hack: use devbox to install nix

I use devbox to install nix in a non-root docker devcontainer environment,
which the other installers (official and detsys) don't support
I dont actually use any of the devbox features

Author: Ramblurr

.devcontainer/Dockerfile

@@ -1,30 +1,13 @@
-FROM mcr.microsoft.com/devcontainers/base:ubuntu-24.04
-
-# Install dependencies for Nix
-RUN apt-get update && export DEBIAN_FRONTEND=noninteractive \
-    && apt-get -y install --no-install-recommends curl xz-utils sudo systemd \
-    && apt-get clean && rm -rf /var/lib/apt/lists/*
-
-#VOLUME /nix
-
-RUN curl --proto '=https' --tlsv1.2 -sSf -L https://install.determinate.systems/nix | sh -s -- install linux \
-  --extra-conf "sandbox = false" \
-  --no-start-daemon \
-  --no-confirm
-
-ENV PATH="/nix/var/nix/profiles/default/bin:${PATH}"
-ENV USER=vscode
-
-# Basic Nix configuration (as root)
-# Ensure /etc/nix exists before trying to write to nix.conf
-RUN mkdir -p /etc/nix && \
-    echo "experimental-features = nix-command flakes" >> /etc/nix/nix.conf && \
-    echo "trusted-users = root ${USER} @wheel" >> /etc/nix/nix.conf
-
+# renovate: datasource=github-tags depName=devbox packageName=jetify-com/devbox
+ARG DEVBOX_VERSION=0.16.0
+FROM jetpackio/devbox:${DEVBOX_VERSION}
+ENV DEVBOX_USER=vscode
 ENV HM_FLAKE_URI=github:Ramblurr/nix-agent-dev
-RUN . /nix/var/nix/profiles/default/etc/profile.d/nix-daemon.sh && \
-  nix build --impure --no-write-lock-file "${HM_FLAKE_URI}#homeConfigurations.${USER}.activationPackage" --no-link
-
-USER ${USER}
-WORKDIR /home/${USER}
-ENV PATH="/nix/var/nix/profiles/default/bin:${PATH}"
+WORKDIR /home/${DEVBOX_USER}
+
+# I use devbox to install nix in a non-root docker devcontainer environment,
+# which the other installers (official and detsys) don't support
+# I dont actually use any of the devbox features
+COPY --chown=${DEVBOX_USER}:${DEVBOX_USER} devbox.json devbox.json
+COPY --chown=${DEVBOX_USER}:${DEVBOX_USER} devbox.lock devbox.lock
+RUN devbox install && nix-store --gc && nix build --extra-experimental-features 'nix-command flakes' --impure --no-write-lock-file "${HM_FLAKE_URI}#homeConfigurations.${DEVBOX_USER}.activationPackage" --no-link

devbox.json

@@ -0,0 +1,14 @@
+{
+    "$schema": "https://raw.githubusercontent.com/jetify-com/devbox/0.16.0/.schema/devbox.schema.json",
+    "packages": [],
+    "shell": {
+      "init_hook": [
+        "echo 'Welcome to devbox!' > /dev/null"
+      ],
+      "scripts": {
+        "test": [
+          "echo \"Error: no test specified\" && exit 1"
+        ]
+      }
+    }
+  }

devbox.lock

@@ -0,0 +1,9 @@
+{
+  "lockfile_version": "1",
+  "packages": {
+    "github:NixOS/nixpkgs/nixpkgs-unstable": {
+      "last_modified": "2025-09-03T14:58:13Z",
+      "resolved": "github:NixOS/nixpkgs/c6a788f552b7b7af703b1a29802a7233c0067908?lastModified=1756911493&narHash=sha256-6n%2Fn1GZQ%2Fvi%2BLhFXMSyoseKdNfc2QQaSBXJdgamrbkE%3D"
+    }
+  }
+}