NIFI-9289: On startup, when enabling a Controller Service & its depen…

[markap14]

…dencies, do not wait for the dependencies to fully enable. Doing so can take 30 seconds per each Controller Service (and per each reference). Due to some previous refactoring, this waiting period is no longer necessary, as the referencing service can now be enabled and will asynchronously complete the enabling once it becomes valid (due to the referenced service becoming enabled).

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Enables X functionality; fixes bug NIFI-YYYY.

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[gresockj]

This is a sensible improvement, and works as designed. To verify, I created a StandardRestrictedSSLContextService with a valid configuration, and an ElasticSearchClientServiceImpl that referenced it, then stopped NiFi and removed one of the property values, making it invalid. Starting up, I saw the controller services trying to enable, and then very quickly the successful server start message:

2021-10-12 07:15:39,379 DEBUG [main] o.a.n.c.s.StandardControllerServiceProvider All dependent services have been enabled for StandardControllerServiceNode[service=SSLContextService[id=74312327-017c-1000-9c2f-fede70ea26cc], name=StandardRestrictedSSLContextService, active=false]; will now start service itself
2021-10-12 07:15:39,380 INFO [main] o.a.n.c.s.StandardProcessScheduler Enabling StandardControllerServiceNode[service=SSLContextService[id=74312327-017c-1000-9c2f-fede70ea26cc], name=StandardRestrictedSSLContextService, active=false]
2021-10-12 07:15:39,380 DEBUG [main] o.a.n.c.service.ServiceStateTransition StandardControllerServiceNode[service=SSLContextService[id=74312327-017c-1000-9c2f-fede70ea26cc], name=StandardRestrictedSSLContextService, active=false] transitioned to ENABLING
2021-10-12 07:15:39,385 DEBUG [Timer-Driven Process Thread-1] o.a.n.c.s.StandardControllerServiceNode Cannot enable StandardControllerServiceNode[service=SSLContextService[id=74312327-017c-1000-9c2f-fede70ea26cc], name=StandardRestrictedSSLContextService, active=true] because it is not currently valid. (Validation State is INVALID: ['Truststore Type' validated against '' is invalid because Given value not found in allowed set 'BCFKS, PKCS12, JKS']). Will try again in 1 second

2021-10-12 07:15:42,738 INFO [main] org.apache.nifi.nar.NarAutoLoader Starting NAR Auto-Loader for directory ./extensions ...
2021-10-12 07:15:42,739 INFO [main] org.apache.nifi.web.server.JettyServer NiFi has started. The UI is available at the following URLs:
2021-10-12 07:15:42,739 INFO [main] org.apache.nifi.web.server.JettyServer https://127.0.0.1:8443/nifi
2021-10-12 07:15:42,740 INFO [main] org.apache.nifi.BootstrapListener Successfully initiated communication with Bootstrap
2021-10-12 07:15:42,740 INFO [main] org.apache.nifi.NiFi Controller initialization took 13767609072 nanoseconds ( 13  seconds).
2021-10-12 07:15:43,391 DEBUG [Timer-Driven Process Thread-8] o.a.n.c.s.StandardControllerServiceNode Cannot enable StandardControllerServiceNode[service=ElasticSearchClientServiceImpl[id=7434fd4a-017c-1000-d3ce-a6856b8fdac4], name=ElasticSearchClientServiceImpl, active=true] because it is not currently valid. (Validation State is INVALID: ['SSL Context Service' validated against '74312327-017c-1000-9c2f-fede70ea26cc' is invalid because Controller Service with ID 74312327-017c-1000-9c2f-fede70ea26cc is disabled]). Will try again in 1 second
2021-10-12 07:15:43,391 DEBUG [Timer-Driven Process Thread-7] o.a.n.c.s.StandardControllerServiceNode Cannot enable StandardControllerServiceNode[service=SSLContextService[id=74312327-017c-1000-9c2f-fede70ea26cc], name=StandardRestrictedSSLContextService, active=true] because it is not currently valid. (Validation State is INVALID: ['Truststore Type' validated against '' is invalid because Given value not found in allowed set 'BCFKS, PKCS12, JKS']). Will try again in 1 second

Notice the first enabling message was at 07:15:39 and the server startup was at 07:15:42. At this point, I was able to navigate on the UI to add the missing value, allowing the service to be enabled. Trying the same procedure on the main branch resulted in a delay of ~30 seconds before the server completed the startup process. Nice work!