Allow developers to use nix-shell to get started

.github/workflows/nix-ci.yml

@@ -0,0 +1,31 @@
+name: Test nix-shell
+
+on:
+  push:
+    branches:
+      - '*'
+
+jobs:
+  nix-shell:
+    strategy:
+      matrix:
+        os: [ macos-latest, ubuntu-latest ]
+    runs-on: ${{ matrix.os }}
+
+    steps:
+        - uses: actions/checkout@v4
+          with:
+            # Fetch the whole history for all tags and branches (required for aleph.__version__)
+            fetch-depth: 0
+
+        - name: Setup empty config file
+          run: touch config.yml
+
+        - name: Set up Nix
+          uses: cachix/install-nix-action@v25
+          with:
+            # Use channel nixos-23.11 for Linux and nixpkgs-23.11-darwin for macOS
+            nix_path: nixpkgs=channel:${{ matrix.os == 'macos-latest' && 'nixpkgs-23.11-darwin' || 'nixos-23.11' }}
+
+        - name: Run tests
+          run: nix-shell --run "pytest"

README.md

@@ -38,6 +38,18 @@ pip install -e .[testing,docs]
 
 You're ready to go!
 
+### Developer setup using Nix
+
+We started to add Nix as an easy way to setup a development environment.
+This is still a work in progress and not all dependencies are covered yet.
+
+To use it, you need to [have Nix installed on your system](https://nixos.org/download.html). Then you can run:
+
+```bash
+nix-shell
+```
+This will provide you with a shell with PostgreSQL, Redis, and IPFS running.
+
 ## Software used
 
 The Aleph CCN is written in Python and requires Python v3.8+. It will not work with older versions of Python.

shell.nix

@@ -0,0 +1,69 @@
+{ pkgs ? import <nixpkgs> {} }:
+
+pkgs.mkShell {
+  buildInputs = [
+    pkgs.postgresql
+    pkgs.redis
+    pkgs.kubo
+
+    pkgs.python311
+    pkgs.python311Packages.virtualenv
+    pkgs.python311Packages.pip
+    pkgs.python311Packages.setuptools
+
+    pkgs.python311Packages.secp256k1
+    pkgs.python311Packages.fastecdsa
+    pkgs.python311Packages.greenlet
+  ];
+
+  shellHook = ''
+    echo "Setting up PostgreSQL environment..."
+    export PGDATA=$(mktemp -d)
+    PG_SOCKET_DIR=$(mktemp -d)
+    echo "Initializing database..."
+    initdb $PGDATA
+
+    echo "Starting PostgreSQL with custom socket directory..."
+    pg_ctl -D $PGDATA -o "-k $PG_SOCKET_DIR" -l logfile start
+
+    # Wait a bit for the server to start
+    sleep 1
+
+    # Create the 'aleph' role and a database
+    createuser -h $PG_SOCKET_DIR aleph
+    createdb -h $PG_SOCKET_DIR aleph -O aleph
+
+    # Create a temporary directory for Redis
+    export REDIS_DATA_DIR=$(mktemp -d)
+    redis-server --daemonize yes --dir $REDIS_DATA_DIR --bind 127.0.0.1 --port 6379
+    echo "Redis server started. Data directory is $REDIS_DATA_DIR"
+