Dockerfile + docker_build.sh script, for eventual use with Jenkins CI.

docker_build.sh

#!/bin/bash
set -e
SCRIPT_DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" && pwd )"

# Dependencies
# HACK: We're manually checking if we should be refreshing the .tar cache, as Docker
#       isn't smart enough to know what our $DEPS_DIR/.git/ updates (caused by the
#       fetch+reset) mean.
DEPS="babushka-deps"
DEPS_DIR="$SCRIPT_DIR/$DEPS"
DEPS_TAR="$SCRIPT_DIR/$DEPS.tar.gz"
if [ ! -d "$DEPS_DIR" ]; then
  git clone git@github.com:foobar/babushka-deps "$DEPS_DIR"
fi
pushd "$DEPS_DIR"
  git fetch origin
  CURRENT_REF=$(git rev-parse HEAD)
  ORIGIN_REF=$(git rev-parse origin/master)
  if [ "$CURRENT_REF" == "$ORIGIN_REF" ] && [ -f "$DEPS_TAR" ]; then
    echo "Up to date... Skipping re-archive."
  else
    git reset --hard origin/master
    rm -f "$DEPS_TAR"
    tar -cvf "$DEPS_TAR" "$DEPS_DIR"
  fi
popd

# Build the image
sudo docker build .

# ... Other stuff follows.

Dockerfile

FROM ubuntu:precise

### Lean on our existing Babushka definitions to pull in Ruby and other dependencies ###

# Babushka bootstrap
RUN apt-get update
RUN apt-get -y install curl
RUN sh -c "`curl https://babushka.me/up`"

# Babushka deps setup
RUN mkdir -p ~/.babushka/sources
ADD ./babushka-deps.tar.gz /root/.babushka/sources/foobar

# Run the Babushka deps
RUN babushka foobar:'example dep'
# ...