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Report for runtime dependencies of a derivation
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# MIT License, see below | |
# | |
# These are some helpers for figuring out the derivations attributes of runtime | |
# dependencies of a derivation, in particular the function `runtimeReport`. At | |
# the bottom of the file you can see it used on `hello`. Spoiler: glibc is a | |
# runtime dependency. | |
# For more info see | |
# | |
# https://nmattia.com/posts/2019-10-08-runtime-dependencies.html | |
# Let's call these "imports". They're functions used throughout the code. | |
# Nothing interesting here. | |
with rec | |
{ pkgs = import <nixpkgs> {}; | |
inherit (pkgs) | |
closureInfo | |
runCommandNoCC | |
writeText | |
jq | |
; | |
inherit (pkgs.lib) | |
concatLists | |
concatMap | |
concatStringsSep | |
filter | |
isAttrs | |
isDerivation | |
isList | |
isString | |
mapAttrsToList | |
; | |
inherit (builtins) | |
genericClosure | |
hasAttr | |
toJSON | |
typeOf | |
unsafeDiscardStringContext | |
; | |
}; | |
let | |
# Create a "runtime report" of the runtime dependencies of `drv`. A "runtime | |
# report" is made up of smaller "dependency reports". A "dependency report" is | |
# a string describing the dependency, made from the dependency's derivation | |
# attributes. Here we use `mkReport` to make the report of any particular | |
# dependency. | |
# | |
# NOTE: we use the following terms: | |
# | |
# * "buildtime" to mean basically any derivation involved in the build of | |
# `drv`. | |
# * "buildtime-only" for the "buildtime" dependencies that _are not_ | |
# referenced anymore by `drv`'s store entry. | |
# * "runtime" for the rest. | |
# | |
# The "runtime report" is created in two steps: | |
# | |
# * Generate reports for all the _buildtime_ dependencies with | |
# `buildtimeReports`. | |
# * Filter out the reports for buildtime-only dependencies. | |
# | |
# Most of the "buildtime" reports won't even be used, because most buildtime | |
# dependencies are buildtime-only dependencies. However Nix does not give us a | |
# way of retrieving the derivation attributes of runtime dependencies, but we | |
# can twist its arm to: | |
# | |
# * Give us the store paths of runtime dependencies (see `cinfo`). | |
# * Give us the derivation attributes of all the buildtime dependencies (see | |
# `buildtimeDerivations`). | |
# | |
# Here's the hack: `buildtimeReports` tags the reports with the (expected) | |
# store path of the "buildtime" dependency, which we cross check against the | |
# list of runtime store paths. If it's a match, we keep it. Otherwise, we | |
# discard it. | |
runtimeReport = drv: | |
runCommandNoCC "${drv.name}-report" { buildInputs = [ jq ]; } | |
# XXX: This is to avoid IFD | |
'' | |
( | |
echo " ---------------------------------" | |
echo " | OFFICIAL REPORT |" | |
echo " | requested by: the lawyers |" | |
echo " | written by: yours truly |" | |
echo " | TOP SECRET - TOP SECRET |" | |
echo " ---------------------------------" | |
echo | |
echo "runtime dependencies of ${drv.name}:" | |
cat ${buildtimeReports drv} |\ | |
jq -r --slurpfile runtime ${cinfo drv} \ | |
' # First, we strip away (path-)duplicates. | |
unique_by(.path) | |
# Then we map over each build-time derivation and use `select()` | |
# to keep only the ones that show up in $runtime | |
| map( # this little beauty checks if "obj.path" is in "runtime" | |
select(. as $obj | $runtime | any(.[] | . == $obj.path)) | |
| .report) | |
| .[]' | |
) > $out | |
''; | |
# Creates reports for all of `drv`'s buildtime dependencies. Each element in | |
# the list has two fields: | |
# | |
# * path = "/nix/store/..." | |
# * report = "some report based on the dependency's derivation attributes" | |
buildtimeReports = drv: writeText "${drv.name}-runtime" ( toJSON ( | |
map (obj: | |
# unsafe: optimization to avoid downloading unused deps | |
{ # XXX: we discard the context of the dependencies' store paths because | |
# they're only ever used for lookup. This matters when fetching a | |
# prebuilt final report -- there's no point downloading all of `drv`'s | |
# buildtime dependencies. | |
path = unsafeDiscardStringContext obj.key; | |
report = mkReport obj.drv; | |
} | |
) | |
(buildtimeDerivations drv) # the heavy lifting is done somewhere else | |
)); | |
# Returns a list of all of `drv0`'s inputs, a.k.a. buildtime dependencies. | |
# Elements in the list has two fields: | |
# | |
# * key: the store path of the input. | |
# * drv: the actual derivation object. | |
# | |
# There are no guarantees that this will find _all_ inputs, but it works well | |
# enough in practice. | |
# | |
buildtimeDerivations = drv0: | |
let | |
# We include all the outputs because they each have different outPaths | |
drvOutputs = drv: | |
# XXX: some derivations, like stdenv, don't have "outputs" | |
if hasAttr "outputs" drv | |
then map (output: drv.${output}) drv.outputs | |
else [ drv ]; | |
# Recurse into the derivation attributes to find new derivations | |
drvDeps = attrs: | |
mapAttrsToList (k: v: | |
if isDerivation v then (drvOutputs v) | |
else if isList v | |
then concatMap drvOutputs (filter isDerivation v) | |
else [] | |
) attrs; | |
in | |
# Walk through the whole DAG of dependencies, using the `outPath` as an | |
# index for the elements. | |
let wrap = drv: { key = drv.outPath ; inherit drv; }; in genericClosure | |
{ startSet = map wrap (drvOutputs drv0) ; | |
operator = obj: map wrap | |
( concatLists (drvDeps obj.drv.drvAttrs) ) ; | |
}; | |
# make a report. Would could also output a json object and process everything | |
# later on. | |
mkReport = drv: | |
let | |
license = | |
if hasAttr "meta" drv && hasAttr "license" drv.meta then | |
if isList drv.meta.license then | |
concatStringsSep ", " ( | |
map renderLicense drv.meta.license) | |
else renderLicense drv.meta.license | |
else "no license"; | |
maintainer = | |
if hasAttr "meta" drv && hasAttr "maintainers" drv.meta | |
then concatStringsSep ", " (map (m: m.name) drv.meta.maintainers) | |
else "nobody"; | |
in " - ${drv.name} (${license}) maintained by ${maintainer}"; | |
# Basically pretty prints a license | |
renderLicense = license: | |
if isAttrs license then license.shortName | |
else if isString license then license | |
else abort "no idea how to handle license of type ${typeOf license}"; | |
# This is a wrapper around nixpkgs' `closureInfo`. It produces a JSON file | |
# containing a list of the store paths of `drv`'s runtime dependencies. | |
cinfo = drv: runCommandNoCC "${drv.name}-cinfo" | |
{ buildInputs = [ jq ]; } | |
# NOTE: we avoid IFD here as well | |
'' | |
cat ${closureInfo { rootPaths = [ drv ]; }}/store-paths |\ | |
grep -v "^$" |\ | |
jq -R -s -c 'split("\n")' |\ | |
jq -c 'map(select( length > 0 ))' > $out | |
''; | |
in runtimeReport | |
# MIT License | |
# | |
# Copyright (c) 2021 Nicolas Mattia | |
# | |
# Permission is hereby granted, free of charge, to any person obtaining a copy | |
# of this software and associated documentation files (the "Software"), to deal | |
# in the Software without restriction, including without limitation the rights | |
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell | |
# copies of the Software, and to permit persons to whom the Software is | |
# furnished to do so, subject to the following conditions: | |
# | |
# The above copyright notice and this permission notice shall be included in all | |
# copies or substantial portions of the Software. | |
# | |
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR | |
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, | |
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE | |
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER | |
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, | |
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE | |
# SOFTWARE. | |
# |
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