#111 Pass tool version to dockerfile

[kkazmierczyk]

Fixes #111.
See Contributing.md how to test it.

The patch is built on top of #110 .

[tjanasiewicz]

@kkazmierczyk is there a reason why you used CMD (to run the analyzer) before using RUN to build and configure the image?
https://www.docker.com/blog/docker-best-practices-choosing-between-run-cmd-and-entrypoint/

[kkazmierczyk]

@kkazmierczyk is there a reason why you used CMD (to run the analyzer) before using RUN to build and configure the image? https://www.docker.com/blog/docker-best-practices-choosing-between-run-cmd-and-entrypoint/

@tjanasiewicz are you asking why I used CMD and RUN instead of different ones or rather why in that order?

I agree that ENTRYPOINT is better than CMD. I have corrected it already in 0c6dc8f

Order of the commands:
Basically for dockerfile the instructions are not run in the order how they are written in the file. But the order matters when you modify the file. If you make any modification in the file, then all the layers since given line must be rebuilt. Therefore it is better to put more frequently modified lines on the bottom of the file to allow more caching.

More about the recommendations:
https://medium.com/@esotericmeans/optimizing-your-dockerfile-dc4b7b527756
https://docs.docker.com/build/building/best-practices/

[kkazmierczyk]

After further reading of https://docs.docker.com/build/building/best-practices/#entrypoint and https://www.docker.com/blog/docker-best-practices-choosing-between-run-cmd-and-entrypoint/ I believe that CMD is more applicable than ENTRYPOINT. Setting back line 17 to CMD.

[tjanasiewicz]

@kkazmierczyk is there a reason why you used CMD (to run the analyzer) before using RUN to build and configure the image? https://www.docker.com/blog/docker-best-practices-choosing-between-run-cmd-and-entrypoint/

@tjanasiewicz are you asking why I used CMD and RUN instead of different ones or rather why in that order?

I agree that ENTRYPOINT is better than CMD. I have corrected it already in 0c6dc8f

Order of the commands: Basically for dockerfile the instructions are not run in the order how they are written in the file. But the order matters when you modify the file. If you make any modification in the file, then all the layers since given line must be rebuilt. Therefore it is better to put more frequently modified lines on the bottom of the file to allow more caching.

More about the recommendations: https://medium.com/@esotericmeans/optimizing-your-dockerfile-dc4b7b527756 https://docs.docker.com/build/building/best-practices/

I am asking because from what I understand and what I found in the shared documentation those commands (RUN, CMD) are for different purposes [1]:
a) RUN:
is an image build step, the state of the container after a RUN command will be committed to the container image. A Dockerfile can have many RUN steps that layer on top of one another to build the image.

b) CMD [2]:
is the command the container executes by default when you launch the built image. A Dockerfile will only use the final CMD defined. The CMD can be overridden when starting a container with docker run $image $other_command.

Also, the example you referred [3] shows the same order. It means first build using RUN (add all references), and after that execute using CMD.

[1] https://docs.docker.com/reference/dockerfile/#run
[2] https://docs.docker.com/reference/dockerfile/#cmd
[3] https://medium.com/@esotericmeans/optimizing-your-dockerfile-dc4b7b527756

[kkazmierczyk]

@kkazmierczyk is there a reason why you used CMD (to run the analyzer) before using RUN to build and configure the image? https://www.docker.com/blog/docker-best-practices-choosing-between-run-cmd-and-entrypoint/

@tjanasiewicz are you asking why I used CMD and RUN instead of different ones or rather why in that order?
I agree that ENTRYPOINT is better than CMD. I have corrected it already in 0c6dc8f
Order of the commands: Basically for dockerfile the instructions are not run in the order how they are written in the file. But the order matters when you modify the file. If you make any modification in the file, then all the layers since given line must be rebuilt. Therefore it is better to put more frequently modified lines on the bottom of the file to allow more caching.
More about the recommendations: https://medium.com/@esotericmeans/optimizing-your-dockerfile-dc4b7b527756 https://docs.docker.com/build/building/best-practices/

I am asking because from what I understand and what I found in the shared documentation those commands (RUN, CMD) are for different purposes [1]: a) RUN: is an image build step, the state of the container after a RUN command will be committed to the container image. A Dockerfile can have many RUN steps that layer on top of one another to build the image.

b) CMD [2]: is the command the container executes by default when you launch the built image. A Dockerfile will only use the final CMD defined. The CMD can be overridden when starting a container with docker run $image $other_command.

Also, the example you referred [3] shows the same order. It means first build using RUN (add all references), and after that execute using CMD.

[1] https://docs.docker.com/reference/dockerfile/#run [2] https://docs.docker.com/reference/dockerfile/#cmd [3] https://medium.com/@esotericmeans/optimizing-your-dockerfile-dc4b7b527756

The first two links are references to CMD and RUN instructions. I didn't find any information about order. The 3rd one is pretty interesting. It mentions:
#1 Place static instructions higher in the order. Instructions like, but not limited to, EXPOSE, VOLUME, CMD, ENTRYPOINT, and WORDIR whose value is not going to change once it is set.
And the first example shows CMD before RUN. But the next example on that page shows another order.

IMO, the profit from placing CMD before RUN is tiny (CMD layer has 0B if I run podman history javacore-analyser). We can keep the order to have CMD at the end of the file.

I rolled it back.