* Updated header and footer
* Moved files around and updated gulpfile to correct the build process when it goes to production
* Updated fonts
* Adjusted grid templating
* Adding images to assets
* Updated account pages, dashboard, and pages in message sending flow
* Updated the styling for the landing pages in the account section once logged in
* Updated header and footer
* Updated fonts
* Moved files around and updated gulpfile to correct the build process when it goes to production
* Adjusted grid templating
* Added images to assets
* Update app/templates/components/uk_components/footer/template.njk
Co-authored-by: Steven Reilly <stvnrlly@users.noreply.github.com>
By default our AJAX calls were 2 seconds. Then they were 5 seconds
because someone reckoned 2 seconds was putting too much load on the
system. Then we made them 10 seconds while we were having an incident.
Then we made them 20 seconds for the heaviest pages, but back to 5
seconds or 2 seconds for the rest of the pages.
This is not a good situation because:
- it slows all services down equally, no matter how much traffic they
have, or which features they have switched on
- it slows everything down by the same amount, no matter how much load
the platform is under
- the values are set based on our worst performance, until we manually
remember to switch them back
- we spend time during incidents deploying changes to slow down the
dashboard refresh time because it’s a nothing-to-lose change that
might relieve some symptoms, when we could be spending time digging
into the underlying cause
This pull request makes the Javascript smarter about how long it waits
until it makes another AJAX call. It bases the delay on how long the
server takes to respond (as a proxy for how much load the server is
under).
It’s based on the square root of the response time, so is more sensitive
to slow downs early on, and less sensitive to slow downs later on. This
helps us give a more pronounced difference in delay between an AJAX call
that is fast (for example the page for a single notification) and one
that is slow (for example a dashboard for a service with lots of
traffic).
*Some examples of what this would mean for various pages*
Page | Response time | Wait until next AJAX call
---|---|---
Check a reply to address | 130ms | 1,850ms
Brand new service dashboard | 229ms | 2,783ms
HM Passport Office dashboard | 634ms | 5,294ms
NHS Coronavirus Service dashboard | 779ms | 5,977ms
_Example of the kind of slowness we’ve seen during an incident_ | 6,000ms | 18,364ms
GOV.UK email dashboard | `HTTP 504` | 😬
Dashboard is the most intensive page we AJAX, and also the highest
traffic one. We’ve already slowed it from 2 to 5 seconds, this slows it
further to 20 seconds to reduce the load.
This leaves other pages (for example looking at a single job) at the
platform-level default of 5 seconds, because we think they cause less
load and the real-timelyness isn’t critical to people’s business
processes.
For looking at a single notification we know from research that someone
sending these one-at-a-time often waits to see if they’re delivered,
so let’s bring this back down to the previous value of 2 seconds.
We’ve done this already for services with the upload letters permission.
And all services can upload letters now.
But we’re still returning it in the JSON response we use to AJAX-ify the
page.
Since the jobs response can query stats for up to 50 jobs at a time this
puts some load on the API/database. Hopefully this might drop that load
a bit.
The default is 2 seconds and this will mean that we are halving traffic
for these ajax calls which can only be good for trying to limit queries
on the database.
I think the user impact on this will likely not be noticable.
Debatable whether we should up them all even further to 10 seconds but
this is definitely a quick although maybe small win.
This follows the pattern of what we’ve done with services, users and
events.
It gives us a way of neatly instantiating a model for each item in the
list we get back from the API and reduces the complexity of the view
layer code.
Now is a good time to do this because we’re going to be making a bunch
of changes to the jobs pages, and those changes will be easier to code
and understand with a sensible model behind them.
