On Wed, Mar 1, 2017, at 15:52, radai wrote:
> quick comment on the request objects:
>
> i see "abstract class NewTopic" and "class NewTopicWithReplication" and "
> NewTopicWithReplicaAssignments"
>
> 1. since the result object is called CreateTopicResults should these be
> called *Request?
Hi radai,
Thanks for taking a look.
I think using the name "request" would be very confusing here, because
we have a whole family of internal Request classes such as
CreateTopicsRequest, TopicMetataRequest, etc. which are used for RPCs.
> 2. this seems like a suboptimal approach to me. imagine we add a
> NewTopicWithSecurity, and then we would need
> NewTopicWithReplicationAndSecurity? (or any composable "traits").
> this wont really scale. Wouldnt it be better to have a single (rather
> complicated)
> CreateTopicRequest, and use a builder pattern to deal with the compexity
> and options? like so:
>
> CreateTopicRequest req =
> AdminRequests.newTopic("bob").replicationFactor(2).withPartitionAssignment(1,
> "boker7", "broker10").withOption(...).build();
>
> the builder would validate any potentially conflicting options and would
> allow piling on the complexity in a more manageable way (note - my code
> above intends to demonstrate both a general replication factor and a
> specific assignment for a partiocular partition of that topic, which may
> be
> too much freedom).
We don't need to express every optional bell and whistle by creating a
subclass. In fact, the proposal already had setConfigs() in the base
class, since it applies to every new topic creation.
Thinking about it a little more, though, the subclasses don't really add
that much value, so we should probably just have NewTopic and no
subclasses. I removed the subclasses.
best,
Colin
>
> On Wed, Mar 1, 2017 at 1:58 PM, Colin McCabe <cmcc...@apache.org> wrote:
>
> > Hi all,
> >
> > Thanks for commenting, everyone. Does anyone have more questions or
> > comments, or should we vote? The latest proposal is up at
> > https://cwiki.apache.org/confluence/display/KAFKA/KIP-117%3A+Add+a+public+
> > AdminClient+API+for+Kafka+admin+operations
> >
> > best,
> > Colin
> >
> >
> > On Thu, Feb 16, 2017, at 15:00, Colin McCabe wrote:
> > > On Thu, Feb 16, 2017, at 14:11, Dong Lin wrote:
> > > > Hey Colin,
> > > >
> > > > Thanks for the update. I have two comments:
> > > >
> > > > - I actually think it is simpler and good enough to have per-topic API
> > > > instead of batch-of-topic API. This is different from the argument for
> > > > batch-of-partition API because, unlike operation on topic, people
> > usually
> > > > operate on multiple partitions (e.g. seek(), purge()) at a time. Is
> > there
> > > > performance concern with per-topic API? I am wondering if we should do
> > > > per-topic API until there is use-case or performance benefits of
> > > > batch-of-topic API.
> > >
> > > Yes, there is a performance concern with only supporting operations on
> > > one topic at a time. Jay expressed this in some of his earlier emails
> > > and some other people did as well. We have cases in mind for management
> > > software where many topics are created at once.
> > >
> > > >
> > > > - Currently we have interface "Consumer" and "Producer". And we also
> > have
> > > > implementations of these two interfaces as "KafkaConsumer" and
> > > > "KafkaProducer". If we follow the same naming pattern, should we have
> > > > interface "AdminClient" and the implementation "KafkaAdminClient",
> > > > instead
> > > > of the other way around?
> > >
> > > That's a good point. We should do that for consistency.
> > >
> > > best,
> > > Colin
> > >
> > > >
> > > > Dong
> > > >
> > > >
> > > > On Thu, Feb 16, 2017 at 10:19 AM, Colin McCabe <cmcc...@apache.org>
> > > > wrote:
> > > >
> > > > > Hi all,
> > > > >
> > > > > So I think people have made some very good points so far. There
> > seems
> > > > > to be agreement that we need to have explicit batch APIs for the
> > sake of
> > > > > efficiency, so I added that back.
> > > > >
> > > > > Contexts seem a little more complex than we thought, so I removed
> > that
> > > > > from the proposal.
> > > > >
> > > > > I removed the Impl class. Instead, we now have a KafkaAdminClient
> > > > > interface and an AdminClient implementation. I think this matches
> > our
> > > > > other code better, as Jay commented.
> > > > >
> > > > > Each call now has an "Options" object that is passed in. This will
> > > > > allow us to easily add new parameters to the calls without having
> > tons
> > > > > of function overloads. Similarly, each call now has a Results
> > object,
> > > > > which will let us easily extend the results we are returning if
> > needed.
> > > > >
> > > > > Many people made the point that Java 7 Futures are not that useful,
> > but
> > > > > Java 8 CompletableFutures are. With CompletableFutures, you can
> > chain
> > > > > calls, adapt them, join them-- basically all the stuff people are
> > doing
> > > > > in Node.js and Twisted Python. Java 7 Futures don't really let you
> > do
> > > > > anything but poll for a value or block. So I felt that it was
> > better to
> > > > > just go with a CompletableFuture-based API.
> > > > >
> > > > > People also made the point that they would like an easy API for
> > waiting
> > > > > on complete success of a batch call. For example, an API that would
> > > > > fail if even one topic wasn't created in createTopics. So I came up
> > > > > with Result objects that provide multiple futures that you can wait
> > on.
> > > > > You can wait on a future that fires when everything is complete, or
> > you
> > > > > can wait on futures for individual topics being created.
> > > > >
> > > > > I updated the wiki, so please take a look. Note that this new API
> > > > > requires JDK8. It seems like JDK8 is coming soon, though, and the
> > > > > disadvantages of sticking to Java 7 are pretty big here, I think.
> > > > >
> > > > > best,
> > > > > Colin
> > > > >
> > > > >
> > > > > On Mon, Feb 13, 2017, at 11:51, Colin McCabe wrote:
> > > > > > On Sun, Feb 12, 2017, at 09:21, Jay Kreps wrote:
> > > > > > > Hey Colin,
> > > > > > >
> > > > > > > Thanks for the hard work on this. I know going back and forth on
> > APIs
> > > > > is
> > > > > > > kind of frustrating but we're at the point where these things
> > live long
> > > > > > > enough and are used by enough people that it is worth the pain.
> > I'm
> > > > > sure
> > > > > > > it'll come down in the right place eventually. A couple things
> > I've
> > > > > found
> > > > > > > helped in the past:
> > > > > > >
> > > > > > > 1. The burden of evidence needs to fall on the complicator.
> > i.e. if
> > > > > > > person X thinks the api should be async they need to produce
> > a set
> > > > > of
> > > > > > > common use cases that require this. Otherwise you are
> > perpetually
> > > > > > > having to
> > > > > > > think "we might need x". I think it is good to have a rule of
> > > > > "simple
> > > > > > > until
> > > > > > > proven insufficient".
> > > > > > > 2. Make sure we frame things for the intended audience. At
> > this
> > > > > point
> > > > > > > our apis get used by a very broad set of Java engineers. This
> > is a
> > > > > > > very
> > > > > > > different audience from our developer mailing list. These
> > people
> > > > > code
> > > > > > > for a
> > > > > > > living not necessarily as a passion, and may not understand
> > details
> > > > > of
> > > > > > > the
> > > > > > > internals of our system or even basic things like
> > multi-threaded
> > > > > > > programming. I don't think this means we want to dumb things
> > down,
> > > > > but
> > > > > > > rather try really hard to make things truly simple when
> > possible.
> > > > > > >
> > > > > > > Okay here were a couple of comments:
> > > > > > >
> > > > > > > 1. Conceptually what is a TopicContext? I think it means
> > something
> > > > > > > like
> > > > > > > TopicAdmin? It is not literally context about Topics right?
> > What is
> > > > > > > the
> > > > > > > relationship of Contexts to clients? Is there a threadsafety
> > > > > > > difference?
> > > > > > > Would be nice to not have to think about this, this is what I
> > mean
> > > > > by
> > > > > > > "conceptual weight". We introduce a new concept that is a bit
> > > > > nebulous
> > > > > > > that
> > > > > > > I have to figure out to use what could be a simple api. I'm
> > sure
> > > > > > > you've
> > > > > > > been through this experience before where you have these
> > various
> > > > > > > objects
> > > > > > > and you're trying to figure out what they represent (the
> > connection
> > > > > to
> > > > > > > the
> > > > > > > server? the information to create a connection? a request
> > session?).
> > > > > >
> > > > > > The intention was to provide some grouping of methods, and also a
> > place
> > > > > > to put request parameters which were often set to defaults rather
> > than
> > > > > > being explicitly set. If it seems complex, we can certainly get
> > rid of
> > > > > > it.
> > > > > >
> > > > > > > 2. We've tried to avoid the Impl naming convention. In
> > general the
> > > > > > > rule
> > > > > > > has been if there is only going to be one implementation you
> > don't
> > > > > > > need an
> > > > > > > interface. If there will be multiple, distinguish it from the
> > > > > others.
> > > > > > > The
> > > > > > > other clients follow this pattern: Producer, KafkaProducer,
> > > > > > > MockProducer;
> > > > > > > Consumer, KafkaConsumer, MockConsumer.
> > > > > >
> > > > > > Good point. Let's change the interface to KafkaAdminClient, and
> > the
> > > > > > implementation to AdminClient.
> > > > > >
> > > > > > > 3. We generally don't use setters or getters as a naming
> > > > > convention. I
> > > > > > > personally think mutating the setting in place seems kind of
> > like
> > > > > late
> > > > > > > 90s
> > > > > > > Java style. I think it likely has thread-safety issues. i.e.
> > even if
> > > > > > > it is
> > > > > > > volatile you may not get the value you just set if there is
> > another
> > > > > > > thread... I actually really liked what you described as your
> > > > > original
> > > > > > > idea
> > > > > > > of having a single parameter object like CreateTopicRequest
> > that
> > > > > holds
> > > > > > > all
> > > > > > > these parameters and defaults. This lets you evolve the api
> > with all
> > > > > > > the
> > > > > > > various combinations of arguments without overloading
> > insanity.
> > > > > After
> > > > > > > doing
> > > > > > > literally tens of thousands of remote APIs at LinkedIn we
> > eventually
> > > > > > > converged on a rule, which is ultimately every remote api
> > needs a
> > > > > > > single
> > > > > > > argument object you can add to over time and it must be
> > batched.
> > > > > Which
> > > > > > > brings me to my next point...
> > > > > >
> > > > > > Just to clarify, volatiles were never a part of the proposal. I
> > think
> > > > > > that context objects or request objects should be used by a single
> > > > > > thread at a time.
> > > > > >
> > > > > > I'm not opposed to request objects, but I think they raise all the
> > same
> > > > > > questions as context objects. Basically, the thread-safety issues
> > need
> > > > > > to be spelled out and understood by the user, and the user needs
> > more
> > > > > > lines of code to make a request. And there will be people trying
> > to do
> > > > > > things like re-use request objects when they should not, and so
> > forth.
> > > > > >
> > > > > > > 4. I agree batch apis are annoying but I suspect we'll end up
> > adding
> > > > > > > one. Doing 1000 requests for 1000 operations if creating or
> > deleting
> > > > > > > will
> > > > > > > be bad, right? This won't be the common case, but when you do
> > it it
> > > > > > > will be
> > > > > > > a deal-breaker problem. I don't think we should try to fix
> > this one
> > > > > > > behind
> > > > > > > the scenes.
> > > > > > > 5. Are we going to do CompletableFuture (which requires java
> > 8) or
> > > > > > > normal Future? Normal Future is utterly useless for most
> > things
> > > > > other
> > > > > > > than
> > > > > > > just calling wait. If we can evolve in place from Future to
> > > > > > > CompletableFuture that is fantastic (we could do it for the
> > producer
> > > > > > > too!).
> > > > > > > My belief was that this was binary incompatible but I
> > actually don't
> > > > > > > know
> > > > > > > (obviously it's source compatible).
> > > > > >
> > > > > > In my testing, replacing a return type with a subclass of that
> > return
> > > > > > type did not break binary compatibility. I haven't been able to
> > find
> > > > > > chapter and verse on this from the Java implementers, though.
> > > > > >
> > > > > > best,
> > > > > > Colin
> > > > > >
> > > > > >
> > > > > > >
> > > > > > > -Jay
> > > > > > >
> > > > > > > On Wed, Feb 8, 2017 at 5:00 PM, Colin McCabe <cmcc...@apache.org
> > >
> > > > > wrote:
> > > > > > >
> > > > > > > > Hi all,
> > > > > > > >
> > > > > > > > I made some major revisions to the proposal on the wiki, so
> > please
> > > > > check
> > > > > > > > it out.
> > > > > > > >
> > > > > > > > The new API is based on Ismael's suggestion of grouping
> > related APIs.
> > > > > > > > There is only one layer of grouping. I think that it's
> > actually
> > > > > pretty
> > > > > > > > intuitive. It's also based on the idea of using Futures, which
> > > > > several
> > > > > > > > people commented that they'd like to see.
> > > > > > > >
> > > > > > > > Here's a simple example:
> > > > > > > >
> > > > > > > > > AdminClient client = new AdminClientImpl(myConfig);
> > > > > > > > > try {
> > > > > > > > > client.topics().create("foo", 3, (short) 2, false).get();
> > > > > > > > > Collection<String> topicNames =
> > client.topics().list(false).
> > > > > get();
> > > > > > > > > log.info("Found topics: {}", Utils.mkString(topicNames,
> > ", "));
> > > > > > > > > Collection<Node> nodes = client.nodes().list().get();
> > > > > > > > > log.info("Found cluster nodes: {}",
> > Utils.mkString(nodes, ",
> > > > > "));
> > > > > > > > > } finally {
> > > > > > > > > client.close();
> > > > > > > > > }
> > > > > > > >
> > > > > > > > The good thing is, there is no Try, no 'get' prefixes, no
> > messing
> > > > > with
> > > > > > > > batch APIs. If there is an error, then Future#get() throws an
> > > > > > > > ExecutionException which wraps the relevant exception in the
> > standard
> > > > > > > > Java way.
> > > > > > > >
> > > > > > > > Here's a slightly less simple example:
> > > > > > > >
> > > > > > > > > AdminClient client = new AdminClientImpl(myConfig);
> > > > > > > > > try {
> > > > > > > > > List<Future<Void>> futures = new LinkedList<>();
> > > > > > > > > for (String topicName: myNewTopicNames) {
> > > > > > > > > creations.add(client.topics().
> > > > > > > > > setClientTimeout(30000).setCreationConfig(
> > myTopicConfig).
> > > > > > > > > create(topicName, 3, (short) 2, false));
> > > > > > > > > }
> > > > > > > > > Futures.waitForAll(futures);
> > > > > > > > > } finally {
> > > > > > > > > client.close();
> > > > > > > > > }
> > > > > > > >
> > > > > > > > I went with Futures because I feel like ought to have some
> > option for
> > > > > > > > doing async. It's a style of programming that has become a
> > lot more
> > > > > > > > popular with the rise of Node.js, Twisted python, etc. etc.
> > Also, as
> > > > > > > > Ismael commented, Java 8 CompletableFuture is going to make
> > Java's
> > > > > > > > support for fluent async programming a lot stronger by
> > allowing call
> > > > > > > > chaining and much more.
> > > > > > > >
> > > > > > > > If we are going to support async, the simplest thing is just
> > to make
> > > > > > > > everything return a future and let people call get() if they
> > want to
> > > > > run
> > > > > > > > synchronously. Having a mix of async and sync APIs is just
> > going to
> > > > > be
> > > > > > > > confusing and redundant.
> > > > > > > >
> > > > > > > > I think we should try to avoid creating single functions that
> > start
> > > > > > > > multiple requests if we can. It makes things much uglier. It
> > means
> > > > > > > > that you have to have some kind of request class that wraps up
> > the
> > > > > > > > request the user is trying to create, so that you can handle an
> > > > > array of
> > > > > > > > those requests. The return value has to be something like
> > Map<Node,
> > > > > > > > Try<Value>> to represent which nodes failed and succeeded.
> > This is
> > > > > the
> > > > > > > > kind of stuff that, in my opinion, makes people scratch their
> > heads.
> > > > > > > >
> > > > > > > > If we need to, we can still get some of the efficiency
> > benefits of
> > > > > batch
> > > > > > > > APIs by waiting for a millisecond or two before sending out a
> > topic
> > > > > > > > create() request to see if other create() requests arrive. If
> > so, we
> > > > > > > > can coalesce them. It might be better to figure out if this
> > is an
> > > > > > > > actual performance issue before implementing it, though.
> > > > > > > >
> > > > > > > > I think it would be good to get something out there, annotate
> > it as
> > > > > > > > @Unstable, and get feedback from people building against trunk
> > and
> > > > > using
> > > > > > > > it. We have removed or changed @Unstable APIs in streams
> > before, so
> > > > > I
> > > > > > > > don't think we should worry that it will get set in stone
> > > > > prematurely.
> > > > > > > > The AdminClient API should get much less developer use than
> > anything
> > > > > in
> > > > > > > > streams, so changing an unstable API should be much easier.
> > > > > > > >
> > > > > > > > best,
> > > > > > > > Colin
> > > > > > > >
> > > > > > > >
> > > > > > > > On Wed, Feb 8, 2017, at 07:49, Ismael Juma wrote:
> > > > > > > > > Thanks for elaborating Jay. I totally agree that we have to
> > be very
> > > > > > > > > careful
> > > > > > > > > in how we use our complexity budget. Easier said than done
> > when
> > > > > people
> > > > > > > > > don't agree on what is complex and what is simple. :) For
> > example,
> > > > > I
> > > > > > > > > think
> > > > > > > > > batch APIs are a significant source of complexity as you
> > have to
> > > > > do a
> > > > > > > > > bunch
> > > > > > > > > of ceremony to group things before sending the request and
> > error
> > > > > handling
> > > > > > > > > becomes more complex due to partial failures (things like
> > `Try` or
> > > > > other
> > > > > > > > > mechanisms that serve a similar role are then needed).
> > > > > > > > >
> > > > > > > > > Maybe a way forward is to write API usage examples to help
> > > > > validate that
> > > > > > > > > the suggested API is indeed easy to use.
> > > > > > > > >
> > > > > > > > > Ismael
> > > > > > > > >
> > > > > > > > > On Wed, Feb 8, 2017 at 4:40 AM, Jay Kreps <j...@confluent.io>
> > > > > wrote:
> > > > > > > > >
> > > > > > > > > > Totally agree on CompletableFuture. Also agree with some
> > of the
> > > > > rough
> > > > > > > > edges
> > > > > > > > > > on the Consumer.
> > > > > > > > > >
> > > > > > > > > > I don't have much of a leg to stand on with the splitting
> > vs not
> > > > > > > > splitting
> > > > > > > > > > thing, really hard to argue one or the other is better. I
> > guess
> > > > > the one
> > > > > > > > > > observation in watching us try to make good public apis
> > over the
> > > > > years
> > > > > > > > is I
> > > > > > > > > > am kind of in favor of a particular kind of simple. In
> > > > > particular I
> > > > > > > > think
> > > > > > > > > > since the bar is sooo high in support and docs and the
> > community
> > > > > of
> > > > > > > > users
> > > > > > > > > > so broad in the range of their capabilities, it makes it so
> > > > > there is a
> > > > > > > > lot
> > > > > > > > > > of value in dead simple interfaces that don't have a lot of
> > > > > conceptual
> > > > > > > > > > weight, don't introduce a lot of new classes or concepts or
> > > > > general
> > > > > > > > > > patterns that must be understood to use them correctly. So
> > > > > things like
> > > > > > > > > > nesting, or the Try class, or async apis, or even just a
> > complex
> > > > > set of
> > > > > > > > > > classes representing arguments or return values kind of
> > all stack
> > > > > > > > > > conceptual burdens on the user to figure out correct
> > usage. So
> > > > > like,
> > > > > > > > for
> > > > > > > > > > example, the Try class is very elegant and represents a
> > whole
> > > > > > > > generalized
> > > > > > > > > > class of possibly completed actions, but the flip side is
> > maybe
> > > > > I'm
> > > > > > > > just a
> > > > > > > > > > working guy who needs to list his kafka topics but doesn't
> > know
> > > > > Rust,
> > > > > > > > take
> > > > > > > > > > pity on me! :-)
> > > > > > > > > >
> > > > > > > > > > Nit picking aside, super excited to see us progress on
> > this.
> > > > > > > > > >
> > > > > > > > > > -Jay
> > > > > > > > > >
> > > > > > > > > > On Tue, Feb 7, 2017 at 3:46 PM Ismael Juma <
> > ism...@juma.me.uk>
> > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Jay,
> > > > > > > > > > >
> > > > > > > > > > > Thanks for the feedback. Comments inline.
> > > > > > > > > > >
> > > > > > > > > > > On Tue, Feb 7, 2017 at 8:18 PM, Jay Kreps <
> > j...@confluent.io>
> > > > > wrote:
> > > > > > > > > > > >
> > > > > > > > > > > > - I think it would be good to not use "get" as the
> > prefix
> > > > > for
> > > > > > > > things
> > > > > > > > > > > > making remote calls. We've tried to avoid the java
> > getter
> > > > > > > > convention
> > > > > > > > > > > > entirely (see code style guide), but for remote
> > calls in
> > > > > > > > particular
> > > > > > > > > > it
> > > > > > > > > > > > kind
> > > > > > > > > > > > of blurs the line between field access and remote
> > RPC in
> > > > > a way
> > > > > > > > that
> > > > > > > > > > > > leads
> > > > > > > > > > > > people to trouble. What about, e.g.,
> > fetchAllGroups() vs
> > > > > > > > > > > getAllGroups().
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > Agreed that we should avoid the `get` prefix for remote
> > calls.
> > > > > There
> > > > > > > > are
> > > > > > > > > > a
> > > > > > > > > > > few possible prefixes for the read operations: list,
> > fetch,
> > > > > describe.
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > > - I think futures and callbacks are a bit of a pain
> > to
> > > > > use. I'd
> > > > > > > > > > second
> > > > > > > > > > > > Becket's comment: let's ensure there a common use
> > case
> > > > > > > > motivating
> > > > > > > > > > > these
> > > > > > > > > > > > that wouldn't be just as easily satisfied with batch
> > > > > operations
> > > > > > > > > > (which
> > > > > > > > > > > > we
> > > > > > > > > > > > seem to have at least for some things). In terms of
> > > > > flexibility
> > > > > > > > > > > > Callbacks >
> > > > > > > > > > > > Futures > Batch Ops but I think in terms of
> > usability it
> > > > > is the
> > > > > > > > > > exact
> > > > > > > > > > > > opposite so let's make sure we have worked out how
> > the
> > > > > API will
> > > > > > > > be
> > > > > > > > > > > used
> > > > > > > > > > > > before deciding. In particular I think java Futures
> > are
> > > > > often an
> > > > > > > > > > > > uncomfortable half-way point since calling get() and
> > > > > blocking
> > > > > > > > the
> > > > > > > > > > > > thread is
> > > > > > > > > > > > often not what you want for chaining sequences of
> > > > > operations in
> > > > > > > > a
> > > > > > > > > > > truly
> > > > > > > > > > > > async way, so 99% of people just use the future as
> > a way
> > > > > to
> > > > > > > > batch
> > > > > > > > > > > calls.
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > We should definitely figure out how the APIs are going
> > to be
> > > > > used
> > > > > > > > before
> > > > > > > > > > > deciding. I agree that callbacks are definitely painful
> > and
> > > > > there's
> > > > > > > > > > little
> > > > > > > > > > > reason to expose them in a modern API unless it's meant
> > to be
> > > > > very
> > > > > > > > low
> > > > > > > > > > > level. When it comes to Futures, I think it's important
> > to
> > > > > > > > distinguish
> > > > > > > > > > what
> > > > > > > > > > > is available in Java 7 and below versus what is
> > available from
> > > > > Java 8
> > > > > > > > > > > onwards. CompletableFuture makes it much easier to
> > > > > compose/chain
> > > > > > > > > > operations
> > > > > > > > > > > (in a similar vein to java.util.Stream, our own Streams
> > API,
> > > > > etc.)
> > > > > > > > and it
> > > > > > > > > > > gives you the ability to register callbacks if you
> > really want
> > > > > to
> > > > > > > > > > (avoiding
> > > > > > > > > > > the somewhat odd situation in the Producer where we
> > return a
> > > > > Future
> > > > > > > > _and_
> > > > > > > > > > > allow you to pass a callback).
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > > - Personally I don't think splitting the admin
> > methods up
> > > > > > > > actually
> > > > > > > > > > > makes
> > > > > > > > > > > > things more usable. It just makes you have to dig
> > through
> > > > > our
> > > > > > > > > > > > hierarchy. I
> > > > > > > > > > > > think a flat class with a bunch of operations (like
> > the
> > > > > consumer
> > > > > > > > > > api)
> > > > > > > > > > > is
> > > > > > > > > > > > probably the easiest for people to grok and find
> > things
> > > > > on. I am
> > > > > > > > > > kind
> > > > > > > > > > > > of a
> > > > > > > > > > > > dumb PHP programmer at heart, though.
> > > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > I am not sure it's fair to compare the AdminClient with
> > the
> > > > > > > > Consumer. The
> > > > > > > > > > > former has APIs for a bunch of unrelated APIs (topics,
> > ACLs,
> > > > > configs,
> > > > > > > > > > > consumer groups, delegation tokens, preferred leader
> > election,
> > > > > > > > partition
> > > > > > > > > > > reassignment, etc.) where the latter is pretty
> > specialised.
> > > > > For each
> > > > > > > > of
> > > > > > > > > > the
> > > > > > > > > > > resources, you may have 3-4 operations, it will get
> > confusing
> > > > > fast.
> > > > > > > > Also,
> > > > > > > > > > > do you really think an API that has one level of
> > grouping will
> > > > > mean
> > > > > > > > that
> > > > > > > > > > > users have to "dig through our hierarchy"? Or are you
> > > > > concerned that
> > > > > > > > once
> > > > > > > > > > > we go in that direction, there is a danger of making the
> > > > > hierarchy
> > > > > > > > more
> > > > > > > > > > > complicated?
> > > > > > > > > > >
> > > > > > > > > > > Finally, I am not sure I would use the consumer as an
> > example
> > > > > of
> > > > > > > > > > something
> > > > > > > > > > > that is easy to grok. :) The fact that methods behave
> > pretty
> > > > > > > > differently
> > > > > > > > > > > (some are blocking while others only have an effect after
> > > > > poll) with
> > > > > > > > no
> > > > > > > > > > > indication from the type signature or naming convention
> > makes
> > > > > it
> > > > > > > > harder,
> > > > > > > > > > > not easier, to understand.
> > > > > > > > > > >
> > > > > > > > > > > Ismael
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > >
> > > > >
> >
