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
