#Error Handling

Introduction

If you're solving complex problems in ObjectScript, you probably have a lot of code that works with %Status values. If you have interacted with persistent classes from an object perspective (%Save, %OpenId, etc.), you have almost certainly seen them. A %Status provides a wrapper around a localizable error message in InterSystems' platforms. An OK status ($$$OK) is just equal to 1, whereas a bad status ($$$ERROR(errorcode,arguments...)) is represented as a 0 followed by a space followed by a $ListBuild list with structured information about the error. $System.Status (see class reference) provides several handy APIs for working with %Status values; the class reference is helpful and I won't bother duplicating it here. There have been a few other useful articles/questions on the topic as well (see links at the end). My focus in this article will be on a few debugging tricks techniques rather than coding best practices (again, if you're looking for those, see links at the end).

A beginner’s guide to Exception Handling in RESTful web services. The article gives an example how the various error conditions during processing a service request can be handled.

We expect our client – server communication working in a flawless operational condition, running error free software. But we are prepared to handle exceptions. Are we? So far in the examples of the previous sessions were not. We did not care about exceptions. The result? In any error incident it took ages to figure out what the problem is and more importantly how to fix it.

Error management on InterSystems languages has been evolving along time. Next, we will show the different implementations and why you should use the TRY/THROW/CATCH mechanism.

You can read official error recommendations here.

Work Queue Manager (WQM) is a feature of InterSystems IRIS that enables you to improve performance by distributing work to multiple concurrent processes programmatically. The idea is that you split the work into chunks, and WQM distributes the chunks across worker processes and can provide the info that the work is done.

However, recently, I got an interesting question: there's a large logical transaction composed of ~1,000,000 individual objects and SQL inserts and updates. Some updates are CPU-intensive, so the original idea was to use WQM to split an update into chunks to speed things up.

But, here's a catch: if one of the individual 1,000,000 changes fails (there's a variety of application-level checks so that it can fail, and that's not even that abnormal a behavior), the entire transaction must be rolled back. That creates a problem: each chunk must report success before committing their individual transactions, and someone must get all these reports and decide if we are committing or not.

Unfortunately, it looks like WQM does not have a bidirectional communication between workers and manager, so I suggested an approach using events:

1. Start jobs.
2. Wait for all jobs to report success using $System.Event.WaitMsg().
3. Send Commit or Rollback using the $System.Event.Signal().

Hi all,

I have a rule to throw a message when there is an error. I want to prevent send the email if the origin of the error is the API to send the email

This is my rule

Now, If there is any error in any process, it works, but if there is an error in MyProduct.BO.SendEmail it is trying to send the error again, and it is a infinite loop.

Is there any way to check what is the origin and don't process if the origin is MyProduct.BO.SendEmail?

Hi InterSystems Community

We recently had an issue where we weren't able to parse a JSON HTTP request, but the issue went by unnoticed. We also did not have a trace of what the raw HTTP request was that we couldn't parse. I'm looking at improving our this by:
Tracing the raw request using $$$TRACE

Raising an alert which will hit our Ens.Alert router which will compose and send an email

Hi developers!

Want to discuss with you the case of %Status.

If you familiar with ObjectScript you know what is it. I'd love to hear the history of the case why it had appeared in ObjectScript but it turned out that almost every system/library classmethods return %Status and there is a whole set of tools to deal with it.

What is does it gives you the responsibility to check the value or %Status of every system method you call.

E.g. if you save the data of the persistent class, you should never call like this:

do obj.%Save()

you need to call:

set sc=obj.%Save()

if $$$ISERR(sc) do // something or quit.

I want to grant access to view the Error Trap in System Management Portal to certain admins, without giving them access to anything that would alter Caché behavior, such as users or database sizes. I was looking for a granular Resource that would do this, but haven't been able to find what I'm looking for.

There does not seem to be any separation between the error code and error text in a %Status object. For custom errors, I simply want to display the message and not Error #5001: Some error text.

Hi,

Hey everyone as you may know I am a beginner and I am kindly asking for some assistance in a problem I have been solving. The problem is that I am calling a user defined function within a procedure called occupiedseatsAdj and the compiler comes up with this error.

Hi Community,

I am trying to read a JSON file and convert into HL7 message.Please find the example below

Set Jsonobj={"Doctype":"ADT^A01","PatientId":"123","PatientName":"Alex"}

Set Dynjsonobj= ##class(%Library.DynamicObject).%FromJSON(Jsonobj)

Hello,

I'm experiencing a recurrent problem that I haven't found the way to solve, so I'm coming here with the hope somebody can give me a new approach.

To make it short: we are creating categories on-demand to be able to place the maximum numbers of workers in memory, avoiding the limits established by system categories. But from time to time, one of this creation fails and system is no able to start the queue. The error we are getting is: