Hi Rajini,
I'd be happy to do that. I'll try to get it done in the next few days.
Although there's been quite a lot of interest this, the vote thread never
got any binding +1, so it's been stuck in limbo for a long time. It would
be great to get this moving again.
Kind regards,
Tom
On Tue, Apr 9, 2019 at 3:04 PM Rajini Sivaram <rajinisiva...@gmail.com>
wrote:
> Hi Tom,
>
> Are you planning to extend this KIP to also include dynamic broker config
> update (currently covered under AlterConfigPolicy)?
>
> May be worth sending another note to make progress on this KIP since it has
> been around a while and reading through the threads, it looks like there
> has been a lot of interest in it.
>
> Thank you,
>
> Rajini
>
>
> On Wed, Jan 9, 2019 at 11:25 AM Tom Bentley <t.j.bent...@gmail.com> wrote:
>
> > Hi Anna and Mickael,
> >
> > Anna, did you have any comments about the points I made?
> >
> > Mickael, we really need the vote to be passed before there's even any
> work
> > to do. With the exception of Ismael, the KIP didn't seem to get the
> > attention of any of the other committers.
> >
> > Kind regards,
> >
> > Tom
> >
> > On Thu, 13 Dec 2018 at 18:11, Tom Bentley <t.j.bent...@gmail.com> wrote:
> >
> > > Hi Anna,
> > >
> > > Firstly, let me apologise again about having missed your previous
> emails
> > > about this.
> > >
> > > Thank you for the feedback. You raise some valid points about
> ambiguity.
> > > The problem with pulling the metadata into CreateTopicRequest and
> > > AlterTopicRequest is that you lose the benefit of being able to eaily
> > write
> > > a common policy across creation and alter cases. For example, with the
> > > proposed design the policy maker could write code like this (forgive my
> > > pseudo-Java)
> > >
> > > public void validateCreateTopic(requestMetadata, ...) {
> > > commonPolicy(requestMetadata.requestedState());
> > > }
> > >
> > > public void validateAlterTopic(requestMetadata, ...) {
> > > commonPolicy(requestMetadata.requestedState());
> > > }
> > >
> > > private void commonPolicy(RequestedTopicState requestedState) {
> > > // ...
> > > }
> > >
> > > I think that's an important feature of the API because (I think) very
> > > often the policy maker is interested in defining the universe of
> > prohibited
> > > configurations without really caring about whether the request is a
> > create
> > > or an alter. Having a single RequestedTopicState for both create and
> > > alter means they can do that trivially in one place. Having different
> > > methods in the two Request classes prevents this and forces the policy
> > > maker to pick apart the different requestState objects before calling
> any
> > > common method(s).
> > >
> > > I think my intention at the time (and it's many months ago now, so I
> > might
> > > not have remembered fully) was that RequestedTopicState would basically
> > > represent what the topic would look like after the requested changes
> were
> > > applied (I accept this isn't how it's Javadoc'd in the KIP), rather
> than
> > > representing the request itself. Thus if the request changed the
> > assignment
> > > of some of the partitions and the policy maker was interested in
> > precisely
> > > which partitions would be changed, and how, they would indeed have to
> > > compute that for themselves by looking up the current topic state from
> > the
> > > cluster state and seeing how they differed. Indeed they'd have to do
> this
> > > diff even to figure out that the user was requesting a change to the
> > topic
> > > assigned (or similarly for topic config, etc). To me this is acceptable
> > > because I think most people writing such policies are just interested
> in
> > > defining what is not allowed, so giving them a representation of the
> > > proposed topic state which they can readily check against is the most
> > > direct API. In this interpretation generatedReplicaAssignment() would
> > > just be some extra metadata annotating whether any difference between
> the
> > > current and proposed states was directly from the user, or generated on
> > the
> > > broker. You're right that it's ambiguous when the request didn't
> actually
> > > change the assignment but I didn't envisage policy makers using it
> except
> > > when the assignments differed anyway. To me it would be acceptable to
> > > Javadoc this.
> > >
> > > Given this interpretation of RequestedTopicState as "what the topic
> would
> > > look like after the requested changes were applied" can you see any
> other
> > > problems with the proposal? Or do you have use cases where the policy
> > maker
> > > is more interested in what the request is changing?
> > >
> > > Kind regards,
> > >
> > > Tom
> > >
> > > On Fri, 7 Dec 2018 at 08:41, Tom Bentley <t.j.bent...@gmail.com>
> wrote:
> > >
> > >> Hi Anna and Mickael,
> > >>
> > >> Sorry for remaining silent on this for so long. I should have time to
> > >> look at this again next week.
> > >>
> > >> Kind regards,
> > >>
> > >> Tom
> > >>
> > >> On Mon, 3 Dec 2018 at 10:11, Mickael Maison <mickael.mai...@gmail.com
> >
> > >> wrote:
> > >>
> > >>> Hi Tom,
> > >>>
> > >>> This is a very interesting KIP. If you are not going to continue
> > >>> working on it, would it be ok for us to grab it and complete it?
> > >>> Thanks
> > >>> On Thu, Jun 14, 2018 at 7:06 PM Anna Povzner <a...@confluent.io>
> > wrote:
> > >>> >
> > >>> > Hi Tom,
> > >>> >
> > >>> > Just wanted to check what you think about the comments I made in my
> > >>> last
> > >>> > message. I think this KIP is a big improvement to our current
> policy
> > >>> > interfaces, and really hope we can get this KIP in.
> > >>> >
> > >>> > Thanks,
> > >>> > Anna
> > >>> >
> > >>> > On Thu, May 31, 2018 at 3:29 PM, Anna Povzner <a...@confluent.io>
> > >>> wrote:
> > >>> >
> > >>> > > Hi Tom,
> > >>> > >
> > >>> > >
> > >>> > > Thanks for the KIP. I am aware that the voting thread was
> started,
> > >>> but
> > >>> > > wanted to discuss couple of concerns here first.
> > >>> > >
> > >>> > >
> > >>> > > I think the coupling of
> > >>> RequestedTopicState#generatedReplicaAssignment()
> > >>> > > and TopicState#replicasAssignments() does not work well in case
> > >>> where the
> > >>> > > request deals only with a subset of partitions (e.g., add
> > >>> partitions) or no
> > >>> > > assignment at all (alter topic config). In particular:
> > >>> > >
> > >>> > > 1) Alter topic config use case: There is no replica assignment in
> > the
> > >>> > > request, and generatedReplicaAssignment() returning either true
> or
> > >>> false
> > >>> > > is both misleading. The user can interpret this as assignment
> being
> > >>> > > generated or provided by the user originally (e.g., on topic
> > >>> create), while
> > >>> > > I don’t think we track such thing.
> > >>> > >
> > >>> > > 2) On add partitions, we may have manual assignment for new
> > >>> partitions.
> > >>> > > What I understood from the KIP, generatedReplicaAssignment()
> will
> > >>> return
> > >>> > > true or false based on whether new partitions were manually
> > assigned
> > >>> or
> > >>> > > not, while TopicState#replicasAssignments() will return replica
> > >>> > > assignments for all partitions. I think it is confusing in a way
> > that
> > >>> > > assignment of old partitions could be auto-generated but new
> > >>> partitions are
> > >>> > > manually assigned.
> > >>> > >
> > >>> > > 3) Generalizing #2, suppose in a future, a user can re-assign
> > >>> replicas for
> > >>> > > a set of partitions.
> > >>> > >
> > >>> > >
> > >>> > > One way to address this with minimal changes to proposed API is
> to
> > >>> rename
> > >>> > > RequestedTopicState#generatedReplicaAssignment() to
> > >>> RequestedTopicState#manualReplicaAssignment()
> > >>> > > and change the API behavior and description to : “True if the
> > client
> > >>> > > explicitly provided replica assignments in this request, which
> > means
> > >>> that
> > >>> > > some or all assignments returned by
> > TopicState#replicasAssignments()
> > >>> are
> > >>> > > explicitly requested by the user”. The user then will have to
> diff
> > >>> > > TopicState#replicasAssignments() from clusterState and
> TopicState#
> > >>> > > replicasAssignments() from RequestedTopicState, and assume that
> > >>> > > assignments that are different are manually assigned (if
> > >>> > > RequestedTopicState#manualReplicaAssignment() returns true). We
> > will
> > >>> > > need to clearly document this and it still seems awkward.
> > >>> > >
> > >>> > >
> > >>> > > I think a cleaner way is to make RequestedTopicState to provide
> > >>> replica
> > >>> > > assignments only for partitions that were manually assigned
> > replicas
> > >>> in the
> > >>> > > request that is being validated. Similarly, for alter topic
> > >>> validation, it
> > >>> > > would be nice to make it more clear for the user what has been
> > >>> changed. I
> > >>> > > remember that you already raised that point earlier by comparing
> > >>> current
> > >>> > > proposed API with having separate methods for each specific
> > command.
> > >>> > > However, I agree that it will make it harder to change the
> > interface
> > >>> in the
> > >>> > > future.
> > >>> > >
> > >>> > >
> > >>> > > Could we explore the option of pushing methods that are currently
> > in
> > >>> > > TopicState to CreateTopicRequest and AlterTopicRequest?
> TopicState
> > >>> will
> > >>> > > still be used for requesting current topic state via
> ClusterState.
> > >>> > >
> > >>> > > Something like:
> > >>> > >
> > >>> > > interface CreateTopicRequest extends AbstractRequestMetadata {
> > >>> > >
> > >>> > > // requested number of partitions or if manual assignment is
> > given,
> > >>> > > number of partitions in the assignment
> > >>> > >
> > >>> > > int numPartitions();
> > >>> > >
> > >>> > > // requested replication factor, or if manual assignment is
> > given,
> > >>> > > number of replicas in assignment for partition 0
> > >>> > >
> > >>> > > short replicationFactor();
> > >>> > >
> > >>> > > // replica assignment requested by the client, or null if
> > >>> assignment is
> > >>> > > auto-generated
> > >>> > >
> > >>> > > map<Integer, List<Integer>> manualReplicaAssignment();
> > >>> > >
> > >>> > > map<String, String> configs();
> > >>> > >
> > >>> > > }
> > >>> > >
> > >>> > >
> > >>> > > interface AlterTopicRequest extends AbstractRequestMetadata {
> > >>> > >
> > >>> > > // updated topic configs, or null if not changed
> > >>> > >
> > >>> > > map<String, String> updatedConfigs();
> > >>> > >
> > >>> > > // proposed replica assignment in this request, or null. For
> > >>> adding new
> > >>> > > partitions request, this is proposed replica assignment for new
> > >>> partitions.
> > >>> > > For replica re-assignment case, this is proposed new assignment.
> > >>> > >
> > >>> > > map<Integer, List<Integer>> proposedReplicaAssignment();
> > >>> > >
> > >>> > > // new number of partitions (due to increase/decrease), or null
> > if
> > >>> > > number of partitions not changed
> > >>> > >
> > >>> > > Integer updatedNumPartitions()
> > >>> > >
> > >>> > > }
> > >>> > >
> > >>> > >
> > >>> > > I did not spend much time on my AlterTopicRequest interface
> > >>> proposal, but
> > >>> > > the idea is basically to return only the parts which were
> changed.
> > >>> The
> > >>> > > advantage of this approach over having separate methods for each
> > >>> specific
> > >>> > > alter topic request is that it is more flexible for future mixing
> > of
> > >>> what
> > >>> > > can be updated in the topic state.
> > >>> > >
> > >>> > >
> > >>> > > What do you think?
> > >>> > >
> > >>> > >
> > >>> > > Thanks,
> > >>> > >
> > >>> > > Anna
> > >>> > >
> > >>> > >
> > >>> > > On Mon, Oct 9, 2017 at 1:39 AM, Tom Bentley <
> t.j.bent...@gmail.com
> > >
> > >>> wrote:
> > >>> > >
> > >>> > >> I've added RequestedTopicState, as discussed in my last email.
> > >>> > >>
> > >>> > >> I've also added a paragraph to the migration plan about old
> > clients
> > >>> making
> > >>> > >> policy-violating delete topics or delete records request.
> > >>> > >>
> > >>> > >> If no further comments a forthcoming in the next day or two
> then I
> > >>> will
> > >>> > >> start a vote.
> > >>> > >>
> > >>> > >> Thanks,
> > >>> > >>
> > >>> > >> Tom
> > >>> > >>
> > >>> > >> On 5 October 2017 at 12:41, Tom Bentley <t.j.bent...@gmail.com>
> > >>> wrote:
> > >>> > >>
> > >>> > >> > I'd like to raise a somewhat subtle point about how the
> proposed
> > >>> API
> > >>> > >> > should behave.
> > >>> > >> >
> > >>> > >> > The current CreateTopicPolicy gets passed either the request
> > >>> partition
> > >>> > >> > count and replication factor, or the requested assignment. So
> if
> > >>> the
> > >>> > >> > request had specified partition count and replication factor,
> > the
> > >>> policy
> > >>> > >> > sees a null replicaAssignments(). Likewise if the request
> > >>> specified a
> > >>> > >> > replica assignment the policy would get back null from
> > >>> numPartitions()
> > >>> > >> and
> > >>> > >> > replicationFactor().
> > >>> > >> >
> > >>> > >> > These semantics mean the policy can't reject an assignment
> that
> > >>> happened
> > >>> > >> > to be auto-generated (or rather, it's obvious to the policy
> that
> > >>> the
> > >>> > >> > assignment is auto generated, because it can't see such
> > >>> assignments),
> > >>> > >> > though it can reject a request because the assignment was
> > >>> > >> auto-generated,
> > >>> > >> > or vice versa.
> > >>> > >> >
> > >>> > >> > Retaining these semantics makes the TopicState less symmetric
> > >>> between
> > >>> > >> it's
> > >>> > >> > use in requestedState() and the current state available from
> the
> > >>> > >> > ClusterState, and also less symmetric between its use for
> > >>> createTopic()
> > >>> > >> and
> > >>> > >> > for alterTopic(). This can make it harder to write a policy.
> For
> > >>> > >> example,
> > >>> > >> > if I want the policy "the number of partitions must be < 100",
> > if
> > >>> the
> > >>> > >> > requestedState().numPartitions() can be null I need to cope
> with
> > >>> that
> > >>> > >> > and figure it out from inspecting the replicasAssignments().
> It
> > >>> would
> > >>> > >> be
> > >>> > >> > much better for the policy writer to just be able to write:
> > >>> > >> >
> > >>> > >> > if (request.requestedState().numPartitions() >= 100)
> > >>> > >> > throw new PolicyViolationException("#partitions must
> be
> > <
> > >>> 100")
> > >>> > >> >
> > >>> > >> > An alternative would be to keep the symmetry (and thus
> > >>> > >> TopicState.replicasAssignments()
> > >>> > >> > would never return null, and TopicState.numPartitions() and
> > >>> > >> > TopicState.replicationFactor() could each be primitives), but
> > >>> expose the
> > >>> > >> > auto-generatedness of the replicaAssignments() explicitly,
> > >>> perhaps by
> > >>> > >> using
> > >>> > >> > a subtype of TopicState for the return type of
> requestedState():
> > >>> > >> >
> > >>> > >> > interface RequestedTopicState extends TopicState {
> > >>> > >> > /**
> > >>> > >> > * True if the {@link
> TopicState#replicasAssignments()}
> > >>> > >> > * in this request we generated by the broker, false
> if
> > >>> > >> > * they were explicitly requested by the client.
> > >>> > >> > */
> > >>> > >> > boolean generatedReplicaAssignments();
> > >>> > >> > }
> > >>> > >> >
> > >>> > >> > Thoughts?
> > >>> > >> >
> > >>> > >> > On 4 October 2017 at 11:06, Tom Bentley <
> t.j.bent...@gmail.com>
> > >>> wrote:
> > >>> > >> >
> > >>> > >> >> Good point. Then I guess I can do those items too. I would
> also
> > >>> need to
> > >>> > >> >> do the same changes for DeleteRecordsRequest and Response.
> > >>> > >> >>
> > >>> > >> >> On 4 October 2017 at 10:37, Ismael Juma <ism...@juma.me.uk>
> > >>> wrote:
> > >>> > >> >>
> > >>> > >> >>> Those two points are related to policies in the following
> > sense:
> > >>> > >> >>>
> > >>> > >> >>> 1. A policy that can't send errors to clients is much less
> > >>> useful
> > >>> > >> >>> 2. Testing policies is much easier with `validateOnly`
> > >>> > >> >>>
> > >>> > >> >>> Ismael
> > >>> > >> >>>
> > >>> > >> >>> On Wed, Oct 4, 2017 at 9:20 AM, Tom Bentley <
> > >>> t.j.bent...@gmail.com>
> > >>> > >> >>> wrote:
> > >>> > >> >>>
> > >>> > >> >>> > Thanks Edoardo,
> > >>> > >> >>> >
> > >>> > >> >>> > I've added that motivation to the KIP.
> > >>> > >> >>> >
> > >>> > >> >>> > KIP-201 doesn't address two points raised in KIP-170:
> > Adding a
> > >>> > >> >>> > validationOnly flag to
> > >>> > >> >>> > DeleteTopicRequest and adding an error message to
> > >>> > >> DeleteTopicResponse.
> > >>> > >> >>> > Since those are not policy-related I think they're best
> left
> > >>> out of
> > >>> > >> >>> > KIP-201. I suppose it is up to you and Mickael whether to
> > >>> narrow the
> > >>> > >> >>> scope
> > >>> > >> >>> > of KIP-170 to address those points.
> > >>> > >> >>> >
> > >>> > >> >>> > Thanks again,
> > >>> > >> >>> >
> > >>> > >> >>> > Tom
> > >>> > >> >>> >
> > >>> > >> >>> > On 4 October 2017 at 08:20, Edoardo Comar <
> > eco...@uk.ibm.com>
> > >>> > >> wrote:
> > >>> > >> >>> >
> > >>> > >> >>> > > Thanks Tom,
> > >>> > >> >>> > > looks got to me and KIP-201 could supersede KIP-170
> > >>> > >> >>> > > but could you please add a missing motivation bullet
> that
> > >>> was
> > >>> > >> behind
> > >>> > >> >>> > > KIP-170:
> > >>> > >> >>> > >
> > >>> > >> >>> > > introducing ClusterState to allow validation of
> > >>> create/alter topic
> > >>> > >> >>> > request
> > >>> > >> >>> > >
> > >>> > >> >>> > > not just against the request metadata but also
> > >>> > >> >>> > > against the current amount of resources already used in
> > the
> > >>> > >> cluster
> > >>> > >> >>> (eg
> > >>> > >> >>> > > number of partitions).
> > >>> > >> >>> > >
> > >>> > >> >>> > > thanks
> > >>> > >> >>> > > Edo
> > >>> > >> >>> > > --------------------------------------------------
> > >>> > >> >>> > >
> > >>> > >> >>> > > Edoardo Comar
> > >>> > >> >>> > >
> > >>> > >> >>> > > IBM Message Hub
> > >>> > >> >>> > >
> > >>> > >> >>> > > IBM UK Ltd, Hursley Park, SO21 2JN
> > >>> > >> >>> > >
> > >>> > >> >>> > >
> > >>> > >> >>> > >
> > >>> > >> >>> > > From: Tom Bentley <t.j.bent...@gmail.com>
> > >>> > >> >>> > > To: dev@kafka.apache.org
> > >>> > >> >>> > > Date: 02/10/2017 15:15
> > >>> > >> >>> > > Subject: Re: [DISCUSS] KIP-201: Rationalising
> > Policy
> > >>> > >> >>> interfaces
> > >>> > >> >>> > >
> > >>> > >> >>> > >
> > >>> > >> >>> > >
> > >>> > >> >>> > > Hi All,
> > >>> > >> >>> > >
> > >>> > >> >>> > > I've updated KIP-201 again so there is now a single
> policy
> > >>> > >> interface
> > >>> > >> >>> (and
> > >>> > >> >>> > > thus a single key by which to configure it) for topic
> > >>> creation,
> > >>> > >> >>> > > modification, deletion and record deletion, which each
> > have
> > >>> their
> > >>> > >> own
> > >>> > >> >>> > > validation method.
> > >>> > >> >>> > >
> > >>> > >> >>> > > There are still a few loose ends:
> > >>> > >> >>> > >
> > >>> > >> >>> > > 1. I currently propose validateAlterTopic(), but it
> would
> > be
> > >>> > >> >>> possible to
> > >>> > >> >>> > > be
> > >>> > >> >>> > > more fine grained about this: validateAlterConfig(),
> > >>> > >> >>> validAddPartitions()
> > >>> > >> >>> > > and validateReassignPartitions(), for example. Obviously
> > >>> this
> > >>> > >> >>> results in
> > >>> > >> >>> > a
> > >>> > >> >>> > > policy method per operation, and makes it more clear
> what
> > >>> is being
> > >>> > >> >>> > > changed.
> > >>> > >> >>> > > I guess the down side is its more work for implementer,
> > and
> > >>> > >> >>> potentially
> > >>> > >> >>> > > makes it harder to change the interface in the future.
> > >>> > >> >>> > >
> > >>> > >> >>> > > 2. A couple of TODOs about what the TopicState interface
> > >>> should
> > >>> > >> >>> return
> > >>> > >> >>> > > when
> > >>> > >> >>> > > a topic's partitions are being reassigned.
> > >>> > >> >>> > >
> > >>> > >> >>> > > Your thoughts on these or any other points are welcome.
> > >>> > >> >>> > >
> > >>> > >> >>> > > Thanks,
> > >>> > >> >>> > >
> > >>> > >> >>> > > Tom
> > >>> > >> >>> > >
> > >>> > >> >>> > > On 27 September 2017 at 11:45, Paolo Patierno <
> > >>> ppatie...@live.com
> > >>> > >> >
> > >>> > >> >>> > wrote:
> > >>> > >> >>> > >
> > >>> > >> >>> > > > Hi Ismael,
> > >>> > >> >>> > > >
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > 1. I don't have a real requirement now but
> "deleting"
> > >>> is an
> > >>> > >> >>> > operation
> > >>> > >> >>> > > > that could be really dangerous so it's always better
> > >>> having a
> > >>> > >> way
> > >>> > >> >>> for
> > >>> > >> >>> > > > having more control on that. I know that we have the
> > >>> authorizer
> > >>> > >> >>> used
> > >>> > >> >>> > for
> > >>> > >> >>> > > > that (delete on topic) but fine grained control could
> be
> > >>> better
> > >>> > >> >>> (even
> > >>> > >> >>> > > > already happens for topic deletion).
> > >>> > >> >>> > > > 2. I know about the problem of restarting broker
> due
> > to
> > >>> > >> changes
> > >>> > >> >>> on
> > >>> > >> >>> > > > policies but what do you mean by doing that on the
> > >>> clients ?
> > >>> > >> >>> > > >
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > Paolo Patierno
> > >>> > >> >>> > > > Senior Software Engineer (IoT) @ Red Hat
> > >>> > >> >>> > > > Microsoft MVP on Azure & IoT
> > >>> > >> >>> > > > Microsoft Azure Advisor
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > Twitter : @ppatierno<
> > >>> > >> >>> > >
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__twitter
> > >>> .
> > >>> > >> >>> > > com_ppatierno&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=
> > >>> > >> >>> > >
> > >>> EzRhmSah4IHsUZVekRUIINhltZK7U0OaeRo7hgW4_tQ&m=h-D-nA7uiy1Z-jta5y-
> > >>> > >> >>> > > yh7dKgV77XtsUnJ9Rab1gheY&s=43hzTLEDKw2v5Vh0zwkMTaaKD-
> > >>> > >> >>> > HdJD8d_F4-Bsw25-Y&e=
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > Linkedin : paolopatierno<
> > >>> > >> >>> > > https://urldefense.proofpoint.com/v2/url?u=http-3A__it.
> > >>> > >> >>> > >
> > linkedin.com_in_paolopatierno&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1
> > >>> > >> ZOg&r=
> > >>> > >> >>> > >
> > >>> EzRhmSah4IHsUZVekRUIINhltZK7U0OaeRo7hgW4_tQ&m=h-D-nA7uiy1Z-jta5y-
> > >>> > >> >>> > >
> yh7dKgV77XtsUnJ9Rab1gheY&s=Ig0N7Nwf9EHfTJ2pH3jRM1JIdlzXw6
> > >>> > >> >>> > R5Drocu0TMRLk&e=
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > Blog : DevExperience<
> > >>> > >> >>> > > https://urldefense.proofpoint.com/v2/url?u=http-3A__
> > >>> > >> >>> > >
> > >>> paolopatierno.wordpress.com_&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=
> > >>> > >> >>> > >
> > >>> EzRhmSah4IHsUZVekRUIINhltZK7U0OaeRo7hgW4_tQ&m=h-D-nA7uiy1Z-jta5y-
> > >>> > >> >>> > >
> yh7dKgV77XtsUnJ9Rab1gheY&s=Tc9NrTtG2GP7-zRjOHkXHfYI0rncO8_
> > >>> > >> >>> > jKpedna692z4&e=
> > >>> > >> >>> > > >
> > >>> > >> >>> > > >
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > ________________________________
> > >>> > >> >>> > > > From: isma...@gmail.com <isma...@gmail.com> on behalf
> > of
> > >>> Ismael
> > >>> > >> >>> Juma <
> > >>> > >> >>> > > > ism...@juma.me.uk>
> > >>> > >> >>> > > > Sent: Wednesday, September 27, 2017 10:30 AM
> > >>> > >> >>> > > > To: dev@kafka.apache.org
> > >>> > >> >>> > > > Subject: Re: [DISCUSS] KIP-201: Rationalising Policy
> > >>> interfaces
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > A couple of questions:
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > 1. Is this a concrete requirement from a user or is it
> > >>> > >> >>> hypothetical?
> > >>> > >> >>> > > > 2. You sure you would want to do this in the broker
> > >>> instead of
> > >>> > >> the
> > >>> > >> >>> > > clients?
> > >>> > >> >>> > > > It's worth remembering that updating broker policies
> > >>> involves a
> > >>> > >> >>> rolling
> > >>> > >> >>> > > > restart of the cluster, so it's not the right place
> for
> > >>> things
> > >>> > >> that
> > >>> > >> >>> > > change
> > >>> > >> >>> > > > frequently.
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > Ismael
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > On Wed, Sep 27, 2017 at 11:26 AM, Paolo Patierno <
> > >>> > >> >>> ppatie...@live.com>
> > >>> > >> >>> > > > wrote:
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > > Hi Ismael,
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > regarding motivations for delete records, as I said
> > >>> during the
> > >>> > >> >>> > > discussion
> > >>> > >> >>> > > > > on KIP-204, it gives the possibility to avoid
> deleting
> > >>> > >> messages
> > >>> > >> >>> for
> > >>> > >> >>> > > > > specific partitions (inside the topic) and starting
> > >>> from a
> > >>> > >> >>> specific
> > >>> > >> >>> > > > offset.
> > >>> > >> >>> > > > > I could think on some users solutions where they
> know
> > >>> exactly
> > >>> > >> >>> what
> > >>> > >> >>> > the
> > >>> > >> >>> > > > > partitions means in a specific topic (because they
> are
> > >>> using a
> > >>> > >> >>> custom
> > >>> > >> >>> > > > > partitioner on the producer side) so they know what
> > >>> kind of
> > >>> > >> >>> messages
> > >>> > >> >>> > > are
> > >>> > >> >>> > > > > inside a partition allowing to delete them but not
> the
> > >>> others.
> > >>> > >> >>> In
> > >>> > >> >>> > > such a
> > >>> > >> >>> > > > > policy a user could also check the timestamp related
> > to
> > >>> the
> > >>> > >> >>> offset
> > >>> > >> >>> > for
> > >>> > >> >>> > > > > allowing or not deletion on time base.
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > Paolo Patierno
> > >>> > >> >>> > > > > Senior Software Engineer (IoT) @ Red Hat
> > >>> > >> >>> > > > > Microsoft MVP on Azure & IoT
> > >>> > >> >>> > > > > Microsoft Azure Advisor
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > Twitter : @ppatierno<
> > >>> > >> >>> > >
> > https://urldefense.proofpoint.com/v2/url?u=http-3A__twitter
> > >>> .
> > >>> > >> >>> > > com_ppatierno&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=
> > >>> > >> >>> > >
> > >>> EzRhmSah4IHsUZVekRUIINhltZK7U0OaeRo7hgW4_tQ&m=h-D-nA7uiy1Z-jta5y-
> > >>> > >> >>> > > yh7dKgV77XtsUnJ9Rab1gheY&s=43hzTLEDKw2v5Vh0zwkMTaaKD-
> > >>> > >> >>> > HdJD8d_F4-Bsw25-Y&e=
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > > Linkedin : paolopatierno<
> > >>> > >> >>> > > https://urldefense.proofpoint.com/v2/url?u=http-3A__it.
> > >>> > >> >>> > >
> > linkedin.com_in_paolopatierno&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1
> > >>> > >> ZOg&r=
> > >>> > >> >>> > >
> > >>> EzRhmSah4IHsUZVekRUIINhltZK7U0OaeRo7hgW4_tQ&m=h-D-nA7uiy1Z-jta5y-
> > >>> > >> >>> > >
> yh7dKgV77XtsUnJ9Rab1gheY&s=Ig0N7Nwf9EHfTJ2pH3jRM1JIdlzXw6
> > >>> > >> >>> > R5Drocu0TMRLk&e=
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > > Blog : DevExperience<
> > >>> > >> >>> > > https://urldefense.proofpoint.com/v2/url?u=http-3A__
> > >>> > >> >>> > >
> > >>> paolopatierno.wordpress.com_&d=DwIBaQ&c=jf_iaSHvJObTbx-siA1ZOg&r=
> > >>> > >> >>> > >
> > >>> EzRhmSah4IHsUZVekRUIINhltZK7U0OaeRo7hgW4_tQ&m=h-D-nA7uiy1Z-jta5y-
> > >>> > >> >>> > >
> yh7dKgV77XtsUnJ9Rab1gheY&s=Tc9NrTtG2GP7-zRjOHkXHfYI0rncO8_
> > >>> > >> >>> > jKpedna692z4&e=
> > >>> > >> >>> > > >
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > ________________________________
> > >>> > >> >>> > > > > From: isma...@gmail.com <isma...@gmail.com> on
> behalf
> > >>> of
> > >>> > >> Ismael
> > >>> > >> >>> > Juma <
> > >>> > >> >>> > > > > ism...@juma.me.uk>
> > >>> > >> >>> > > > > Sent: Wednesday, September 27, 2017 10:18 AM
> > >>> > >> >>> > > > > To: dev@kafka.apache.org
> > >>> > >> >>> > > > > Subject: Re: [DISCUSS] KIP-201: Rationalising Policy
> > >>> > >> interfaces
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > A couple more comments:
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > 1. "If this KIP is accepted for Kafka 1.1.0 this
> > >>> removal could
> > >>> > >> >>> happen
> > >>> > >> >>> > > in
> > >>> > >> >>> > > > > Kafka 1.2.0 or a later release." -> we only remove
> > code
> > >>> in
> > >>> > >> major
> > >>> > >> >>> > > > releases.
> > >>> > >> >>> > > > > So, if it's deprecated in 1.1.0, it would be removed
> > in
> > >>> 2.0.0.
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > 2. Deleting all messages in a topic is not really
> the
> > >>> same as
> > >>> > >> >>> > deleting
> > >>> > >> >>> > > a
> > >>> > >> >>> > > > > topic. The latter will cause consumers and producers
> > to
> > >>> error
> > >>> > >> out
> > >>> > >> >>> > > while
> > >>> > >> >>> > > > the
> > >>> > >> >>> > > > > former will not. It would be good to motivate the
> need
> > >>> for the
> > >>> > >> >>> delete
> > >>> > >> >>> > > > > records policy more.
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > Ismael
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > On Wed, Sep 27, 2017 at 11:12 AM, Ismael Juma <
> > >>> > >> ism...@juma.me.uk
> > >>> > >> >>> >
> > >>> > >> >>> > > wrote:
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > > > > Another quick comment: the KIP states that having
> > >>> multiple
> > >>> > >> >>> > > interfaces
> > >>> > >> >>> > > > > > imply that the logic must be in 2 places. That is
> > not
> > >>> true
> > >>> > >> >>> because
> > >>> > >> >>> > > the
> > >>> > >> >>> > > > > same
> > >>> > >> >>> > > > > > class can implement multiple interfaces (this
> aspect
> > >>> was
> > >>> > >> >>> considered
> > >>> > >> >>> > > > when
> > >>> > >> >>> > > > > we
> > >>> > >> >>> > > > > > decided to introduce policies incrementally).
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > > > The main reason why I think the original approach
> > >>> doesn't
> > >>> > >> work
> > >>> > >> >>> well
> > >>> > >> >>> > > is
> > >>> > >> >>> > > > > > that there is no direct mapping between an
> operation
> > >>> and the
> > >>> > >> >>> > policy.
> > >>> > >> >>> > > > That
> > >>> > >> >>> > > > > > is, we initially thought we would have
> > >>> create/alter/delete
> > >>> > >> >>> topics,
> > >>> > >> >>> > > but
> > >>> > >> >>> > > > > that
> > >>> > >> >>> > > > > > didn't work out as the alter case is better served
> > by
> > >>> > >> multiple
> > >>> > >> >>> > > request
> > >>> > >> >>> > > > > > types. Given that, it's a bit awkward to maintain
> > the
> > >>> > >> original
> > >>> > >> >>> > > approach
> > >>> > >> >>> > > > > and
> > >>> > >> >>> > > > > > a policy for topic management seemed easier to
> > >>> understand.
> > >>> > >> On
> > >>> > >> >>> that
> > >>> > >> >>> > > > note,
> > >>> > >> >>> > > > > > would `TopicManagementPolicy` be a better name?
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > > > Looking at the updated KIP, I notice that we
> > actually
> > >>> have a
> > >>> > >> >>> > > > > > TopicDeletionPolicy with a separate config. That
> > >>> seems to
> > >>> > >> be a
> > >>> > >> >>> > > halfway
> > >>> > >> >>> > > > > > house. Not sure about that.
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > > > Ismael
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > > > On Wed, Sep 27, 2017 at 10:47 AM, Tom Bentley
> > >>> > >> >>> > > <t.j.bent...@gmail.com>
> > >>> > >> >>> > > > > > wrote:
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > > >> I have updated the KIP to add a common policy
> > >>> interface for
> > >>> > >> >>> topic
> > >>> > >> >>> > > and
> > >>> > >> >>> > > > > >> message deletion. This included pulling
> > ClusterState
> > >>> and
> > >>> > >> >>> > TopicState
> > >>> > >> >>> > > > > >> interfaces up to the top level so that they can
> be
> > >>> shared
> > >>> > >> >>> between
> > >>> > >> >>> > > the
> > >>> > >> >>> > > > > two
> > >>> > >> >>> > > > > >> policies.
> > >>> > >> >>> > > > > >>
> > >>> > >> >>> > > > > >> Cheers,
> > >>> > >> >>> > > > > >>
> > >>> > >> >>> > > > > >> Tom
> > >>> > >> >>> > > > > >>
> > >>> > >> >>> > > > > >> On 26 September 2017 at 18:09, Edoardo Comar <
> > >>> > >> >>> eco...@uk.ibm.com>
> > >>> > >> >>> > > > wrote:
> > >>> > >> >>> > > > > >>
> > >>> > >> >>> > > > > >> > Thanks Tom,
> > >>> > >> >>> > > > > >> > In my original KIP-170 I mentioned that the
> > method
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > public Map<String, Integer>
> > topicsPartitionCount();
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > was just a starting point for a general purpose
> > >>> > >> ClusterState
> > >>> > >> >>> > > > > >> > as it happened to be exactly the info we needed
> > >>> for our
> > >>> > >> >>> policy
> > >>> > >> >>> > > > > >> > implementation :-)
> > >>> > >> >>> > > > > >> > it definitely doesn't feel general purpose
> > enough.
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > what about
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > interface ClusterState {
> > >>> > >> >>> > > > > >> > public TopicState topicState(String
> > >>> topicName);
> > >>> > >> >>> > > > > >> > public Set<String> topics();
> > >>> > >> >>> > > > > >> > }
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > I think that the implementation of ClusterState
> > >>> that the
> > >>> > >> >>> server
> > >>> > >> >>> > > will
> > >>> > >> >>> > > > > >> pass
> > >>> > >> >>> > > > > >> > to the policy.validate method
> > >>> > >> >>> > > > > >> > would just lazily tap into MetadataCache. No
> need
> > >>> for big
> > >>> > >> >>> > upfront
> > >>> > >> >>> > > > > >> > allocations.
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > ciao,
> > >>> > >> >>> > > > > >> > Edo
> > >>> > >> >>> > > > > >> >
> > --------------------------------------------------
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > Edoardo Comar
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > IBM Message Hub
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > IBM UK Ltd, Hursley Park, SO21 2JN
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > From: Tom Bentley <t.j.bent...@gmail.com>
> > >>> > >> >>> > > > > >> > To: dev@kafka.apache.org
> > >>> > >> >>> > > > > >> > Date: 26/09/2017 17:39
> > >>> > >> >>> > > > > >> > Subject: Re: [DISCUSS] KIP-201:
> > >>> Rationalising
> > >>> > >> Policy
> > >>> > >> >>> > > > interfaces
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > Hi Edoardo,
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > what about a single method in ClusterState
> > >>> > >> >>> > > > > >> > >
> > >>> > >> >>> > > > > >> > > interface ClusterState {
> > >>> > >> >>> > > > > >> > > public Map<String,TopicState>
> > >>> topicsState();
> > >>> > >> >>> > > > > >> > >
> > >>> > >> >>> > > > > >> > > }
> > >>> > >> >>> > > > > >> > >
> > >>> > >> >>> > > > > >> > > which could return a read-only snapshot of
> the
> > >>> cluster
> > >>> > >> >>> > metadata
> > >>> > >> >>> > > ?
> > >>> > >> >>> > > > > >> > >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > Sure that would work too. A concern with that
> is
> > >>> that we
> > >>> > >> >>> end up
> > >>> > >> >>> > > > > >> allocating
> > >>> > >> >>> > > > > >> > a potentially rather large amount for the Map
> and
> > >>> the
> > >>> > >> >>> > collections
> > >>> > >> >>> > > > > >> present
> > >>> > >> >>> > > > > >> > in the TopicStates in order to provide the
> > >>> snapshot. The
> > >>> > >> >>> caller
> > >>> > >> >>> > > > might
> > >>> > >> >>> > > > > >> only
> > >>> > >> >>> > > > > >> > be interested in one item from the TopicState
> for
> > >>> one
> > >>> > >> topic
> > >>> > >> >>> in
> > >>> > >> >>> > > the
> > >>> > >> >>> > > > > map.
> > >>> > >> >>> > > > > >> > Accessing this information via methods means
> the
> > >>> caller
> > >>> > >> only
> > >>> > >> >>> > pays
> > >>> > >> >>> > > > for
> > >>> > >> >>> > > > > >> what
> > >>> > >> >>> > > > > >> > they use.
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > Cheers,
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > Tom
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >> > Unless stated otherwise above:
> > >>> > >> >>> > > > > >> > IBM United Kingdom Limited - Registered in
> > England
> > >>> and
> > >>> > >> Wales
> > >>> > >> >>> > with
> > >>> > >> >>> > > > > number
> > >>> > >> >>> > > > > >> > 741598.
> > >>> > >> >>> > > > > >> > Registered office: PO Box 41, North Harbour,
> > >>> Portsmouth,
> > >>> > >> >>> > > Hampshire
> > >>> > >> >>> > > > PO6
> > >>> > >> >>> > > > > >> 3AU
> > >>> > >> >>> > > > > >> >
> > >>> > >> >>> > > > > >>
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > > >
> > >>> > >> >>> > > > >
> > >>> > >> >>> > > >
> > >>> > >> >>> > >
> > >>> > >> >>> > >
> > >>> > >> >>> > >
> > >>> > >> >>> > > Unless stated otherwise above:
> > >>> > >> >>> > > IBM United Kingdom Limited - Registered in England and
> > >>> Wales with
> > >>> > >> >>> number
> > >>> > >> >>> > > 741598.
> > >>> > >> >>> > > Registered office: PO Box 41, North Harbour, Portsmouth,
> > >>> Hampshire
> > >>> > >> >>> PO6
> > >>> > >> >>> > 3AU
> > >>> > >> >>> > >
> > >>> > >> >>> >
> > >>> > >> >>>
> > >>> > >> >>
> > >>> > >> >>
> > >>> > >> >
> > >>> > >>
> > >>> > >
> > >>> > >
> > >>>
> > >>
> >
>
