In Kubernetes controller what's the preferred way to get an item from the informer cache?












2















I am looking at following 2 examples, in the first example A lister is used to retrieve the item.



In the second example , an index is used.



I am wondering which is the preferred way and way to retrieve an element from the local cache.










share|improve this question



























    2















    I am looking at following 2 examples, in the first example A lister is used to retrieve the item.



    In the second example , an index is used.



    I am wondering which is the preferred way and way to retrieve an element from the local cache.










    share|improve this question

























      2












      2








      2








      I am looking at following 2 examples, in the first example A lister is used to retrieve the item.



      In the second example , an index is used.



      I am wondering which is the preferred way and way to retrieve an element from the local cache.










      share|improve this question














      I am looking at following 2 examples, in the first example A lister is used to retrieve the item.



      In the second example , an index is used.



      I am wondering which is the preferred way and way to retrieve an element from the local cache.







      controller kubernetes kube-controller-manager






      share|improve this question













      share|improve this question











      share|improve this question




      share|improve this question










      asked Nov 24 '18 at 0:08









      Always_BeginnerAlways_Beginner

      4691016




      4691016
























          1 Answer
          1






          active

          oldest

          votes


















          2














          The examples you showed above, they both use indexer, if you go deeper you will see it.



          For First example (see here)



          // Get retrieves the Node from the index for a given name.
          func (s *nodeLister) Get(name string) (*v1.Node, error) {
          obj, exists, err := s.indexer.GetByKey(name)
          if err != nil {
          return nil, err
          }
          if !exists {
          return nil, errors.NewNotFound(v1.Resource("node"), name)
          }
          return obj.(*v1.Node), nil
          }


          For second example



          item, exists, err := c.informer.GetIndexer().GetByKey(keyRaw)





          share|improve this answer
























          • Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

            – Always_Beginner
            Nov 24 '18 at 10:05






          • 1





            Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

            – nightfury1204
            Nov 24 '18 at 10:12













          Your Answer






          StackExchange.ifUsing("editor", function () {
          StackExchange.using("externalEditor", function () {
          StackExchange.using("snippets", function () {
          StackExchange.snippets.init();
          });
          });
          }, "code-snippets");

          StackExchange.ready(function() {
          var channelOptions = {
          tags: "".split(" "),
          id: "1"
          };
          initTagRenderer("".split(" "), "".split(" "), channelOptions);

          StackExchange.using("externalEditor", function() {
          // Have to fire editor after snippets, if snippets enabled
          if (StackExchange.settings.snippets.snippetsEnabled) {
          StackExchange.using("snippets", function() {
          createEditor();
          });
          }
          else {
          createEditor();
          }
          });

          function createEditor() {
          StackExchange.prepareEditor({
          heartbeatType: 'answer',
          autoActivateHeartbeat: false,
          convertImagesToLinks: true,
          noModals: true,
          showLowRepImageUploadWarning: true,
          reputationToPostImages: 10,
          bindNavPrevention: true,
          postfix: "",
          imageUploader: {
          brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
          contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
          allowUrls: true
          },
          onDemand: true,
          discardSelector: ".discard-answer"
          ,immediatelyShowMarkdownHelp:true
          });


          }
          });














          draft saved

          draft discarded


















          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53454091%2fin-kubernetes-controller-whats-the-preferred-way-to-get-an-item-from-the-inform%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown

























          1 Answer
          1






          active

          oldest

          votes








          1 Answer
          1






          active

          oldest

          votes









          active

          oldest

          votes






          active

          oldest

          votes









          2














          The examples you showed above, they both use indexer, if you go deeper you will see it.



          For First example (see here)



          // Get retrieves the Node from the index for a given name.
          func (s *nodeLister) Get(name string) (*v1.Node, error) {
          obj, exists, err := s.indexer.GetByKey(name)
          if err != nil {
          return nil, err
          }
          if !exists {
          return nil, errors.NewNotFound(v1.Resource("node"), name)
          }
          return obj.(*v1.Node), nil
          }


          For second example



          item, exists, err := c.informer.GetIndexer().GetByKey(keyRaw)





          share|improve this answer
























          • Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

            – Always_Beginner
            Nov 24 '18 at 10:05






          • 1





            Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

            – nightfury1204
            Nov 24 '18 at 10:12


















          2














          The examples you showed above, they both use indexer, if you go deeper you will see it.



          For First example (see here)



          // Get retrieves the Node from the index for a given name.
          func (s *nodeLister) Get(name string) (*v1.Node, error) {
          obj, exists, err := s.indexer.GetByKey(name)
          if err != nil {
          return nil, err
          }
          if !exists {
          return nil, errors.NewNotFound(v1.Resource("node"), name)
          }
          return obj.(*v1.Node), nil
          }


          For second example



          item, exists, err := c.informer.GetIndexer().GetByKey(keyRaw)





          share|improve this answer
























          • Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

            – Always_Beginner
            Nov 24 '18 at 10:05






          • 1





            Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

            – nightfury1204
            Nov 24 '18 at 10:12
















          2












          2








          2







          The examples you showed above, they both use indexer, if you go deeper you will see it.



          For First example (see here)



          // Get retrieves the Node from the index for a given name.
          func (s *nodeLister) Get(name string) (*v1.Node, error) {
          obj, exists, err := s.indexer.GetByKey(name)
          if err != nil {
          return nil, err
          }
          if !exists {
          return nil, errors.NewNotFound(v1.Resource("node"), name)
          }
          return obj.(*v1.Node), nil
          }


          For second example



          item, exists, err := c.informer.GetIndexer().GetByKey(keyRaw)





          share|improve this answer













          The examples you showed above, they both use indexer, if you go deeper you will see it.



          For First example (see here)



          // Get retrieves the Node from the index for a given name.
          func (s *nodeLister) Get(name string) (*v1.Node, error) {
          obj, exists, err := s.indexer.GetByKey(name)
          if err != nil {
          return nil, err
          }
          if !exists {
          return nil, errors.NewNotFound(v1.Resource("node"), name)
          }
          return obj.(*v1.Node), nil
          }


          For second example



          item, exists, err := c.informer.GetIndexer().GetByKey(keyRaw)






          share|improve this answer












          share|improve this answer



          share|improve this answer










          answered Nov 24 '18 at 5:13









          nightfury1204nightfury1204

          1,68449




          1,68449













          • Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

            – Always_Beginner
            Nov 24 '18 at 10:05






          • 1





            Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

            – nightfury1204
            Nov 24 '18 at 10:12





















          • Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

            – Always_Beginner
            Nov 24 '18 at 10:05






          • 1





            Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

            – nightfury1204
            Nov 24 '18 at 10:12



















          Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

          – Always_Beginner
          Nov 24 '18 at 10:05





          Right, thanks for pointing out. So for writing a custom controller either of the ways can be used right?

          – Always_Beginner
          Nov 24 '18 at 10:05




          1




          1





          Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

          – nightfury1204
          Nov 24 '18 at 10:12







          Right. I used this c.Informer.GetIndexer().GetByKey(key). all the time

          – nightfury1204
          Nov 24 '18 at 10:12






















          draft saved

          draft discarded




















































          Thanks for contributing an answer to Stack Overflow!


          • Please be sure to answer the question. Provide details and share your research!

          But avoid



          • Asking for help, clarification, or responding to other answers.

          • Making statements based on opinion; back them up with references or personal experience.


          To learn more, see our tips on writing great answers.




          draft saved


          draft discarded














          StackExchange.ready(
          function () {
          StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fstackoverflow.com%2fquestions%2f53454091%2fin-kubernetes-controller-whats-the-preferred-way-to-get-an-item-from-the-inform%23new-answer', 'question_page');
          }
          );

          Post as a guest















          Required, but never shown





















































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown

































          Required, but never shown














          Required, but never shown












          Required, but never shown







          Required, but never shown







          Popular posts from this blog

          404 Error Contact Form 7 ajax form submitting

          How to know if a Active Directory user can login interactively

          TypeError: fit_transform() missing 1 required positional argument: 'X'