How can I have a shell script point to a .dll? (Docker ENTRYPOINT)

Question

I am using Docker to deploy a .NET Core application. By default, the ENTRYPOINT in the DockerFile for an application is something like:

ENTRYPOINT ["dotnet", "applicationStartingPoint.dll"]

However, I need to have a shell script execute in the container before the application begins. The CMD designation is not working for me for this purpose, so I need to have a shell script as my ENTRYPOINT and then have that start the application by the DLL.

Any insight you could provide would be greatly beneficial.

Answer 1

You can simply create a script called entrypoint.sh. Inside of this script you can do whatever you want, then call the command to start the application. So:

entrypoint.sh:

#!/usr/bin/env sh

... my crazy pre-script

dotnet applicationStartingPoint.dll

Dockerfile:

COPY entrypoint.sh /entrypoint.sh
RUN chmod +x /entrypoint.sh
ENTRYPOINT ["/entrypoint.sh"]

UPDATE: I've added to the Dockerfile how you can copy the file to the container while building it and also give the necessary permissions.