[GAP Forum] Using GAP with Docker

[Alexander Konovalov]

Dear Forum,

The README file for the GAP container for the virtualisation 
platform Docker (https://www.docker.com/) has been updated.
It could be found at https://github.com/gap-system/gap-docker
and is also appended below.

Hope you may find this interesting to use, for example:

- if some GAP packages and external dependencies are provided 
  in Docker but are hard to install on your machine

- if you're using GAP from time to time and don't want to 
  spend much time on reinstalling a new version yourself

- if you need a reference GAP and packages installation to
  check how something works

- if you need to quickly deploy GAP on some other machine

etc.

Best wishes
Alexander


# Docker container for GAP and packages.

We have a prebuilt Docker image for GAP and packages at 

	https://registry.hub.docker.com/u/gapsystem/gap-docker/.

If you install Docker, you may start the container as follows:

	$ docker run --rm -i -t gapsystem/gap-docker

Note that you may have to run `docker` with `sudo`, particularly if you are on Ubuntu.

After that, you may call `gap` to start a new GAP session:

gap at 11d9377db2bd:~$ gap
 *********   GAP, Version 4.7.9 of 29-Nov-2015 (free software, GPL)
 *  GAP  *   http://www.gap-system.org
 *********   Architecture: x86_64-unknown-linux-gnu-gcc-default64
 Libs used:  gmp, readline
 Loading the library and packages ...
 Components: trans 1.0, prim 2.1, small* 1.0, id* 1.0
 Packages:   AClib 1.2, Alnuth 3.0.0, AtlasRep 1.5.0, AutPGrp 1.6, 
             Browse 1.8.6, CRISP 1.3.9, Cryst 4.1.12, CrystCat 1.1.6, 
             CTblLib 1.2.2, FactInt 1.5.3, FGA 1.3.0, GAPDoc 1.5.1, IO 4.4.4, 
             IRREDSOL 1.2.4, LAGUNA 3.7.0, Polenta 1.3.2, Polycyclic 2.11, 
             RadiRoot 2.7, ResClasses 3.4.0, Sophus 1.23, SpinSym 1.5, 
             TomLib 1.2.5
 Try '?help' for help. See also  '?copyright' and  '?authors'
gap> 

When you will leave GAP, you still will be logged in into container and 
will need to type `exit` to close it.

Alternatively, you may just type 

  docker run --rm -i -t gapsystem/gap-docker gap

to start GAP immediately (and return to the host filesystem after the end 
of the GAP session). You may put this command in a shell script and make 
it a default or optional way to start GAP on your system. GAP command line 
options may be appended after `gap`, for example 

  docker run --rm -i -t gapsystem/gap-docker gap -A

However, note that you will not be able to read a file our local directory 
into GAP just by supplying the filename in the command line. Instead of 
that, it is necessary to use `-v` option to mount local directory. For 
example, if the current directory contains the subdirectory `examples` with 
the file `examples/useful.g`, then with `-v $PWD/examples:/data` will 
mount `examples` as `/data` on the Docker container. Then to start GAP and 
read the file `examples/useful.g` into it, one should proceed as follows:

  docker run -v $PWD/examples:/data -t -i gapsystem/gap-docker gap /data/useful.g

Note that the path to `useful.g` is the path in the container, 
and not in the GAP system.

If you need network access (for example, for packages downloading external 
data like AtlasRep), call `docker` with `--net="host"` option, e.g.:

  docker run --rm -i -t --net="host" gapsystem/gap-docker

For example, the following command mounts `pkg/scscp/example` directory from 
the GAP distribution as `/scscp` directory on the container and starts GAP 
SCSCP server using the configuration file `gap4r7p9/pkg/scscp/example/myserver.g`:

  docker run --rm -i -t --net="host" -v ~/gap4r7p9/pkg/scscp/example:/scscp gapsystem/gap-docker gap /scscp/myserver.g

At the moment, almost all of the packages are in the working order. External 
software needed by some packages at the moment includes:

* Ubuntu packages libmpfr-dev libmpfi-dev libmpc-dev libfplll-dev (needed by the float package)
* Polymake 2.14 (and dependencies, listed on polymake.org)
* Singular (git version of the day)
* 4ti2 1.6.3
* PARI/GP.

The work in progress is to configure remaining packages with non-standard 
installation and dependencies on external components: Carat, ITC, Linboxing, 
ParGAP and XGAP.

***