From b1c0778bde59043b51204288395601b7ef4f0718 Mon Sep 17 00:00:00 2001
From: Chris Hill-Scott <me@quis.cc>
Date: Wed, 28 Nov 2018 15:39:08 +0000
Subject: [PATCH] Since moving to putting the admin app on Cloudfront anything
 on the `www.notifications.service.gov.uk` domain is: - not gzipped
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

The PaaS proxy used to GZip and set headers for anything served from a
path starting with `/static/`:
https://github.com/alphagov/notifications-aws/blob/76dd511a8aaa2e4f8ffec17662bbe08841c52455/ansible/roles/paas-proxy/templates/admin.conf.j2#L53-L64

Anything served from `static.notifications.service.gov.uk` is:
- GZipped
- and as a bonus, cached by Cloudfront where possible (meaning the
requests won’t ever hit our app)

This commit moves to serving static asset from `/static/` to
`static.notifications.service.gov.uk`, to get the above listed benefits.

***

We could do even better by setting long cache expiry headers on the static subdomain (currently they’re only set to cache for 60 seconds). But that’s out of scope for this commit.
---
 app/__init__.py | 2 +-
 app/config.py   | 5 +++++
 2 files changed, 6 insertions(+), 1 deletion(-)

diff --git a/app/__init__.py b/app/__init__.py
index 04029a83f..79899c5ca 100644
--- a/app/__init__.py
+++ b/app/__init__.py
@@ -194,7 +194,7 @@ def init_app(application):
     @application.context_processor
     def inject_global_template_variables():
         return {
-            'asset_path': '/static/',
+            'asset_path': application.config['ASSET_PATH'],
             'header_colour': application.config['HEADER_COLOUR'],
             'asset_url': asset_fingerprinter.get_url
         }
diff --git a/app/config.py b/app/config.py
index 0325b4ce3..2db0dfddb 100644
--- a/app/config.py
+++ b/app/config.py
@@ -74,6 +74,8 @@ class Config(object):
     REDIS_URL = os.environ.get('REDIS_URL')
     REDIS_ENABLED = os.environ.get('REDIS_ENABLED') == '1'
 
+    ASSET_PATH = '/static/'
+
 
 class Development(Config):
     NOTIFY_LOG_PATH = 'application.log'
@@ -117,6 +119,7 @@ class Preview(Config):
     MOU_BUCKET_NAME = 'notify.works-mou'
     NOTIFY_ENVIRONMENT = 'preview'
     CHECK_PROXY_HEADER = False
+    ASSET_PATH = 'https://static.notify.works/'
 
 
 class Staging(Config):
@@ -129,6 +132,7 @@ class Staging(Config):
     MOU_BUCKET_NAME = 'staging-notify.works-mou'
     NOTIFY_ENVIRONMENT = 'staging'
     CHECK_PROXY_HEADER = False
+    ASSET_PATH = 'https://static.staging-notify.works/'
 
 
 class Live(Config):
@@ -141,6 +145,7 @@ class Live(Config):
     MOU_BUCKET_NAME = 'notifications.service.gov.uk-mou'
     NOTIFY_ENVIRONMENT = 'live'
     CHECK_PROXY_HEADER = False
+    ASSET_PATH = 'https://static.notifications.service.gov.uk/'
 
 
 class CloudFoundryConfig(Config):