The README document

-- mode: org --

The Guix Data Service processes, stores and provides data about Guix over time.

It's written in Guile, stores data in a PostgreSQL database, and provides a web interface and API to browse and access the data.

1 Overview

The aim of the Guix Data Service is to provide a complementary interface to Guix itself, providing a different way of interacting with Guix data, which hopefully enables tools and services that otherwise wouldn't be feasible to write.

For example, with the command line tooling or Guile API for Guix, you can quickly and easily access information about packages, and manipulate derivations. However, if you wish to compare two revisions of Guix, or look at the history of the derivations for a package over recent Guix revisions, it could take some time until you have the information you're looking for.

However, with the Guix Data Service, this information can be gathered continuously, and stored in a way that makes these kind of queries much quicker to answer. By storing data about multiple Guix revisions in a SQL database (PostgreSQL), it becomes possible to quickly compare the data for different revisions. By configuring the Guix Data Service to listen for changes in the Guix Git repository, the database can be kept up to date.

2 Local Development

There's no one right way of doing local development, but outlined here is a recommended approach.

You will need to have:

  • The Guix package manager, either installed on any GNU/Linux distribution, or be using Guix as a system.
  • A running PostgreSQL service, version 10 or above is recommended
  • Git, so you can clone the repository
  • direnv, to manage environment variables

If you have any problems with the instructions here, you can ask for help on the #guix IRC channel on Freenode. You can also email help-guix@gnu.org, please include the step you got to, and the problem you encountered (with the error message if applicable).

2.1 Cloning the repository

To clone the Git repository, run the following command:

git clone https://git.savannah.gnu.org/git/guix/data-service.git guix-data-service

2.2 Getting direnv working

direnv is used to update the environment within the shell to contain the dependencies of the Guix Data Service. If you've just installed direnv, check you've hooked it in to your shell https://direnv.net/docs/hook.html .

Change in to the guix-data-service directory. You should see direnv prompting to trust the .envrc file contained within the repository.

Check the contents of the .envrc file, and if you trust it, run direnv allow.

2.3 Setup the database

Dumps of the database behind data.guix.gnu.org are available at http://data.guix.gnu.org/dumps, use the following URL to download the latest small dump.

http://data.guix.gnu.org/dumps/latest/guix_data_service_small.dump

There are multiple ways you can setup the database, the instructions here involve creating a guix_data_service user with a password, then connecting to the database over the local network interface.

To create the user and database use the scripts from PostgreSQL. The createuser command will prompt for a password for the database user, you'll need this at multiple points so it might be useful to keep it simple.

createuser guix_data_service --pwprompt
createdb guix_data_service --owner=guix_data_service

You may need to run these commands as the postgres user.

To restore the downloaded dump, run pg_restore. This command should prompt for a password, at which point enter the password for the database user that you set earlier.

pg_restore --jobs=4 --user=guix_data_service --no-tablespaces --host=127.0.0.1 --dbname=guix_data_service guix_data_service_small.dump

2.4 Set the database paramstring

To setup the configuration for your local environment, create a file called .local.envrc. To provide the password you've set for the guix_data_service user, you'll need to set the GUIX_DATA_SERVICE_DATABASE_PARAMSTRING environment variable in this file. Add the following line, replacing THEPASSWORD with the password you set earlier.

export GUIX_DATA_SERVICE_DATABASE_PARAMSTRING="dbname=guix_data_service user=guix_data_service password=THEPASSWORD host=127.0.0.1"

After, run direnv reload to update the environment in your shell.

2.5 Building the source files

The following three commands will compile the .go files and generate the scripts used as entry points to the Guix Data Service.

./bootstrap.sh
./configure
make

2.6 Run the web server

The guix-data-service script is the main entry point in to the service, run it from the shell.

guix-data-service

You should now be able to access the Guix Data Service web interface through a web browser using the URL http://localhost:8765/

To automatically restart the Guix Data Service when a change to the code is made, you can use the rerun command:

rerun -d guix-data-service -p "**/*.scm" guix-data-service

2.7 Checking the setup

You now should be ready to do local development. To double check that you can change the code and see those changes, try changing the "Guix Data Service" text within the index function, in the (guix-data-service web view html) module (contained in the guix-data-service/web/view/html.scm file). That text appears towards the top of the index page (the page with the path /).

3 Roadmap

Ideas for future enhancements to the Guix Data Service, in no particular order.

3.1 WebSub support for subscribing to branches and other changable state

3.2 Link to other sites (Free Software Directory, Wikidata, Debian, …)

3.3 Track package replacements (grafts)

3.4 Provide data in RDF formats (TTL, XML, …)

3.5 Provide statistics about Guix over time (with graphs)