central command (#8)

* WIP: eval target

* rename nixos-build to nixos-generate

* rename target to format

* allow to pass arbitrary format paths

* add --help option

* add --list option

* port the rest of the formats

* add short options

* be more precise with the file selection

* use new trick I learned

* support the --run option

for the no-gui version:

    ./nixos-generate --run -f vm-no-gui

* document

* fixup! port the rest of the formats

* fix kexec-bundle

README.md

@@ -1,32 +1,37 @@
-A simple collection of nixos image builders.
+# nixos-generators - one config, multiple formats
+
+The nixos-generators project allows to take the same NixOS configuration, and
+generate outputs for different target formats.
+
 Just put your stuff into the config.nix and then call one of the image builders.
 
 for example:
 ```
-bin/make-iso
+./nixos-generate -f iso
 ```
 or
+
 ```
-bin/make-iso config.nix
+./nixos-generate -f iso -c /etc/nixos/configuration.nix
 ```
 
-it echoes the path to a iso image, which you then can flash onto an usb-stick or mount & boot in a virtual machine.
+it echoes the path to a iso image, which you then can flash onto an usb-stick
+or mount & boot in a virtual machine.
 
-we currently have following generators:
+## Supported formats
 
-format | script | description
---- | --- | ---
-gce | bin/make-gce | Google Compute Image
-iso | bin/make-iso
-kexec | bin/make-kexec
-kexec-bundle | bin/make-kexec-bundle
-openstack | bin/make-openstack
-qcow2 | bin/make-qcow
-virtualbox | bin/make-virtualbox
-
-we also have following runners:
-
-platform | script
+format | description
 --- | ---
-qemu-kvm | bin/run-vm
-qemu-kvm (without gui) | bin/run-vm-nogui
+gce | Google Compute Image
+iso | Installer ISO
+kexec | 
+kexec-bundle |
+openstack |
+qcow2 |
+virtualbox |
+vm | only used as a qemu-kvm runner
+vm-nogui | same as before, but without a GUI
+
+## Usage
+
+Run `./nixos-generate --help` for detailed usage information

bin/make-gce

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-out=$(nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.googleComputeImage -I nixos-config=lib/gce.nix -I nixcfg=${CONFIG} "$@" )
-echo "$out"/*.tar.gz

bin/make-install-iso

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-ISO_DIR=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.isoImage -I nixos-config=lib/install-iso.nix -I nixcfg=${CONFIG} "$@" )
-find $ISO_DIR/iso/ -type f

bin/make-iso

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-ISO_DIR=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.isoImage -I nixos-config=lib/iso.nix -I nixcfg=${CONFIG} "$@" )
-echo $ISO_DIR/iso/nixos.iso

bin/make-kexec

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-TAR_DIR=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.kexec_tarball -I nixos-config=lib/kexec.nix -I nixcfg=${CONFIG} "$@" )
-find $TAR_DIR/tarball -type f

bin/make-kexec-bundle

@@ -1,4 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.kexec_bundle -I nixos-config=lib/kexec.nix -I nixcfg=${CONFIG} "$@"

bin/make-openstack

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-OPENSTACK_DIR=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.novaImage -I nixos-config=lib/openstack.nix -I nixcfg=${CONFIG} "$@" )
-echo $OPENSTACK_DIR/*.qcow2

bin/make-qcow

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-QCOW_DIR=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.qcow -I nixos-config=lib/qcow.nix -I nixcfg=${CONFIG} "$@" )
-echo $QCOW_DIR/nixos.qcow2

bin/make-virtualbox

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-VBOX_DIR=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.virtualBoxOVA -I nixos-config=lib/virtualbox.nix -I nixcfg=${CONFIG} "$@" )
-echo $VBOX_DIR/*.ova

bin/run-vm

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-VM=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.vm -I nixos-config=lib/vm.nix -I nixcfg=${CONFIG} "$@" )
-${VM}/bin/run-nixos-vm

bin/run-vm-nogui

@@ -1,5 +0,0 @@
-#!/bin/sh
-CONFIG=${1:-config.nix}
-shift
-VM=$( nix-build --no-out-link '<nixpkgs/nixos>' -A config.system.build.vm -I nixos-config=lib/vm-nogui.nix -I nixcfg=${CONFIG} "$@" )
-${VM}/bin/run-nixos-vm

eval-format.nix

@@ -0,0 +1,24 @@
+{ nixpkgs ? <nixpkgs>
+, configuration ? 
+  import "${toString nixpkgs}/nixos/lib/from-env.nix" "NIXOS_CONFIG" <nixos-config>
+, formatConfig
+, system ? builtins.currentSystem
+}:
+let
+  module = { lib, ... }: {
+    options = {
+      formatAttr = lib.mkOption {
+        type = lib.types.str;
+        description = "Declare the default attribute to build";
+      };
+    };
+  };
+in
+import "${toString nixpkgs}/nixos/lib/eval-config.nix" {
+  inherit system;
+  modules = [
+    module
+    formatConfig
+    configuration
+  ];
+}

formats/gce.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     "${toString modulesPath}/virtualisation/google-compute-image.nix"
-    <nixcfg>
   ];
+
+  formatAttr = "googleComputeImage";
 }

formats/install-iso.nix

@@ -2,7 +2,6 @@
 {
   imports = [
     <nixpkgs/nixos/modules/installer/cd-dvd/installation-cd-base.nix>
-    <nixcfg>
   ];
 
   # for installer
@@ -12,4 +11,5 @@
   systemd.services.wpa_supplicant.wantedBy = lib.mkForce [ "multi-user.target" ];
   systemd.services.sshd.wantedBy = lib.mkForce [ "multi-user.target" ];
 
+  formatAttr = "isoImage";
 }

formats/iso.nix

@@ -2,7 +2,6 @@
 {
   imports = [
     <nixpkgs/nixos/modules/installer/cd-dvd/iso-image.nix>
-    <nixcfg>
   ];
 
   # EFI booting
@@ -11,4 +10,5 @@
   # USB booting
   isoImage.makeUsbBootable = true;
 
+  formatAttr = "isoImage";
 }

formats/kexec-bundle.nix

@@ -0,0 +1,6 @@
+{ lib, ... }:
+{
+  imports = [ ./kexec.nix ];
+
+  formatAttr = lib.mkForce "kexec_bundle";
+}

formats/kexec.nix

@@ -7,7 +7,6 @@
 in {
   imports = [
     <nixpkgs/nixos/modules/installer/netboot/netboot-minimal.nix>
-    <nixcfg>
     "${clever-tests}/kexec/autoreboot.nix"
     "${clever-tests}/kexec/kexec.nix"
     "${clever-tests}/kexec/justdoit.nix"
@@ -54,5 +53,6 @@ in {
   ];
   systemd.services.sshd.wantedBy = lib.mkForce [ "multi-user.target" ];
   networking.hostName = lib.mkDefault "kexec";
-}
 
+  formatAttr = "kexec_tarball";
+}

formats/openstack.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     <nixpkgs/nixos/maintainers/scripts/openstack/nova-image.nix>
-    <nixcfg>
   ];
+
+  formatAttr = "novaImage";
 }

formats/qcow.nix

@@ -1,9 +1,5 @@
 { config, lib, pkgs, ... }:
 {
-  imports = [
-    <nixcfg>
-  ];
-
   fileSystems."/" = {
     device = "/dev/disk/by-label/nixos";
     autoResize = true;
@@ -20,4 +16,6 @@
     diskSize = 8192;
     format = "qcow2";
   };
+
+  formatAttr = "qcow";
 }

formats/virtualbox.nix

@@ -2,6 +2,7 @@
 {
   imports = [
     <nixpkgs/nixos/modules/virtualisation/virtualbox-image.nix>
-    <nixcfg>
   ];
+
+  formatAttr = "virtualBoxOVA";
 }

formats/vm.nix

@@ -2,11 +2,12 @@
 {
   imports = [
     <nixpkgs/nixos/modules/virtualisation/qemu-vm.nix>
-    <nixcfg>
   ];
 
   virtualisation.qemu.networkingOptions = [
     "-net nic,netdev=user.0,model=virtio"
     "-netdev user,id=user.0\${QEMU_NET_OPTS:+,$QEMU_NET_OPTS},hostfwd=tcp::8088-:80,hostfwd=tcp::8022-:22"
   ];
+
+  formatAttr = "vm";
 }

nixos-generate

@@ -0,0 +1,103 @@
+#!/usr/bin/env bash
+set -euo pipefail
+
+## Configuration
+
+libexec_dir="${0%/*}"
+configuration_path=${NIX_CONFIG:-$libexec_dir/config.nix}
+format_dir=$libexec_dir/formats
+format_path=
+run=
+
+## Functions
+
+showUsage() {
+  cat <<USAGE
+Usage: $0 [options]
+
+Options:
+
+* --help: shows this help
+* -c, --configuration PATH:
+    select the nixos configuration to build. Default: $configuration_path
+* -f, --format NAME: select one of the pre-determined formats
+* --format-path PATH: pass a custom format
+* --list: list the available built-in formats
+* --run: runs the configuration in a VM
+         only works for the "vm" and "vm-no-gui" formats
+USAGE
+}
+
+listFormats() {
+  for format in "$format_dir"/*.nix; do
+    basename "$format" ".nix"
+  done
+}
+
+abort() {
+  echo "aborted: $*" >&2
+  exit 1
+}
+
+## Main ##
+
+while [[ $# -gt 0 ]]; do
+  case "$1" in
+    -c | --configuration)
+      configuration_path=$2
+      shift
+      ;;
+    -f | --format)
+      format_path=$format_dir/$2.nix
+      shift
+      ;;
+    --format-path)
+      format_path=$2
+      shift
+      ;;
+    --help)
+      showUsage
+      exit
+      ;;
+    --list)
+      listFormats
+      exit
+      ;;
+    --run)
+      run=1
+      # default to the VM format
+      if [[ -z $format_path ]]; then
+        format_path=$format_dir/vm.nix
+      fi
+      ;;
+    *)
+      abort "unknown option $1"
+      ;;
+  esac
+  shift
+done
+
+if [[ -z $format_path ]]; then
+  abort "missing format. use --help for more details"
+fi
+
+if [[ ! -e $format_path ]]; then
+  abort "format '$format_path' not found"
+fi
+
+args=(
+  "$libexec_dir/eval-format.nix"
+  --arg configuration "$configuration_path"
+  --arg formatConfig "$format_path"
+)
+
+formatAttr=$(nix-instantiate "${args[@]}" --eval --json -A config.formatAttr | jq -r .)
+
+out=$(nix-build "${args[@]}" --no-out-link -A "config.system.build.$formatAttr")
+
+if [[ -z $run ]]; then
+  # show the first file
+  find "$out" -type f -print -quit
+else
+  "$out/bin/run-nixos-vm"
+fi