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Install your Lino developer environment

This document describes how to install a Lino developer environment on your computer.

developer environment

A set of tools installed on your computer so you can develop your own Lino application.

Set up a virtual Python environment

Rather than installing Lino into your site-wide Python installation, you install it to a separate virtual Python environment, also known as a virtualenv

If virtualenvs are new to you: the reason for creating a new environment is to separate Lino from your system-wide Python. There are at least two reasons for this:

  • other software on your computer might require different Python packages than those required by Lino, and there is the chance of version or dependency conflicts.

  • if you wish to remove Lino from your system you only need to remove the virtual environment rather than trying to remove Lino's dependencies from the system environment without breaking any other programs that use python.

Before using virtualenvs, we must install the feature:

$ sudo apt-get install python3-venv  # Debian
$ sudo dnf install python3-virtualenv  # RedHat

In a developer environment we suggest ~/lino/env as your default environment. So here we go:

$ mkdir ~/lino
$ python3 -m venv ~/lino/env
$ . ~/lino/env/bin/activate

The dot (.) is a synonym for the source command. If you didn't know it, read the manpage and What does 'source' do?

After creating a new environment, you should always update pip and setuptools to the latest version:

$ pip install -U pip setuptools
Collecting pip
  Using cached https://files.pythonhosted.org/packages/43/84/23ed6a1796480a6f1a2d38f2802901d078266bda38388954d01d3f2e821d/pip-20.1.1-py2.py3-none-any.whl
Collecting setuptools
  Downloading https://files.pythonhosted.org/packages/8e/11/9e10f1cad4518cb307b484c255cae61e97f05b82f6d536932b1714e01b47/setuptools-49.2.0-py3-none-any.whl (789kB)
    100% |████████████████████████████████| 798kB 1.1MB/s
Installing collected packages: pip, setuptools
Successfully installed pip-20.1.1 setuptools-49.2.0

Did you know?

You can deactivate a virtual environment with the command deactivate. This switches you back to your machine's system-wide environment.

You can switch to another virtualenv simply by activating it, you don't need to deactivate the current one first.

You should never rename a virtualenv (they are not designed for that), but you can easily create a new one and remove the old one.

To learn more, read Dan Poirier's post Managing multiple Python projects: Virtual environments where he explains what they are and why you want them.

Set your default virtualenv

As a developer you probably don't want to type source ~/lino/env/bin/activate each time you open a new terminal with Ctrl+Alt+T. So you should set your default environment.

default environment

The default virtualenv you use when developing.

How to set up your default environment

  1. Add the following line to your ~/.bashrc file:

    source ~/lino/env/bin/activate

(#) Instruct your favourite code editor to use this default environment when doing syntax checks or finding definitions.

Run getlino

Make sure your default environment is activated and then install getlino via pip:

$ pip install getlino

In case you have used getlino on your machine before (maybe in another virtualenv, but on the same machine), then you might want to delete your configuration files before going on:

$ rm ~/.getlino.conf
$ sudo rm /etc/getlino/getlino.conf

Now run getlino configure with the following options:

$ getlino configure --clone --devtools

It asks a lot of questions, but you can hit ENTER for each of them. When it does not react to ENTER but asks a [y or n] question, then you should read it and understand it before you hit y. getlino overwrites certain configuration files without making a backup copy. Read twice before you hit y! For details about each question or if something doesn't work as expected, see Troubleshooting below or the documentation about getlino.

When getlino has finished, add manually the following line to your .bashrc file:

source ~/.lino_bash_aliases

Play with the demo projects

Getlino also installs the Lino Book project. The Lino book is a special project. It is not an application, and it is not released on PyPI. It makes sense only for developers. It contains the main test suite for Lino. It contains a lot of demo projects.

You can now cd to any subdir of lino_book.projects and run a development server. Before starting a development server on a demo project for the first time, you must initialize its database using the pm prep command.

Try one of the demo projects:

$ go noi1r
$ pm prep
$ pm runserver

Point your browser to http://localhost:8000

We will have a deeper look at some demo projects in Discover Lino.


Using virtual environments can be a challenge for newbies. Here are some diagnostic tricks.

How to see which is your current virtualenv:


$ which python

How to see what's installed in your current virtualenv:

$ pip freeze

The output will be about 60 lines of text, here is an excerpt:

-e git+git+ssh://git@github.com/lino-framework/lino.git@91c28245c970210474e2cc29ab2223fa4cf49c4d#egg=lino
-e git+git+ssh://git@github.com/lino-framework/book.git@e1ce69aaa712956cf462498aa768d2a0c93ba5ec#egg=lino_book
-e git+git+ssh://git@github.com/lino-framework/noi.git@2e56f2d07a940a42e563cfb8db4fa7444d073e7b#egg=lino_noi
-e git+git@github.com:lino-framework/xl.git@db3875a6f7d449490537d68b08daf471a7f0e573#egg=lino_xl

Behind the scenes

Note the difference between inv prep and the pm prep command. inv prep runs the pm prep command for each demo project of a repository. The demo projects of a repository are declared in the tasks.py file. You can run the pm prep command for all demo projects by going to the root directory of the book project and saying inv prep:

$ cd ~/lino/env/repositories/book
$ inv prep

The getlino script does a lot of work. These commands take some time when you run them the first time on your machine because they will download and install all Python packages needed by Lino. If you install them a second time into another environment, the process will be quicker because pip caches the downloaded packages.

Remarks about some questions:

  • languages (The languages to set on new sites) [en]: This is just the default value that getlino will put for languages in the settings.py of new sites.

In some circumstances getlino will say "The following command was not executed because you cannot sudo", followed by an "apt-get install" command. Consider running these commands manually.

The -e command-line switch for pip causes it to use the "development" mode. The first argument after -e is not a project name but a path to a directory of your local filesystem. Development mode means that these modules run "directly from source". pip does not copy the sources to your Python site_packages, but instead adds a link to them.

A quick test when you want to see whether Lino is installed is to say "hello" to Lino:

$ python -m lino.hello
Lino 23.9.1, Django 4.2.2, Python 3.10.12, Babel 2.12.1, Jinja 3.1.2, python-dateutil 2.8.2

In case you didn't know: Python's -m command-line switch instructs it to just import the specified module (here lino.hello) and then to return to the command line.