tvl-depot/default.nix
Vincent Ambo 9c482d6238 feat(ci): Add subtarget support for builds
We have naturally evolved a distinction between logical and physical
targets.

Physical targets are those which correspond directly to a tree
location on disk and can be built with `-A path.to.files`, while
logical targets are those that are exported from within an expression
but do not have a corresponding file on disk.

This change adds support for exporting logical targets from any tree
location by adding a `meta.targets` attribute containing keys into
itself, which will be consumed by the CI target gathering logic and
included in the generated pipeline.

Note that the labels for subtargets are syntactically different to
emphasise that they do not correspond to a file location. For example,
this change enables 'ops.nixos.whitbySystem' as a subtarget, which is
labeled in CI as `ops/nixos:whitbySystem`.

Change-Id: Ied09647a62c2ba98e3914548e3742ad422c63ecf
Reviewed-on: https://cl.tvl.fyi/c/depot/+/1893
Tested-by: BuildkiteCI
Reviewed-by: glittershark <grfn@gws.fyi>
2020-08-31 23:14:11 +00:00

109 lines
3.5 KiB
Nix

# This file sets up the top-level package set by traversing the package tree
# (see read-tree.nix for details) and constructing a matching attribute set
# tree.
#
# This makes packages accessible via the Nixery instance that is configured to
# use this repository as its nixpkgs source.
{ ... }@args:
with builtins;
let
# This definition of fix is identical to <nixpkgs>.lib.fix, but the global
# package set is not available here.
fix = f: let x = f x; in x;
# Global configuration that all packages are called with.
config = depot: {
inherit depot;
# Expose lib & ciBuilds attributes to packages.
inherit (depot) ciBuilds lib;
# Pass third_party as 'pkgs' (for compatibility with external
# imports for certain subdirectories)
pkgs = depot.third_party;
};
readTree' = import ./nix/readTree {};
localPkgs = readTree: {
fun = readTree ./fun;
lisp = readTree ./lisp;
net = readTree ./net;
nix = readTree ./nix;
ops = readTree ./ops;
third_party = readTree ./third_party;
tools = readTree ./tools;
users = readTree ./users;
web = readTree ./web;
};
# To determine build targets, we walk through the depot tree and
# fetch attributes that were imported by readTree and are buildable.
#
# Any build target that contains `meta.ci = false` will be skipped.
# Is this tree node eligible for build inclusion?
eligible = node: (node ? outPath) && (node.meta.ci or true);
# Walk the tree starting with 'node', recursively extending the list
# of build targets with anything that looks buildable.
#
# Any tree node can specify logical targets by exporting a
# 'meta.targets' attribute containing a list of keys in itself. This
# enables target specifications that do not exist on disk directly.
gather = node:
if node ? __readTree then
# Include the node itself if it is eligible.
(if eligible node then [ node ] else [])
# Include eligible children of the node
++ concatMap gather (attrValues node)
# Include specified sub-targets of the node
++ filter eligible (map
(k: (node."${k}" or {}) // {
# Keep the same tree location, but explicitly mark this
# node as a subtarget.
__readTree = node.__readTree;
__subtarget = k;
})
(node.meta.targets or []))
else [];
in fix(self: {
config = config self;
# Elevate 'lib' from nixpkgs
lib = import (self.third_party.nixpkgsSrc + "/lib");
# Expose readTree for downstream repo consumers.
readTree = {
__functor = x: (readTree' x.config);
config = self.config;
};
# Make the path to the depot available for things that might need it
# (e.g. NixOS module inclusions)
depotPath = ./.;
# List of all buildable targets, for CI purposes.
#
# Note: To prevent infinite recursion, this *must* be a nested
# attribute set (which does not have a __readTree attribute).
ci.targets = gather (self // {
# remove the pipelines themselves from the set over which to
# generate pipelines because that also leads to infinite
# recursion.
ops = self.ops // { pipelines = null; };
});
}
# Add local packages as structured by readTree
// (localPkgs (readTree' self.config))
# Load overrides into the top-level.
#
# This can be used to move things from third_party into the top-level, too (such
# as `lib`).
// (readTree' { depot = self; pkgs = self.third_party; }) ./overrides
)