Environment variables beginning 'DB_' cause errors

[batearedcollie]

Hi,

I discovered an issue where it looks like all environment variables beginning 'DB_' are interpreted as data base connection strings. This caused an issue on my system where the variable 'DB_ENPOINT' provides just the host name for the database server. Looking at the code on or around line 33 in engine.py looks like the area to focus on.

Would it possible to do one of the following?

1 - Provide a config option that specifies the environment variable prefix. So the user can choose somehting other than 'DB_'

2- Provide catch so that environment variables that might clash are filtered out

Thanks