Grab upstream nodejs for RHEL6

RHEL6 has no nodejs in main packages or in EPEL.  The easiest way is
to just install the upstream binary version which works fine for the
very minimal usage by lesscss.

Change-Id: Ia35e7dbaf4c7add43797d6b7d0c846bab1cf0cb0

lib/horizon

@@ -61,16 +61,47 @@ function _horizon_config_set() {
     fi
 }
 
+# Basic install of upstream nodejs for platforms that want it
+function install_nodejs() {
+    if [[ $(which node) ]]; then
+        echo "You already appear to have nodejs, skipping install"
+        return
+    fi
+
+    # There are several node deployment scripts; one may be more
+    # appropriate at some future point, but for now direct download is
+    # the simplest way.  The version barely matters for lesscss which
+    # doesn't use anything fancy.
+    local ver=0.10.1
+    local nodejs=node-v${ver}-linux-x64
+    local tar=$nodejs.tar.gz
+    local nodejs_url=http://nodejs.org/dist/v${ver}/${tar}
+
+    curl -Ss ${nodejs_url} | tar -C ${DEST} -xz
+    if [ $? -ne 0 ]; then
+        echo "*** Download of nodejs failed"
+        return 1
+    fi
+
+    # /usr/bin so it gets found in the PATH available to horizon
+    sudo ln -s $DEST/$nodejs/bin/node /usr/bin/node
+}
+
 # Entry Points
 # ------------
 
 # cleanup_horizon() - Remove residual data files, anything left over from previous
 # runs that a clean run would need to clean up
 function cleanup_horizon() {
-    # kill instances (nova)
-    # delete image files (glance)
-    # This function intentionally left blank
-    :
+
+    if [[ is_fedora && $DISTRO =~ (rhel6) ]]; then
+    # if the /usr/bin/node link looks like it's pointing into $DEST,
+    # then we installed it via install_nodejs
+        if [[ $(readlink -f /usr/bin/node) =~ ($DEST) ]]; then
+            sudo rm /usr/bin/node
+        fi
+    fi
+
 }
 
 # configure_horizon() - Set config files, create data dirs, etc
@@ -159,6 +190,14 @@ function install_horizon() {
         exit_distro_not_supported "apache installation"
     fi
 
+    if [[ is_fedora && $DISTRO =~ (rhel6) ]]; then
+        # RHEL6 currently has no native way to get nodejs, so we do a
+        # basic install here (see cleanup_horizon too).
+        # TODO: does nova have a better way that we can limit
+        # requirement of site-wide nodejs install?
+        install_nodejs
+    fi
+
     # NOTE(sdague) quantal changed the name of the node binary
     if is_ubuntu; then
         if [[ ! -e "/usr/bin/node" ]]; then