RFR: 1478: Add metrics and loggin measuring time before WorkItems start to run [v2]

[Magnus Ihse Bursie]

On Tue, 14 Jun 2022 14:12:00 GMT, Erik Joelsson <erikj at openjdk.org> wrote:

>> In order to investigate and assess performance issues with the Skara bots, I need more data. One key class of data I'm missing is the time it takes from when a WorkItem is created or submitted to when it actually starts to run. This patch adds both metric gauges and log messages that include this information.
>
> Erik Joelsson has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Added comment

bot/src/main/java/org/openjdk/skara/bot/BotRunner.java line 68:

> 66:      */
> 67:     private static class PendingWorkItem {
> 68:         private final WorkItem item;

Maybe I'm a bit old-fashioned, but I think it looks a bit strange to have private fields but no accesses to them from within the class. (I was actually a bit surprised when I realized an outer class can access private fields in a static nested class...) 

I'm thinking either:
1) create getters
2) declare the fields public, or
3) mabe even consider if this should be a record.

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PR: https://git.openjdk.org/skara/pull/1337