Update Dockerfile

[elyezer]

Do the following:

• Use Fedora 30 as the base image
• Install receptor from source rather than wheel
• Set /var/lib/receptor as the home directory for receptor

[matburt]

I think we're going to need to find a better way to propogate the code into the image than adding the dev directory.

[elyezer]

@matburt I've updated the PR to remove the /receptor from the container file system. I saw about multi-stage build (https://docs.docker.com/develop/develop-images/multistage-build/) and that may allow us to build the receptor wheel and get it installed. I will continue taking a look how we could improve the container image and will send a PR later if I found something better to use.

[elyezer]

I found that running dnf update is adding about 80MB to the image but I think that is advised to ensure everything is up to date and with all the security fixes in. Any concerns/suggestions about that?

[matburt]

The problem is you're adding the entire dev directory to the image, which would include the .git directory. The goal of this dockerfile is to generate a functional production image of Receptor so we need to generate a whl or something and install it into this.

[matburt]

https://github.com/project-receptor/receptor/pull/36/files#diff-f311f62c5fdfdc737647797c7afac2beR3

Don't do this

[elyezer]

@matburt I was adding the entire git repo and then removing afterwards but I get your concern. I've update the PR to add the whl generated by make dist and then installs from it.

Also I've removed the dnf update which is generating a smaller image. I can add it back in case anyone things that is important to get the most updated RPM packages.

[matburt]

We probably do need that DNF update... what's the size delta after that?

[elyezer]

The image was updated recently (about an hour ago) and therefore there is no difference anymore, it was 80MB more before.

See below for the generated image size without the dnf update:

receptor             latest              b570cf745c20        12 seconds ago      255MB

And with the dnf update:

receptor             latest              66c36ab87aad        3 seconds ago       255MB

I'll update the PR with the dnf update in place.

[elyezer]

Another change that I've made was to use the recent released Fedora 31 image and that is giving a smaller image:

receptor             latest              8bd93f5eca9c        About a minute ago   220MB

[matburt]

This looks good. We may still need to tweak the mechanism for getting the right dist into the image but this is good under a make clean && make image workflow.