Run SQL script after start of SQL Server on docker

Question

I have a Dockerfile with below code

FROM microsoft/mssql-server-windows-express
COPY ./create-db.sql .
ENV ACCEPT_EULA=Y
ENV sa_password=##$wo0RD!
CMD sqlcmd -i create-db.sql

and I can create image but when I run container with the image I don't see created database on the SQL Server because the script is executed before SQL Server was started.

Can I do that the script will be execute after start the service with SQL Server?

Answer 1

RUN gets used to build the layers in an image. CMD is the command that is run when you launch an instance (a "container") based on the image.

Also, if your script depends on those environment variables, if it's an older version of Docker, it might fail because those variables are not defined the way you want them defined!

In older versions of docker the Dockerfile ENV command uses spaces instead of "="

Your Dockerfile should probably be:

FROM microsoft/mssql-server-windows-express
COPY ./create-db.sql .
ENV ACCEPT_EULA Y
ENV sa_password ##$wo0RD!
RUN sqlcmd -i create-db.sql 

This will create an image containing the database with your password inside it.

(If the SQL file somehow uses the environment variables, this wouldn't make sense as you might as well update the SQL file before you copy it over.) If you want to be able to override the password between the docker build and docker run steps, by using docker run --env sa_password=##$wo0RD! ..., you will need to change the last line to:

CMD sqlcmd -i create-db.sql && .\start -sa_password $env:sa_password \
-ACCEPT_EULA $env:ACCEPT_EULA -attach_dbs \"$env:attach_dbs\" -Verbose

Which is a modified version of the CMD line that is inherited from the upstream image.