Improve static deploy (#2609)

* Add a utility for purging Fastly by Surrogate-Key

* add a postdeploy step to purge surroage-keys for static files

Procfile

@@ -2,3 +2,4 @@ release: python manage.py migrate --noinput
 web: bin/start-nginx gunicorn -c gunicorn.conf pydotorg.wsgi
 worker: celery -A pydotorg worker -l INFO
 worker-beat: celery -A pydotorg beat -l INFO --scheduler django_celery_beat.schedulers:DatabaseScheduler
+postdeploy: python manage.py postdeploy

fastly/utils.py

@@ -20,3 +20,23 @@ def purge_url(path):
         return response
 
     return None
+
+
+def purge_surrogate_key(key):
+    """
+    Purge a Fastly.com Surrogate-Key given a key.
+    """
+    if settings.DEBUG:
+        return
+
+    api_key = getattr(settings, 'FASTLY_API_KEY', None)
+    service_id = getattr(settings, 'FASTLY_SERVICE_ID', None)
+    if api_key and service_id:
+        response = requests.request(
+            "POST",
+            f'https://api.fastly.com/service/{service_id}/purge/{key}',
+            headers={'Fastly-Key': api_key},
+        )
+        return response
+
+    return None

pydotorg/management/commands/postdeploy.py

@@ -0,0 +1,14 @@
+from django.core.management.base import BaseCommand
+from django.conf import settings
+
+from fastly.utils import purge_surrogate_key
+
+
+class Command(BaseCommand):
+    """ Do things after deployment is complete """
+
+    def handle(self, *args, **kwargs):
+        # If we have a STATIC_SURROGATE_KEY set, purge static files to ensure
+        # that anything cached mid-deploy is ignored (like 404s).
+        if settings.STATIC_SURROGATE_KEY:
+            purge_surrogate_key(settings.STATIC_SURROGATE_KEY)

pydotorg/settings/base.py

@@ -285,8 +285,10 @@
 MAILING_LIST_PSF_MEMBERS = "psf-members-announce-request@python.org"
 
 ### Fastly ###
-FASTLY_API_KEY = False  # Set to Fastly API key in production to allow pages to
-                        # be purged on save
+FASTLY_SERVICE_ID = False  # Set to a Fastly Service ID in production to allow
+                           # purges by Surrogate-Key
+FASTLY_API_KEY = False     # Set to Fastly API key in production to allow
+                           # pages to be purged on save
 
 # Jobs
 JOB_THRESHOLD_DAYS = 90
@@ -349,6 +351,10 @@
 
 GLOBAL_SURROGATE_KEY = 'pydotorg-app'
 
+### pydotorg.settings.cabotage.add_surrogate_keys_to_static
+
+STATIC_SURROGATE_KEY = 'pydotorg-static'
+
 ### PyCon Integration for Sponsor Voucher Codes
 PYCON_API_KEY = config("PYCON_API_KEY", default="deadbeef-dead-beef-dead-beefdeadbeef")
 PYCON_API_SECRET = config("PYCON_API_SECRET", default="deadbeef-dead-beef-dead-beefdeadbeef")

pydotorg/settings/cabotage.py

@@ -53,6 +53,11 @@
     },
 }
 
+def add_surrogate_keys_to_static(headers, path, url):
+    headers['Surrogate-Key'] = STATIC_SURROGATE_KEY
+
+WHITENOISE_ADD_HEADERS_FUNCTION = add_surrogate_keys_to_static
+
 EMAIL_HOST = config('EMAIL_HOST')
 EMAIL_HOST_USER = config('EMAIL_HOST_USER')
 EMAIL_HOST_PASSWORD = config('EMAIL_HOST_PASSWORD')
@@ -63,7 +68,8 @@
 PEP_REPO_PATH = None
 PEP_ARTIFACT_URL = config('PEP_ARTIFACT_URL')
 
-# Fastly API Key
+# Fastly
+FASTLY_SERVICE_ID = config('FASTLY_SERVICE_ID')
 FASTLY_API_KEY = config('FASTLY_API_KEY')
 
 SECURE_SSL_REDIRECT = True