NixOS · Jun 18, 2019
Showing with 82 additions and 0 deletions.

+12 −0 README.md

+8 −0 default.nix

+7 −0 publish.sh

+55 −0 snap.nix
diff --git a/README.md b/README.md
@@ -0,0 +1,12 @@
+Have a Snapcraft-capable machine
+
+Hint: NixOS doesn't have Snapcraft at the time of publishing.
+
+Then:
+
+1. `snapcraft login`
+2. `./publish.sh`
+
+However, good news, you will probably never need to do this since the
+base image has almost nothing in it but the minimum necessary
+directories plus `/nix`.
diff --git a/default.nix b/default.nix
@@ -0,0 +1,8 @@
+let
+  nixpkgs = builtins.fetchTarball {
+    url = "https://github.com/NixOS/nixpkgs/archive/e6d320ec0ceefa56f9e711e389a6f39cdc985634.tar.gz";
+    sha256 = "1zzp6h0mnz7qkhvzrgrlmlp6ljwnkn5k942gldkmajhcbs6jddhb";
+  };
+
+  pkgs = import nixpkgs { system = "x86_64-linux"; };
+in pkgs.callPackage ./snap.nix { }
diff --git a/publish.sh b/publish.sh
@@ -0,0 +1,7 @@
+#!/bin/sh
+
+set -eux
+
+resultpath=$(nix-build .)
+snapcraft push --release=stable \
+          "$resultpath/nix-base_*_all.snap"
diff --git a/snap.nix b/snap.nix
@@ -0,0 +1,55 @@
+{
+  lib, runCommand, squashfsTools, closureInfo, jq
+}:
+let
+  meta = {
+    name = "nix-base";
+    type = "base";
+    confinement = "strict";
+    architectures = [ "all" ] ;
+    license = "CC0-1.0";
+  };
+
+  # from: https://github.com/snapcore/snapcraft/blob/b88e378148134383ffecf3658e3a940b67c9bcc9/snapcraft/internal/lifecycle/_packer.py#L96-L98
+  # These options need to match the review tools:
+  # http://bazaar.launchpad.net/~click-reviewers/click-reviewers-tools/trunk/view/head:/clickreviews/common.py#L38
+  mksquashfs_args = [
+    "-noappend" "-comp" "xz" "-no-xattrs" "-no-fragments"
+
+    # https://github.com/snapcore/snapcraft/blob/b88e378148134383ffecf3658e3a940b67c9bcc9/snapcraft/internal/lifecycle/_packer.py#L100
+    "-all-root"
+  ];
+in runCommand "nix-base" {
+  nativeBuildInputs = [ squashfsTools jq ];
+
+  snapMeta = builtins.toJSON meta;
+  passAsFile = [ "snapMeta" ];
+}
+''
+  root=$PWD/root
+  mkdir $root
+
+  version=$(echo $out | cut -d/ -f4 | cut -d- -f1)
+
+  (
+    mkdir $root/meta
+    cat $snapMetaPath | jq  ". + { version: \"$version\" }" \
+    > $root/meta/snap.yaml
+  )
+
+  (
+    cd $root
+    mkdir --mode 755 -p meta sys tmp usr/lib/snapd usr/src \
+      bin nix snap etc root run dev home proc var/lib/snapd \
+      var/tmp var/snap var/log media \
+      usr/share/fonts usr/local/share/fonts \
+      var/cache/fontconfig
+  )
+
+  # Generate the squashfs image.
+  mksquashfs $root ./nix-base_''${version}_all.snap \
+    ${lib.concatStringsSep " " mksquashfs_args}
+
+  mkdir $out
+  mv ./nix-base_*_all.snap $out/
+''