@Dennis TIO doesn't seem to have the words file: tio.run/nexus/bash#@5@coqBfWlykX5yRWJSqn5KZXMKVU6ygm/j/PwA

Or can I just not find it?

@AndrewSavinykh It might be better to use yum instead of dnf on CentOS. By default, dnf terminates on error (e.g. package not found), while yum by default installs everything that can be found. As far as I can see, there's not really a reason to install dnf at all.

@AndrewSavinykh Actually python3 is also in EPEL. The name is a bit more verbose. E.g. to use python 3.4 from EPEL, the package name is python34.

@mınxomaτ, yeah, I did not install dnf

Oh, just because the CentOS branch still uses dnf everywhere.

@mınxomaτ ln -s /usr/bin/yum /usr/local/bin/dnf

Not sure that's a good idea, since dnf is also available on CentOS. I guess it's fine if no one else is using the script.

@mınxomaτ just so you know I parked this investigation for now. There is a lot of problems and without certainty that we definitely want to use Centos I decided not to invest more time in it at this stage

@mınxomaτ totally. this is not a production ready script this is a preliminary investigation

So as such I felt I could cut this corner to get to the goal faster. Of course if we actually go ahead with centos this will need to be re-visited.

@AndrewSavinykh A bit off topic: Have you ever looked at compilebox as a sandbox? It uses docker to separate the running program from the system. This means 1) One server can contain the web interface and the sandbox/arena, 2) You get full system isolation without needing to configure SEL policies. New languages are maintained as the arena docker image. You can check out the code here: github.com/remoteinterview/compilebox and a TIO-ish demo here: compile.remoteinterview.io

I recommend reading the whole README and testing the demo in-depth. This is basically what I had in mind in our earlier Docker discussion, but I was unaware that what I imagined actually existed as this project. There's nothing new under the sun :)

@mınxomaτ This is something @Dennis will need to look at, I have very limited experience with sandboxing, so he is better positioned to respond something intelligent.

Not really meant for TIO, I just wanted to explain what I mean earlier by example.

@Dennis which brainfuck implementation does TIO use?

@DuctrTape AFAIK: github.com/TryItOnline/tio-transpilers

Alright, thanks!

@Dennis I have some time today, if you're available within the next several hours

@aditsu Today will be difficult. A couple of friends are coming over for a visit.

OK, so I tested the docker variant a bit more in terms of sandboxing and setup. I am convinced that this would be a much better way of maintaining TIO and executing code. You don't need to configure a sandbox, adding languages remains easy or gets even easier, arena and web server no longer need to be separate, SEL is not required, user code can use everything it wants (including system files and sudo) inside the sandbox etc. pp. I'll try to setup a more TIO-ish prototype on Github.

Spawing and destroying a system-wide sandbox takes about 100ms. So running a small python script takes about 230ms (avg 5 runs), I think that is acceptable.

@Dennis if you're not busy, could you pull reticular?

@ConorO'Brien Done.

@Dennis add Flobnar please?