The document summarizes error handling techniques in MuleSoft. There are two types of errors: system errors and messaging errors. Error objects are created for messaging errors. Components like try scope, error handlers, and custom error handling allow controlling error behavior. Batch processing and scatter-gather patterns require special error handling considerations. Dataweave provides functions like fail(), failIf(), try(), orElse(), and orElseTry() for error handling. The meetup covered various error handling cases and techniques through examples and questions.

1. Error Handling With MuleSoft
Surat MuleSoft Meetup Group
Sept 2, 2022

2. Safe Harbour Statement
● Both the speaker and the host are organizing this meet-up in individual capacity only. We are
not representing our companies here.
● This presentation is strictly for learning purposes only. Organizer/Presenter do not hold any
responsibility that same solution will work for your business requirements.
● This presentation is not meant for any promotional activities.
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Housekeeping
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4. Organizers
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Jitendra Bafna
Senior Solution Architect
EPAM Systems
Nitish Jain
Application Developer
Accenture

5. Speaker
Nikhil Kunkulol
Lead Engineer, Apisero Inc.
About the Speaker:
● Working as Senior Lead Engineer at Apisero Inc.
● 4+ year of Total Experience. 3+ years in MuleSoft.
● Certified MuleSoft Developer and Integration Architect.
● Kolhapur Meetup Leader

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Contents:
●Error Types
●Error Components
●Try-Catch Scope
●Error Handling in Private Flow vs Sub flow
●Raise Custom Errors
●Error Handling in Parallel- For-Each/For-Each
●Error Handling in Batch-Processing, Scatter Gather
●Error Handling in Dataweave
Error Handling

7. There are 2 types of Errors:
● System errors
● Messaging errors
* Error Object is created when a Messaging Error occurs. In order to do this, we have to
understand what an Error Object in Mule 4 is.
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8. Selector Expressions for Mule Errors
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9. Error Hierarchy
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10. Components
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11. On Error-Continue vs Propagate
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12. Configuring Global-Error Handler
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13. Custom-Error Handling
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14. Try scope
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15. Try Scope: On Error Continue
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16. Try Scope: On Error Propagate
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17. Child Flow Error-Handling
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18. Behaviour - For-Each ,Parallel-For-Each
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19. Error Handling - For-Each ,Parallel - For-Each
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20. Error Handling-Scatter Gather
When to use Scatter Gather :
● Scatter-Gather is best suited for Multicast scenarios.
● The Scatter-Gather messages are processed in-parallel with aggregate responses.
● More than one process is required for Scatter-Gather to function according to its discussed
merits.
● The MuleSoft Scatter-Gather has many features to control the execution flow in case of route
failures.
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21. Error Handling-Scatter Gather
Points to remember:
● What happens to the initial payload, when one of the processes in the Scatter-Gather
fails?
● What happens if the variable in one process is modified and not in the other?
● What would be the result of Scatter-Gather if “On-Error propagates” is used instead of
“On-Error continue” when one of the routes fails?
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22. Case - 1
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23. Case - 2
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24. Error handling Batch processing
Points to remember in batch process error handling:
● Any error occur inside batch job will never propagate to Main flow error
handler. But if error occurs in the source section then it will come to Main Flow
error handler
● maxFailedRecords – 0 – Stop processing when a failed record is found.
maxFailedRecords – 1 – Continue processing indefinitely, regardless of the
number of failed records.
maxFailedRecords – integer – Continue processing until reaching maximum
number of failed records.
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25. Error handling Batch processing
There are 2 ways you can handle errors in batch processing
● Add a batch step with accept policy as “ONLY_FAILURES” to know all those
records which have failed in earlier batch steps.
● Add try catch activity in Batch Steps
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26. Batch Processing Case-1
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27. Batch Processing Case-2
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28. Error Handling in Dataweave
● fail()
● failIf()
● Try()
● orElse()
● orElseTry()
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29. Q & A

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What’s next?

32. 20
● 21st May 2022 - Understanding the Anypoint Flex Gateway
● 11th June 2022 - Implementing and Understanding SAGA (Orchestration and
Choreography) Patterns With MuleSoft
● 24th June 2022 - Combine Service Mesh With Anypoint API Management to
power Microservices
● 30th June 2022 - Understanding EKS/RTF Architecture and Components
● 9th July 2022 - Driving Digital Transformation in Banking Industries With
MuleSoft
Upcoming Meetups

33. Quiz Time
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34. Thank you