How to pass environment array configuration properties with docker-compose dynamically? - asp.net-core

Question

I have an ASP .NET Core Web API app that is deployed on a docker linux container.
Now I need to upgrade my app configuration including an emails array, it is not a problem until I need to pass this array using docker-compose.yml.
This is the C# code I use to retrieve the configuration:
List<string> emails = _config.GetSection("Checker:EMails").Get<List<string>>();
These are my linux environments variables as explained by microsoft:
export Checker__RefreshTime="86400000"
export Checker__DaysToCheck="15"
#emails array
export Checker__EMails__0="my_email1#my.com"
export Checker__EMails__1="my_email2p#my.com"
docker-compose.yml file:
environment:
# the following line passes the host environment var to the container created from the image
# Checker configuration
- Checker__RefreshTime=${Checker__RefreshTime}
- Checker__DaysToCheck=${Checker__DaysToCheck}
How can I include the emails array dynamically without the necessity to change docker-compose.yml file every time? Because now I need to do something like:
environment:
# the following line passes the host environment var to the container created from the image
# Checker configuration
- Checker__RefreshTime=${Checker__RefreshTime}
- Checker__DaysToCheck=${Checker__DaysToCheck}
- Checker__EMails__0=${Checker__EMails__0}
- Checker__EMails__1=${Checker__EMails__1}
# etc..

Answer 1

You can use an file to store the environment variables and call the file from your docker-compose file.
Instead of:
environment:
- Checker__RefreshTime=${Checker__RefreshTime}
- Checker__DaysToCheck=${Checker__DaysToCheck}
- Checker__EMails__0=${Checker__EMails__0}
- Checker__EMails__1=${Checker__EMails__1}
use:
env_file: filename.env