Shrink docker image

Don't install apt recommendations and use the ADD directive instead of
running curl in the image. Saves ~380MB in docker image size.

test/Dockerfile

@@ -1,12 +1,29 @@
 FROM ubuntu:18.04
 MAINTAINER Tim Byrne <sultan@locehilios.com>
 
-# No input during build
+# Shellcheck and esh versions
-ENV DEBIAN_FRONTEND noninteractive
+ARG SC_VER=0.7.1
+ARG ESH_VER=0.3.0
+
+# Install prerequisites and configure UTF-8 locale
+RUN \
+  echo "en_US.UTF-8 UTF-8" > /etc/locale.gen \
+  && apt-get update \
+  && DEBIAN_FRONTEND=noninteractive \
+    apt-get install -y --no-install-recommends \
+    expect \
+    git \
+    gnupg \
+    locales \
+    lsb-release \
+    make \
+    man \
+    python3-pip \
+    vim-tiny \
+    xz-utils \
+  && rm -rf /var/lib/apt/lists/* \
+  && update-locale LANG='en_US.UTF-8' LANGUAGE='en_US:en' LC_ALL='en_US.UTF-8'
 
-# UTF8 locale
-RUN apt-get update && apt-get install -y locales
-RUN locale-gen en_US.UTF-8
 ENV LANG='en_US.UTF-8' LANGUAGE='en_US:en' LC_ALL='en_US.UTF-8'
 
 # Convenience settings for the testbed's root account
@@ -15,43 +32,33 @@ RUN echo 'set -o vi' >> /root/.bashrc
 # Create a flag to identify when running inside the yadm testbed
 RUN touch /.yadmtestbed
 
-# Install prerequisites
+# Install shellcheck
-RUN \
+ADD https://github.com/koalaman/shellcheck/releases/download/v$SC_VER/shellcheck-v$SC_VER.linux.x86_64.tar.xz /opt
-  apt-get update && \
+RUN cd /opt \
-  apt-get install -y \
+  && tar xf shellcheck-v$SC_VER.linux.x86_64.tar.xz \
-    curl \
+  && rm -f shellcheck-v$SC_VER.linux.x86_64.tar.xz \
-    expect \
+  && ln -s /opt/shellcheck-v$SC_VER/shellcheck /usr/local/bin
-    git \
-    gnupg \
-    lsb-release \
-    make \
-    man \
-    python3-pip \
-    vim \
-  && rm -rf /var/lib/apt/lists/*;
-
-ARG SC_VER=0.7.1
-RUN \
-  curl -fLo - \
-  https://github.com/koalaman/shellcheck/releases/download/v$SC_VER/shellcheck-v$SC_VER.linux.x86_64.tar.xz | \
-  tar -xJv && \
-  mv shellcheck-v$SC_VER/shellcheck /usr/bin && \
-  rm -rf shellcheck-v$SC_VER
 
+# Upgrade pip3 and install requirements
 COPY test/requirements.txt /tmp/requirements.txt
-RUN pip3 install --upgrade pip setuptools
+RUN python3 -m pip install --upgrade pip setuptools \
-RUN pip3 install --upgrade -r /tmp/requirements.txt
+  && python3 -m pip install --upgrade -r /tmp/requirements.txt \
+  && rm -f /tmp/requirements
 
-RUN \
+# Install esh
-  curl https://raw.githubusercontent.com/jirutka/esh/v0.3.0/esh > /usr/local/bin/esh && \
+ADD https://raw.githubusercontent.com/jirutka/esh/v$ESH_VER/esh /usr/local/bin
-  chmod +x /usr/local/bin/esh
+RUN chmod +x /usr/local/bin/esh
+
+# Create workdir and dummy Makefile to be used if no /yadm volume is mounted
+RUN mkdir /yadm \
+  && echo "test:" > /yadm/Makefile \
+  && echo "\t@echo 'The yadm project must be mounted at /yadm'" >> /yadm/Makefile \
+  && echo "\t@echo 'Try using a docker parameter like -v \"\$\$PWD:/yadm:ro\"'" >> /yadm/Makefile \
+  && echo "\t@false" >> /yadm/Makefile
 
 # /yadm will be the work directory for all tests
 # docker commands should mount the local yadm project as /yadm
 WORKDIR /yadm
 
-# Create a Makefile to be used if no /yadm volume is mounted
-RUN echo "test:\n\t@echo 'The yadm project must be mounted at /yadm'\n\t@echo 'Try using a docker parameter like -v \"\$\$PWD:/yadm:ro\"'\n\t@false" > /yadm/Makefile
-
 # By default, run all tests defined
 CMD make test