Support multiple comma-separated databases in "MYSQL_DATABASE"

[elifarley]

For now, SQL scripts inside "/docker-entrypoint-initdb.d" will be executed on the first database only.

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This change is

[tianon]

I think docker-library/mysql#86 (comment) sums up the current state of opinion on "how to create multiple databases".

[sirgalleto]

Why are avoiding this PR?

[elifarley]

I don't think this PR is overly complex - it only adds 10 lines and removes 3.

And since users can already provide 1 database name, it can be argued that providing 2 or more database names separated by commas is something users can expect to 'just work'.

[yosifkit]

Why are avoiding this PR?

I still agree with @tianon. The solution is to drop scripts in /docker-entrypoint-initdb.d. I think it should be closed like docker-library/mysql#86.

[sirgalleto]

Yeah so, I'm trying to use that thing with Docker compose, and at this moment I have many problems with that execution.

[yosifkit]

Compose supports either method of getting the custom script into the container; a volume of the single script to mount at run (volumes: \n - /path/to/custom.sql:/docker-entrypoint-initdb.d/custom.sql), or a build directive with a simple Dockerfile:

FROM mariadb:10
COPY ./custom.sql /docker-entrypoint-initdb.d/

[sirgalleto]

Thanks for your help, I had a problem with my Docker volumes and the script was not running. It's working right now.

[yosifkit]

Closing since it can already be solved with custom scripts in docker-entrypoint-initdb.d.