Embed serve as default command to run the server container

[haoming29]

Closes #945

[brianhlin]

If you specify the CMD instead of appending this to ENTRYPOINT, you'll get the default behavior we want but still allow people to specify other commands when starting the container. See https://docs.docker.com/reference/dockerfile/#cmd

Also, I /think/ you could do this in the final-stage layer so that you don't have to repeat it across every single one of the separated images

[haoming29]

@brianhlin I ended up doing ENTRYPOINT [ "/entrypoint.sh" ,"pelican", "director"] with CMD ["serve"] so that users only need to specify serve [args...] if they prefer running other command.

I didn't think of a way to put ENTRYPOINT into final-stage as the entrypoint has the server name attached and that's what distinguish different server images right?

[brianhlin]

@brianhlin I ended up doing ENTRYPOINT [ "/entrypoint.sh" ,"pelican", "director"] with CMD ["serve"] so that users only need to specify serve [args...] if they prefer running other command.

I think this limits your flexibility a bit too much, though I'll admit that I'm not too familiar with each host's commands other than serve or token. I don't think it's too much to ask users to specify serve <additional options> if they want to do something outside of the defaults.

I didn't think of a way to put ENTRYPOINT into final-stage as the entrypoint has the server name attached and that's what distinguish different server images right?

Yeah, that's one benefit of putting the serve in the CMD instead so that you could have per-image ENTRYPOINT but a shared default CMD

[haoming29]

I don't think it's too much to ask users to specify serve <additional options> if they want to do something outside of the defaults.

Oops. This is what I did lol. I meant that if I only put ENTRYPOINT [ "/entrypoint.sh"] with CMD ["pelican", "director", "serve"], then users must specify pelican director serve -p xxx for additional arguments

[haoming29]

Yeah, that's one benefit of putting the serve in the CMD instead so that you could have per-image ENTRYPOINT but a shared default CMD

That makes sense. Will do!

[haoming29]

OK so I figured that if I have CMD set prior to ENTRYPOINT, it is ignored. So I have put to CMD in each product-stage. But I do removed WORKDIR from product-stage

[brianhlin]

OK so I figured that if I have CMD set prior to ENTRYPOINT

Ah bummer! This LGTM, though