Send all the Diagnostics logs to the stdout, instead of local files

[buraksezer]

This PR implements #16844. Now we can send all the diagnostics logs to the stdout by using the following:

java -jar -Dhazelcast.diagnostics.enabled=true -Dhazelcast.diagnostics.stdout=true hazelcast/target/hazelcast-4.1-SNAPSHOT.jar

Could you please review my PR?

[devOpsHazelcast]

All committers have signed the CLA.

[pveentjer]

Could you add a line of logging:

if file based logging enabled, write the path of the file
if stdout based logging enabled, write that it is enabled.

This will make debugging easier.

Apart from that it looks good to go. No major remarks.

[buraksezer]

I fixed the naming problem and added more log lines about diagnostics log output. Could you review again?

[mmedenjak]

run-lab-run

[mmedenjak]

Sorry, wrong button.

[pveentjer]

Minor logging improvement request. Otherwise good to go.

[tkountis]

Changes LGTM, but wondering whether we want to keep escaping the more natural and dev friendly logger approach. Dev & Op teams are accustomed by now to having a logger and its configuration.

[buraksezer]

Hi team,

Is there any update on this topic?

[mmedenjak]

Sorry for the long wait @buraksezer and thank you for the contribution (cc @Holmistr ). I must admit I was delaying merging it because I wanted to take a closer look.

Regarding @tkountis 's comment, I agree we could switch the whole diagnostics to use a logger, then users could seamlessly switch between file, stdout, network and more outputs. I'll create an issue as I see it as a breaking change for the future.

Again, thank you for your contribution and hope to see you around soon.

[rdasilva-fispan]

Is this configuration working on 4.2?
I just tried it but I still see logs going to a log file. If something else has improved, can someone please point me to the docs as I don't see anything here?

Thank you!