RFR: 8294402: Add diagnostic logging to VMProps.checkDockerSupport [v4]

[Mikhailo Seledtsov]

On Wed, 1 Feb 2023 04:42:18 GMT, David Holmes <dholmes at openjdk.org> wrote:

>> Mikhailo Seledtsov has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   Review feedback: printing stdout and stderr files to log()
>
> test/jtreg-ext/requires/VMProps.java line 519:
> 
>> 517:     private String redirectOutputToLogFile(String msg, ProcessBuilder pb, String fileNameBase) {
>> 518:         if (!Boolean.getBoolean("jtreg.log.vmprops")) {
>> 519:             return "";
> 
> I think having to explicitly enable this somewhat defeats the purpose of using it for diagnostics. If we get an unexpected failure we will have to reproduce it with logging enabled to see what went wrong.

If I remove this conditional guard then we will see extra output at the beginning of test run which might be undesirable. For instance: 

jtreg -v1 -conc:4 -Djtreg.log.vmprops=true open/test/hotspot/jtreg/containers/docker/                    

VMProps: Entering call()
VMProps: Entering dockerSupport()
VMProps: dockerSupport(): platform check: isSupported = false
VMProps: dockerSupport(): returning isSupported = false
VMProps: Leaving call()
Test results: no tests selected


I am not sure what is the best thing to do here, so I stayed on a "safe" side and added this conditional guard. The model in my mind is that such logging is normally off but can be turned on in case the issue is suspected. However if you believe it should be always on I can remove the guard.

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PR: https://git.openjdk.org/jdk/pull/12239