Synchronous versus Fire-and-Forget Process to Process Invocation by Jan Kettenis

imageIn the following article I explain why you should implement a Structured to Structured Process call as synchronous when you need that call to be recoverable in case of an issue.

To call a Structured Process (that is initiated by a Message Start event) from another one, there are 2 ways to do so (actually there are 3 if you count in the Micro Process feature but that is a variation of one of these, I suspect the first):

  • Using the /ic/api/process/v1/processes API
  • Using the WSDL of the called process

I typically do the latter, as I find it to be simpler than using the API because importing the WSDL involves an automatic import of the XSD schema containing the request definition. Copy & paste of the WSDL URL and you’re done and when the interface changes, all I have to do is re-import the schema (in contrast, when using the API I have to manually figure out the proper JSON sample).

However, whichever way you use both concern a web service based interface, which you can configure to invoke in one of two ways:

  • As Fire-and-Forget
  • As synchronous (request/response)

Question is which one to use? The answer is simple: use synchronous in case there is no callback and you want to be sure the invocation either succeeds or can be recovered when it fails. If you don’t care, use Fire-and-Forget. Read on to find out why.
First let me point out the Fire-and-Forget Enterprise Integration Pattern. As it will tell you, in case of Fire-and-Forget error handling is not possible and you would need some Guaranteed Delivery mechanism to prevent the risk of losing messages. Mind that web service based invocation is not message based (which would involve using a Message Channel and with that typically an Invalid Message Channel to capture bad messages). So, in case of Fire-and-Forget there will be the risk of running into a non-recoverable error (hence the conclusion). OIC has no "magic feature" supporting recovery from failed invocations to Fire-and-Forget web services. And mind you, this is consistent with the pattern. Read the complete article here.

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Technorati Tags: SOA Community,Oracle SOA,Oracle BPM,OPN,Jürgen Kress

About Jürgen Kress
As a middleware expert Jürgen works at Oracle EMEA Alliances and Channels, responsible for Oracle’s EMEA Fusion Middleware partner business. He is the founder of the Oracle SOA & BPM and the WebLogic Partner Communities and the global Oracle Partner Advisory Councils. With more than 5000 members from all over the world the Middleware Partner Community is the most successful and active community at Oracle. Jürgen manages the community with monthly newsletters, webcasts and conferences. He hosts his annual Fusion Middleware Partner Community Forums and the Fusion Middleware Summer Camps, where more than 200 partners get product updates, roadmap insights and hands-on trainings. Supplemented by many web 2.0 tools like twitter, discussion forums, online communities, blogs and wikis. For the SOA & Cloud Symposium by Thomas Erl, Jürgen is a member of the steering board. He is also a frequent speaker at conferences like the SOA & BPM Integration Days, JAX, UKOUG, OUGN, or OOP.

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