easily allow sourcing .env-file in bash

[woutervh]

python-dotenv is a python-library, and used in python-code.
Currently .env-files can only contain:

• key/value-pairs
• blank lines
• comments

But sometimes, env-vars are also used by executables outside your python-code.
E.g In a django-project with a postgresql-backend, I have these env-vars:

# postgres - used in django-settings + by postgres-executables (pg_* )
PGHOSTADDR="127.0.0.1"
PGPORT="5432"
PGDATABASE="my-db"
PGUSER="my-dbadmin"
PGPASSWORD="SUPERSECRET"
PGOPTIONS=""

# used only by postgres-executables, 
# cfr. https://www.postgresql.org/docs/12.1/libpq-envars.html
PGDATA="..."
PGHOST="..."

I use following snippet to load all these key/value-pairs in my current bash-session
to use the postgresql-commands:
`

set -a && source .env && set +a
`

You can find many oneliners to source a .env-file in bash, many using grep/sed/xargs/...

If we would allow setting bash-options in the .env-file:

set -o allexport
PGHOSTADDR="127.0.0.1"
...
set -o allexport

these option-lines can just be skipped in the python-parsing of the dotenv,
this would simplify to:

 > source .env

just source the .env!

[bbc2]

As documented in our readme (https://github.com/theskumar/python-dotenv#file-format), you may prepend export to your lines defining variables. Would that work for you?

There are several ways to do this in Bash and I'm not sure we want to add support for all the cases in Python-dotenv (i.e. ignore all possible forms of the "export" directives).

[woutervh]

ignore all possible forms of the "export" directives

ÌMHO, only needed is to skip/ignore lines starting with :

set -o ...
set +o ...

no?