From e250c83c21c2130c8b26a55c9500e5f0677effbd Mon Sep 17 00:00:00 2001
From: Daniel Patterson <danpat@danpat.net>
Date: Thu, 17 Jan 2019 16:14:58 -0800
Subject: [PATCH] Add BUILD_CONCURRENCY argument so that we can limit
 concurrency on Docker Hub (and thus reduce peak memory need for build)

---
 docker/Dockerfile  | 3 ++-
 docker/hooks/build | 2 +-
 2 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/docker/Dockerfile b/docker/Dockerfile
index 9da5d43f8..056f8c7b6 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,10 +1,11 @@
 FROM debian:stretch-slim as builder
 ARG DOCKER_TAG
+ARG BUILD_CONCURRENCY
 RUN mkdir -p /src  && mkdir -p /opt
 COPY . /src
 WORKDIR /src
 
-RUN NPROC=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || 1) && \
+RUN NPROC=${BUILD_CONCURRENCY:-$(grep -c ^processor /proc/cpuinfo 2>/dev/null || 1)} && \
     apt-get update && \
     apt-get -y --no-install-recommends install cmake make git gcc g++ libbz2-dev libxml2-dev \
     libzip-dev libboost1.62-all-dev lua5.2 liblua5.2-dev libtbb-dev -o APT::Install-Suggests=0 -o APT::Install-Recommends=0 && \
diff --git a/docker/hooks/build b/docker/hooks/build
index d1eac8ab0..c27c851ad 100644
--- a/docker/hooks/build
+++ b/docker/hooks/build
@@ -6,4 +6,4 @@
 # ensure that "COPY . /src" is referring to the repo root, not the directory
 # that contains the Dockerfile.
 # This script gets executed with a pwd of wherever the Dockerfile is.
-docker build --build-arg DOCKER_TAG=${DOCKER_TAG} -t $IMAGE_NAME -f Dockerfile ..
+docker build --build-arg BUILD_CONCURRENCY=${CONCURRENCY:-1} --build-arg DOCKER_TAG=${DOCKER_TAG} -t $IMAGE_NAME -f Dockerfile ..