If you want single spout to emit different fields, you can do so by
giving a stream.
By default all the fields are in default stream.
So you emit a different steam like business parameters stream and let
bolt1 and 2 subscribe to this stream.
collector.emit("business_parameters", "param1", new value(...))
The default stream will work as it is now.
On 12/22/14, 余昊 <[email protected]> wrote:
> Hi,
>
> Considering a simple topology:
> spoutD -> boltA -> boltB
> where spoutD receives business data, and forwards to boltA for processing,
> the results are then sent to boltB for further processing.
>
> In our scenario, it is required that the parameters (or configuration) of
> processing logics in boltA or boltB can be modified at runtime.
>
> Our solution A is to send new paramter values directly to the specific
> bolt.
> But we think this is not practical, since in storm it seems data input (no
> matter what kind of data) should be done
> in spout, and bolt gets input either from the upstream bolt or from spout -
> is that right?
>
> So we thought about solution B, which is adding a spoutC which is
> specifically for receiving configuration data.
> Then the topology turns to:
> spoutD -> boltA -> boltB
> | |
> spoutC
> where spoutC can dispatch the new processing parameter values to the boltA
> or boltB.
> Well, the cost is that as you can see the topology gets more complicating.
> That's why we do not like solution B.
>
> If solution A can work in a practical way, we prefer it to solution B. But
> is it possible? Or do you have any better suggestions?
>
>
>
> Best regards,
>
> Hao Yu
>
