Hello Pavel, +1 for external API.
On Tue, 15 Sep 2020 at 19:58, Zhenya Stanilovsky <arzamas...@mail.ru.invalid> wrote: > > I understand now, thanks Pavel, initial discussion didn`t touch kuber > theme ... > > > >Вторник, 15 сентября 2020, 18:22 +03:00 от Pavel Tupitsyn < > ptupit...@apache.org>: > > > >Zhenya, sure, let me explain. > > > >Health checks are a common practice in modern deployments, quote [1]: > >"Health probes can be used by container orchestrators and load balancers > to check an app's status. > >For example, a container orchestrator may respond to a failing health > check by halting a rolling deployment or restarting a container. > >A load balancer might react to an unhealthy app by routing traffic away > from the failing instance to a healthy instance." > > > >Kubernetes has various probes [2] to determine the pod status. > > > >So Ignite users need a proper mechanism to determine connectivity status > of the thin client > >to integrate with frameworks and orchestrators. > > > >[1] > https://docs.microsoft.com/en-us/aspnet/core/host-and-deploy/health-checks > >[2] > https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/ > > >On Tue, Sep 15, 2020 at 4:36 PM Zhenya Stanilovsky < > arzamas...@mail.ru.invalid > wrote: > > > >>Pavel, i read whole thread, show me the reason why this functionality > need to be external ? > >> > >>> > >>> > >>>Health checks are the primary use case. See linked user list thread. > >>> > >>>On Tue, Sep 15, 2020 at 12:26 PM Zhenya Stanilovsky > >>>< arzamas...@mail.ru.invalid > wrote: > >>> > >>>> > >>>> Whats the usage of such API ? Igor can you clarify please ? > >>>> > >>>> >Personally I believe that public API still can be helpful, as it > gives > >>>> user > >>>> >an ability to check connection in the specific point in time, even if > >>>> >automatic > >>>> >ping is implemented (which is more complex and hard-to-maintain > feature > >>>> >by the way). > >>>> > > >>>> >Not sure there should be "ping" in API though, maybe something more > like > >>>> >client.checkConnection(); > >>>> > > >>>> >Best Regards, > >>>> >Igor > >>>> > > >>>> > > >>>> >On Mon, Sep 14, 2020 at 11:37 AM Alex Plehanov < > plehanov.a...@gmail.com > >>>> > > >>>> >wrote: > >>>> > > >>>> >> Hello guys, > >>>> >> > >>>> >> We've already raised the question about ping requests here [1]. > >>>> >> > >>>> >> I'm not sure about public API, but at least we can have auto-ping > as an > >>>> >> internal mechanism. This will be helpful if the client doesn't > send any > >>>> new > >>>> >> requests but only waits for server-side notifications (for > example, if > >>>> the > >>>> >> client subscribed to CQ events). The client can't detect a > connection > >>>> lost > >>>> >> until sending something to the server. Using periodic ping > requests this > >>>> >> problem can be solved. > >>>> >> > >>>> >> So, +1 to add ping to the protocol, +0 to expose it to public API. > >>>> >> > >>>> >> [1] > >>>> >> > >>>> >> > >>>> > http://apache-ignite-developers.2346864.n4.nabble.com/IEP-44-Thin-Client-Discovery-tp47129p47318.html > >>>> >> > >>>> >> пн, 14 сент. 2020 г. в 10:32, Pavel Tupitsyn < > ptupit...@apache.org >: > >>>> >> > >>>> >> > Nikolay, > >>>> >> > > >>>> >> > See the discussion on the user list: > >>>> >> > > >>>> >> > 1. It is not immediately obvious which APIs perform server calls > and > >>>> >> which > >>>> >> > don't. > >>>> >> > 2. It is not clear which APIs can cause heavy resource usage on > the > >>>> >> server > >>>> >> > side. > >>>> >> > We don't want to stress servers by pinging them. > >>>> >> > cache.size() is an example - it is tempting to use and seems to > be > >>>> >> > simple, but actually queries every server node in the cluster. > >>>> >> > > >>>> >> > > dedicated `ping` operation makes our API heavier > >>>> >> > The operation is so trivial that I would not worry about > increased > >>>> >> > complexity or future maintenance. > >>>> >> > > >>>> >> > On Mon, Sep 14, 2020 at 10:17 AM Nikolay Izhikov < > >>>> nizhi...@apache.org > > >>>> >> > wrote: > >>>> >> > > >>>> >> > > Hello, Igor. > >>>> >> > > > >>>> >> > > On the other hand, dedicated `ping` operation makes our API > heavier > >>>> >> > > without adding new feature - > >>>> >> > > We can do the same with the other part of the API. > >>>> >> > > > >>>> >> > > Moreover, response to the ping doesn’t mean that SQL or cache > query > >>>> can > >>>> >> > be > >>>> >> > > served. > >>>> >> > > > >>>> >> > > > 14 сент. 2020 г., в 10:08, Igor Sapego < > isap...@apache.org > > >>>> >> > написал(а): > >>>> >> > > > > >>>> >> > > > Николай, > >>>> >> > > > > >>>> >> > > > It looks a little bit hacky to me. I believe SQL drivers > usually > >>>> use > >>>> >> > that > >>>> >> > > > approach > >>>> >> > > > as a workaround because there is no other common way to do > that. > >>>> >> > > > > >>>> >> > > > Sure we can recommend users to use cache.size() or anything > other > >>>> >> > > > similar way > >>>> >> > > > to ensure the connection is alive, but it still looks like a > >>>> >> workaround > >>>> >> > > to > >>>> >> > > > me. > >>>> >> > > > > >>>> >> > > > Best Regards, > >>>> >> > > > Igor > >>>> >> > > > > >>>> >> > > > > >>>> >> > > > On Sun, Sep 13, 2020 at 10:16 PM Николай Ижиков < > >>>> nizhi...@apache.org > >>>> >> > > >>>> >> > > wrote: > >>>> >> > > > > >>>> >> > > >> Hello, Pavel. > >>>> >> > > >> > >>>> >> > > >> SQL drivers usually use “SELECT 1” query to ensure > connection is > >>>> >> > alive. > >>>> >> > > >> > >>>> >> > > >> Can we use similar approach? > >>>> >> > > >> > >>>> >> > > >> Отправлено с iPhone > >>>> >> > > >> > >>>> >> > > >>> 13 сент. 2020 г., в 13:26, Pavel Tupitsyn < > >>>> ptupit...@apache.org > > >>>> >> > > >> написал(а): > >>>> >> > > >>> > >>>> >> > > >>> Igniters, > >>>> >> > > >>> > >>>> >> > > >>> There is a feature request for a thin client Ping > operation on > >>>> the > >>>> >> > user > >>>> >> > > >>> list [1]. > >>>> >> > > >>> I think that is a good idea - IgniteClient.ping() will be a > >>>> >> valuable > >>>> >> > > >>> addition. > >>>> >> > > >>> > >>>> >> > > >>> Any objections? > >>>> >> > > >>> > >>>> >> > > >>> [1] > >>>> >> > > >>> > >>>> >> > > >> > >>>> >> > > > >>>> >> > > >>>> >> > >>>> > http://apache-ignite-users.70518.x6.nabble.com/Feature-request-method-to-test-active-connection-in-Ignite-thin-client-td33985.html > >>>> >> > > >> > >>>> >> > > > >>>> >> > > > >>>> >> > > >>>> >> > >>>> > >>>> > >>>> > >>>> > >> > >> > >> > >> > > > >
