Enable envvars to be used

[borpin]

Update code to enable Envvars to be specified in the settings.ini

Needs testing!!!!!!

Discussion in #1452 refers

[relnah]

Disregard my last comment, I deleted it.
Seems to work.
Using this settings.ini (chopped upp the password just to try two envvars with static characters mixed in)

[sql]
server = {{MYSQL_HOST}}
username = {{MYSQL_USER}}
password = {{MYSQL_PASSWORD1}}1{{MYSQL_PASSWORD2}}

[redis]
enabled = {{REDIS}}

[mqtt]
enabled = false

[log]
level = {{LOG_LEVEL}}

[borpin]

Seems to work.

Great, thanks.

For formatting code blocks, use 3 backticks on a line before and 3 on a line after. The single backticks just work within a single line (no CR).

Cheers

[TrystanLea]

Thanks @borpin @relnah, finally tested here both using the emoncms-docker and a standard image, working well, merged in.