Hi Chia-Ping, Kirk and Matthias,
@Chia-Ping: You were right - after investigating, Time doesn't need to be
public.
@Kirk: You are right - the OAuth examples are instantiated via reflection,
not direct user code.
@Matthias: Good points. I investigated whether Metrics can be changed to
not expose Time.
Findings:
- new Metrics() - users call this (internally uses Time.SYSTEM)
- new Metrics(Time time) and other variants - only called by internal Kafka
code (KafkaProducer, KafkaAdminClient, etc) and tests
Proposed approach:
- Withdraw KIP-1311 (Make Time public)
- Create JIRA: "Deprecate Time-accepting constructors"
- Deprecate Time constructors in both KafkaStreams and Metrics:
- KafkaStreams(Topology, Properties, Time)
- KafkaStreams(Topology, StreamsConfig, Time)
- KafkaStreams(Topology, Properties, KafkaClientSupplier, Time)
- Metrics(Time)
- Metrics(MetricConfig, Time)
- Metrics(MetricConfig, List<MetricsReporter>, Time)
- (and other Metrics variants accepting Time)
- In version 5.0, make these constructors package-private
- Internal Kafka code continues using them
Result: Time remains internal.
Does this approach work? If so, I'll withdraw KIP-1311 and create the JIRA.
Thank you,
Siddhartha
On Tue, Apr 21, 2026 at 5:22 AM Matthias J. Sax <[email protected]> wrote:
> Thanks for the KIP. I am not sure if I understand why `KafkaStreamsMock`
> would be anything public?
>
> Also, why would we put it into some new `...test...` package? If we
> change the package, we need to have `protected` access, which is already
> "semi-public"...
>
> If we want to keep `Time` internal, we would eventually make the
> constructors that are marked deprecated, package-private, what allows us
> to add `org.apache.kafka.streams.KafkaStreamsMock` (same package name,
> but int `test/` module) to still use these constructors, and the
> corresponding unit test would use the new mock-factory instead of
> calling `new`?
>
> For this case, the KIP does not need to mention anything about
> `KafkaStreamsMock` as it's an helper in our `test/` module only, but not
> public API. -- If we want, we can still mention this plan on the KIP,
> but atm the KIP is written in a way as if `KafkaStreamsMock` would
> become public API, but to my understanding it should be an impl/testing
> details only?
>
> Or did I misunderstand something?
>
>
> Also wondering, if we could also change `Metrics` in a way, that we
> would not need to make `Time` public to begin with?
>
>
>
> -Matthias
>
> On 4/20/26 4:53 PM, Kirk True wrote:
> > Hi Siddhartha,
> >
> > The OAuth examples use Time in their constructors for unit tests.
> They're not intended to be instantiated by any user code since they're in
> an internals package.
> >
> > Thanks,
> > Kirk
> >
> > On Wed, Apr 15, 2026, at 8:52 AM, Siddhartha Devineni wrote:
> >> Hi Chia-Ping,
> >>
> >> Sorry that i didn't mention the following examples in the KIP earlier.
> >> Now, I have updated the KIP with the following public packages examples,
> >> where "Time" is exposed in the public constructors:
> >>
> >> // couple of examples from multiple
> >> "org.apache.kafka.common.metrics.Metrics.java" constructors
> >> public Metrics(Time time) {}
> >> public Metrics(MetricConfig defaultConfig, Time time) {}
> >>
> >> // in the public package "org.apache.kafka.common.security.oauthbearer"
> >> public JwtBearerJwtRetriever(Time time) {}
> >> public ClientCredentialsJwtRetriever(Time time) {}
> >>
> >> Now, it should be clear.
> >> Thanks for your time.
> >>
> >> Best regards,
> >> Siddhartha
> >>
> >> On Tue, Apr 14, 2026 at 11:14 AM Chia-Ping Tsai <[email protected]>
> wrote:
> >>
> >>> hi Siddhartha
> >>>
> >>> Thanks for this KIP.
> >>>
> >>> What is the exact benefit of exposing Time as a public API? Since this
> KIP
> >>> proposes deprecating KafkaStreams(Topology, Properties, Time), it seems
> >>> there are no public interfaces relying on it anymore.
> >>>
> >>> Thus, it should be fine to just keep Time as an internal API, right?
> >>>
> >>> Best,
> >>> Chia-Ping
> >>>
> >>>
> >>> Siddhartha Devineni <[email protected]> 於 2026年4月7日週二
> >>> 下午2:19寫道：
> >>>
> >>>> Apologies, as I forgot to add the link to the KIP:
> >>>>
> >>>>
> >>>
> https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=406623925
> >>>>
> >>>>
> >>>> On Tue, Apr 7, 2026 at 9:13 AM Siddhartha Devineni <
> >>>> [email protected]> wrote:
> >>>>
> >>>>> Hello everyone,
> >>>>>
> >>>>> I would like to start a discussion on [DISCUSS] KIP-1311: Make
> >>> Time/Timer
> >>>>> public API.
> >>>>>
> >>>>> Following KIP-1247 (Make Bytes part of public API), the Time
> interface
> >>>> and
> >>>>> Timer class are the next candidates from
> >>> "org.apache.kafka.common.utils"
> >>>> to
> >>>>> be made officially public. Time is currently exposed through public
> >>> APIs
> >>>>> (e.g., in clients, KafkaStreams constructors, etc) but not officially
> >>>>> designated as a public API.
> >>>>>
> >>>>> An earlier version of this KIP explored splitting Time into focused
> >>>>> interfaces (Clock, MonotonicClock, etc.), but this would require
> >>>> rewriting
> >>>>> thousands of method signatures across the Kafka codebase. The simpler
> >>>>> approach of making Time public as-is seems more appropriate to avoid
> >>>>> breaking changes.
> >>>>>
> >>>>> Looking forward to your feedback.
> >>>>>
> >>>>> Thank you,
> >>>>> Siddhartha
> >>>>>
> >>>>
> >>>
> >>
> >
>
>
