From fef1cfb05a1fa5596591058fe56fbb120b83d550 Mon Sep 17 00:00:00 2001
From: OPNA2608 <christoph.neidahl@gmail.com>
Date: Wed, 22 Feb 2023 13:20:22 +0100
Subject: [PATCH] python3Packages.grpcio: Fix build parallelism

---
 pkgs/development/python-modules/grpcio/default.nix | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/pkgs/development/python-modules/grpcio/default.nix b/pkgs/development/python-modules/grpcio/default.nix
index 486742ccb605..a8dade04a36f 100644
--- a/pkgs/development/python-modules/grpcio/default.nix
+++ b/pkgs/development/python-modules/grpcio/default.nix
@@ -26,7 +26,14 @@ buildPythonPackage rec {
   propagatedBuildInputs = [ six protobuf ]
     ++ lib.optionals (isPy27) [ enum34 futures ];
 
-  preBuild = lib.optionalString stdenv.isDarwin "unset AR";
+  preBuild = ''
+    export GRPC_PYTHON_BUILD_EXT_COMPILER_JOBS="$NIX_BUILD_CORES"
+    if [ -z "$enableParallelBuilding" ]; then
+      GRPC_PYTHON_BUILD_EXT_COMPILER_JOBS=1
+    fi
+  '' + lib.optionalString stdenv.isDarwin ''
+    unset AR
+  '';
 
   GRPC_BUILD_WITH_BORING_SSL_ASM = "";
   GRPC_PYTHON_BUILD_SYSTEM_OPENSSL = 1;
@@ -36,6 +43,8 @@ buildPythonPackage rec {
   # does not contain any tests
   doCheck = false;
 
+  enableParallelBuilding = true;
+
   pythonImportsCheck = [ "grpc" ];
 
   meta = with lib; {