[dockerfile_for_local_execution] Integrated PR feedback

Clean up container after each command

docker/Dockerfile

@@ -2,6 +2,8 @@ FROM ubuntu:14.04
 
 MAINTAINER WebOps MoJ <platforms@digital.justice.gov.uk>
 
+# Common tool that we can use to clean up the container after commands, but
+# before the layer commit
 ADD docker/clean-up-docker-container /usr/local/bin/
 
 # Support tools for building Python apps
@@ -13,30 +15,32 @@ ADD docker/clean-up-docker-container /usr/local/bin/
 #   - git
 #   - libgit2-dev
 #   - libffi-dev
+#   - libssh2-1
 #   - libyaml-dev
 # Specific packages for libgit2:
 #   - cmake
+#   - python-git
 RUN apt-get update && apt-get install -y \
     build-essential python-dev python-setuptools \
-    git libgit2-dev libffi-dev libyaml-dev \
+    git libffi-dev libssh2-1 libssh2-1-dev libyaml-dev \
     cmake && \
-    clean-up-docker-container
+    /usr/local/bin/clean-up-docker-container
 
 # Install libgit2 - http://www.pygit2.org/install.html
 RUN mkdir /tmp/libgit2
 WORKDIR /tmp/libgit1
 ADD https://github.com/libgit2/libgit2/archive/v0.22.0.tar.gz /tmp/libgit1/
 RUN tar zxf v0.22.0.tar.gz
-# Perform the build
+# Perform the build. Run ldconfig to add the new file to the library index.
 WORKDIR /tmp/libgit1/libgit2-0.22.0
-RUN cmake . && make && make install && clean-up-docker-container
+RUN cmake . && make && make install && ldconfig && /usr/local/bin/clean-up-docker-container
 
 WORKDIR /
-RUN easy_install pip
+RUN easy_install pip && /usr/local/bin/clean-up-docker-container
 
 # Copy and work on just the requirements.txt file, so that the 'pip install' step is cacheable
 COPY requirements.txt /tmp/requirements.txt
-RUN pip install -r /tmp/requirements.txt
+RUN pip install -r /tmp/requirements.txt && /usr/local/bin/clean-up-docker-container
 
 WORKDIR /usr/src/bootstrap_cfn
 COPY . /usr/src/bootstrap_cfn

docker/clean-up-docker-container

@@ -4,4 +4,4 @@ apt-get -y autoremove --purge
 apt-get clean && rm -rf /var/lib/apt/lists/* /tmp/* /var/tmp/*
 truncate -s 0 /var/log/*log
 
-exit 0
+exit 0