Add install-dependencies script and use it for .travis.yml install.

.travis.yml

@@ -59,8 +59,7 @@ before_install:
   - chmod -R og-w $PYTHON_EGG_CACHE
 
 install:
-  - sudo apt-get install -qq --no-install-suggests --no-install-recommends build-essential openssl sqlite3 python-dev python-setuptools libgeoip-dev geoip-database
-  - pip install -q --no-use-wheel -r .travis.requirements.txt
+  - ./scripts/install-dependencies
   - pip install -q --no-use-wheel Twisted==$TWISTED_VERSION pyOpenSSL==$PYOPENSSL_VERSION
   - make install
 

scripts/install-dependencies

@@ -0,0 +1,38 @@
+#!/usr/bin/env bash
+
+set -x --
+
+# $1 should be $TWISTED_VERSION from .travis.yml
+# $2 should be $PYOPENSSL_VERSION from .travis.yml
+
+SUDO=
+APT_GET=$(which apt-get)
+APT_FLAGS='-q --no-install-suggests --no-install-recommends'
+PIP=$(which pip)
+PIP_FLAGS='--no-use-wheel'
+DEPENDS="build-essential openssl sqlite3 python-dev python-setuptools"
+DEPENDS="${DEPENDS} libgeoip-dev geoip-database libjpeg-dev"
+HERE=$(dirname $0)
+
+if [ "$EUID" != "0" ] ; then SUDO=$(which sudo); fi
+# pip is pre-installed on Travis-CI machines in their Python environment, so
+# we should avoid reinstalling it (as that might do odd things to the
+# virtualenv that we're already inside):
+if [ "$TRAVIS" != "true" ] ; then
+    DEPENDS="${DEPENDS} python-pip"
+fi
+
+MISSING=""
+for dep in $DEPENDS ; do
+    if ! test "$(dpkg -l $dep | grep \"ii  $dep\")" ; then
+        MISSING="${MISSING} $dep"
+    fi
+done
+
+$SUDO $APT_GET install ${APT_FLAGS} ${MISSING}
+
+if [ "$TRAVIS" == "true" ] ; then
+    $PIP install $PIP_FLAGS -r "$HERE/../.travis.requirements.txt"
+else
+    $PIP install $PIP_FLAGS -r "$HERE/../requirements.txt"
+fi