Added Ubuntu 18.04 based dockerfile (#156)

* Changed to ubuntu18.04

* Updated dockerfile to lib build

* Added some usage docs

* Added dockerignore

Author: Enrico Steffinlongo

.dockerignore

@@ -1,2 +1,5 @@
 # A local cmake cache will affect the docker image build
 CMakeCache.txt
+# Typical build directory name - if copied in from the host, the image will 
+# be very bloated and could interfere with the build process
+build

DOCKER_USAGE.md

@@ -0,0 +1,16 @@
+# Dockerized usage
+To create an Ubuntu 18.04-based docker image with HElib and its dependencies
+installed, use the following steps:
+
+1. Clone HElib and `cd` into it.
+2. Run `docker build .`, optionally tagging with `-t helib` or similar.  This
+   will create an image with HElib installed globally in `/usr/local`.  Most
+   build systems and compilers will look in here.  Furthermore, `cmake` can be
+   used with `find_package(helib)` and invoked with no special command-line
+   arguments.
+3. The image is now ready to be used.  Some possibilities include:
+   - Create a Dockerfile which begins with `FROM helib`, where `helib` may be
+   any tag you used in step 2, and include your application logic in this
+   Dockerfile.
+   - Run a container from the HElib docker image directly to experiment, with
+   `docker run -it helib bash`

Dockerfile

@@ -1,23 +1,21 @@
-FROM alpine:3.8
+FROM ubuntu:18.04
 
-# Location of the src in the contrainer
-ARG helibDir=/helib
-# Location of the build in the contrainer
-ARG buildDir=/build
+COPY ./ /root/HElib/
 
-COPY . ${helibDir}
-
-# Currently fails when cmake is invoked
-RUN apk add --update \
-    g++              \
-    make             \
-    cmake            \
-    libtool          \
-  && rm -rf /var/cache/apk/* \
-  && mkdir ${buildDir}       \
-  && cd ${buildDir}          \
-  && cmake ${helibDir}       \
-  && make          
-
-CMD [ "" ]
+RUN apt update && \
+    apt install -y build-essential wget cmake m4 libgmp-dev file && \
+    cd ~ && \
+    wget https://www.shoup.net/ntl/ntl-11.3.2.tar.gz && \
+    tar xf ntl-11.3.2.tar.gz && \
+    cd ntl-11.3.2/src && \
+    ./configure SHARED=on NTL_GMP_LIP=on NTL_THREADS=on NTL_THREAD_BOOST=on && \
+    make -j4 && \
+    make install && \
+    cd ~ && \
+    mkdir HElib/build && \
+    cd HElib/build && \
+    cmake -DCMAKE_BUILD_TYPE=RelWithDebInfo -DBUILD_SHARED=ON -DENABLE_THREADS=ON .. && \
+    make -j4 && \
+    make install && \
+    ldconfig