From 19d2e82d15a71cc92dea1482891f2c0ff0708741 Mon Sep 17 00:00:00 2001
From: Daniel Patterson <daniel@mapbox.com>
Date: Tue, 31 Oct 2017 23:31:32 -0400
Subject: [PATCH] Reduce docker image size to about 20MB by using a multistage
 build.

---
 .dockerignore     |  2 ++
 docker/Dockerfile | 48 ++++++++++++++++++++---------------------------
 2 files changed, 22 insertions(+), 28 deletions(-)
 create mode 100644 .dockerignore

diff --git a/.dockerignore b/.dockerignore
new file mode 100644
index 000000000..77c25935a
--- /dev/null
+++ b/.dockerignore
@@ -0,0 +1,2 @@
+test
+build
diff --git a/docker/Dockerfile b/docker/Dockerfile
index e3444e60c..50f531ed6 100644
--- a/docker/Dockerfile
+++ b/docker/Dockerfile
@@ -1,34 +1,20 @@
-FROM alpine:3.5
+FROM alpine:3.6 as buildstage
 
-RUN mkdir /opt
-WORKDIR /opt
+ARG DOCKER_TAG
+RUN mkdir -p /src  && mkdir -p /opt
+COPY . /src
+WORKDIR /src
 
 RUN NPROC=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || 1) && \
     echo "@testing http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories && \
     apk update && \
     apk upgrade && \
     apk add git cmake wget make libc-dev gcc g++ bzip2-dev boost-dev zlib-dev expat-dev lua5.2-dev libtbb@testing libtbb-dev@testing && \
-    \
-    echo "Building libstxxl" && \
-    cd /opt && \
-    git clone --depth 1 --branch 1.4.1 https://github.com/stxxl/stxxl.git && \
-    cd stxxl && \
-    mkdir build && \
-    cd build && \
-    cmake -DCMAKE_BUILD_TYPE=Release .. && \
-    make -j${NPROC} && \
-    make install
-
-ARG DOCKER_TAG
-RUN mkdir /src
-COPY . /src
-WORKDIR /src
-
-RUN NPROC=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || 1) && \
+    NPROC=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || 1) && \
     echo "Building OSRM ${DOCKER_TAG}" && \
     git show --format="%H" | head -n1 > /opt/OSRM_GITSHA && \
     echo "Building OSRM gitsha $(cat /opt/OSRM_GITSHA)" && \
-    mkdir build && \
+    mkdir -p build && \
     cd build && \
     BUILD_TYPE="Release" && \
     ENABLE_ASSERTIONS="Off" && \
@@ -41,13 +27,19 @@ RUN NPROC=$(grep -c ^processor /proc/cpuinfo 2>/dev/null || 1) && \
     cd ../profiles && \
     cp -r * /opt && \
     \
-    echo "Cleaning up" && \
     strip /usr/local/bin/* && \
-    rm /usr/local/lib/libstxxl* && \
-    cd /opt && \
-    apk del boost-dev && \
-    apk del g++ cmake libc-dev expat-dev zlib-dev bzip2-dev lua5.2-dev git make gcc && \
-    apk add boost-filesystem boost-program_options boost-regex boost-iostreams boost-thread libgomp lua5.2 expat && \
-    rm -rf /src /opt/stxxl /usr/local/bin/stxxl_tool /usr/local/lib/libosrm*
+    rm -rf /src /usr/local/lib/libosrm*
+
+
+# Multistage build to reduce image size - https://docs.docker.com/engine/userguide/eng-image/multistage-build/#use-multi-stage-builds
+# Only the content below ends up in the image, this helps remove /src from the image (which is large)
+FROM alpine:3.6 as runstage
+RUN mkdir -p /src  && mkdir -p /opt
+RUN echo "@testing http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories && \
+    apk update && \
+    apk add boost-filesystem boost-program_options boost-regex boost-iostreams boost-thread libgomp lua5.2 expat libtbb@testing
+COPY --from=buildstage /usr/local /usr/local
+COPY --from=buildstage /opt /opt
+WORKDIR /opt
 
 EXPOSE 5000