add multiple envs for packages

README.md

@@ -1,6 +1,141 @@
 # dots
 
+This repository contains my dotfiles and a Nix flake that supports multiple hosts (machines) with a shared base and per-host configuration.
+
+- On NixOS: hosts are built via `nixosConfigurations`.
+- On non-NixOS (e.g., Ubuntu): hosts are applied via Home Manager using `homeConfigurations`.
+
+## Bootstrap
+
 ```shell
 pip install pipx ansible
 ansible-playbook --ask-become-pass ansible/main.yml
+# Then apply dotfiles with dotter
 dotter
+```
+
+## NixOS: multi-host layout
+
+- nix/base/packages.nix — packages installed on all hosts
+- nix/hosts/<host>/
+  - configuration.nix — host-specific NixOS configuration
+  - hardware-configuration.nix — generated per-machine
+  - packages.nix — extra packages for this host
+- nix/flake.nix — exposes each host under nixosConfigurations
+
+Current hosts:
+- limgrave — my main system
+- carpates — scaffolded/minimal, ready to extend
+
+## Naming rule (important)
+Your machine hostname must match the Nix flake host name. For example:
+- networking.hostName = "limgrave" in the host configuration
+- The flake exports nixosConfigurations.limgrave
+- The system hostname (output of `hostname -s`) is limgrave
+
+This allows the upgrade function to pick the right configuration automatically.
+
+## Build or switch
+From repo root:
+
+```bash
+# Limgrave (current system)
+sudo nixos-rebuild switch --flake ./nix#limgrave
+
+# carpates (on target machine)
+sudo nixos-rebuild switch --flake ./nix#carpates
+# Or during install:
+# nixos-install --flake <repo-path>/nix#carpates
+```
+
+## Upgrades: nix_upgrade
+A convenience Fish function is provided in fish/conf.d/functions.fish: `nix_upgrade`.
+It updates flake inputs and rebuilds the system using a host name that matches the machine hostname.
+
+Usage:
+```fish
+# Automatic: uses (hostname -s) → must match a host in nix/flake.nix
+nix_upgrade
+
+# Override the host explicitly (useful for recovery or chroots)
+nix_upgrade limgrave
+```
+What it does:
+1) sudo nix flake update --flake /home/catalin/.dotfiles/nix
+2) sudo nixos-rebuild switch --flake /home/catalin/.dotfiles/nix#<host> --upgrade
+
+Safety checks:
+- Verifies nix/flake.nix exists
+- Verifies the host is declared in nix/flake.nix
+- Prints clear error if the hostname doesn’t map to a known host
+
+Tip: ensure your system hostname matches one of the directories in nix/hosts/ and the entry under nixosConfigurations in nix/flake.nix.
+
+## Adding a new host
+1) Create a directory: nix/hosts/<newhost>/
+2) Add configuration files (start by copying limgrave and trimming, or use the minimal example from carpates)
+3) Generate hardware config on the new machine:
+```bash
+sudo nixos-generate-config
+# Move merge the generated hardware-configuration.nix into nix/hosts/<newhost>/
+```
+4) Add the host to nix/flake.nix under nixosConfigurations
+5) Make sure networking.hostName = "<newhost>" in the host configuration
+6) Build or install:
+```bash
+sudo nixos-rebuild switch --flake ./nix#<newhost>
+# or during install:
+nixos-install --flake <repo-path>/nix#<newhost>
+```
+
+## Notes
+- Old single-host files nix/configuration.nix and nix/packages.nix are kept for reference but are not used by the flake. You can remove them once comfortable with the new layout.
+- limgrave includes nix-snapd and Home Manager; carpates currently includes Home Manager only.
+
+## Nix on non-NixOS (Ubuntu, etc.)
+You can also use this flake on non-NixOS systems (e.g., Ubuntu) via Home Manager. For that path, hosts are defined under `homeConfigurations` in `nix/flake.nix` and typically live next to their NixOS counterparts. In this repo, `carpates` is prepared for non-NixOS via Home Manager.
+
+- Naming rule: your machine's hostname (output of `hostname -s`) should match the `homeConfigurations.<host>` entry. Example: `carpates`.
+- Packages: non-NixOS hosts usually install user-scoped packages via Home Manager, using the shared base set from `nix/base/packages.nix`.
+
+### Prerequisites
+- Install Nix (multi-user is recommended):
+  ```bash
+  sh <(curl -L https://nixos.org/nix/install) --daemon
+  ```
+- Enable flakes (if not already). On non-NixOS, set in `/etc/nix/nix.conf` or `$XDG_CONFIG_HOME/nix/nix.conf`:
+  ```
+  experimental-features = nix-command flakes
+  ```
+- Install Home Manager (no separate channel needed when using flakes; we can run it via `nix run` or install it on PATH):
+  ```bash
+  # Optional, to have `home-manager` on PATH:
+  nix profile install github:nix-community/home-manager
+  ```
+
+### Apply the configuration (non-NixOS)
+From repo root:
+```bash
+# Use the prepared Home Manager host (example: carpates)
+home-manager switch --flake ./nix#carpates
+# If `home-manager` is not installed, you can run it via nix:
+nix run github:nix-community/home-manager -- switch --flake ./nix#carpates
+```
+
+### Upgrades (non-NixOS)
+`nix_upgrade` also works on non-NixOS:
+```fish
+# Auto-detects host from (hostname -s) and runs Home Manager switch
+nix_upgrade
+
+# Or override explicitly
+nix_upgrade carpates
+```
+What it does on non-NixOS:
+- `nix flake update --flake /home/catalin/.dotfiles/nix`
+- `home-manager switch --flake /home/catalin/.dotfiles/nix#<host>` (or `nix run ... -- switch` if HM is not on PATH)
+
+### NixOS vs. non-NixOS summary
+- NixOS hosts are declared under `nixosConfigurations` and are applied with `nixos-rebuild`.
+- non-NixOS hosts are declared under `homeConfigurations` and are applied with `home-manager switch`.
+- The `nix_upgrade` function detects the OS and selects the correct path automatically based on the hostname.