Onion Networks AntFlow™: Hotfolder Driven Workflow and Automation is interesting but
as Steve: Developing on the Edge: AntFlow: Workflow in Ant questions, is Ant the right basis for this type of tool?
Personally I would much rather look towards using queues as the basis for a workflow. That could use the Amazon.com Simple Queue Service following the Starbuck model (see Starbucks Does Not Use Two-Phase Commit - Enterprise Integration Patterns). So when you drop files into a directory a simple process adds them to a queue. By simply connecting queues with processes you can move items through a pipeline, that pipeline can then scale to as many servers as you want and can be distributed how you like.
However, I would like to see a more REST like interface on top of Amazons API. For example. Instead of
http:/webservices.amazon.com/onca/xml?Service=AWSSimpleQueueService &SubscriptionId=[Your Subscription ID Here]
&Operation=CreateQueue
&QueueName=[The Queue Name]
I would rather see an HTTP POST to
http:/webservices.amazon.com/[myid]/createqueue
with the queue name as a parameter.
Instead of
http://webservices.amazon.com/onca/xml?Service=AWSSimpleQueueService
&SubscriptionId=[Your Subscription ID Here]
&Operation=ListMyQueues
&QueueNamePrefix=[The Queue Name Prefix]
I would rather see an HTTP GET to
http:/webservices.amazon.com/QueueService/[myid]/listqueues
To get the items in a queue an HTTP GET to
http:/webservices.amazon.com/QueueService/[myid]/[queuename]/read
To add an item to a queue an HTTP POST
http:/webservices.amazon.com/QueueService/[myid]/[queuename]/enqueue with the XML body as a parameter.
etc.
I think a nice library ought to be able to hide the details anyway and hopefully allow an appplication to move seamlessly between multiple different queue services.
Thus antflow should be replaced with very simple work flow components that process queues. I suspect that this will prove another placxe where scripting languages rule ok.
Thanks to Link: Sean McGrath, CTO, Propylon Something to read over coffee. and Cafe au Lait Java News and Resources for the links.
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