Since this is my first contribution to one of my all-time favorite
libraries, this is pretty exciting for me. I would be glad to update the
blog post immediately. I will also add the things that we discussed with
regard to how this is a glue component, etc etc. If you need me to change
(or shorten) it, let me know and I can turn that around quickly, as well.
On Tue, Jan 11, 2022 at 2:06 PM Claus Ibsen <claus.ib...@gmail.com> wrote:
> On Tue, Jan 11, 2022 at 7:13 PM Steve973 <steve...@gmail.com> wrote:
> >
> > Thank you for the review and comments. I completely agree with you that
> it
> > is cumbersome to require users to create a java object. Your suggestion
> of
> > making the subscription URI-based is good, and I still need to figure out
> > how to provide the filter (Predicate) for evaluating exchanges for
> > participant suitability. Do you think that including a Camel bean ID in
> > the url (and a corresponding bean in the registry) for the Predicate
> would
> > be a good approach?
> >
>
> Yes we could allow both kind, eg the user can send the java object and
> have full control from java.
>
> Then in the uri, you can have a filter parameter of type predicate.
> Then in the uri you can refer to a bean with the #bean:myFilter
> syntax.
> If you think that a predicate based on the simple language makes
> sense, then we could also use that via the uri
>
> filter=${body} > 100
>
> The file component has some option that allows this, but lets fight
> one battle at a time, and just get a #bean:xxx syntax to work first.
>
>
> But before doing all of this, then I think the current PR can be merged as
> is.
>
> Can you update the blog post date to today?
>
>
>
>
> > On Tue, Jan 11, 2022 at 8:04 AM Claus Ibsen <claus.ib...@gmail.com>
> wrote:
> >
> > > On Sat, Jan 8, 2022 at 4:09 PM Steve973 <steve...@gmail.com> wrote:
> > > >
> > > > Hello. I would like to add a little more to this conversation,
> since you
> > > > mentioned my reason for contributing this code. My motivation to add
> > > this
> > > > EIP component was because a couple of years ago, I read about the
> dynamic
> > > > router EIP within Camel, and I thought that it would be perfect for
> what
> > > I
> > > > needed to do in my project at work. It looked like my clients could
> > > > register with the dynamic router processor, but further reading of
> the
> > > docs
> > > > and my own use of it revealed that this was not how it was
> implemented.
> > > I
> > > > was not able to use it for my use case, but I had to move on and
> > > implement
> > > > this behavior myself.
> > > >
> > > > Now that I had some time, I thought that I would contribute this
> idea to
> > > > Camel so that others would be able to use this particular type of
> "glue"
> > > > right out of the box that fits use cases that are like others in
> camel,
> > > but
> > > > expanded in certain areas that include, but are probably not limited
> to:
> > > >
> > > > - the content-based router (choice), but the choices are fully
> > > > subscriber-initiated and do not need to be known at compile time
> > > > - the dynamic router (processor in Camel core), and I outlined the
> > > > differences in the previous email, so no need to re-hash here
> > > > - the message filter, but instead of creating the filter at
> compile
> > > > time, consumers provide their own filter at runtime
> > > > - the selective consumer, but turned the other way around:
> instead of
> > > > sending messages to (potentially a list of) recipients, and
> letting
> > > them
> > > > all determine which messages to process or discard, this component
> > > allows a
> > > > consumer to subscribe with its filter so that the router can
> handle
> > > this
> > > > (centrally) and only send messages to the (first) appropriate
> > > subscriber.
> > > > If we need a recipient list mode, that can easily be added so
> that it
> > > sends
> > > > to all matching recipients.
> > > > - the "To Dynamic" EIP, but the sender does not need to know about
> > > > dynamic recipients, and variables do not have to be set
> > > >
> > >
> > > That is a good break-down and perspective
> > >
> > > > I hope this shows how this contribution is not only "glue", but that
> it
> > > is
> > > > useful glue that provides simplified routing for developers that
> have use
> > > > cases that overlap in the list of features above. While you could
> > > achieve
> > > > anything in software by composing a solution of several different
> pieces,
> > > > and implementing the glue that helps them to work together and, in
> this
> > > > case, also implementing the runtime registration of recipients, this
> > > > component ties these things together and makes it simple. It is not
> > > > intended to be its own messaging system, but to facilitate messaging
> to,
> > > > and from, other sources where the decision is truly runtime-based.
> > > Indeed,
> > > > you might have another messaging system that provides filtering,
> etc, but
> > > > this component introduces a new feature to provide this in a way
> that is
> > > > independent of other components/transports, and can, therefore, be
> used
> > > as
> > > > a dynamic integration point between completely different messaging
> > > systems.
> > > >
> > >
> > > Yes I can see the validation, when you accept that it's not a
> > > messaging system with client/server actors.
> > > So when you say that you can subscribe/unsubscribe then it's not on
> > > the same page as it would be with a JMS/Kafka client that subscribes
> > > to a broker system.
> > >
> > > I wonder if you could research if you can make the subscription
> > > simpler, as I think it's a little bit of a "hurdle" that Camel users
> > > would
> > > need to construct a java object to subscribe for basic subscription.
> > >
> > > You could have sub context for the action and channel, so if you just
> > > want to subscribe you can send an empty message to
> > >
> > > dynamic-router:control/subscribe/my-channel?id=123
> > >
> > > You could also allow to auto-gen uuid for the subscription id, so if
> > > id is omitted then one is returned
> > >
> > > String uid = requestBody(....)
> > >
> > > Anyway that is food for thoughts for improvements.
> > >
> > > What you have sent today as PR - lets review it. I can see its
> > > usefulness and its potential if you continue to work on it.
> > >
> > >
> > >
> > >
> > > > Thanks again,
> > > > Steve
> > > >
> > > > On Fri, Jan 7, 2022 at 6:08 AM Claus Ibsen <claus.ib...@gmail.com>
> > > wrote:
> > > >
> > > > > Hi Steve
> > > > >
> > > > > We can see from your work that you have put a lot of effort and
> > > > > devotion into this, with an example and blog post as well.
> > > > >
> > > > > However you say that the reason you wanted this was due to the
> dynamic
> > > > > pattern in the EIP book.
> > > > >
> > > > > The issue is that the EIP book is about messaging and integration
> > > > > patterns and that these patterns
> > > > > does not apply to all software projects.
> > > > >
> > > > > The dynamic pattern as in the EIP book is actuall a pattern in
> > > > > messaging systems like ActiveMQ, Kafka, RabbitMQ, and all the many
> of
> > > > > them out there.
> > > > > They all offer a way for clients to subscribe and unsubscribe to
> > > > > topics (and or queues) and very often have filtering as well so a
> > > > > client can say they the only want message that matches X criteria.
> > > > >
> > > > > In other words its a domain that is for a messaging system, and
> this
> > > > > gets quickly complex when you have distributed systems, and HA with
> > > > > failover, and now also with "the cloud", and even across multiple
> > > > > cloud vendors with hybrid cloud.
> > > > > Your implementation in Camel would be very limited in use-case as
> its
> > > > > a single context / in-memory only "queue".
> > > > >
> > > > >
> > > > > If on the other hand there was a new messaging system (called
> foobar),
> > > > > and it was a well used system, then it would be worthwhile to
> > > > > implement a camel component for such system.
> > > > > In other words Camel is the glue to systems, but its "not a
> "server"
> > > > > system itself".
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > >
> > > > > On Sat, Dec 25, 2021 at 4:44 PM Steve973 <steve...@gmail.com>
> wrote:
> > > > > >
> > > > > > Hello. I have sent a few messages here on this list about an
> > > alternate
> > > > > > Dynamic Router EIP component implementation that I have been
> working
> > > on.
> > > > > > If anyone has some time, I would like to get more community
> input and
> > > > > > opinion on what I have done so far. You can see the ticket here:
> > > > > >
> > > > > > https://issues.apache.org/jira/browse/CAMEL-17154
> > > > > >
> > > > > > It contains a link to the component module on my fork of the
> Camel
> > > repo
> > > > > (in
> > > > > > the comments), and I have included a blog post draft ODT
> attachment
> > > that
> > > > > > introduces this component, why I wanted to implement it, and
> basic
> > > > > > discussion on how to use it.
> > > > > >
> > > > > > If any of you would be kind enough to take a quick glance and
> let me
> > > know
> > > > > > what you think, I would be quite grateful.
> > > > > >
> > > > > > Happy holidays, if you are celebrating. Take care, and be well,
> > > > > regardless.
> > > > > >
> > > > > > Thanks,
> > > > > > Steve
> > > > >
> > > > >
> > > > >
> > > > > --
> > > > > Claus Ibsen
> > > > > -----------------
> > > > > http://davsclaus.com @davsclaus
> > > > > Camel in Action 2: https://www.manning.com/ibsen2
> > > > >
> > >
> > >
> > >
> > > --
> > > Claus Ibsen
> > > -----------------
> > > http://davsclaus.com @davsclaus
> > > Camel in Action 2: https://www.manning.com/ibsen2
> > >
>
>
>
> --
> Claus Ibsen
> -----------------
> http://davsclaus.com @davsclaus
> Camel in Action 2: https://www.manning.com/ibsen2
>
