Is there a more efficient way to dockerize Luarocks? - docker

Question

I am trying to build a lean alpine docker container for unit testing Lua in Google Cloud Build.
It runs fine, but takes about 30 - 50 seconds to build. When I run busted and luacheck, it only takes a few seconds for each. Any thoughts on how I could optimize this build process?
I was using wget and then switched to git. I added curl and unzip since luarocks expects it and openssl for one of luacheck's dependencies. Are there different dependencies I could/should use?
FROM alpine
ENV LUA_VERSION 5.1
RUN apk update
RUN apk add lua${LUA_VERSION}
RUN apk add lua${LUA_VERSION}-dev
RUN apk add bash build-base curl git openssl unzip
RUN cd /tmp && \
git clone https://github.com/keplerproject/luarocks.git && \
cd luarocks && \
sh ./configure && \
make build install && \
cd && \
rm -rf /tmp/luarocks
RUN luarocks install busted
RUN luarocks install luacheck
RUN luarocks install luacov

Answer 1

You can try this
Dockerfile
FROM alpine:3.12
# Set environment
ENV LUA_VERSION=5.1.5 \
LUAROCKS_VERSION=3.4.0
# Install dependency packages
RUN set -xe && \
apk add --no-cache --virtual .build-deps \
curl \
gcc \
g++ \
libc-dev \
make \
readline-dev \
&& \
apk add --no-cache \
readline \
&& \
# Install Lua
wget http://www.lua.org/ftp/lua-${LUA_VERSION}.tar.gz && \
tar zxf lua-${LUA_VERSION}.tar.gz && rm -f lua-${LUA_VERSION}.tar.gz && \
cd lua-${LUA_VERSION} && \
make -j $(getconf _NPROCESSORS_ONLN) linux && make install && \
cd / && rm -rf lua-${LUA_VERSION} && \
# Install LuaRocks
wget https://luarocks.org/releases/luarocks-${LUAROCKS_VERSION}.tar.gz && \
tar zxf luarocks-${LUAROCKS_VERSION}.tar.gz && rm -f luarocks-${LUAROCKS_VERSION}.tar.gz && \
cd luarocks-${LUAROCKS_VERSION} && \
./configure && \
make -j $(getconf _NPROCESSORS_ONLN) build && make install && \
cd / && rm -rf luarocks-${LUAROCKS_VERSION} && \
# Remove all build deps
apk del .build-deps && \
# Test
lua -v && luarocks
COPY docker-entrypoint.sh /usr/local/bin
docker-entrypoint.sh
#!/bin/sh
set -e
buildDepsApk="
curl
libc-dev
gcc
wget
"
pm='unknown'
if [ -e /lib/apk/db/installed ]; then
pm='apk'
fi
if [ "$pm" = 'apk' ]; then
apk add --no-cache ${buildDepsApk}
fi
luarocks install $#
if [ "$pm" = 'apk' ]; then
apk del ${buildDepsApk}
fi

Answer 2

You don't have to build luarocks. You can just install the package using,
RUN apk add luarocks