Changing order of RUN vs COPY?

[andyshinn]

I don't think it is currently possible to do so. But I'd like to have some of my RUN commands happen before the COPY. My use case is for package management and dependencies that don't change that often. Right now, the COPY happens first and invalidates the cache of those RUN, which causes them to be done again. Those are costly steps in terms of bandwidth and time.

I wonder if it makes sense to allow multiple runCmds sections and move the optimize to it as well. It could look something like:

<runCmds>
  <beforeCopy>true</beforeCopy>
  <run>apt-get -q update</run>
  <run>apt-get -qy install mypkgs</run>
  <optimise>true</optimise>
</runCmds>
<assembly>...</assembly>
<runCmds>
  <run>java -jar my.jar setupotherstuff</run>
</runCmds>

[jgangemi]

this might be better suited to an external Dockerfile, would that work for you?

[andyshinn]

Probably. I read in another issue that the assembly stuff may be working with a custom Dockerfile soon. Is there any examples of that currently?

[jgangemi]

could you be a little more specific or point me to that specific issue? i'm not sure what you're referencing.

[andyshinn]

The specific comment I was thinking of was https://github.com/rhuss/docker-maven-plugin/issues/327#issuecomment-160878652. It looks like they were referring to https://github.com/rhuss/docker-maven-plugin/issues/205 and https://github.com/rhuss/docker-maven-plugin/issues/203.

[jgangemi]

i don't think so - if you have questions on what you need to do to make the assembly work, feel free to ask.

[rhuss]

@andyshinn adding the possibility to refer to an assembly from within Dockerfile is indeed planned for one of the next versions. I'm just thinking about how this could be done best without breaking the Dockerfile syntax (to much).

[andyshinn]

OK great. I guess the combination of that + using the alternative Dockerfile method would solve what I want to do. Is there another issue already open for the Dockerfile assembly part? If so, we can just close this.

[rhuss]

Its tracked via #205, so I'll close this one for now.