Add fabric task to clear cached templates

leenagupte · leenagupte · commit 6fbd409ae512 · 2017-04-12T17:43:43.000+01:00
The templates in static and frontend are cached in the application.

When the emergency banner is deployed (and removed) we need to purge
these caches so that static will regenerate the templates.

There is already a fabric function that clears down the wrapper
templates that display the banner on most pages. We need to add the
homepage template to this list.

We also need to purge tmp/cache in the frontend app.

Set the `warn_only` flag to True so that fabric won't throw an error
and quit if the template it's trying to purge has already been removed.

This fabric script is a temporary work around until centralised
caching is implemented.
diff --git a/campaigns.py b/campaigns.py
@@ -1,6 +1,6 @@
 import StringIO
 
-from fabric.api import env, put, roles, runs_once, sudo, task
+from fabric.api import env, put, roles, runs_once, settings, sudo, task
 from fabric.operations import prompt
 from fabric.tasks import execute
 
@@ -14,6 +14,12 @@
 
 APPLICATIONS = ['static', 'frontend']
 CAMPAIGN_CLASSES = ['red', 'black', 'green']
+TEMPLATES = [
+    'wrapper.html.erb',
+    'homepage.html.erb',
+    'header_footer_only.html.erb',
+    'core_layout.html.erb',
+]
 
 
 def validate_classes(campaign_class):
@@ -70,8 +76,13 @@ def clear_static_generated_templates():
     This function clears the public/template directory to force it to
     be regenerated to include the emergency campaign.
     """
-    for template in ('wrapper.html.erb', 'header_footer_only.html.erb', 'core_layout.html.erb'):
-        sudo('rm /var/apps/static/public/templates/{}'.format(template))
+    for template in TEMPLATES:
+        with settings(warn_only=True):
+            sudo('rm /var/apps/static/public/templates/{}'.format(template))
+
+
+def clear_frontend_cache():
+    sudo("rm -rf /var/apps/frontend/tmp/cache/*")
 
 
 def deploy_banner(application):
@@ -117,3 +128,13 @@ def remove_emergency_banner():
     """Remove all banners from GOV.UK"""
     for application in APPLICATIONS:
         remove_banner(application)
+
+
+@task
+@roles('class-frontend')
+def clear_cached_templates():
+    for application in APPLICATIONS:
+        if application == 'frontend':
+            clear_frontend_cache()
+        if application == 'static':
+            clear_static_generated_templates()
