Errors in routing rules are not logged

[abridgett]

In HaGatewayProviderModule.java#196 any exceptions from the FILE or EXTERNAL initialisation seem to be swallowed and the default routing group is (silently) used instead.

I'm currently using the Java debugger to see the stack track so that I can fix my routing_rules.yaml file :-)

TBH I'd prefer a fail (and retry - especially given that "RuleReloadingRoutingGroupSelector" seems to pick up changes to the file - but presumably only if it was valid).

[andythsu]

In the documentation it says If there is error parsing the routing rules configuration file, an error is logged, and requests are routed using the routing group header X-Trino-Routing-Group as default.. We should look into why it's not logging erroneous routing rules. Have you found anything yet?

cc @willmostly

[mosabua]

I mean .. maybe it should even fail much harder .. since this could cause all sort of wrong routing and headaches if for example different clusters are for different teams or paid for by different orgs and so on. Maybe we should discuss this in the next dev sync .. personally I see the benefit of falling back to a default but I think its just too risky.. better to fail hard .. and prevent start up of server, or saving of rules in db in future, or in filesystem with the upcoming UI .. wdyt @willmostly @oneonestar @vishalya @Chaho12 ? .. I agree with @abridgett there