284 lines
8.6 KiB
Nix
284 lines
8.6 KiB
Nix
# Copyright (c) 2019 Vincent Ambo
|
||
# Copyright (c) 2020-2021 The TVL Authors
|
||
# SPDX-License-Identifier: MIT
|
||
#
|
||
# Provides a function to automatically read a a filesystem structure
|
||
# into a Nix attribute set.
|
||
#
|
||
# Called with an attribute set taking the following arguments:
|
||
#
|
||
# path: Path to a directory from which to start reading the tree.
|
||
#
|
||
# args: Argument set to pass to each imported file.
|
||
#
|
||
# filter: Function to filter `args` based on the tree location. This should
|
||
# be a function of the form `args -> location -> args`, where the
|
||
# location is a list of strings representing the path components of
|
||
# the current readTree target. Optional.
|
||
{ ... }:
|
||
|
||
let
|
||
inherit (builtins)
|
||
attrNames
|
||
concatMap
|
||
concatStringsSep
|
||
elem
|
||
elemAt
|
||
filter
|
||
hasAttr
|
||
head
|
||
isAttrs
|
||
listToAttrs
|
||
map
|
||
match
|
||
readDir
|
||
substring;
|
||
|
||
argsWithPath = args: parts:
|
||
let meta.locatedAt = parts;
|
||
in meta // (if isAttrs args then args else args meta);
|
||
|
||
readDirVisible = path:
|
||
let
|
||
children = readDir path;
|
||
isVisible = f: f == ".skip-subtree" || (substring 0 1 f) != ".";
|
||
names = filter isVisible (attrNames children);
|
||
in
|
||
listToAttrs (map
|
||
(name: {
|
||
inherit name;
|
||
value = children.${name};
|
||
})
|
||
names);
|
||
|
||
# Create a mark containing the location of this attribute and
|
||
# a list of all child attribute names added by readTree.
|
||
marker = parts: children: {
|
||
__readTree = parts;
|
||
__readTreeChildren = builtins.attrNames children;
|
||
};
|
||
|
||
# Create a label from a target's tree location.
|
||
mkLabel = target:
|
||
let label = concatStringsSep "/" target.__readTree;
|
||
in if target ? __subtarget
|
||
then "${label}:${target.__subtarget}"
|
||
else label;
|
||
|
||
# Merge two attribute sets, but place attributes in `passthru` via
|
||
# `overrideAttrs` for derivation targets that support it.
|
||
merge = a: b:
|
||
if a ? overrideAttrs
|
||
then
|
||
a.overrideAttrs
|
||
(prev: {
|
||
passthru = (prev.passthru or { }) // b;
|
||
})
|
||
else a // b;
|
||
|
||
# Import a file and enforce our calling convention
|
||
importFile = args: scopedArgs: path: parts: filter:
|
||
let
|
||
importedFile =
|
||
if scopedArgs != { }
|
||
then builtins.scopedImport scopedArgs path
|
||
else import path;
|
||
pathType = builtins.typeOf importedFile;
|
||
in
|
||
if pathType != "lambda"
|
||
then builtins.throw "readTree: trying to import ${toString path}, but it’s a ${pathType}, you need to make it a function like { depot, pkgs, ... }"
|
||
else importedFile (filter parts (argsWithPath args parts));
|
||
|
||
nixFileName = file:
|
||
let res = match "(.*)\\.nix" file;
|
||
in if res == null then null else head res;
|
||
|
||
readTree = { args, initPath, rootDir, parts, argsFilter, scopedArgs }:
|
||
let
|
||
dir = readDirVisible initPath;
|
||
joinChild = c: initPath + ("/" + c);
|
||
|
||
self =
|
||
if rootDir
|
||
then { __readTree = [ ]; }
|
||
else importFile args scopedArgs initPath parts argsFilter;
|
||
|
||
# Import subdirectories of the current one, unless the special
|
||
# `.skip-subtree` file exists which makes readTree ignore the
|
||
# children.
|
||
#
|
||
# This file can optionally contain information on why the tree
|
||
# should be ignored, but its content is not inspected by
|
||
# readTree
|
||
filterDir = f: dir."${f}" == "directory";
|
||
children = if hasAttr ".skip-subtree" dir then [ ] else
|
||
map
|
||
(c: {
|
||
name = c;
|
||
value = readTree {
|
||
inherit argsFilter scopedArgs;
|
||
args = args;
|
||
initPath = (joinChild c);
|
||
rootDir = false;
|
||
parts = (parts ++ [ c ]);
|
||
};
|
||
})
|
||
(filter filterDir (attrNames dir));
|
||
|
||
# Import Nix files
|
||
nixFiles =
|
||
if hasAttr ".skip-subtree" dir then [ ]
|
||
else filter (f: f != null) (map nixFileName (attrNames dir));
|
||
nixChildren = map
|
||
(c:
|
||
let
|
||
p = joinChild (c + ".nix");
|
||
childParts = parts ++ [ c ];
|
||
imported = importFile args scopedArgs p childParts argsFilter;
|
||
in
|
||
{
|
||
name = c;
|
||
value =
|
||
if isAttrs imported
|
||
then merge imported (marker childParts { })
|
||
else imported;
|
||
})
|
||
nixFiles;
|
||
|
||
nodeValue = if dir ? "default.nix" then self else { };
|
||
|
||
allChildren = listToAttrs (
|
||
if dir ? "default.nix"
|
||
then children
|
||
else nixChildren ++ children
|
||
);
|
||
|
||
in
|
||
if isAttrs nodeValue
|
||
then merge nodeValue (allChildren // (marker parts allChildren))
|
||
else nodeValue;
|
||
|
||
# Helper function to fetch subtargets from a target. This is a
|
||
# temporary helper to warn on the use of the `meta.targets`
|
||
# attribute, which is deprecated in favour of `meta.ci.targets`.
|
||
subtargets = node:
|
||
let targets = (node.meta.targets or [ ]) ++ (node.meta.ci.targets or [ ]);
|
||
in if node ? meta.targets then
|
||
builtins.trace ''
|
||
[1;31mWarning: The meta.targets attribute is deprecated.
|
||
|
||
Please move the subtargets of //${mkLabel node} to the
|
||
meta.ci.targets attribute.
|
||
[0m
|
||
''
|
||
targets else targets;
|
||
|
||
# Function which can be used to find all readTree targets within an
|
||
# attribute set.
|
||
#
|
||
# This function will gather physical targets, that is targets which
|
||
# correspond directly to a location in the repository, as well as
|
||
# subtargets (specified in the meta.ci.targets attribute of a node).
|
||
#
|
||
# This can be used to discover targets for inclusion in CI
|
||
# pipelines.
|
||
#
|
||
# Called with the arguments:
|
||
#
|
||
# eligible: Function to determine whether the given derivation
|
||
# should be included in the build.
|
||
gather = eligible: node:
|
||
if node ? __readTree then
|
||
# Include the node itself if it is eligible.
|
||
(if eligible node then [ node ] else [ ])
|
||
# Include eligible children of the node
|
||
++ concatMap (gather eligible) (map (attr: node."${attr}") node.__readTreeChildren)
|
||
# Include specified sub-targets of the node
|
||
++ filter eligible (map
|
||
(k: (node."${k}" or { }) // {
|
||
# Keep the same tree location, but explicitly mark this
|
||
# node as a subtarget.
|
||
__readTree = node.__readTree;
|
||
__readTreeChildren = [ ];
|
||
__subtarget = k;
|
||
})
|
||
(subtargets node))
|
||
else [ ];
|
||
|
||
# Determine whether a given value is a derivation.
|
||
# Copied from nixpkgs/lib for cases where lib is not available yet.
|
||
isDerivation = x: isAttrs x && x ? type && x.type == "derivation";
|
||
in
|
||
{
|
||
inherit gather mkLabel;
|
||
|
||
__functor = _:
|
||
{ path
|
||
, args
|
||
, filter ? (_parts: x: x)
|
||
, scopedArgs ? { }
|
||
}:
|
||
readTree {
|
||
inherit args scopedArgs;
|
||
argsFilter = filter;
|
||
initPath = path;
|
||
rootDir = true;
|
||
parts = [ ];
|
||
};
|
||
|
||
# In addition to readTree itself, some functionality is exposed that
|
||
# is useful for users of readTree.
|
||
|
||
# Create a readTree filter disallowing access to the specified
|
||
# top-level folder in the repository, except for specific exceptions
|
||
# specified by their (full) paths.
|
||
#
|
||
# Called with the arguments:
|
||
#
|
||
# folder: Name of the restricted top-level folder (e.g. 'experimental')
|
||
#
|
||
# exceptions: List of readTree parts (e.g. [ [ "services" "some-app" ] ]),
|
||
# which should be able to access the restricted folder.
|
||
#
|
||
# reason: Textual explanation for the restriction (included in errors)
|
||
restrictFolder = { folder, exceptions ? [ ], reason }: parts: args:
|
||
if (elemAt parts 0) == folder || elem parts exceptions
|
||
then args
|
||
else args // {
|
||
depot = args.depot // {
|
||
"${folder}" = throw ''
|
||
Access to targets under //${folder} is not permitted from
|
||
other repository paths. Specific exceptions are configured
|
||
at the top-level.
|
||
|
||
${reason}
|
||
At location: ${builtins.concatStringsSep "." parts}
|
||
'';
|
||
};
|
||
};
|
||
|
||
# This definition of fix is identical to <nixpkgs>.lib.fix, but is
|
||
# provided here for cases where readTree is used before nixpkgs can
|
||
# be imported.
|
||
#
|
||
# It is often required to create the args attribute set.
|
||
fix = f: let x = f x; in x;
|
||
|
||
# Takes an attribute set and adds a meta.ci.targets attribute to it
|
||
# which contains all direct children of the attribute set which are
|
||
# derivations.
|
||
#
|
||
# Type: attrs -> attrs
|
||
drvTargets = attrs:
|
||
attrs // {
|
||
# preserve .meta from original attrs
|
||
meta = (attrs.meta or { }) // {
|
||
# preserve .meta.ci (except .targets) from original attrs
|
||
ci = (attrs.meta.ci or { }) // {
|
||
targets = builtins.filter
|
||
(x: isDerivation attrs."${x}")
|
||
(builtins.attrNames attrs);
|
||
};
|
||
};
|
||
};
|
||
}
|