Nothing is more frustrating when you're working on a project than having to : - Find the tools you need to work on the project (compilation, development, etc.). - Manage the versions of installed packages according to their installation date. - Manage the distributions on which these packages are installed (package manager used).

During the development phase of a project, maintaining a coherent development environment that evolves over time is quite difficult, mainly because of the following factors:

  * Some packages are not available on all Windows, MacOS and Linux distributions (Ubuntu, Archlinux, Fedora, Suse, etc.).
  * Versions of packages may become unavailable when a distribution evolves.

Some modern programming languages are well aware of this, and have dependency management systems with locking functions to ensure the reproducibility of development environments, such as :

  * Go
  * Python
  * Ruby
  * Rust
  * etc ...

These systems make it possible to maintain the same dependencies throughout the life of the project, but this only applies to the libraries used and not to all the third-party tools.

This is why I use the :

  * **Nix:** Provides a reproducible system.
  * **Direnv:** Allows a command to be executed when entering a directory.
  * **Just:** Provides a command manager as well as displaying help.

====== Example of use ======

Here is an example of use for the [[https://devops.jesuislibre.org|JSL Devops]]

Firstly, you will notice that the ''%%just%%'' and ''%%hugo%%'' are not available in the user's distribution. However, without any intervention from the user, you will notice that they become available thanks to ''%%Nix%%'' and the file ''%%flake.nix%% file''.

{{l_atelier:demo-onboarding.gif|}}

====== Installation ======

===== Direnv =====

Install the direnv package

# install direnv

''%%curl -sfL https://direnv.net/install.sh | bash%%''

Configure the shell to take into account ''%%direnv%%'' when a new shell is created. ### Shells

=== Bash ===

Add the following line to the end of the file ''%%~/.bashrc%%'' :


''%%eval "$(direnv hook bash)"%%''

Add the following line to the end of the file ''%%~/.zshrc%%'' :

=== ZSH ===


''%%eval "$(direnv hook zsh)"%%''

=== Fish ===

Add the following line to the end of the file ''%%~/.config/fish/config.fish%%'' :


''%%direnv hook fish | source%%''

Fish supports 3 modes that you can define with the global environment variable ''%%direnv_fish_mode%%'' :

<code fish>
set -g direnv_fish_mode eval_on_arrow    # Déclenche direnv à l'invite, et à chaque changement de répertoire par flèche (par défaut)
set -g direnv_fish_mode eval_after_arrow # Déclenche direnv à l'invite, et seulement après les changements de répertoire par flèche avant d'exécuter la commande 
set -g direnv_fish_mode disable_arrow    # Déclenche direnv à l'invite uniquement, il s'agit d'une fonctionnalité similaire au comportement original
</code>

===== Nix =====

==== OS Installation ====

==== Linux ====


<code bash>
sh <(curl -L https://nixos.org/nix/install) --daemon
grep 'experimental-features' /etc/nix/nix.conf || (echo 'experimental-features = nix-command flakes' | sudo tee -a /etc/nix/nix.conf)
</code>

==== Windows ====

<code bash>
sh <(curl -L https://nixos.org/nix/install) --daemon
grep 'experimental-features' /etc/nix/nix.conf || (echo 'experimental-features = nix-command flakes' | sudo tee -a /etc/nix/nix.conf)
</code>

==== MacOS ====

<code bash>
sh <(curl -L https://nixos.org/nix/install)
grep 'experimental-features' /etc/nix/nix.conf || (echo 'experimental-features = nix-command flakes' | sudo tee -a /etc/nix/nix.conf)
</code>
<WRAP info>
Once **nix** and **direnv** have been installed, the first time you access a project directory you will need to authorise automatic execution of **direnv** with the following command: ''%%direnv allow%%''
 
You can also launch onboarding with the following command ''%%nix develop%%''</WRAP>

===== just =====

The tool ''%%just%% tool'' tool will be installed automatically with ''%%nix%%'' and ''%%flake%%''see the next section.

====== Configuring project onboarding ======

To activate project onboarding, simply copy the 3 files below into your project's root directory.

<code>
projet
├─ .envrc
├─ flake.nix
└─ justfile
</code>

Configuration of the **.envrc file**


''%%use flake%%''

File configuration **flake.nix**

<code nix>
{
  inputs = {
    nixpkgs.url = "github:NixOS/nixpkgs/nixos-unstable";
    flake-utils.url = "github:numtide/flake-utils";
  };
  outputs = { nixpkgs, flake-utils, ... }:
    flake-utils.lib.eachDefaultSystem (system:
      let
        pkgs = import nixpkgs { inherit system; };
      in
      {
        devShells.default = with pkgs;
          mkShell {
            name = "Default developpement shell";
            packages = [
              cocogitto
              nixpkgs-fmt
              nodePackages.markdownlint-cli
              pre-commit

              deno
              gum
              just
            ];
            shellHook = ''
              export PROJ="devops.jesuislibre.org"

              echo ""
              echo "⭐ Welcome to the $PROJ project ⭐"
              echo ""
            '';
          };
      });
}
</code>

Configuration of the **justfile**

<code just>
#!/usr/bin/env just -f

# This help
# Help it showed if just is called without arguments
@help:
    just -lu | column -s '#' -t | sed 's/[ \t]*$//'

###############################################################################
# pre-commit
###############################################################################

# Setup pre-commit
precommit-install:
    #!/usr/bin/env bash
    test ! -f .git/hooks/pre-commit && pre-commit install || true

# Update pre-commit
@precommit-update:
    pre-commit autoupdate

# precommit check
@precommit-check:
    pre-commit run --all-files

###############################################################################
# Tools
###############################################################################

# Update documentation
@doc-update FAKEFILENAME:
    ./updatedoc.ts

# Lint the project
@lint:
    pre-commit run --all-files

# Repl the project
@repl:
    nix repl --extra-experimental-features repl-flake .#

# Show installed packages
@packages:
    echo $PATH | tr ":" "\n" | grep -E "/nix/store" | sed -e "s/\/nix\/store\/[a-z0-9]\+\-//g" | sed -e "s/\/.*//g"
</code>

===== Sources =====
  * [[en:CharteIA]]
    * openai
      * Rephrasing sentences
      * Correction of spelling mistakes