I just upgraded my omnibus install (on Debian) from 13.0.2 to 13.0.3, and my mattermost service (which was working fine) stopped working, giving a 502 bad gateway error. The log in
/var/log/gitlab/mattermost/current shows this error repeatedly:
2020-06-01_08:41:21.23824 Error: failed to load configuration: failed to load: failed to unmarshal config with env overrides: parsing error at line 1, character 1: unexpected end of JSON input
Looking for the config file led me to
/var/opt/gitlab/mattermost/config.json, which is completely empty. Running
gitlab-ctl reconfigure didn’t do anything,
gitlab-ctl check-config shows no errors,
gitlab-rake gitlab:check only mentions that I need to upgrade to hashed storage, which has nothing to do with mattermost.
How can I resurrect my Mattermost config?