Enable Standalone User Event Dev mode

[chetanmeh]

With #4656 support was added in standalone mode to launch the User Event service along with required Prometheus and Grafana service. This PR adds support for reusing an existing user-event service (say running with IDE) for faster local developement

Description

To enable fast local development of user-event service the Standalone OpenWhisk now support connecting to an existing running service instead of launching a new one via Docker

First launch the standalone server with Kafka and pass the port where user-event service would be running (9095 by default)

java -jar openwhisk-standalone.jar --dev-user-events-port 9095 --kafka --kafka-ui

Then launch the org.apache.openwhisk.core.monitoring.metrics.Main via IDE with env set to KAFKA_HOSTS=localhost:9092

After this one can do normal action invocation and see metrics appear in Grafana

Related issue and scope

• I opened an issue to propose and discuss this change (#????)

My changes affect the following components

• API
• Controller
• Message Bus (e.g., Kafka)
• Loadbalancer
• Invoker
• Intrinsic actions (e.g., sequences, conductors)
• Data stores (e.g., CouchDB)
• Tests
• Deployment
• CLI
• General tooling
• Documentation

Types of changes

• Bug fix (generally a non-breaking change which closes an issue).
• Enhancement or new feature (adds new functionality).
• Breaking change (a bug fix or enhancement which changes existing behavior).

Checklist:

• I signed an Apache CLA.
• I reviewed the style guides and followed the recommendations (Travis CI will check :).
• I added tests to cover my changes.
• My changes require further changes to the documentation.
• I updated the documentation where necessary.

[selfxp]

👍

[selfxp]

Would it make sense to have optional and default to 9095? If user-events is run with an IDE, it will start on this port by default.

[chetanmeh]

Tried to support that but scallop arg parser does not support it. If I specify --dev-user-events-port then need to provide an explicit value otherwise it gives an error like below

[openwhisk] Error: Bad arguments for option 'dev-user-events-port': '' - you should provide exactly one argument for this option

[codecov-io]

Codecov Report

Merging #4680 into master will decrease coverage by 4.68%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master    #4680      +/-   ##
==========================================
- Coverage   82.95%   78.26%   -4.69%     
==========================================
  Files         194      194              
  Lines        8728     8728              
  Branches      607      607              
==========================================
- Hits         7240     6831     -409     
- Misses       1488     1897     +409

Impacted Files	Coverage Δ
...core/database/cosmosdb/RxObservableImplicits.scala	0% <0%> (-100%)	⬇️
...ore/database/cosmosdb/cache/CacheInvalidator.scala	0% <0%> (-100%)	⬇️
...core/database/cosmosdb/CosmosDBArtifactStore.scala	0% <0%> (-96.17%)	⬇️
...tabase/cosmosdb/cache/CacheInvalidatorConfig.scala	0% <0%> (-94.74%)	⬇️
...sk/core/database/cosmosdb/CosmosDBViewMapper.scala	0% <0%> (-92.6%)	⬇️
...e/database/cosmosdb/cache/ChangeFeedListener.scala	0% <0%> (-86.67%)	⬇️
...e/database/cosmosdb/cache/KafkaEventProducer.scala	0% <0%> (-76.48%)	⬇️
...whisk/core/database/cosmosdb/CosmosDBSupport.scala	0% <0%> (-74.08%)	⬇️
...a/org/apache/openwhisk/common/ExecutorCloser.scala	0% <0%> (-66.67%)	⬇️
...abase/cosmosdb/CosmosDBArtifactStoreProvider.scala	7.69% <0%> (-50%)	⬇️
... and 31 more

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