This guide explains how to use Nix to set up a reproducible development environment for xrpld. Using Nix eliminates the need to manually install utilities and ensures consistent tooling across different machines.

Benefits of Using Nix

Reproducible environment: Everyone gets the same versions of tools and compilers
No system pollution: Dependencies are isolated and don't affect your system packages
Multiple compiler versions: Easily switch between different GCC and Clang versions
Quick setup: Get started with a single command
Works on Linux and macOS: Consistent experience across platforms

Install Nix

Please follow the official installation instructions of nix package manager for your system.

Entering the Development Shell

Basic Usage

From the root of the xrpld repository, enter the default development shell:

nix --experimental-features 'nix-command flakes' develop

This will:

Download and set up all required development tools (CMake, Ninja, Conan, etc.)
Configure the appropriate compiler for your platform:
- macOS: Apple Clang (default system compiler)
- Linux: GCC 15

The first time you run this command, it will take a few minutes to download and build the environment. Subsequent runs will be much faster.

‍[!TIP] To avoid typing ‘--experimental-features 'nix-command flakes’every time, you can permanently enable flakes by creating~/.config/nix/nix.conf`:

mkdir -p ~/.config/nix

echo "experimental-features = nix-command flakes" >> ~/.config/nix/nix.conf

After this, you can simply use nix develop instead.

‍[!NOTE] The examples below assume you've enabled flakes in your config. If you haven't, add ‘--experimental-features 'nix-command flakes’after eachnix` command.

Choosing a different compiler

A compiler can be chosen by providing its name with the .# prefix, e.g. nix develop .#gcc15. Use nix flake show to see all the available development shells.

Use nix develop .#no_compiler to use the compiler from your system.

Example Usage

# Use GCC 14
nix develop .#gcc14
 
# Use Clang 19
nix develop .#clang19
 
# Use default for your platform
nix develop

Using a different shell

nix develop opens bash by default. If you want to use another shell this could be done by adding -c flag. For example:

nix develop -c zsh

Building xrpld with Nix

Once inside the Nix development shell, follow the standard build instructions. The Nix shell provides all necessary tools (CMake, Ninja, Conan, etc.).

Automatic Activation with direnv

direnv or nix-direnv can automatically activate the Nix development shell when you enter the repository directory.

Conan and Prebuilt Packages

Please note that there is no guarantee that binaries from conan cache will work when using nix. If you encounter any errors, please use ‘--build ’*'` to force conan to compile everything from source:

conan install .. --output-folder . --build '*' --settings build_type=Release

Updating <tt>flake.lock</tt> file

To update flake.lock to the latest revision use nix flake update command.