I have tried the latest discourse with official Docker image few days, and I found the regular backup operation would be failed every time, the error log contains:
FATAL: Peer authentication failed for user "postgres"
When I typed this issue, I got few similar topic in the right, after I checked them I think this is still a new unfixed problem. And the solution comes from here, as current postgresql installed built in docker image, need change the configuration of postgresql like:
#TYPE DATABASE USER ADDRESS METHOD local all all trust
So with this configuration the backup function would be work. I didn’t checked a lot in current issue list, if there is fix about it, please ignore this.