, selectors []Selector) string {
var labelSelectors, fieldSelectors []string
for _, s := range selectors {
if s.Role != role {
continue
}
if s.Label != "" {
labelSelectors = append(labelSelectors, s.Label)
}
if s.Field != "" {
fieldSelectors = append(fieldSelectors, s.Field)
}
}
var args []string
if len(labelSelectors) > 0 {
args = append(args, "labelSelector="+url.QueryEscape(strings.Join(labelSelectors, ",")))
}
if len(fieldSelectors) > 0 {
args = append(args, "fieldSelector="+url.QueryEscape(strings.Join(fieldSelectors, ",")))
}
return strings.Join(args, "&")
}
func getObjectNameByRole(role string) string {
switch role {
case "node":
return "nodes"
case "pod":
return "pods"
case "service":
return "services"
case "endpoints":
return "endpoints"
case "endpointslices":
return "endpointslices"
case "ingress":
return "ingresses"
default:
logger.Panicf("BUG: unknonw role=%q", role)
return ""
}
}
func getObjectParsersForRole(role string) (parseObjectFunc, parseObjectListFunc) {
switch role {
case "node":
return parseNode, parseNodeList
case "pod":
return parsePod, parsePodList
case "service":
return parseService, parseServiceList
case "endpoints":
return parseEndpoints, parseEndpointsList
case "endpointslices":
return parseEndpointSlice, parseEndpointSliceList
case "ingress":
return parseIngress, parseIngressList
default:
logger.Panicf("BUG: unsupported role=%q", role)
return nil, nil
}
}

0
lib/promscrape/discovery/kubernetes/api_test.go → lib/promscrape/discovery/kubernetes/api_watcher_test.go
View file