Issue #22: Create a Docker image.

* After much debugging, it seems xvfb (virtual frame buffer) needed to be
  implemented to get opengl working properly.
* Switched to using our own from-stratch Dockerfile based on Ubuntu 14.04
* Switched to x11vnc instead of tightvnc since tightvnc didn't seem to work,
  but not sure if that's still an issue or not.
* Added lots of documentation around the various settings used.
* Using fluxbox instead of lxdm because it was lighter weight.

.docker/startup.sh

@@ -0,0 +1,33 @@
+#!/bin/bash
+
+# Remove VNC lock (if process already killed)
+rm -f /tmp/.X1-lock /tmp/.X11-unix/X1
+
+# Set the DISPLAY that will be used by default. Makes lab show up in our xvfb display
+export DISPLAY=:1
+
+# Start the X virtual frame buffer which uses memory instead of an actual device.
+# Allows lab to be run headless.
+Xvfb "$DISPLAY" -screen 0 "$XVFB_RESOLUTION" &
+
+# Run a lightweight Window Manager (fluxbox is smaller than lxdm, gnome, unity, kde, etc)
+# (pretty sure this is required.)
+fluxbox &
+
+# Run the x11vnc server
+# Explanation of options:
+#   -display : This needs to match the xvfb display number
+#   -passwd : Use the password from an ENV var here instead of using ~/.vnc/passwd
+#   -o : Specifies where to send the log output.
+#   -noipv6 : Skip trying to serve vnc on ipv6 (avoids warnings)
+#   -bg : Run in the background
+#   -forever : Don't die when the first user disconnects from vnc (which is the default)
+#   -N : Makes it use port 5900+N where N is the display.. so 5901. (default is 5900)
+x11vnc \
+    -display "$DISPLAY" \
+    -passwd "$VNC_PASSWORD" \
+    -o /dev/stderr \
+    -noipv6 \
+    -bg \
+    -forever \
+    -N

Dockerfile

@@ -1,15 +1,29 @@
-FROM kaixhin/vnc
+FROM ubuntu:14.04
 
 MAINTAINER [email protected]
 
+# Temporarily shut up warnings.
+ENV DISPLAY :0
+ENV TERM xterm
+
+# Basic Dependencies
 RUN apt-get update && apt-get install -y \
     curl \
     zip \
     unzip \
     software-properties-common \
     python-software-properties && \
-    apt-get clean && \
-    rm -rf /var/lib/apt/lists/*
+  apt-get clean && \
+  rm -rf /var/lib/apt/lists/*
+
+# Dependencies for vnc setup.
+RUN apt-get update && apt-get install -y \
+    xvfb \
+    fluxbox \
+    x11vnc && \
+  apt-get clean && \
+  rm -rf /var/lib/apt/lists/*
+
 
 # We need to add a custom PPA to pick up JDK8, since trusty doesn't
 # have an openjdk8 backport.  openjdk-r is maintained by a reliable contributor:
@@ -18,13 +32,14 @@ RUN apt-get update && apt-get install -y \
 # finally backported to trusty; see e.g.
 #   https://bugs.launchpad.net/trusty-backports/+bug/1368094
 RUN add-apt-repository -y ppa:openjdk-r/ppa && \
-    apt-get update && \
-    apt-get install -y openjdk-8-jdk openjdk-8-jre-headless && \
-    apt-get clean && \
-    rm -rf /var/lib/apt/lists/* && \
-    which java && \
-    java -version && \
-    update-ca-certificates -f
+  apt-get update && apt-get install -y \
+    openjdk-8-jdk \
+    openjdk-8-jre-headless && \
+  apt-get clean && \
+  rm -rf /var/lib/apt/lists/* && \
+  which java && \
+  java -version && \
+  update-ca-certificates -f
 
 # Running bazel inside a `docker build` command causes trouble, cf:
 #   https://github.com/bazelbuild/bazel/issues/134
@@ -48,34 +63,44 @@ RUN mkdir /bazel && \
 
 # Install deepmind-lab dependencies
 RUN apt-get update && apt-get install -y \
-  lua5.1 \
-  liblua5.1-0-dev \
-  libffi-dev \
-  gettext \
-  freeglut3-dev \
-  libsdl2-dev \
-  libosmesa6-dev \
-  python-dev \
-  python-numpy \
-  realpath \
-  build-essential
+    lua5.1 \
+    liblua5.1-0-dev \
+    libffi-dev \
+    gettext \
+    freeglut3-dev \
+    libsdl2-dev \
+    libosmesa6-dev \
+    python-dev \
+    python-numpy \
+    realpath \
+    build-essential && \
+  apt-get clean && \
+  rm -rf /var/lib/apt/lists/*
 
-#Enable RANDR option for vnc server.
-COPY ./vnc.sh /opt/vnc.sh
 
 # Set the default X11 Display.
 ENV DISPLAY :1
+ENV VNC_PASSWORD=password
+ENV XVFB_RESOLUTION=800x600x16
 
+# Set up deepmind-lab folder and copy in the code.
 ENV lab_dir /lab
 RUN mkdir /$lab_dir
 COPY . /$lab_dir
 WORKDIR $lab_dir
 
-RUN bazel build :deepmind_lab.so --define headless=osmesa
-
-# RUN bazel run :python_module_test --define headless=osmesa
-
-#RUN bazel run :random_agent --define headless=false
+# Run an actual (headless) build since this should make subsequent builds much faster.
+# Alternative commands based on the Documentation:
+# RUN bazel run :random_agent --define headless=false
+# RUN bazel build :deepmind_lab.so --define headless=osmesa
+RUN bazel run :python_module_test --define headless=osmesa
 
+# This port is the default for connecting to VNC display :1
+EXPOSE 5901
 
+# Copy VNC script that handles restarts and make it executable.
+COPY ./.docker/startup.sh /opt/
+RUN chmod u+x /opt/startup.sh
 
+# Finally, start VNC using our script.
+CMD ["/opt/startup.sh"]