From 2b4e624ee80391e9cb86572cf1c8bbddd8865bde Mon Sep 17 00:00:00 2001
From: DavHau <d.hauer.it@gmail.com>
Date: Mon, 19 May 2025 18:36:50 +0700
Subject: [PATCH] clan-app/devshell: add script to launch qemu VMs for testing

---
 pkgs/clan-app/bin/start-qemu-vm.sh | 47 ++++++++++++++++++++++++++++++
 pkgs/clan-app/bin/start-vm         | 17 +++++++++++
 pkgs/clan-app/shell.nix            | 10 ++++---
 3 files changed, 70 insertions(+), 4 deletions(-)
 create mode 100755 pkgs/clan-app/bin/start-qemu-vm.sh
 create mode 100755 pkgs/clan-app/bin/start-vm

diff --git a/pkgs/clan-app/bin/start-qemu-vm.sh b/pkgs/clan-app/bin/start-qemu-vm.sh
new file mode 100755
index 000000000..86ba7f3d9
--- /dev/null
+++ b/pkgs/clan-app/bin/start-qemu-vm.sh
@@ -0,0 +1,47 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+getIso() {
+  # get the ssh public key of the current user
+  ssh_key=$(ssh-add -L)
+  # TODO: make this cross platform compatible by downloading a pre-built image
+  #   and injecting the ssh private key into it
+  nix build --impure --expr "
+    let
+      pkgs = import <nixpkgs> { crossSystem = \"x86_64-linux\"; };
+    in
+    (pkgs.nixos {
+      services.openssh.enable = true;
+      environment.systemPackages = [ pkgs.nixos-facter ];
+      users.users.root.openssh.authorizedKeys.keys = [ \"$ssh_key\" ];
+      users.users.root.password = \"root\";
+    }).config.system.build.images.iso
+  " -o iso
+  iso=$(realpath iso)
+  # iso=/nix/store/xgkfnwhi3c2lcpsvlpcw3dygwgifinbq-nixos-minimal-23.05pre483386.f212785e1ed-x86_64-linux.iso
+  # nix-store -r "$iso"
+}
+
+id="${1:-1}"
+
+CPUS="${CPUS:-2}"
+MEMORY="${MEMORY:-4096}"
+IMAGE_SIZE="${IMAGE_SIZE:-10G}"
+SSH_PORT="${SSH_PORT:-2200${id}}"
+
+img_file="nixos-nvme${id}.img"
+getIso
+truncate -s"$IMAGE_SIZE" "$img_file"
+set -x
+qemu-system-x86_64 \
+  -m "${MEMORY}" \
+  -boot n \
+  -smp "${CPUS}" \
+  -enable-kvm \
+  -cpu max \
+  -netdev "user,id=mynet0,hostfwd=tcp::${SSH_PORT}-:22" \
+  -device virtio-net-pci,netdev=mynet0 \
+  -drive "file=$img_file,if=none,id=nvme1,format=raw" \
+  -device nvme,serial=deadbeef1,drive=nvme1 \
+  -cdrom "$iso"/iso/*.iso
diff --git a/pkgs/clan-app/bin/start-vm b/pkgs/clan-app/bin/start-vm
new file mode 100755
index 000000000..a55733668
--- /dev/null
+++ b/pkgs/clan-app/bin/start-vm
@@ -0,0 +1,17 @@
+#!/usr/bin/env bash
+
+set -euo pipefail
+
+script_dir=$(dirname "$(realpath "$0")")
+
+trap 'rm -rf "$tmpdir"' EXIT
+tmpdir=$(mktemp -d)
+cd "$tmpdir"
+
+number_vms="$1"
+
+for i in $(seq 1 "$number_vms"); do
+  "$script_dir/start-qemu-vm.sh" "$i" &
+done
+
+while true; do sleep 1; done
diff --git a/pkgs/clan-app/shell.nix b/pkgs/clan-app/shell.nix
index 970b025a6..526bf294b 100644
--- a/pkgs/clan-app/shell.nix
+++ b/pkgs/clan-app/shell.nix
@@ -9,6 +9,10 @@
   json2ts,
   self',
 }:
+let
+  GREEN = "\\033[1;32m";
+  NC = "\\033[0m";
+in
 
 mkShell {
   name = "ui";
@@ -72,10 +76,8 @@ mkShell {
     if test -f "$GIT_ROOT/pkgs/clan-app/.local.env"; then
       source "$GIT_ROOT/pkgs/clan-app/.local.env"
     fi
-    # Define the yellow color code
-    YELLOW='\033[1;33m'
-    # Define the reset color code
-    NC='\033[0m'
     export PC_CONFIG_FILES="$CLAN_CORE_PATH/pkgs/clan-app/process-compose.yaml"
+
+    echo -e "${GREEN}To launch a qemu VM for testing, run:\n  start-vm <number of VMs>${NC}"
   '';
 }