sincedb_path handling

[pazoozooCH]

I've noticed some problems with the sincedb handling for file parsing: By default, Logstash will try to store it's sincedb-file in the $HOME directory. In this image, this will be evaluated to /root, but Logstash runs as user logstash and will not have permissions to save in this folder.

Another problem is that the sincedb file will be lost if the container is removed (e.g. with a version update). Obviously, this can be solved using volume mounting or a data container. Maybe it would be possible to change the $HOME directory for the logstash user and declare it as a volume in the Dockerfile at the same time?

[yosifkit]

So, $HOME should be working correctly since #12. Would something like docker-library/elasticsearch#77 be helpful to allow you to specify any non-root user and group to run as, using the --user flag on docker run?

[tianon]

Given that #11 is tracking the ability to run as a different user easily and that the HOME issue described here is fixed, I'm closing this one. 👍