1364441 - Use Cache-Control immutable

Status: RESOLVED FIXED

(Socorro :: Infra, task)

Description

[Peter Bengtsson [:peterbe]]

Firefox, as of version 49, supports 'Cache-Control: immutable'. It means that the server doesn't even bother to send a GET with 'If-Modified-Since	' (to which our Nginx most likely will respond 304 Not Modified).

Basically, if you reload the page (e.g. to see if the data has changed) the client will send a GET for every single asset and Nginx will respond 304 for each one. 

For example, loading https://crash-stats.mozilla.com/search/?product=Firefox&version=54.0b&_dont_run=1 and hitting the Reload button will make 28 GET requests that all got a 304 response. 

If you use `Cache-Control: immutable` the browser doesn't even bother sending those GETs again (...to see if they've changed). Ultimately, this makes reloads faster for the users and less requests to your Nginx.

Comment 1

[Peter Bengtsson [:peterbe]]

Attachment: Screen Shot 2017-05-12 at 9.58.50 AM.png

SHIFT-Reload first.

Comment 2

[Peter Bengtsson [:peterbe]]

Attachment: Screen Shot 2017-05-12 at 9.59.01 AM.png

Regular Reload (before adding 'immutable')

Comment 3

[Peter Bengtsson [:peterbe]]

Attachment: Screen Shot 2017-05-12 at 10.02.57 AM.png

Regular Reload (after 'immutable' has been added and 1 Shift-Reload was done). 

Note! I also had a `tail -f /tmp/socorro.access.log` running when I did this reload. Only the HTML document and the one (or two) XHR requests appeared there. Before, it was a whole page (of 304 requests).

Comment 4

[Peter Bengtsson [:peterbe]]

PR https://github.com/mozilla/socorro-infra/pull/307

Comment 5

[Peter Bengtsson [:peterbe]]

Here's a good article about the feature: https://www.keycdn.com/blog/cache-control-immutable/

Comment 6

[[github robot]]

Commit pushed to master at https://github.com/mozilla/socorro-infra

https://github.com/mozilla/socorro-infra/commit/3fd949bf16506792f1174bfc02c0b7d2a72582e3
fixes bug 1364441 - Use Cache-Control immutable (#307)