nixpkgs/pkgs/build-support/build-bazel-package/default.nix
Matthew Bauer 27fb209194 build-bazel-package: add dontAddBazelOpts arg
This adds an option to skip adding --copt and --linkopt to Bazel
flags. In some cases, Bazel doesn’t like these flags, like when a
custom toolchain is being used (as opposed to the builtin one. The
compiler can still get the dependencies since it is invoked through
gcc wrapper and picks up the NIX_CFLAGS_COMPILE / NIX_LDFLAGS.
2020-08-28 15:10:59 -05:00

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{ stdenv
, bazel
, cacert
, lib
}:
let
bazelPkg = bazel;
in
args@{
name
, bazel ? bazelPkg
, bazelFlags ? []
, bazelBuildFlags ? []
, bazelFetchFlags ? []
, bazelTarget
, buildAttrs
, fetchAttrs
# Newer versions of Bazel are moving away from built-in rules_cc and instead
# allow fetching it as an external dependency in a WORKSPACE file[1]. If
# removed in the fixed-output fetch phase, building will fail to download it.
# This can be seen e.g. in #73097
#
# This option allows configuring the removal of rules_cc in cases where a
# project depends on it via an external dependency.
#
# [1]: https://github.com/bazelbuild/rules_cc
, removeRulesCC ? true
, removeLocalConfigCc ? true
, removeLocal ? true
# Use build --nobuild instead of fetch. This allows fetching the dependencies
# required for the build as configured, rather than fetching all the dependencies
# which may not work in some situations (e.g. Java code which ends up relying on
# Debian-specific /usr/share/java paths, but doesn't in the configured build).
, fetchConfigured ? false
# Dont add Bazel --copt and --linkopt from NIX_CFLAGS_COMPILE /
# NIX_LDFLAGS. This is necessary when using a custom toolchain which
# Bazel wants all headers / libraries to come from, like when using
# CROSSTOOL. Weirdly, we can still get the flags through the wrapped
# compiler.
, dontAddBazelOpts ? false
, ...
}:
let
fArgs = removeAttrs args [ "buildAttrs" "fetchAttrs" "removeRulesCC" ];
fBuildAttrs = fArgs // buildAttrs;
fFetchAttrs = fArgs // removeAttrs fetchAttrs [ "sha256" ];
in stdenv.mkDerivation (fBuildAttrs // {
inherit name bazelFlags bazelBuildFlags bazelFetchFlags bazelTarget;
deps = stdenv.mkDerivation (fFetchAttrs // {
name = "${name}-deps.tar.gz";
inherit bazelFlags bazelBuildFlags bazelFetchFlags bazelTarget;
impureEnvVars = lib.fetchers.proxyImpureEnvVars;
nativeBuildInputs = fFetchAttrs.nativeBuildInputs or [] ++ [ bazel ];
preHook = fFetchAttrs.preHook or "" + ''
export bazelOut="$(echo ''${NIX_BUILD_TOP}/output | sed -e 's,//,/,g')"
export bazelUserRoot="$(echo ''${NIX_BUILD_TOP}/tmp | sed -e 's,//,/,g')"
export HOME="$NIX_BUILD_TOP"
export USER="nix"
# This is needed for git_repository with https remotes
export GIT_SSL_CAINFO="${cacert}/etc/ssl/certs/ca-bundle.crt"
# This is needed for Bazel fetchers that are themselves programs (e.g.
# rules_go using the go toolchain)
export SSL_CERT_FILE="${cacert}/etc/ssl/certs/ca-bundle.crt"
'';
buildPhase = fFetchAttrs.buildPhase or ''
runHook preBuild
# Bazel computes the default value of output_user_root before parsing the
# flag. The computation of the default value involves getting the $USER
# from the environment. I don't have that variable when building with
# sandbox enabled. Code here
# https://github.com/bazelbuild/bazel/blob/9323c57607d37f9c949b60e293b573584906da46/src/main/cpp/startup_options.cc#L123-L124
#
# On macOS Bazel will use the system installed Xcode or CLT toolchain instead of the one in the PATH unless we pass BAZEL_USE_CPP_ONLY_TOOLCHAIN
# We disable multithreading for the fetching phase since it can lead to timeouts with many dependencies/threads:
# https://github.com/bazelbuild/bazel/issues/6502
BAZEL_USE_CPP_ONLY_TOOLCHAIN=1 \
USER=homeless-shelter \
bazel \
--output_base="$bazelOut" \
--output_user_root="$bazelUserRoot" \
${if fetchConfigured then "build --nobuild" else "fetch"} \
--loading_phase_threads=1 \
$bazelFlags \
$bazelFetchFlags \
$bazelTarget
runHook postBuild
'';
installPhase = fFetchAttrs.installPhase or ''
runHook preInstall
# Remove all built in external workspaces, Bazel will recreate them when building
rm -rf $bazelOut/external/{bazel_tools,\@bazel_tools.marker}
${if removeRulesCC then "rm -rf $bazelOut/external/{rules_cc,\\@rules_cc.marker}" else ""}
rm -rf $bazelOut/external/{embedded_jdk,\@embedded_jdk.marker}
${if removeLocalConfigCc then "rm -rf $bazelOut/external/{local_config_cc,\@local_config_cc.marker}" else ""}
${if removeLocal then "rm -rf $bazelOut/external/{local_*,\@local_*.marker}" else ""}
# Clear markers
find $bazelOut/external -name '@*\.marker' -exec sh -c 'echo > {}' \;
# Remove all vcs files
rm -rf $(find $bazelOut/external -type d -name .git)
rm -rf $(find $bazelOut/external -type d -name .svn)
rm -rf $(find $bazelOut/external -type d -name .hg)
# Removing top-level symlinks along with their markers.
# This is needed because they sometimes point to temporary paths (?).
# For example, in Tensorflow-gpu build:
# platforms -> NIX_BUILD_TOP/tmp/install/35282f5123611afa742331368e9ae529/_embedded_binaries/platforms
find $bazelOut/external -maxdepth 1 -type l | while read symlink; do
name="$(basename "$symlink")"
rm "$symlink"
test -f "$bazelOut/external/@$name.marker" && rm "$bazelOut/external/@$name.marker"
done
# Patching symlinks to remove build directory reference
find $bazelOut/external -type l | while read symlink; do
new_target="$(readlink "$symlink" | sed "s,$NIX_BUILD_TOP,NIX_BUILD_TOP,")"
rm "$symlink"
ln -sf "$new_target" "$symlink"
done
echo '${bazel.name}' > $bazelOut/external/.nix-bazel-version
(cd $bazelOut/ && tar czf $out --sort=name --mtime='@1' --owner=0 --group=0 --numeric-owner external/)
runHook postInstall
'';
dontFixup = true;
allowedRequisites = [];
outputHashAlgo = "sha256";
outputHash = fetchAttrs.sha256;
});
nativeBuildInputs = fBuildAttrs.nativeBuildInputs or [] ++ [ (bazel.override { enableNixHacks = true; }) ];
preHook = fBuildAttrs.preHook or "" + ''
export bazelOut="$NIX_BUILD_TOP/output"
export bazelUserRoot="$NIX_BUILD_TOP/tmp"
export HOME="$NIX_BUILD_TOP"
'';
preConfigure = ''
mkdir -p "$bazelOut"
(cd $bazelOut && tar xfz $deps)
test "${bazel.name}" = "$(<$bazelOut/external/.nix-bazel-version)" || {
echo "fixed output derivation was built for a different bazel version" >&2
echo " got: $(<$bazelOut/external/.nix-bazel-version)" >&2
echo "expected: ${bazel.name}" >&2
exit 1
}
chmod -R +w $bazelOut
find $bazelOut -type l | while read symlink; do
ln -sf $(readlink "$symlink" | sed "s,NIX_BUILD_TOP,$NIX_BUILD_TOP,") "$symlink"
done
'' + fBuildAttrs.preConfigure or "";
inherit dontAddBazelOpts;
buildPhase = fBuildAttrs.buildPhase or ''
runHook preBuild
# Bazel sandboxes the execution of the tools it invokes, so even though we are
# calling the correct nix wrappers, the values of the environment variables
# the wrappers are expecting will not be set. So instead of relying on the
# wrappers picking them up, pass them in explicitly via `--copt`, `--linkopt`
# and related flags.
#
copts=()
host_copts=()
linkopts=()
host_linkopts=()
if [ -z "''${dontAddBazelOpts:-}" ]; then
for flag in $NIX_CFLAGS_COMPILE; do
copts+=( "--copt=$flag" )
host_copts+=( "--host_copt=$flag" )
done
for flag in $NIX_CXXSTDLIB_COMPILE; do
copts+=( "--copt=$flag" )
host_copts+=( "--host_copt=$flag" )
done
for flag in $NIX_LDFLAGS; do
linkopts+=( "--linkopt=-Wl,$flag" )
host_linkopts+=( "--host_linkopt=-Wl,$flag" )
done
fi
BAZEL_USE_CPP_ONLY_TOOLCHAIN=1 \
USER=homeless-shelter \
bazel \
--output_base="$bazelOut" \
--output_user_root="$bazelUserRoot" \
build \
-j $NIX_BUILD_CORES \
"''${copts[@]}" \
"''${host_copts[@]}" \
"''${linkopts[@]}" \
"''${host_linkopts[@]}" \
$bazelFlags \
$bazelBuildFlags \
$bazelTarget
runHook postBuild
'';
})