ISPN-13873 Handle Accept header to serialize the events

[jabolina]

https://issues.redhat.com/browse/ISPN-13873

• Created an EventLog serializer using the
  ConfigurationSerializer interface.

I am using the stuff that we already have to serialize configuration, since that can handle the EventLog object, but pretty much all of the serialization classes have Configuration in the name.

Now we have:

{
  "log" : {
    "instant" : "2022-07-26T11:33:08.666580Z",
    "category" : "LIFECYCLE",
    "content" : {
      "level" : "INFO",
      "message" : "ISPN100010: Finished rebalance with members [jbolina-34174, jbolina-58560], topology id 2"
    },
    "additional" : {
      "context" : "caching-listen",
      "scope" : "jbolina-58560",
      "detail" : null,
      "who" : null
    }
  }
}

log: 
  instant: "2022-07-26T11:11:22.912906Z"
  category: "LIFECYCLE"
  content: 
    level: "INFO"
    message: "ISPN100002: Starting rebalance with members [jbolina-9736, jbolina-46792], phase READ_OLD_WRITE_ALL, topology id 2"
  additional: 
    context: "caching-listen"
    scope: "jbolina-9736"
    detail: ~
    who: ~

<?xml version="1.0"?>
<log instant="2022-07-26T11:31:07.318201Z" category="LIFECYCLE">
    <content level="INFO" message="ISPN100002: Starting rebalance with members [jbolina-23979, jbolina-17669], phase READ_OLD_WRITE_ALL, topology id 2"/>
    <additional context="caching-listen" scope="jbolina-23979" detail="" who=""/>
</log>

Want to check with you all first. This is changes the object format for the log, currently is:

{
  "message":"ISPN100002: Starting rebalance with members [jbolina-29050, jbolina-38947], phase READ_OLD_WRITE_ALL, topology id 2",
  "category":"LIFECYCLE",
  "level":"INFO",
  "time":1658846192341,
  "owner":"",
  "context":"caching-listen",
  "scope":"jbolina-38947"
}

Do we keep the format that is currently used or it is OK to change it?

[ryanemerson]

Do we keep the format that is currently used or it is OK to change it?

It's OK to change it as the current format was never in a stable release, only DevXX.

Overall I really the approach, good use of existing interfaces/components. However, tt would be good if we could include an integration test consuming the events in the various formats via server/tests.

[jabolina]

However, tt would be good if we could include an integration test consuming the events in the various formats via server/tests.

Added a simpler version for now, where we verify specifically the log events. What do you think? When we publish more events in the listener we update the tests to be more generic on the content validation.

[jabolina]

Oooops, I need to update the docs to reference the headers.
Updated.

[ryanemerson]

Just one comment and then I think we're good to go.

[ryanemerson]

Thanks @jabolina