a few comments on the KIP as it is now:
1. instead of add(Header) + add (Iterable<Header>) i suggest we use add +
addAll. this is more in line with how java collections work and may
therefor be more intuitive
2. common user code dealing with headers will want get("someKey") /
set("someKey"), or equivalent. code using multiple headers under the same
key will be rare, and code iterating over all headers would be even rarer
(probably only for kafka-connect equivalent use cases, really). as the API
looks right now, the most common and trivial cases will be gnarly:
get("someKey") -->
record.headers().headers("someKey").iterator().next().value(). and this is
before i start talking about how nulls/emptys are handled.
replace("someKey") -->
record.headers().remove(record.headers().headers("someKey"));
record.headers().append(new Header("someKey", value));
this is why i think we should start with get()/set() which are single-value
map semantics (so set overwrites), then add getAll() (multi-map), append()
etc on top. make the common case pretty.
On Sun, Feb 26, 2017 at 2:01 AM, Michael Pearce <[email protected]>
wrote:
> Hi Becket,
>
> On 1)
>
> Yes truly we wanted mutable headers also. Alas we couldn't think of a
> solution would address Jason's point around, once a record is sent it
> shouldn't be possible to mutate it, for cases where you send twice the same
> record.
>
> Thank you so much for your solution i think this will work very nicely :)
>
> Agreed we only need to do mutable to immutable conversion
>
> I think you solution with a ".close()" taken from else where in the kafka
> protocol where mutability is existent is a great solution, and happy middle
> ground.
>
> @Jason you agree, this resolves your concerns if we had mutable headers?
>
>
> On 2)
> Agreed, this was only added as i couldn't think of a solution to that
> would address Jason's concern, but really didn't want to force end users to
> constantly write ugly boiler plate code. If we agree on you solution for 1,
> very happy to remove these.
>
> On 3)
> I also would like to keep the scope of this KIP limited to Message Headers
> for now, else we run the risk of not getting even these delivered for next
> release and we're almost now there on getting this KIP to the state
> everyone is happy. As you note address that later if theres the need.
>
>
> Ill leave it 24hrs and update the kip if no strong objections based on
> your solution for 1 & 2.
>
> Cheers
> Mike
>
> __________ ______________________________
> From: Becket Qin <[email protected]>
> Sent: Saturday, February 25, 2017 10:33 PM
> To: [email protected]
> Subject: Re: [DISCUSS] KIP-82 - Add Record Headers
>
> Hey Michael,
>
> Thanks for the KIP. It looks good overall and it looks we only have few
> things to agree on.
>
> 1. Regarding the mutability.
>
> I think it would be a big convenience to have headers mutable during
> certain stage in the message life cycle for the use cases you mentioned. I
> agree there is a material benefit especially given that we may have to
> modify the headers for each message.
>
> That said, I also think it is fair to say that in the producer, in order to
> guarantee the correctness of the entire logic, it is necessary that at some
> point we need to make producer record immutable. For example we probably
> don't want to see that users accidentally updated the headers when the
> producer is doing the serialization or compression.
>
> Given that, would it be possible to make Headers to be able to switch from
> mutable to immutable? We have done this for the Batch in the producer. For
> example, initially the headers are mutable, but after it has gone through
> all the interceptors, we can call Headers.close() to make it immutable
> afterwards.
>
> On the consumer side, we can probably always leave the the ConsumerRecord
> mutable because after we give the messages to the users, Kafka consumer
> itself does not care about whether the headers are modified or not anymore.
>
> So far I think we only need to do the mutable to immutable conversion. If
> there are use case require immutable to mutable conversion, we may need
> something more than a closable.
>
> 2. If we agree on what mentioned above, I think it probably makes sense to
> put the addHeaders()/removeHeaders() methods into Headers class and just
> leave the headers() method in ProducerRecord and ConsumerRecord.
>
> 3. It might be useful to have headers at MessageSet level as well so we can
> avoid decompression in some cases. But given this KIP is already
> complicated, I would rather leave this out of the scope and address that
> later when needed, e.g. after having batch level interceptors.
>
> Thanks,
>
> Jiangjie (Becket) Qin
>
> On Fri, Feb 24, 2017 at 3:56 PM, Michael Pearce <[email protected]>
> wrote:
>
> > KIP updated in response to the below comments:
> >
> > > 1. Is the intent of `Headers.filter` to include or exclude the
> > headers
> > > matching the key? Can you add a javadoc to clarify?
> > > 2. The KIP mentions that we will introduce V4 of FetchRequest
> > and V4 of
> > > ProduceRequest. Can you change this to say that the changes
> will
> > > piggyback
> > > onto V3 of ProduceRequest and V4 of FetchRequest which were
> > introduced
> > > in
> > > KIP-98?
> >
> >
> >
> >
> > On 24/02/2017, 23:20, "Michael Pearce" <[email protected]> wrote:
> >
> > We’re trying to make an eco-system for people to be able to use
> > headers, I think we want to ensure some least common features are
> supported
> > and not limited.
> >
> >
> > Some examples we have already.
> >
> > On consume interceptors a security interceptor may need to take the
> > current header, decrypt the data and replace the token with the next
> token
> > for the next processing, in case of a single decryption token being one
> > time use only.
> >
> > On produce it could be the interceptors add some values in the clear
> > from the systems that supply them, but later a security header
> interceptor
> > needs to encrypt some headers, as such needs to replace the current value
> > with new one.
> >
> > I note Radai already requested this in the thread, I assume he has
> > some use case also. S
> >
> > Simple add / remove is a least common feature.
> >
> > Rgds,
> > Mike
> >
> >
> > On 24/02/2017, 23:00, "Jason Gustafson" <[email protected]> wrote:
> >
> > Hey Michael,
> >
> > I'm not strongly opposed to them; I just don't see a lot of
> > benefit. One
> > thing it would be good to understand is why a consumer
> interceptor
> > would
> > need to add headers and why a producer interceptor would need to
> > remove
> > them. Maybe we only need the common cases?
> >
> > Thanks,
> > Jason
> >
> > On Fri, Feb 24, 2017 at 2:22 PM, Michael Pearce <
> > [email protected]>
> > wrote:
> >
> > > Hi Jason,
> > >
> > > Sorry I thought this was the agreed compromise to provide an
> api
> > that
> > > avoid boiler plate in return for immutabilty.
> > >
> > > If not then mutability will be needed as a goal is to have a
> > single clean
> > > method call to append/remove a header.
> > >
> > > Cheers
> > > Mike
> > >
> > > On 24/02/2017, 22:15, "Jason Gustafson" <[email protected]>
> > wrote:
> > >
> > > Hey Michael,
> > >
> > > I didn't actually comment on the new methods for
> > ProducerRecord and
> > > ConsumerRecord. If they only save some boilerplate, I'd
> just
> > as well
> > > not
> > > have them.
> > >
> > > Also a couple minor comments:
> > >
> > > 1. Is the intent of `Headers.filter` to include or exclude
> > the headers
> > > matching the key? Can you add a javadoc to clarify?
> > > 2. The KIP mentions that we will introduce V4 of
> > FetchRequest and V4 of
> > > ProduceRequest. Can you change this to say that the changes
> > will
> > > piggyback
> > > onto V3 of ProduceRequest and V4 of FetchRequest which were
> > introduced
> > > in
> > > KIP-98?
> > >
> > > The rest of the KIP looks good to me.
> > >
> > > -Jason
> > >
> > > On Fri, Feb 24, 2017 at 12:46 PM, Michael Pearce <
> > > [email protected]>
> > > wrote:
> > >
> > > > I’ve added the methods on the ProducerRecord that will
> > return a new
> > > > instance of ProducerRecord with modified headers.
> > > >
> > > > On 24/02/2017, 19:22, "Michael Pearce" <
> > [email protected]>
> > > wrote:
> > > >
> > > > Pattern.compile is expensive, and even if cached
> > String.equals is
> > > > faster than matched. also if we end up with an internal
> > map in
> > > future for
> > > > performance it will be easier to be by key.
> > > >
> > > > As all that's needed is to get header by key.
> > > >
> > > > With like the other arguements of let's implement
> > simple and
> > > then we
> > > > can always add pattern later as well if it's found it's
> > needed. (As
> > > noted
> > > > it's easier to add methods than to take away)
> > > >
> > > > Great I'll update kip with extra methods on
> > producerecord and a
> > > note
> > > > that new objects are returned by method calls.
> > > >
> > > >
> > > >
> > > > Sent using OWA for iPhone
> > > > ________________________________________
> > > > From: Jason Gustafson <[email protected]>
> > > > Sent: Friday, February 24, 2017 6:51:45 PM
> > > > To: [email protected]
> > > > Subject: Re: [DISCUSS] KIP-82 - Add Record Headers
> > > >
> > > > The APIs in the current KIP look good to me. Just a
> > couple
> > > questions:
> > > > why
> > > > does filter not return Headers? Also would it be
> > useful if the
> > > key is a
> > > > regex?
> > > >
> > > > On the point of immutability.. One option might be to
> > use a
> > > mutable
> > > > object
> > > > only when passing the headers through the interceptor
> > chain. I
> > > think as
> > > > long as we resort to mutability only when clear
> > performance
> > > results
> > > > show
> > > > that it is worthwhile, I am satisfied. As Ismael
> > noted, for
> > > common
> > > > scenarios it is possible to get reasonable
> performance
> > with
> > > immutable
> > > > objects.
> > > >
> > > > -Jason
> > > >
> > > > On Fri, Feb 24, 2017 at 8:48 AM, Michael Pearce <
> > > [email protected]
> > > > >
> > > > wrote:
> > > >
> > > > > Hi
> > > > >
> > > > > On 1, How can you guarantee two separate
> > implemented clients
> > > would
> > > > add
> > > > > the headers in the same order we are not specifying
> > an order
> > > at the
> > > > > protocol level (nor should we) with regards to
> keyA
> > being
> > > ordered
> > > > before
> > > > > keyB? We shouldn’t be expecting keyA to be always
> > set before
> > > keyB.
> > > > >
> > > > > On 2, I believe we have changed the naming based on
> > feedback
> > > from
> > > > Jason
> > > > > already, e.g. we don’t have “get” method that
> > inferred O(1)
> > > > performance,
> > > > > like wise nor “put” but we have an “append”
> > > > >
> > > > > On 3, in the KafkaProducer, I think we have
> > mutability
> > > already, the
> > > > value
> > > > > for time is changed if it is null, at the point of
> > send:
> > > > > “
> > > > > long timestamp = record.timestamp() ==
> > null ?
> > > > > time.milliseconds() : record.timestamp();
> > > > > “
> > > > >
> > > > > As such the timestamp is already mutable, so what’s
> > the
> > > difference
> > > > here,
> > > > > we already have some mixed semantics. On timestamp.
> > > > > e.g. currently if I send to records with timestamp
> > not set,
> > > the wire
> > > > > binary sent the value for the timestamp would be
> > different, as
> > > such
> > > > we have
> > > > > mutation for the same record.
> > > > >
> > > > > On 4, I think we should not expect not 1 or 2
> > headers, but
> > > infact
> > > > 10’s of
> > > > > headers. This is the concern on immutable headers,
> > whilst the
> > > append
> > > > > self-reference works nicely, what if someone needs
> > to remove a
> > > > header?
> > > > >
> > > > > Trying to get this moving:
> > > > >
> > > > > If we really wanted Immutable Headers and
> > essentially you guys
> > > wont
> > > > give
> > > > > +1 for it without.
> > > > >
> > > > > Whats the feeling for adding methods to
> > ProducerRecord that
> > > does the
> > > > > boiler plate code or creating a new ProducerRecord
> > with the
> > > altered
> > > > new
> > > > > headers (appended or removed) inside. E.g.
> > > > >
> > > > > ProducerRecord {
> > > > >
> > > > >
> > > > > ProducerRecord append(Iterable<Headers>
> > headersToAppend){
> > > > > return new ProducerRecord(key, value,
> > headers.append(
> > > > headersToAppend),
> > > > > ….)
> > > > > }
> > > > >
> > > > > ProducerRecord remove(Iterable<Headers>
> > headersToAppend){
> > > > > return new ProducerRecord(key, value,
> > headers.remove(
> > > > headersToAppend),
> > > > > ….)
> > > > > }
> > > > >
> > > > > }
> > > > >
> > > > > Were the headers methods actually returns new
> > objects, and the
> > > > producer
> > > > > records methods create a new producer record with
> > all the
> > > current
> > > > values,
> > > > > but with the new modified headers.
> > > > >
> > > > > Then interceptors / code return this new object?
> > > > >
> > > > >
> > > > > Cheers
> > > > > Mike
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On 24/02/2017, 16:02, "[email protected] on behalf
> > of Ismael
> > > Juma" <
> > > > > [email protected] on behalf of [email protected]>
> > wrote:
> > > > >
> > > > > Hi Michael,
> > > > >
> > > > > Did you mean that you were happy to compromise
> > to keep it
> > > > mutable or
> > > > > immutable? You wrote the former, but it sounded
> > from the
> > > > sentence that
> > > > > it
> > > > > could have been a typo. So, my thoughts on this
> > is that
> > > there
> > > > are a few
> > > > > things to take into account:
> > > > >
> > > > > 1. Semantics
> > > > > 2. Simplicity of use (the common operations
> > should be easy
> > > to do)
> > > > > 3. If it's easy to reason about and safe
> > (immutability
> > > helps
> > > > with this)
> > > > > 4. Efficiency (both memory and CPU usage)
> > > > >
> > > > > Regarding 1, I think it would be good to be
> very
> > clear
> > > about the
> > > > > guarantees
> > > > > that we are providing. It seems that we are
> > saying that
> > > keys are
> > > > > unordered,
> > > > > but what about the case where there are
> multiple
> > values
> > > for the
> > > > same
> > > > > key?
> > > > > It seems that for some use cases (e.g.
> lineage),
> > it may be
> > > > useful to
> > > > > add
> > > > > values to the same key while preserving the
> > order.
> > > > >
> > > > > Regarding 2, I agree that it's useful to have
> > methods in
> > > > `Headers` for
> > > > > the
> > > > > very common use cases although we have to be
> > careful with
> > > the
> > > > naming to
> > > > > avoid giving the wrong impression. Also, when
> it
> > comes to
> > > > `Map.Entry`,
> > > > > I
> > > > > think I'd prefer a `toMap` method that simply
> > gives the
> > > user a
> > > > Map if
> > > > > that's what they want (it makes it clear that
> > there's a
> > > > conversion
> > > > > happening).
> > > > >
> > > > > Regarding 3, the concern I have if we make the
> > headers
> > > mutable
> > > > is that
> > > > > it
> > > > > seems to introduce some inconsistencies and
> > potential edge
> > > > cases. At
> > > > > the
> > > > > moment, it's safe to keep a ProducerRecord and
> > resend it,
> > > for
> > > > example.
> > > > > If
> > > > > the record is mutated by an interceptor, then
> > this can
> > > lead to
> > > > weird
> > > > > behaviour. Also, it seems inconsistent that one
> > has to
> > > create a
> > > > new
> > > > > ProducerRecord to modify the record timestamp,
> > but that
> > > one has
> > > > to
> > > > > mutate
> > > > > the record to add headers. It seems like one
> > should either
> > > > embrace
> > > > > immutability or mutability, but mixing both is
> > not ideal.
> > > > >
> > > > > Regarding 4, for the cases where there are a
> > small number
> > > of
> > > > headers
> > > > > and/or
> > > > > 1 or 2 interceptors, it doesn't seem difficult
> > to come up
> > > with
> > > > > reasonable
> > > > > implementations for mutable and immutable cases
> > that do a
> > > good
> > > > enough
> > > > > job.
> > > > > However, if the number of headers and
> > interceptors is
> > > large,
> > > > then care
> > > > > is
> > > > > needed for the immutable case to avoid
> > unnecessary
> > > copying. A
> > > > simple
> > > > > option
> > > > > that adds little memory overhead if we have
> > Header
> > > instances is
> > > > to
> > > > > simply
> > > > > add a self-reference to the previous Header in
> > the linked
> > > list.
> > > > >
> > > > > Ismael
> > > > >
> > > > > On Thu, Feb 23, 2017 at 1:09 AM, Michael
> Pearce <
> > > > [email protected]
> > > > > >
> > > > > wrote:
> > > > >
> > > > > > Im happy to compromise to keep it mutable but
> > move to an
> > > append
> > > > > style api.
> > > > > > (as in guava interables concat)
> > > > > >
> > > > > > class Headers {
> > > > > > Headers append(Iterable<Header>
> > headers);
> > > > > > }
> > > > > >
> > > > > >
> > > > > > I don’t think we’d want prepend, this would
> > give the
> > > idea of
> > > > > guaranteed
> > > > > > ordering, when in actual fact we don’t
> provide
> > that
> > > guarantee
> > > > (.e.g
> > > > > one
> > > > > > client can put headerA, then headerB, but
> > another could
> > > put
> > > > headerB
> > > > > then
> > > > > > headerA, this shouldn’t cause issues), Also
> > what if we
> > > changed
> > > > to a
> > > > > hashmap
> > > > > > for the internal implementation, its just a
> > bucket of
> > > entries
> > > > no
> > > > > ordering.
> > > > > > I think we just need to provide an api to
> > add/append
> > > headers.
> > > > > >
> > > > > > This ok? If so ill update KIP to record this.
> > > > > >
> > > > > > Cheers
> > > > > > Mike
> > > > > >
> > > > > > On 23/02/2017, 00:37, "Jason Gustafson" <
> > > [email protected]>
> > > > wrote:
> > > > > >
> > > > > > The point about usability is fair. It's
> > also
> > > reasonable to
> > > > > expect that
> > > > > > common use cases such as appending
> headers
> > should be
> > > done
> > > > > efficiently.
> > > > > >
> > > > > > Perhaps we could compromise with
> something
> > like this?
> > > > > >
> > > > > > class Headers {
> > > > > > Headers append(Iterable<Header>
> headers);
> > > > > > Headers prepend(Iterable<Header>
> headers);
> > > > > > }
> > > > > >
> > > > > > That retains ease of use while still
> giving
> > > ourselves some
> > > > > flexibility
> > > > > > in
> > > > > > the implementation.
> > > > > >
> > > > > > -Jason
> > > > > >
> > > > > >
> > > > > > On Wed, Feb 22, 2017 at 3:03 PM, Michael
> > Pearce <
> > > > > [email protected]
> > > > > > >
> > > > > > wrote:
> > > > > >
> > > > > > > I wasn’t referring to the headers
> > needing to be
> > > copied,
> > > > im
> > > > > meaning
> > > > > > the
> > > > > > > fact we’d be forcing a new producer
> > record to be
> > > > created, with
> > > > > all
> > > > > > the
> > > > > > > contents copied.
> > > > > > >
> > > > > > > i.e what will happen is utility method
> > will be
> > > created
> > > > or end
> > > > > up
> > > > > > being
> > > > > > > used, which does this, and returns the
> > new
> > > ProducerRecord
> > > > > instance.
> > > > > > >
> > > > > > > ProducerRecord
> addHeader(ProducerRecord
> > record,
> > > Header
> > > > > header){
> > > > > > > Return New ProducerRecord(record.key,
> > record.value,
> > > > > > record.timestamp…..,
> > > > > > > record.headers.concat(header))
> > > > > > > }
> > > > > > >
> > > > > > > To me this seems ugly, but will be
> > inevitable if we
> > > > don’t make
> > > > > adding
> > > > > > > headers to existing records a simple
> > clean method
> > > call.
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > On 22/02/2017, 22:57, "Michael Pearce"
> <
> > > > [email protected]>
> > > > > > wrote:
> > > > > > >
> > > > > > > Lazy init can achieve/avoid that.
> > > > > > >
> > > > > > > Re the concat, why don’t we
> > implement that
> > > inside the
> > > > > Headers
> > > > > > rather
> > > > > > > than causing everyone to implement this
> > as adding
> > > > headers in
> > > > > > interceptors
> > > > > > > will be a dominant use case. We want a
> > user
> > > friendly API.
> > > > > Having as
> > > > > > a user
> > > > > > > having to code this instead of having
> > the headers
> > > handle
> > > > this
> > > > > for me
> > > > > > seems
> > > > > > > redundant.
> > > > > > >
> > > > > > > On 22/02/2017, 22:34, "Jason
> > Gustafson" <
> > > > > [email protected]>
> > > > > > wrote:
> > > > > > >
> > > > > > > I thought the argument was
> > against
> > > creating the
> > > > extra
> > > > > objects
> > > > > > > unnecessarily
> > > > > > > (i.e. if they were not
> > accessed). And note
> > > that
> > > > making
> > > > > the
> > > > > > Headers
> > > > > > > immutable doesn't necessarily
> > mean that
> > > they
> > > > need to be
> > > > > > copied:
> > > > > > > you can do
> > > > > > > a trick like Guava's
> > Iterables.concat to
> > > add
> > > > additional
> > > > > > headers
> > > > > > > without
> > > > > > > changing the underlying
> > collections.
> > > > > > >
> > > > > > > -Jason
> > > > > > >
> > > > > > > On Wed, Feb 22, 2017 at 2:22
> PM,
> > Michael
> > > Pearce <
> > > > > > > [email protected]>
> > > > > > > wrote:
> > > > > > >
> > > > > > > > If the argument for not
> having
> > a map
> > > holding
> > > > the
> > > > > key, value
> > > > > > > pairs is due
> > > > > > > > to garbage creation of
> HashMap
> > entry's,
> > > > forcing the
> > > > > > creation of
> > > > > > > a whole new
> > > > > > > > producer record to simply add
> > a head,
> > > surely is
> > > > > creating
> > > > > > a-lot
> > > > > > > more?
> > > > > > > >
> ______________________________
> > __________
> > > > > > > > From: Jason Gustafson <
> > > [email protected]>
> > > > > > > > Sent: Wednesday, February 22,
> > 2017 10:09
> > > PM
> > > > > > > > To: [email protected]
> > > > > > > > Subject: Re: [DISCUSS] KIP-82
> > - Add
> > > Record
> > > > Headers
> > > > > > > >
> > > > > > > > The current producer
> > interceptor API is
> > > this:
> > > > > > > >
> > > > > > > > ProducerRecord<K, V>
> > > onSend(ProducerRecord<K,
> > > > V>
> > > > > record);
> > > > > > > >
> > > > > > > > So adding a header means
> > creating a new
> > > > > ProducerRecord
> > > > > > with a
> > > > > > > new header
> > > > > > > > added to the current headers
> > and
> > > returning it.
> > > > Would
> > > > > that
> > > > > > not
> > > > > > > work?
> > > > > > > >
> > > > > > > > -Jason
> > > > > > > >
> > > > > > > > On Wed, Feb 22, 2017 at 1:45
> > PM, Michael
> > > > Pearce <
> > > > > > > [email protected]>
> > > > > > > > wrote:
> > > > > > > >
> > > > > > > > > So how would you have this
> > work if not
> > > > mutable
> > > > > where
> > > > > > > interceptors would
> > > > > > > > > add headers?
> > > > > > > > >
> > > > > > > > > Sent using OWA for iPhone
> > > > > > > > >
> > ______________________________
> > > __________
> > > > > > > > > From: Jason Gustafson <
> > > [email protected]>
> > > > > > > > > Sent: Wednesday, February
> > 22, 2017
> > > 8:42:27 PM
> > > > > > > > > To: [email protected]
> > > > > > > > > Subject: Re: [DISCUSS]
> > KIP-82 - Add
> > > Record
> > > > Headers
> > > > > > > > >
> > > > > > > > > I think the point on the
> > mutability of
> > > > Headers is
> > > > > worth
> > > > > > > discussing a
> > > > > > > > little
> > > > > > > > > more. As far as I can tell,
> > once the
> > > > > ProducerRecord (or
> > > > > > > ConsumerRecord)
> > > > > > > > is
> > > > > > > > > constructed, there should
> be
> > no need to
> > > > further
> > > > > change
> > > > > > the
> > > > > > > headers. Is
> > > > > > > > that
> > > > > > > > > correct? If so, then why
> not
> > enforce
> > > that
> > > > that is
> > > > > the
> > > > > > case
> > > > > > > through the
> > > > > > > > API?
> > > > > > > > > One problem with mutability
> > it that it
> > > > constrains
> > > > > the
> > > > > > > implementation of
> > > > > > > > > Headers. For example, if we
> > were
> > > backing
> > > > with a
> > > > > byte
> > > > > > slice,
> > > > > > > would we
> > > > > > > > recopy
> > > > > > > > > the bytes if a header is
> > added or
> > > would we
> > > > > maintain a
> > > > > > satellite
> > > > > > > > collection
> > > > > > > > > of added records. Seems not
> > great
> > > either
> > > > way. If we
> > > > > > really
> > > > > > > think
> > > > > > > > mutability
> > > > > > > > > is needed, perhaps we could
> > add a
> > > method to
> > > > > headers to
> > > > > > convert
> > > > > > > it to a
> > > > > > > > > mutable type (e.g. a
> > Headers.toMap)?
> > > > > > > > >
> > > > > > > > > I'm also with Ismael about
> > exposing
> > > > Headers.get().
> > > > > I
> > > > > > thought
> > > > > > > it might
> > > > > > > > make
> > > > > > > > > sense to have a method like
> > this
> > > instead:
> > > > > > > > >
> > > > > > > > > Iterable<Header>
> > findMatching(Pattern
> > > > pattern);
> > > > > > > > >
> > > > > > > > > This makes the (potential)
> > need to
> > > scan the
> > > > headers
> > > > > > clear in
> > > > > > > the API. I'd
> > > > > > > > > also be fine exposing no
> > getter at
> > > all. In
> > > > > general, Ï
> > > > > > think
> > > > > > > it's good to
> > > > > > > > > start with a minimalistic
> > API and work
> > > from
> > > > there
> > > > > since
> > > > > > it's
> > > > > > > always
> > > > > > > > easier
> > > > > > > > > to add methods than remove
> > them.
> > > > > > > > >
> > > > > > > > > -Jason
> > > > > > > > >
> > > > > > > > > On Wed, Feb 22, 2017 at
> 9:16
> > AM,
> > > Michael
> > > > Pearce <
> > > > > > > [email protected]>
> > > > > > > > > wrote:
> > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > Hi Ismael
> > > > > > > > > >
> > > > > > > > > > On point 1,
> > > > > > > > > >
> > > > > > > > > > Sure makes sense will
> > update shortly.
> > > > > > > > > >
> > > > > > > > > > On point 2,
> > > > > > > > > >
> > > > > > > > > > Setter/getter typical to
> > > > properties/headers api’s
> > > > > > > traditionally are map
> > > > > > > > > > styled interfaces and
> what
> > I believe
> > > is
> > > > most
> > > > > expected
> > > > > > styled
> > > > > > > thus the
> > > > > > > > > Key,
> > > > > > > > > > Value setter.
> > > > > > > > > > Also it would mean rather
> > than an
> > > > interface, we
> > > > > would
> > > > > > be
> > > > > > > making our
> > > > > > > > > > internal header impl
> > object we have
> > > for the
> > > > > array,
> > > > > > exposed.
> > > > > > > E.g. if we
> > > > > > > > > had
> > > > > > > > > > a Map really this would
> be
> > Map.Entry
> > > > interface,
> > > > > this
> > > > > > is the
> > > > > > > same
> > > > > > > > reasons
> > > > > > > > > on
> > > > > > > > > > the map interface I
> cannot
> > actually
> > > make
> > > > the
> > > > > > underlying Node
> > > > > > > object
> > > > > > > > > that’s
> > > > > > > > > > the implementation for
> > HashMap, so
> > > that
> > > > > internals can
> > > > > > be
> > > > > > > changed.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On point 3,
> > > > > > > > > >
> > > > > > > > > > I think it people do
> > expect it to be
> > > > performant,
> > > > > thus
> > > > > > why
> > > > > > > originally
> > > > > > > > > > concern I raised with
> > using an array
> > > for
> > > > to me
> > > > > is an
> > > > > > early
> > > > > > > memory
> > > > > > > > > > optimisation. I think the
> > user
> > > experience
> > > > of
> > > > > > > properties/headers is on a
> > > > > > > > > > get/set model. This is
> why
> > its
> > > important
> > > > we have
> > > > > > > encapsulated logic
> > > > > > > > that
> > > > > > > > > > then allows us to change
> > this to a
> > > map, if
> > > > this
> > > > > > becomes and
> > > > > > > issue, and
> > > > > > > > > the
> > > > > > > > > > memory overhead of
> hashmap
> > is less
> > > so.
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > On 22/02/2017, 15:56, "
> > > [email protected]
> > > > on
> > > > > behalf of
> > > > > > > Ismael Juma" <
> > > > > > > > > > [email protected] on
> > behalf of
> > > > [email protected]
> > > > > >
> > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > Hi all,
> > > > > > > > > >
> > > > > > > > > > Great to see the
> > progress that
> > > has been
> > > > > achieved
> > > > > > on this
> > > > > > > one. :) A
> > > > > > > > > few
> > > > > > > > > > comments regarding
> the
> > APIs (I'm
> > > still
> > > > > reviewing
> > > > > > the
> > > > > > > message format
> > > > > > > > > > changes):
> > > > > > > > > >
> > > > > > > > > > 1. Nit: `getHeaders`
> in
> > > > `ProducerRecord` and
> > > > > > > `ConsumerRecord`
> > > > > > > > should
> > > > > > > > > be
> > > > > > > > > > named `headers` (we
> > avoid the
> > > `get`
> > > > prefix in
> > > > > > Kafka)
> > > > > > > > > >
> > > > > > > > > > 2. The `Headers`
> class
> > is mutable
> > > > (there's
> > > > > an `add`
> > > > > > > method). Does
> > > > > > > > it
> > > > > > > > > > need
> > > > > > > > > > to be? If so, it
> would
> > be good to
> > > > explain
> > > > > why.
> > > > > > Related
> > > > > > > to that, we
> > > > > > > > > > should
> > > > > > > > > > also explain the
> > thinking around
> > > > > thread-safety. If
> > > > > > we
> > > > > > > keep the
> > > > > > > > `add`
> > > > > > > > > > method, it may make
> > sense for it
> > > to
> > > > take a
> > > > > `Header`
> > > > > > > (that way we
> > > > > > > > can
> > > > > > > > > > add
> > > > > > > > > > things to `Header`
> > without
> > > changing the
> > > > > interface).
> > > > > > > > > >
> > > > > > > > > > 3. Do we need the
> > `Headers.get()`
> > > > method?
> > > > > People
> > > > > > usually
> > > > > > > assume
> > > > > > > > that
> > > > > > > > > > `get`
> > > > > > > > > > would be efficient,
> but
> > > depending on
> > > > the
> > > > > > implementation
> > > > > > > (the
> > > > > > > > current
> > > > > > > > > > proposal states that
> > an array
> > > would be
> > > > > used), it
> > > > > > may not
> > > > > > > be. If we
> > > > > > > > > > expect
> > > > > > > > > > the number of headers
> > to be
> > > small, it
> > > > doesn't
> > > > > > matter
> > > > > > > though.
> > > > > > > > > >
> > > > > > > > > > Ismael
> > > > > > > > > >
> > > > > > > > > > On Tue, Feb 21, 2017
> > at 6:38 PM,
> > > > Michael
> > > > > Pearce <
> > > > > > > > > [email protected]
> > > > > > > > > > >
> > > > > > > > > > wrote:
> > > > > > > > > >
> > > > > > > > > > > Hi Jason,
> > > > > > > > > > >
> > > > > > > > > > > Have converted the
> > > interface/api
> > > > bullets
> > > > > into
> > > > > > > interface code
> > > > > > > > > > snippets.
> > > > > > > > > > >
> > > > > > > > > > > Agreed
> > implementation won’t
> > > take too
> > > > long.
> > > > > We
> > > > > > have
> > > > > > > early versions
> > > > > > > > > > already.
> > > > > > > > > > > Maybe a week before
> > you think
> > > about
> > > > > merging I
> > > > > > would
> > > > > > > assume it
> > > > > > > > would
> > > > > > > > > > be more
> > > > > > > > > > > stabilised? I was
> > thinking
> > > then we
> > > > could
> > > > > fork
> > > > > > from
> > > > > > > your confluent
> > > > > > > > > > branch,
> > > > > > > > > > > making and then
> > holding KIP-82
> > > > changes in
> > > > > a patch
> > > > > > > file, that we
> > > > > > > > can
> > > > > > > > > > then
> > > > > > > > > > > re-fork from apache
> > once KIP98
> > > final
> > > > is
> > > > > merged,
> > > > > > and
> > > > > > > apply patch
> > > > > > > > > with
> > > > > > > > > > last
> > > > > > > > > > > minute changes.
> > > > > > > > > > >
> > > > > > > > > > > Cheers
> > > > > > > > > > > Mike
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > On 22/02/2017,
> > 00:56, "Jason
> > > > Gustafson" <
> > > > > > > [email protected]>
> > > > > > > > > wrote:
> > > > > > > > > > >
> > > > > > > > > > > Hey Michael,
> > > > > > > > > > >
> > > > > > > > > > > Awesome. I have
> > a minor
> > > request.
> > > > The
> > > > > APIs are
> > > > > > > currently
> > > > > > > > > > documented as a
> > > > > > > > > > > wiki list.
> Would
> > you mind
> > > adding
> > > > a code
> > > > > > snippet
> > > > > > > instead?
> > > > > > > > It's a
> > > > > > > > > > bit
> > > > > > > > > > > easier
> > > > > > > > > > > to process.
> > > > > > > > > > >
> > > > > > > > > > > How will be
> best
> > to manage
> > > this,
> > > > as we
> > > > > will
> > > > > > > obviously build
> > > > > > > > off
> > > > > > > > > > your
> > > > > > > > > > > KIP’s
> > > > > > > > > > > > protocol
> > changes, to
> > > avoid a
> > > > merge
> > > > > hell,
> > > > > > should
> > > > > > > we branch
> > > > > > > > > from
> > > > > > > > > > your
> > > > > > > > > > > branch
> > > > > > > > > > > > in the
> > confluent repo or
> > > is it
> > > > worth
> > > > > > having a
> > > > > > > KIP-98
> > > > > > > > special
> > > > > > > > > > branch
> > > > > > > > > > > in the
> > > > > > > > > > > > apache git,
> > that we can
> > > > branch/fork
> > > > > from?
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > I was thinking
> > about this
> > > also.
> > > > > Ideally we'd
> > > > > > like
> > > > > > > to get the
> > > > > > > > > > changes
> > > > > > > > > > > in as
> > > > > > > > > > > close together
> > as possible
> > > since
> > > > we
> > > > > only
> > > > > > want one
> > > > > > > magic bump
> > > > > > > > > and
> > > > > > > > > > some
> > > > > > > > > > > users
> > > > > > > > > > > deploy trunk.
> > The level of
> > > > effort to
> > > > > change
> > > > > > the
> > > > > > > format for
> > > > > > > > > > headers
> > > > > > > > > > > seems
> > > > > > > > > > > not too high.
> Do
> > you
> > > agree? My
> > > > guess
> > > > > is that
> > > > > > the
> > > > > > > KIP-98
> > > > > > > > message
> > > > > > > > > > format
> > > > > > > > > > > patch will take
> > 2-3 weeks
> > > to
> > > > review
> > > > > before we
> > > > > > > merge to trunk,
> > > > > > > > > so
> > > > > > > > > > you
> > > > > > > > > > > could
> > > > > > > > > > > hold off
> > implementing
> > > until that
> > > > patch
> > > > > has
> > > > > > somewhat
> > > > > > > > stabilized.
> > > > > > > > > > That
> > > > > > > > > > > would
> > > > > > > > > > > save some
> > potential rebase
> > > pain.
> > > > > > > > > > >
> > > > > > > > > > > -Jason
> > > > > > > > > > >
> > > > > > > > > > >
> > > > > > > > > > > The information
> > contained in
> > > this
> > > > email is
> > > > > > strictly
> > > > > > > confidential
> > > > > > > > > and
> > > > > > > > > > for
> > > > > > > > > > > the use of the
> > addressee only,
> > > unless
> > > > > otherwise
> > > > > > > indicated. If you
> > > > > > > > > > are not
> > > > > > > > > > > the intended
> > recipient, please
> > > do
> > > > not read,
> > > > > > copy, use
> > > > > > > or disclose
> > > > > > > > > to
> > > > > > > > > > others
> > > > > > > > > > > this message or any
> > attachment.
> > > > Please also
> > > > > > notify the
> > > > > > > sender by
> > > > > > > > > > replying
> > > > > > > > > > > to this email or by
> > telephone
> > > > (+44(020
> > > > > 7896 0011)
> > > > > > and
> > > > > > > then delete
> > > > > > > > > the
> > > > > > > > > > > email and any
> copies
> > of it.
> > > Opinions,
> > > > > conclusion
> > > > > > (etc)
> > > > > > > that do
> > > > > > > > not
> > > > > > > > > > relate
> > > > > > > > > > > to the official
> > business of
> > > this
> > > > company
> > > > > shall be
> > > > > > > understood as
> > > > > > > > > > neither
> > > > > > > > > > > given nor endorsed
> > by it. IG
> > > is a
> > > > trading
> > > > > name
> > > > > > of IG
> > > > > > > Markets
> > > > > > > > > Limited
> > > > > > > > > > (a
> > > > > > > > > > > company registered
> > in England
> > > and
> > > > Wales,
> > > > > company
> > > > > > > number 04008957)
> > > > > > > > > > and IG
> > > > > > > > > > > Index Limited (a
> > company
> > > registered
> > > > in
> > > > > England
> > > > > > and
> > > > > > > Wales, company
> > > > > > > > > > number
> > > > > > > > > > > 01190902).
> > Registered address
> > > at
> > > > Cannon
> > > > > Bridge
> > > > > > House,
> > > > > > > 25 Dowgate
> > > > > > > > > > Hill,
> > > > > > > > > > > London EC4R 2YA.
> > Both IG
> > > Markets
> > > > Limited
> > > > > > (register
> > > > > > > number 195355)
> > > > > > > > > > and IG
> > > > > > > > > > > Index Limited
> > (register number
> > > > 114059) are
> > > > > > authorised
> > > > > > > and
> > > > > > > > regulated
> > > > > > > > > > by the
> > > > > > > > > > > Financial Conduct
> > Authority.
> > > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > >
> > > > > > > > > > The information contained
> > in this
> > > email is
> > > > > strictly
> > > > > > > confidential and
> > > > > > > > for
> > > > > > > > > > the use of the addressee
> > only, unless
> > > > otherwise
> > > > > > indicated.
> > > > > > > If you are
> > > > > > > > not
> > > > > > > > > > the intended recipient,
> > please do
> > > not read,
> > > > > copy, use
> > > > > > or
> > > > > > > disclose to
> > > > > > > > > others
> > > > > > > > > > this message or any
> > attachment.
> > > Please also
> > > > > notify the
> > > > > > > sender by
> > > > > > > > replying
> > > > > > > > > > to this email or by
> > telephone
> > > (+44(020 7896
> > > > > 0011) and
> > > > > > then
> > > > > > > delete the
> > > > > > > > > email
> > > > > > > > > > and any copies of it.
> > Opinions,
> > > conclusion
> > > > (etc)
> > > > > that
> > > > > > do not
> > > > > > > relate to
> > > > > > > > > the
> > > > > > > > > > official business of this
> > company
> > > shall be
> > > > > understood
> > > > > > as
> > > > > > > neither given
> > > > > > > > > nor
> > > > > > > > > > endorsed by it. IG is a
> > trading name
> > > of IG
> > > > > Markets
> > > > > > Limited
> > > > > > > (a company
> > > > > > > > > > registered in England and
> > Wales,
> > > company
> > > > number
> > > > > > 04008957)
> > > > > > > and IG Index
> > > > > > > > > > Limited (a company
> > registered in
> > > England
> > > > and
> > > > > Wales,
> > > > > > company
> > > > > > > number
> > > > > > > > > > 01190902). Registered
> > address at
> > > Cannon
> > > > Bridge
> > > > > House,
> > > > > > 25
> > > > > > > Dowgate Hill,
> > > > > > > > > > London EC4R 2YA. Both IG
> > Markets
> > > Limited
> > > > > (register
> > > > > > number
> > > > > > > 195355) and
> > > > > > > > IG
> > > > > > > > > > Index Limited (register
> > number
> > > 114059) are
> > > > > authorised
> > > > > > and
> > > > > > > regulated by
> > > > > > > > > the
> > > > > > > > > > Financial Conduct
> > Authority.
> > > > > > > > > >
> > > > > > > > > The information contained
> in
> > this
> > > email is
> > > > strictly
> > > > > > > confidential and for
> > > > > > > > > the use of the addressee
> > only, unless
> > > > otherwise
> > > > > > indicated. If
> > > > > > > you are not
> > > > > > > > > the intended recipient,
> > please do not
> > > read,
> > > > copy,
> > > > > use or
> > > > > > > disclose to
> > > > > > > > others
> > > > > > > > > this message or any
> > attachment. Please
> > > also
> > > > notify
> > > > > the
> > > > > > sender
> > > > > > > by replying
> > > > > > > > > to this email or by
> > telephone (+44(020
> > > 7896
> > > > 0011)
> > > > > and
> > > > > > then
> > > > > > > delete the
> > > > > > > > email
> > > > > > > > > and any copies of it.
> > Opinions,
> > > conclusion
> > > > (etc)
> > > > > that do
> > > > > > not
> > > > > > > relate to
> > > > > > > > the
> > > > > > > > > official business of this
> > company
> > > shall be
> > > > > understood as
> > > > > > > neither given
> > > > > > > > nor
> > > > > > > > > endorsed by it. IG is a
> > trading name
> > > of IG
> > > > Markets
> > > > > > Limited (a
> > > > > > > company
> > > > > > > > > registered in England and
> > Wales,
> > > company
> > > > number
> > > > > > 04008957) and
> > > > > > > IG Index
> > > > > > > > > Limited (a company
> > registered in
> > > England and
> > > > Wales,
> > > > > > company
> > > > > > > number
> > > > > > > > > 01190902). Registered
> > address at Cannon
> > > > Bridge
> > > > > House, 25
> > > > > > > Dowgate Hill,
> > > > > > > > > London EC4R 2YA. Both IG
> > Markets
> > > Limited
> > > > (register
> > > > > number
> > > > > > > 195355) and IG
> > > > > > > > > Index Limited (register
> > number 114059)
> > > are
> > > > > authorised and
> > > > > > > regulated by
> > > > > > > > the
> > > > > > > > > Financial Conduct
> Authority.
> > > > > > > > >
> > > > > > > > The information contained in
> > this email
> > > is
> > > > strictly
> > > > > > confidential
> > > > > > > and for
> > > > > > > > the use of the addressee
> only,
> > unless
> > > otherwise
> > > > > indicated.
> > > > > > If
> > > > > > > you are not
> > > > > > > > the intended recipient,
> please
> > do not
> > > read,
> > > > copy,
> > > > > use or
> > > > > > > disclose to others
> > > > > > > > this message or any
> > attachment. Please
> > > also
> > > > notify
> > > > > the
> > > > > > sender by
> > > > > > > replying
> > > > > > > > to this email or by telephone
> > (+44(020
> > > 7896
> > > > 0011)
> > > > > and then
> > > > > > > delete the email
> > > > > > > > and any copies of it.
> Opinions,
> > > conclusion
> > > > (etc)
> > > > > that do
> > > > > > not
> > > > > > > relate to the
> > > > > > > > official business of this
> > company shall
> > > be
> > > > > understood as
> > > > > > neither
> > > > > > > given nor
> > > > > > > > endorsed by it. IG is a
> > trading name of
> > > IG
> > > > Markets
> > > > > Limited
> > > > > > (a
> > > > > > > company
> > > > > > > > registered in England and
> > Wales, company
> > > number
> > > > > 04008957)
> > > > > > and IG
> > > > > > > Index
> > > > > > > > Limited (a company registered
> > in England
> > > and
> > > > Wales,
> > > > > company
> > > > > > > number
> > > > > > > > 01190902). Registered address
> > at Cannon
> > > Bridge
> > > > > House, 25
> > > > > > Dowgate
> > > > > > > Hill,
> > > > > > > > London EC4R 2YA. Both IG
> > Markets Limited
> > > > (register
> > > > > number
> > > > > > > 195355) and IG
> > > > > > > > Index Limited (register
> number
> > 114059)
> > > are
> > > > > authorised and
> > > > > > > regulated by the
> > > > > > > > Financial Conduct Authority.
> > > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > >
> > > > > > > The information contained in this email
> > is strictly
> > > > > confidential and
> > > > > > for
> > > > > > > the use of the addressee only, unless
> > otherwise
> > > > indicated. If
> > > > > you
> > > > > > are not
> > > > > > > the intended recipient, please do not
> > read, copy,
> > > use or
> > > > > disclose to
> > > > > > others
> > > > > > > this message or any attachment. Please
> > also notify
> > > the
> > > > sender
> > > > > by
> > > > > > replying
> > > > > > > to this email or by telephone (+44(020
> > 7896 0011)
> > > and
> > > > then
> > > > > delete
> > > > > > the email
> > > > > > > and any copies of it. Opinions,
> > conclusion (etc)
> > > that do
> > > > not
> > > > > relate
> > > > > > to the
> > > > > > > official business of this company shall
> > be
> > > understood as
> > > > > neither
> > > > > > given nor
> > > > > > > endorsed by it. IG is a trading name of
> > IG Markets
> > > > Limited (a
> > > > > company
> > > > > > > registered in England and Wales,
> company
> > number
> > > > 04008957) and
> > > > > IG
> > > > > > Index
> > > > > > > Limited (a company registered in
> England
> > and Wales,
> > > > company
> > > > > number
> > > > > > > 01190902). Registered address at Cannon
> > Bridge
> > > House, 25
> > > > > Dowgate
> > > > > > Hill,
> > > > > > > London EC4R 2YA. Both IG Markets
> Limited
> > (register
> > > number
> > > > > 195355)
> > > > > > and IG
> > > > > > > Index Limited (register number 114059)
> > are
> > > authorised and
> > > > > regulated
> > > > > > by the
> > > > > > > Financial Conduct Authority.
> > > > > > >
> > > > > >
> > > > > >
> > > > > > The information contained in this email is
> > strictly
> > > > confidential and
> > > > > for
> > > > > > the use of the addressee only, unless
> otherwise
> > > indicated. If
> > > > you
> > > > > are not
> > > > > > the intended recipient, please do not read,
> > copy, use or
> > > > disclose to
> > > > > others
> > > > > > this message or any attachment. Please also
> > notify the
> > > sender
> > > > by
> > > > > replying
> > > > > > to this email or by telephone (+44(020 7896
> > 0011) and
> > > then
> > > > delete
> > > > > the email
> > > > > > and any copies of it. Opinions, conclusion
> > (etc) that do
> > > not
> > > > relate
> > > > > to the
> > > > > > official business of this company shall be
> > understood as
> > > > neither
> > > > > given nor
> > > > > > endorsed by it. IG is a trading name of IG
> > Markets
> > > Limited (a
> > > > company
> > > > > > registered in England and Wales, company
> number
> > > 04008957) and
> > > > IG
> > > > > Index
> > > > > > Limited (a company registered in England and
> > Wales,
> > > company
> > > > number
> > > > > > 01190902). Registered address at Cannon
> Bridge
> > House, 25
> > > > Dowgate
> > > > > Hill,
> > > > > > London EC4R 2YA. Both IG Markets Limited
> > (register number
> > > > 195355)
> > > > > and IG
> > > > > > Index Limited (register number 114059) are
> > authorised and
> > > > regulated
> > > > > by the
> > > > > > Financial Conduct Authority.
> > > > > >
> > > > >
> > > > >
> > > > > The information contained in this email is strictly
> > > confidential and
> > > > for
> > > > > the use of the addressee only, unless otherwise
> > indicated. If
> > > you
> > > > are not
> > > > > the intended recipient, please do not read, copy,
> > use or
> > > disclose to
> > > > others
> > > > > this message or any attachment. Please also notify
> > the sender
> > > by
> > > > replying
> > > > > to this email or by telephone (+44(020 7896 0011)
> > and then
> > > delete
> > > > the email
> > > > > and any copies of it. Opinions, conclusion (etc)
> > that do not
> > > relate
> > > > to the
> > > > > official business of this company shall be
> > understood as
> > > neither
> > > > given nor
> > > > > endorsed by it. IG is a trading name of IG Markets
> > Limited (a
> > > company
> > > > > registered in England and Wales, company number
> > 04008957) and
> > > IG
> > > > Index
> > > > > Limited (a company registered in England and Wales,
> > company
> > > number
> > > > > 01190902). Registered address at Cannon Bridge
> > House, 25
> > > Dowgate
> > > > Hill,
> > > > > London EC4R 2YA. Both IG Markets Limited (register
> > number
> > > 195355)
> > > > and IG
> > > > > Index Limited (register number 114059) are
> > authorised and
> > > regulated
> > > > by the
> > > > > Financial Conduct Authority.
> > > > >
> > > > The information contained in this email is strictly
> > confidential
> > > and
> > > > for the use of the addressee only, unless otherwise
> > indicated. If
> > > you are
> > > > not the intended recipient, please do not read, copy, use
> > or
> > > disclose to
> > > > others this message or any attachment. Please also notify
> > the sender
> > > by
> > > > replying to this email or by telephone (+44(020 7896
> 0011)
> > and then
> > > delete
> > > > the email and any copies of it. Opinions, conclusion
> (etc)
> > that do
> > > not
> > > > relate to the official business of this company shall be
> > understood
> > > as
> > > > neither given nor endorsed by it. IG is a trading name of
> > IG Markets
> > > > Limited (a company registered in England and Wales,
> > company number
> > > > 04008957) and IG Index Limited (a company registered in
> > England and
> > > Wales,
> > > > company number 01190902). Registered address at Cannon
> > Bridge House,
> > > 25
> > > > Dowgate Hill, London EC4R 2YA. Both IG Markets Limited
> > (register
> > > number
> > > > 195355) and IG Index Limited (register number 114059) are
> > authorised
> > > and
> > > > regulated by the Financial Conduct Authority.
> > > >
> > > >
> > > >
> > > >
> > >
> > >
> > > The information contained in this email is strictly
> confidential
> > and for
> > > the use of the addressee only, unless otherwise indicated. If
> > you are not
> > > the intended recipient, please do not read, copy, use or
> > disclose to others
> > > this message or any attachment. Please also notify the sender
> by
> > replying
> > > to this email or by telephone (+44(020 7896 0011) and then
> > delete the email
> > > and any copies of it. Opinions, conclusion (etc) that do not
> > relate to the
> > > official business of this company shall be understood as
> neither
> > given nor
> > > endorsed by it. IG is a trading name of IG Markets Limited (a
> > company
> > > registered in England and Wales, company number 04008957) and
> IG
> > Index
> > > Limited (a company registered in England and Wales, company
> > number
> > > 01190902). Registered address at Cannon Bridge House, 25
> Dowgate
> > Hill,
> > > London EC4R 2YA. Both IG Markets Limited (register number
> > 195355) and IG
> > > Index Limited (register number 114059) are authorised and
> > regulated by the
> > > Financial Conduct Authority.
> > >
> >
> >
> > The information contained in this email is strictly confidential and
> > for the use of the addressee only, unless otherwise indicated. If you are
> > not the intended recipient, please do not read, copy, use or disclose to
> > others this message or any attachment. Please also notify the sender by
> > replying to this email or by telephone (+44(020 7896 0011) and then
> delete
> > the email and any copies of it. Opinions, conclusion (etc) that do not
> > relate to the official business of this company shall be understood as
> > neither given nor endorsed by it. IG is a trading name of IG Markets
> > Limited (a company registered in England and Wales, company number
> > 04008957) and IG Index Limited (a company registered in England and
> Wales,
> > company number 01190902). Registered address at Cannon Bridge House, 25
> > Dowgate Hill, London EC4R 2YA. Both IG Markets Limited (register number
> > 195355) and IG Index Limited (register number 114059) are authorised and
> > regulated by the Financial Conduct Authority.
> >
> >
> >
> The information contained in this email is strictly confidential and for
> the use of the addressee only, unless otherwise indicated. If you are not
> the intended recipient, please do not read, copy, use or disclose to others
> this message or any attachment. Please also notify the sender by replying
> to this email or by telephone (+44(020 7896 0011) and then delete the email
> and any copies of it. Opinions, conclusion (etc) that do not relate to the
> official business of this company shall be understood as neither given nor
> endorsed by it. IG is a trading name of IG Markets Limited (a company
> registered in England and Wales, company number 04008957) and IG Index
> Limited (a company registered in England and Wales, company number
> 01190902). Registered address at Cannon Bridge House, 25 Dowgate Hill,
> London EC4R 2YA. Both IG Markets Limited (register number 195355) and IG
> Index Limited (register number 114059) are authorised and regulated by the
> Financial Conduct Authority.
>
