Pattern for Claim Check for large messages #138

[ybyzek]

Description

https://github.com/confluentinc/event-streaming-patterns/issues/138

This pattern is a sister to https://github.com/confluentinc/event-streaming-patterns/pull/146

@benstopford @miguno this pattern was not on the original list, so in addition to normal review, please also validate:

1. Title
2. Categorization

New Pattern Checklist

• [x] Pattern file name should follow docs/pattern-category/pattern-name.md
• [x] Create an on-brand diagram (https://docs.google.com/presentation/d/1Zf256Z6fBvre3uclIbmxXsDpnTIxiBX66b13pHbGIYc/edit?usp=sharing)
• [x] Implement ksqlDB or code example (not all patterns will have code, but highly desired)
• [x] Provide references
• [x] Validate hyperlinks
• [x] Spell check (e.g. using aspell)

[benstopford]

Nice. Just thinking about the name. "Message By Reference" might be better or something along those lines.

[ybyzek]

Nice. Just thinking about the name. "Message By Reference" might be better or something along those lines.

@benstopford @miguno I've also seen this pattern referred to as Bag Check or Claim Check. Additional references for this name:

• https://www.enterpriseintegrationpatterns.com/patterns/messaging/StoreInLibrary.html
• https://confluent.slack.com/archives/C1MTRDZGC/p1611696866084800

So renaming options include:

1. Message by Reference
2. Bag Check
3. Claim Check
4. ...

Based on frequency in my brief searching, my leaning is number 3 Claim Check. Thoughts?

[rspurgeon]

@ybyzek in the diagram, the Event Processor has an arrow pointing to the external data source, that might confuse someone thinking that the event processor is writing to it. IMO The event processor should indicate that it reads only from the external source based on the address in the event.

[miguno]

About the pattern name: I don't have a strong opinion. I'm fine with "Claim Check". What also works for me is "Event Reference" or "Event By Reference".