Mark Allanson: Hi! Is this history service used by DMN part of the Zeebe cluster, or does it reside outside the Zeebe nodes?
Josh Wulf: What is this history service of what you speak?
Do you mean the exported events that are sent to ElasticSearch in the standard Camunda Platform 8 architecture?
Mark Allanson: The one mentioned in the “Get advanced decision execution” diagram on the DMN page here https://camunda.com/platform/decision-engine/
Josh Wulf: That is Camunda 7
Josh Wulf: There is no History Service in Camunda Platform 8. There is an event stream export to ElasticSearch, which you could use in this way in Self-Managed, by rolling your own ES queries.
In Operate on C8 SaaS, you have a REST API, but there are no methods that deal specifically with DMN decisions.
In Zeebe 8.2 (upcoming), there will be a gRPC API for evaluating decisions, so you can remotely query the DMN engine and execute a decision. But that’s not a History Service.
Josh Wulf: But generally, all historical data in Camunda Platform 8 lives outside the Zeebe cluster - in ElasticSearch by default, but with Self-Managed you can export it anywhere that you like
Mark Allanson: > In Zeebe 8.2 (upcoming), there will be a gRPC API for evaluating decisions, so you can remotely query the DMN engine and execute a decision. But that’s not a History Service.
Nice that will be useful
Mark Allanson: Thanks! This makes perfect sense
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