Fix cluster mode logs

[arelra]

What does this change?

When cluster mode was enabled in #8929 the log count from the ec2 -> kinesis stream dropped by ~half. On investigation the logs from the child processes were not being written to the log file by log4js.

I tried two approaches to fix this:

1. Write separate files for each process. This worked except amazon-kinesis-agent would sporadically duplicate log entries in ELK. Although amazon-kinesis-agent accepts a file pattern I suspect this is for log rotation and it does not support mulitple active log files as per: https://docs.aws.amazon.com/firehose/latest/dev/writing-with-agents.html#config-start

   Although this approach is cleaner I abandoned it due to the amazon-kinesis-agent issue.

2. Write to one log for all processes. log4js states that it will handle this transparently and it works as expected when tested on CODE.

I've also added the (existing) field thread_name to the log object to aid querying in ELK.

Why?

Log from all processes

After

[github-actions]

Size Change: 0 B 🆕

Total Size: 0 B

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