lix/docker.nix
John Ericson 8368a8aff1 Make docker.nix match Nixpkgs's idioms
1. `target` is the wrong name, that is just for compilers per out
standard terminology. We just need to worry about "build" and "host".

2. We only need one `pkgs`. `pkgs.buildPackages` is how we get anything
we need at build time.

3. `crossSystem` is the name of a nixpkgs parameter that is actually an
attribute set, not a 2-part "cpu-os" string.

3. `pkgsCross` effectively evaluates Nixpkgs twice, which is
inefficient. It is just there for people poking around the CLI / REPL
(and I am skeptical even that is a good idea), and *not* what written
code should use, especially code that is merely parametric in the package set
it is given.

4. We don't need to memoize Nixpkgs here because we are only doing one
pkg set at a time (no `genAttrs`) so it's better to just delete all this
stuff. `flake.nix` instead would do something like that, with
`genAttrs` (though without `pkgsCross`), if and when we have hydra jobs
for cross builds.
2021-11-16 11:04:25 -05:00

251 lines
6.3 KiB
Nix

{ pkgs ? import <nixpkgs> { }
, lib ? pkgs.lib
, name ? "nix"
, tag ? "latest"
, channelName ? "nixpkgs"
, channelURL ? "https://nixos.org/channels/nixpkgs-unstable"
}:
let
defaultPkgs = with pkgs; [
nix
bashInteractive
coreutils-full
gnutar
gzip
gnugrep
which
curl
less
wget
man
cacert.out
findutils
];
users = {
root = {
uid = 0;
shell = "/bin/bash";
home = "/root";
gid = 0;
};
} // lib.listToAttrs (
map
(
n: {
name = "nixbld${toString n}";
value = {
uid = 30000 + n;
gid = 30000;
groups = [ "nixbld" ];
description = "Nix build user ${toString n}";
};
}
)
(lib.lists.range 1 32)
);
groups = {
root.gid = 0;
nixbld.gid = 30000;
};
userToPasswd = (
k:
{ uid
, gid ? 65534
, home ? "/var/empty"
, description ? ""
, shell ? "/bin/false"
, groups ? [ ]
}: "${k}:x:${toString uid}:${toString gid}:${description}:${home}:${shell}"
);
passwdContents = (
lib.concatStringsSep "\n"
(lib.attrValues (lib.mapAttrs userToPasswd users))
);
userToShadow = k: { ... }: "${k}:!:1::::::";
shadowContents = (
lib.concatStringsSep "\n"
(lib.attrValues (lib.mapAttrs userToShadow users))
);
# Map groups to members
# {
# group = [ "user1" "user2" ];
# }
groupMemberMap = (
let
# Create a flat list of user/group mappings
mappings = (
builtins.foldl'
(
acc: user:
let
groups = users.${user}.groups or [ ];
in
acc ++ map
(group: {
inherit user group;
})
groups
)
[ ]
(lib.attrNames users)
);
in
(
builtins.foldl'
(
acc: v: acc // {
${v.group} = acc.${v.group} or [ ] ++ [ v.user ];
}
)
{ }
mappings)
);
groupToGroup = k: { gid }:
let
members = groupMemberMap.${k} or [ ];
in
"${k}:x:${toString gid}:${lib.concatStringsSep "," members}";
groupContents = (
lib.concatStringsSep "\n"
(lib.attrValues (lib.mapAttrs groupToGroup groups))
);
nixConf = {
sandbox = "false";
build-users-group = "nixbld";
trusted-public-keys = "cache.nixos.org-1:6NCHdD59X431o0gWypbMrAURkbJ16ZPMQFGspcDShjY=";
};
nixConfContents = (lib.concatStringsSep "\n" (lib.mapAttrsFlatten (n: v: "${n} = ${v}") nixConf)) + "\n";
baseSystem =
let
nixpkgs = pkgs.path;
channel = pkgs.runCommand "channel-nixos" { } ''
mkdir $out
ln -s ${nixpkgs} $out/nixpkgs
echo "[]" > $out/manifest.nix
'';
rootEnv = pkgs.buildPackages.buildEnv {
name = "root-profile-env";
paths = defaultPkgs;
};
profile = pkgs.buildPackages.runCommand "user-environment" { } ''
mkdir $out
cp -a ${rootEnv}/* $out/
cat > $out/manifest.nix <<EOF
[
${lib.concatStringsSep "\n" (builtins.map (drv: let
outputs = drv.outputsToInstall or [ "out" ];
in ''
{
${lib.concatStringsSep "\n" (builtins.map (output: ''
${output} = { outPath = "${lib.getOutput output drv}"; };
'') outputs)}
outputs = [ ${lib.concatStringsSep " " (builtins.map (x: "\"${x}\"") outputs)} ];
name = "${drv.name}";
outPath = "${drv}";
system = "${drv.system}";
type = "derivation";
meta = { };
}
'') defaultPkgs)}
]
EOF
'';
in
pkgs.runCommand "base-system"
{
inherit passwdContents groupContents shadowContents nixConfContents;
passAsFile = [
"passwdContents"
"groupContents"
"shadowContents"
"nixConfContents"
];
allowSubstitutes = false;
preferLocalBuild = true;
} ''
env
set -x
mkdir -p $out/etc
cat $passwdContentsPath > $out/etc/passwd
echo "" >> $out/etc/passwd
cat $groupContentsPath > $out/etc/group
echo "" >> $out/etc/group
cat $shadowContentsPath > $out/etc/shadow
echo "" >> $out/etc/shadow
mkdir -p $out/usr
ln -s /nix/var/nix/profiles/share $out/usr/
mkdir -p $out/nix/var/nix/gcroots
mkdir $out/tmp
mkdir -p $out/etc/nix
cat $nixConfContentsPath > $out/etc/nix/nix.conf
mkdir -p $out/root
mkdir -p $out/nix/var/nix/profiles/per-user/root
ln -s ${profile} $out/nix/var/nix/profiles/default-1-link
ln -s $out/nix/var/nix/profiles/default-1-link $out/nix/var/nix/profiles/default
ln -s /nix/var/nix/profiles/default $out/root/.nix-profile
ln -s ${channel} $out/nix/var/nix/profiles/per-user/root/channels-1-link
ln -s $out/nix/var/nix/profiles/per-user/root/channels-1-link $out/nix/var/nix/profiles/per-user/root/channels
mkdir -p $out/root/.nix-defexpr
ln -s $out/nix/var/nix/profiles/per-user/root/channels $out/root/.nix-defexpr/channels
echo "${channelURL} ${channelName}" > $out/root/.nix-channels
mkdir -p $out/bin $out/usr/bin
ln -s ${pkgs.coreutils}/bin/env $out/usr/bin/env
ln -s ${pkgs.bashInteractive}/bin/bash $out/bin/sh
'';
in
pkgs.dockerTools.buildLayeredImageWithNixDb {
inherit name tag;
contents = [ baseSystem ];
extraCommands = ''
rm -rf nix-support
ln -s /nix/var/nix/profiles nix/var/nix/gcroots/profiles
'';
config = {
Cmd = [ "/root/.nix-profile/bin/bash" ];
Env = [
"USER=root"
"PATH=${lib.concatStringsSep ":" [
"/root/.nix-profile/bin"
"/nix/var/nix/profiles/default/bin"
"/nix/var/nix/profiles/default/sbin"
]}"
"MANPATH=${lib.concatStringsSep ":" [
"/root/.nix-profile/share/man"
"/nix/var/nix/profiles/default/share/man"
]}"
"SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"
"GIT_SSL_CAINFO=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"
"NIX_SSL_CERT_FILE=/nix/var/nix/profiles/default/etc/ssl/certs/ca-bundle.crt"
"NIX_PATH=/nix/var/nix/profiles/per-user/root/channels:/root/.nix-defexpr/channels"
];
};
}