Add Varnish to web container as optional

etc/docker/web/Dockerfile

@@ -14,7 +14,7 @@ ENV LJHOME /dw
 # Install some packages we need in web only.
 RUN echo $COMMIT && \
     apt-get update && \
-    apt-get install -y mysql-client vim-tiny && \
+    apt-get install -y mysql-client vim-tiny varnish && \
     curl https://raw.githubusercontent.com/dreamwidth/dw-free/master/doc/dependencies-system | \
         xargs apt-get -y install && \
     curl https://raw.githubusercontent.com/dreamwidth/dw-free/master/doc/dependencies-cpanm | \
@@ -39,7 +39,10 @@ ADD config/ /dw/ext/local
 RUN bash /opt/setup.sh
 
 # We run on 80, TLS is handled by a proxy of some kind.
-EXPOSE 80
+EXPOSE 80/tcp
+
+# Varnish is here and is layered in front of Apache typically.
+EXPOSE 6081/tcp
 
 # Kick off the startup script, which does some healthcheck and then starts
 # Apache if things look good.

etc/docker/web/config/etc/varnish/dreamwidth.vcl

@@ -0,0 +1,6 @@
+vcl 4.0;
+
+backend default {
+    .host = "127.0.0.1";
+    .port = "80";
+}

etc/docker/web/scripts/setup.sh

@@ -7,3 +7,7 @@
 # Set up Apache2.
 rm -rf /etc/apache2
 ln -s /dw/ext/local/etc/apache2 /etc/apache2
+
+# Set up Varnish.
+rm -rf /etc/varnish/default.vcl
+ln -s /dw/ext/local/etc/varnish/dreamwidth.vcl /etc/varnish/default.vcl

etc/docker/web/scripts/startup-prod.sh

@@ -11,6 +11,9 @@ mkdir $LJHOME/ext/local/etc/apache2/sites-enabled || true
 cp $LJHOME/ext/local/dreamwidth-prod.conf $LJHOME/ext/local/etc/apache2/sites-enabled/dreamwidth.conf
 /usr/sbin/apache2ctl start
 
+# Kick off Varnish
+service varnish start
+
 # Sleep a few seconds to ensure things get up and running
 sleep 5