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· Nov 6, 2018

ENSEMBLE: What Adapter do I use for simply running a global check in Ensemble

#Ensemble

Hi, I want to create a service which on start will simply go through a list of values in a global and compare dates. If criteria is met, it will send an email.

But what kind of Adapter do I use? I see SQL, FILE, HTTP etc..etc.. But I dont want to use them

Please can you advice on how I should go about this?

Should I create a BS. Class and do onAdapterTASK() and simply build a method? Even then it is asking the kind of adapter I want

Would appreciate some guidance on this

Regards,

Eric

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Chris Thompson · Nov 6, 2018

Steve,

Thank you for clearing up some things I left out. I actually learned a little which I greatly appreciate! I would like to take this time to somewhat hijack the thread (sorry) but when it comes to using the Ensemble scheduler don't you need to consider how often you are scheduling a task? The quicker you need it to occur doesn't CallInterval become more beneficial? We have quite a few Ensemble services that need to kick off (~30 seconds) and we have had this debate for some time when we need to invoke the Ensemble scheduler. 

Thanks!

- Chris

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Chris Thompson · Nov 6, 2018

You would override the OnInit method in your business service, it's what is called when a business host starts up when a production comes up (assuming it was enabled when the production went down)

You can even set a call interval so that it does that X amount of seconds / minutes / hours. 

Also, Ens.Director is not a business host class that you can use, it's a class that allows you to control various features of a production as well as monitor its state.

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Steve Pisani · Nov 6, 2018

Hi Chris,

I agree - note the Schedular basically STARTS or STOPS a business host automatically, on a pre-defined schedule -  (so it applies to Operations and Processes too, not just Services, which are the items that have a CallInterval feature).

For regular invocations of work on services,  in almost all cases,  absolutely - CallInterval is the way to go, and is what is used mostly. I certainly would prefer looking at the production and status of my business hosts and see all of them 'green' and running - even though, running might actually means 'idle in between call intervals' .  Using the Schedular the stopped business host will appear 'gray' when it is not started (ie, it is disabled) 

There are valid use cases -  though, a Schedule on, say, a Business Operation makes sense. For example, you may want to send out messages to business operation that interacts with a fee-per-transaction end point that is cheaper during certain times of the day. In this case, you can disable the operation, send queue it messages all day (which will accumulate in it's queue), then, at the appropriate time, enable the business operation via the schedular, then, disable it again after a period of choice.

In this thread's case, the easiest approach is to use OnInit to prepare the data and send the data. OnProcessInput (called by the interval, which can be very long), would do nothing but quit. That would work. Of course there are other approaches.

I wanted to include the Schedular information as it is often overlooked, and, sometimes, the full story and use case of the original poster might not be evident, and, schedular might have been appropriate. 

Thanks for your feedback.

Steve

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Steve Pisani · Nov 6, 2018

Hi Eric

If you want your service t0 be part of the framework, but not actually use any specific connection functionality typically offered by adapters (SQL, FILE, ..etc)  Just ensure that the adapter is first set to  'Ens.InboundAdapter':

Parameter ADAPTER ="Ens.InboundAdapter" ;

And - set your PoolSize is set to 1, so a job is started. with the production.  Note that for every cycle of the Call Interval setting, the OnProcessInput method will be called.

If you want to regularly do your work (ie:  "go through a list of values in a global and compare dates. If criteria is met, it will send an email."),  then, do this in the OnProcessInput method at your desired CallInterval.

However - As you said "on start..." I'm assuming you meant, on start of the production as a whole -   In this case, leave the OnProcessInput method empty with just a 

Quit $$$OK

statement, and, (as others mentioned here), put the logic in the OnInit() method of your service, which will be invoked on production startup or enabling/disabling of the service.

Note that without the Adapter parameter setting above, and the pool size set to 1 - neither OnInit, nor OnProcessInput are called.

Now - Productions are meant to keep on running. You may eventually move away from putting this logic in the OnInit code or somewhere which requires a Production re-start in order to execute, as this effects other running business hosts ....  To explore other options further you can

(a) Work with the CallInterval which calls OnProcessInput after n seconds, and build in logic that determines if a particular cycle should just do nothing, or (say, on the change of the day, or other controlling factors, like, the size of your global entries) - would go ahead and do the emails.  Note that you can set Properties for your business service, to record state - which you can initialise  a value for in the OnInit, and update regularly during the running state of the service if you need to.

(b) Look at the Schedular feature.  The Schedular feature controls the running state of a business host. With the schedular you can elect to Enable/Disable any service on a pre-defined schedule. So - You can enable  your service, (with OnInit code to check globals and send emails), at an interval of choice without needing to stop/start the production. click : here for documentation.

Sincerely -

Steve

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