Marelle: logic-based devops with Prolog

http://larsyencken.github.io/marelle/

by alexatkeplar • 13 years ago

73 23 13 years ago

larsyencken.github.io

nodata4• 13 years ago

This looks like scripting to me, not describing the desired state of a system:

    % we can install by running apt-get in shell
    meet(python, linux(_)) :-
      % could also use: install_apt('python-dev')
      bash('sudo apt-get install -y python-dev').

artificialidiot2• 13 years ago

Give them a break. It is not prolog had been hip for a long time. Using it more idiomatically will take some practice, maybe a few web frameworks and a couple of package managers.

nodata4• 13 years ago

Give them a break? Why? They're trying to push this as a better way of managing a system.

mcguire• 13 years ago

So, how do you describe how to install a package without looking like "scripting"?

nodata4• 13 years ago

Package { "bash": ensure => installed }

lars5123• 13 years ago

You describe the desired state in your met block, or more properly, tests meant to indicate if your desired state is met.

Your meet block is the scripting which is supposed to get you there, but which is considered fallible. The met block checks after to see if it actually worked.

cfrss• 13 years ago

Babushka not found

peter-fogg• 13 years ago

https://github.com/benhoskings/babushka

Looks like the repo has moved to a new Github account.

anonymous2• 13 years ago

Quickstart
Run the bootstrap script:

    bash -c "`curl https://raw.github.com/larsyencken/marelle/master/bootstrap.sh`"

PFHAHAHAHAHAHAHAHAHAHAHAHAHAHA

x1024• 13 years ago

Ahm, that's the way to install pretty much everything these days.

I mean, I know it's a security risk. But it isn't any more (or less) of a risk than installing nvm or just running git clone.

anonymous2• 13 years ago

No, it's not. I only see it on the odd hip-n-cool project by people with less experience than my server's uptime. Everything I install is either from a distro's package, from a tarball or by compiling from source.

I don't mind having a script that sets up the environment, there is a lot of software out there that does have these set up scripts in the tarball, or is distributed as a self-extracting archive, but you can always see it is marked as such. What I really balk at is "run this random script, trust me it installs". Would it kill them to write "download this script which will run apt-get pkg1 ... pkg10, then extract an inline tarball to ~/.local/lib"? I'm not going to run a random script that I have ZERO idea what it will do. It's not about security, it's about knowing that a good-intentioned non-compromised script won't crap all over my environment.

adient• 13 years ago

Not relevant to devops. Please change the title.

ghotli• 13 years ago

I'd like to hear your argument for this change. Seems apt to me.

richo• 13 years ago

Not sure what could be more relevant to devops than idiomatically updating state.

lars5123• 13 years ago

Hi guys, I'm the author. I've been playing with this for a little while, and trying to work out an idiomatic style for it. Suggestions for improvement are most welcome.

Some pleasant parts have been writing metapackage rules. For example, playing with Julia yesterday:

  % if P is a Julia package, it's also a general package
  pkg(P) :- julia_pkg(P).

  meet(P, _) :-
    julia_pkg(P), !,
    % install the package using the Julia interpreter
    ...

  met(P, _) :-
    julia_pkg(P), !,
    % try to import the package in Julia
    ...

  julia_pkg('PyCall').
  julia_pkg('DataFrames').

The only potential problem (on the horizon) is namespacing, which IMHO Babushka does well, but which is less obvious with Prolog's fact system.

e12e• 13 years ago

Interesting project.

The home page could use more contrast though, that grey on white is nearly unreadable.

Marelle: logic-based devops with Prolog

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