Using Windows agent, file content not synced to Cloud Watch when first line empty

[Krule]

I am running an off-the-shelf application in the Windows EC2 container and attempting to sync the logs to Cloud-Watch using Amazon SSM Agent. EC2 container is destroyed and rebuilt weekly with latest updates (these including the SSM agent I assume). This worked fine for a while until suddenly it didn't.

A way longer than I wanted investigation resulted in:

1. Off-the-shelf software outputs file logs starting with an empty line.
2. Amazon SSM agent ignores files starting with an empty line.

The problem,for me, is now mitigated by pre-allocating 1 week worth of the log files (there is a deterministic naming scheme), containing filled first line, at machine creation time. Never the less, this might be an issue troubling others, so I wanted to raise awareness here.

A bit more details about the issue can be found here: https://stackoverflow.com/questions/59845475/amazon-ssm-agent-not-syncing-a-log-starting-with-empty-line