Fix varnish config for arbitrary hostnames (#2573)

Author: rhysyngsun

config/default.vcl

@@ -1,22 +1,7 @@
 # specify the VCL syntax version to use
 vcl 4.1;
 
-# import vmod_dynamic for better backend name resolution
-import dynamic;
-
-# we won't use any static backend, but Varnish still need a default one
-backend default none;
-
-# set up a dynamic director
-# for more info, see https://github.com/nigoroll/libvmod-dynamic/blob/master/src/vmod_dynamic.vcc
-sub vcl_init {
-        new d = dynamic.director(port = "8013");
-}
-
-sub vcl_recv {
-	# force the host header to match the backend (not all backends need it,
-	# but example.com does)
-	set req.http.host = "mitxonline.odl.local:8013";
-	# set the backend
-	set req.backend_hint = d.backend("mitxonline.odl.local");
+backend default {
+  .host = "nginx";
+  .port = "8013";
 }

docker-compose.yml

@@ -66,6 +66,9 @@ services:
     environment:
       << : *py-environment
       PORT: 8011
+      # these are necessary to get the hostname from the varnish proxy
+      USE_X_FORWARDED_HOST: true
+      USE_X_FORWARDED_PORT: true
     env_file: .env
     links:
       - db
@@ -86,7 +89,7 @@ services:
     ports:
       - "8012:8012"
     environment:
-      PUBLIC_PATH: http://${MITX_ONLINE_HOSTNAME:-mitxonline.odl.local}:8012/
+      PUBLIC_PATH: ${MITX_ONLINE_WATCH_BASE_URL:-http://mitxonline.odl.local:8012/}
       NODE_ENV: ${NODE_ENV:-development}
       DOCKER_HOST: ${DOCKER_HOST:-missing}
       CONTAINER_NAME: 'watch'
@@ -128,7 +131,7 @@ services:
     ports:
        - "8016:8016"
     environment:
-      PUBLIC_PATH: http://${MITX_ONLINE_HOSTNAME:-mitxonline.odl.local}:8016/
+      PUBLIC_PATH: ${MITX_ONLINE_REFINE_BASE_URL:-http://mitxonline.odl.local:8016/}
       PORT: 8016
       NODE_ENV: ${NODE_ENV:-development}
     volumes: