Fix Gemfile

[fsimonis]

The Gemfile currently lacks many dependencies.

This PR uses the gem github-pages as a central dependency for the jekyll website and adds rake for support of the Rakefile

[StephanJanosch]

I always delete the Gemfile.lock coming from the repo. I don't understand why, but my local install does not like it.

I don't want to accept this PR blindly but really understand it. Maybe I have time later to review it closely.

[knarrff]

I have to say: I am not at all an expert here. But, these are a lot of dependencies. How can I check that we do indeed need all of those for the current website?

[fsimonis]

@StephanJanosch Do you run jekyll via bundle? bundle exec jekyll serve

@knarrff I totally agree. github-pages bundles a huge pile of common dependencies. The tradeoff is that this bundle is directly maintained by github and many web developers are familiar with it.

[StephanJanosch]

@StephanJanosch Do you run jekyll via bundle? bundle exec jekyll serve

usually not. jekyll s is what I type. I might have used the bundle way once. I have no clue about this ruby world. I did the bare minimum to make it work.

[fsimonis]

usually not. jekyll s is what I type. I might have used the bundle way once. I have no clue about this ruby world. I did the bare minimum to make it work.

I quite understand.

For the sake of completeness, bundle install creates a local installation of the dependencies declared in the Gemfile with the locked versions declared in the Gemfile.lock (most recent working setup).
To run something restricted to this local install, one has to use bundle exec <cmd>.

By running the bare command, you use the system install and probably run into problems with conflicting versions.

[knarrff]

By running the bare command, you use the system install and probably run into problems with conflicting versions.

I do understand the intention that everything should work smoothly when people want to run software. That is very important and often overlooked.

Connected to that is to declare dependencies. Although, for me this also includes to only specify as dependency something you actually depend on, and it includes to specify the oldest version of a dependency that your code still works with, instead of only what happens to be current or installed in your system.

Therefore my question, is there a good, (semi-)automatic way to get to such a list of dependencies in our case here? I am not too familiar with this setup. What I did is to try to build the pages with the short list of dependencies installed on a fresh system, and it worked. This is no proof that it would have worked with "less", but can I take it as indication that it is likely sufficient?

[fsimonis]

@knarrff I see you point and I tried to boil down the dependencies as much as possible.
Can you please give it a try?

[knarrff]

Just tried this today. I cannot make this build with my currently system-installed ruby using 'bundle', neither the master-version, nor the one from this pull request.

What does work though, is simply 'jekyll build' without using bundle. Now I wonder why I would need 'bundle' at all, and if all the packages and versions given in either of the two Gemfile.lock versions are really necessary - since it apparently works just fine without installing anything extra.

I am not familiar with Gemfile.lock and Gemfile files. How are those files generated? In particular, how is the list of dependencies and their versions generated? Because, it seems I can build this project just fine, without some of the packages listed in there, and without updating others to the versions listed there.

I have the suspicion that it's just the versions that happened to be installed on the machine the file in generated on, or maybe the then current versions of packages. If it is any of these, it's no good. What we need is a true list of dependencies with their really needed version dependencies. But maybe my suspicion is wrong and I do miss something?

[fsimonis]

What command do you execute to build the website?
It should be something like this:

$ bundle install
$ bundle exec jekyll build

Running jekyll build uses the system/user installed version which most likely differs between systems and can lead to all sorts of hidden problems. Using the prefix bundle exec runs the command "inside" the local installation.

The Gemfile is provided by the user and explicitly defines version constraints of the direct dependencies.

By executing bundle install, two things can happen

1. If there is a Gemfile.lock present, bundler installs all listed packages at their specified version. This allows for a painless installation and reproduces the latest build environment.
2. If there is no Gemfile.lock present, bundler builds a version graph that satisfies the constraints expressed in the Gemfile while using the most up-to-date package versions. All dependencies and their selected versions are then saved to the Gemfile.lock. By committing the lock file, the developer publishes the latest working configuration of dependencies of the project. ( Reproducible build environment )

[nuest]

Thanks @fsimonis for the explanations and your contributions. Your changes were also a solution for the broken feed #139 and is includes in #140