Yes. The poll happens in the client's internal thread.
Thanks,
Yunze
On Sun, Jan 22, 2023 at 6:56 PM Asaf Mesika <asaf.mes...@gmail.com> wrote:
>
> and the client will poll the ConnectInfoProvider and check if something was
> changed?
>
> On Fri, Jan 20, 2023 at 11:19 AM Yunze Xu <y...@streamnative.io.invalid>
> wrote:
>
> > > I think the `updateServiceUrl` is not the initial purpose of exposing to
> > the Client API.
> >
> > I agree. We might need an API like
> >
> > ```java
> > ClientBuilder serviceUrlProvider(ServiceUrlProvider
> > serviceUrlProvider, Duration interval)
> > ```
> >
> > But not only the service URL, as you can see, the
> > `AutoClusterFailover` implementation is already beyond the scope of
> > service URL, it uses two internal APIs `updateAuthentication` and
> > `updateTlsTrustCertsFilePath` to update other states of
> > PulsarClientImpl.
> >
> > > So from the user's perspective, they only need to apply a service URL
> > provided to the client
> >
> > Yes. That's when I thought of when I saw the C++ client catch up [1].
> > The `initialize` and `close` methods are not necessary. If let me
> > design the interface, I would like the following solution, which is
> > more simple and can accept a lambda.
> >
> > ```java
> > public interface ServiceUrlProvider {
> > String getServiceUrl();
> > }
> > ```
> >
> > However, as I've mentioned again, now authentication and TLS info also
> > need updates, so I have an initial design like:
> >
> > ```java
> > public class ConnectInfo {
> > String serviceUrl;
> > Authentication authentication;
> > String tlsCertificatesFile;
> > // ...
> > }
> >
> > interface ConnectInfoProvider extends Supplier<ConnectInfo> {
> > }
> > ```
> >
> > When configuring the `ConnectInfoProvider`, we should provide an interval.
> >
> > And I'm going to open a PIP for it to deprecate `ServiceUrlProvider`.
> > BTW, I found this issue when I reviewed the PR to migrate the
> > ServiceUrlProvider into C++ client. IMO, the current design in Java
> > client is bad and I don't want to adopt the same design in C++ client.
> >
> > Thanks,
> > Yunze
> >
> > On Thu, Jan 19, 2023 at 4:51 PM PengHui Li <peng...@apache.org> wrote:
> > >
> > > Is it better to introduce a service URL detect interval to the service
> > URL
> > > provider?
> > > I think the `updateServiceUrl` is not the initial purpose of exposing to
> > > the Client API.
> > >
> > > It looks like users just provide the interval of checking whether the
> > > service URL is changed.
> > > The Pulsar client will check it automatically. Using updateServiceUrl can
> > > also achieve the purpose,
> > > but users need to provide a fake service URL first or fetch the service
> > URL
> > > before
> > > creating the client.
> > >
> > > Another reason we need service URL provider API is that one team will
> > > usually
> > > provide an extra pulsar client lib with the service URL provider
> > > implementation.
> > > The lib
> > > can be used across multiple teams. So from the user's perspective, they
> > > only need to apply
> > > a service URL provided to the client, they don't care about what is the
> > > service URL and how to
> > > update it.
> > >
> > > Thanks,
> > > Penghui
> > >
> > > On Thu, Jan 19, 2023 at 3:43 PM Baodi Shi <ba...@apache.org> wrote:
> > >
> > > > Hi, Yunze:
> > > >
> > > > Obviously, the `ServiceUrlProvider` config is redundant.
> > > > >
> > > >
> > > > Agree. In fact, The client already provides the updateServiceUrl
> > method,
> > > > which the user can use to implement a dynamic update service URL. As
> > for
> > > > how the user implements it and how to close his resources, I think it
> > can
> > > > be left to the user.
> > > >
> > > >
> > > > 在 2023年1月19日 15:16:52 上，Yunze Xu <y...@streamnative.io.invalid> 写道：
> > > >
> > > > > Hi all,
> > > > >
> > > > > Currently we have a `ServiceUrlProvider` interface to configure when
> > > > > constructing a PulsarClient in `ClientBuilder#serviceUrlProvider`.
> > > > > From the beginning, I thought the `getServiceUrl` method is called
> > > > > each time the service URL is used, e.g. topic metadata lookup.
> > > > > However, the `getServiceUrl` method is only called when constructing
> > > > > the PulsarClient object. To update the PulsarClient's internal
> > service
> > > > > URL, `PulsarClient#updateServiceUrl` must be called. Therefore, if we
> > > > > want to implement a `ServiceUrlProvider` that retrieves the latest
> > > > > service URL from a database, I have to implement it like:
> > > > >
> > > > > ```java
> > > > > class DataBaseServiceUrlProvider implements ServiceUrlProvider {
> > > > >
> > > > > private final ScheduledExecutorService executor =
> > > > > Executors.newSingleThreadScheduledExecutor();
> > > > >
> > > > > @Override
> > > > > public void initialize(PulsarClient client) {
> > > > > executor.schedule(() -> {
> > > > > try {
> > > > > client.updateServiceUrl(readServiceUrlFromDB()/* a
> > > > > fake method */);
> > > > > } catch (PulsarClientException e) {
> > > > > throw new RuntimeException(e);
> > > > > }
> > > > > }, 1, TimeUnit.SECONDS);
> > > > > }
> > > > >
> > > > > @Override
> > > > > public String getServiceUrl() {
> > > > > return "pulsar://localhost:6650";
> > > > > }
> > > > >
> > > > > @Override
> > > > > public void close() {
> > > > > executor.shutdown();
> > > > > }
> > > > > }
> > > > > ```
> > > > >
> > > > > The key point is, if we didn't call `client.updateServiceUrl` and
> > only
> > > > > modified the returned value of `getServiceUrl` periodically, the
> > > > > internal service URL would never be updated.
> > > > >
> > > > > Based on the provider above, the following two code snippets could be
> > > > > nearly the same.
> > > > >
> > > > > ```java
> > > > > var client = PulsarClient.builder().serviceUrlProvider(new
> > > > > DataBaseServiceUrlProvider()).build();
> > > > > /* ... */
> > > > > client.close();
> > > > > ```
> > > > >
> > > > > ```java
> > > > > var client =
> > > > > PulsarClient.builder().serviceUrl("pulsar://localhost:6650").build();
> > > > > var provider = new DataBaseServiceUrlProvider();
> > > > > provider.initialize(client);
> > > > > /* ... */
> > > > > provider.close();
> > > > > client.close();
> > > > > ```
> > > > >
> > > > > Obviously, the `ServiceUrlProvider` config is redundant.
> > > > >
> > > > > PIP-121 implements the `AutoClusterFailover` as the service URL
> > > > > provider. However, it also calls the following methods periodically:
> > > > > - PulsarClientImpl#updateAuthentication
> > > > > - PulsarClientImpl#updateTlsTrustCertsFilePath
> > > > >
> > > > > It's unnatural and intuitive to say a service URL provider could
> > > > > modify the internal states of `PulsarClient`, including:
> > > > > - the service URL
> > > > > - the authentication
> > > > > - the TLS trust certificate file
> > > > > - ...
> > > > >
> > > > > BTW, the implementation of PIP-121 [1] is different from the design
> > [2].
> > > > >
> > > > > [1] https://github.com/apache/pulsar/pull/13316
> > > > > [2] https://github.com/apache/pulsar/issues/13315
> > > > >
> > > > > Thanks,
> > > > > Yunze
> > > > >
> > > >
> >
