This changeset updates a try/except block to catch Exception instead of BaseException. Using BaseException is an anti-pattern and is not intended for user-defined code; it can also lead to other unintended side effects if not handled properly.
This is enough of a concern that the new release of flake8-bugbear now issues warnings when it sees BaseException being caught without an immediate re-raise.
Signed-off-by: Carlo Costino <carlo.costino@gsa.gov>
Previously we used a combination of "provider.name" and "get_name()"
which was confusing. Using a non-property function also gave me the
impression that the name was more dynamic than it actually is.
At the moment, when we are processing and sending an SMS we open
a DB connection at the start of the celery task and then close it
at the end of the celery task. Nice and simple.
However, during that celery task we make an HTTP call out to our
SMS providers. If our SMS providers have problems or response times
start to slow then it means we have an open DB connection sat waiting
for our SMS providers to respond which could take seconds. If our
SMS providers grind to a halt, this would cause all of the
celery tasks to hold on to their connections and we would run out
of DB connections and Notify would fall over.
We think we can solve this by closing the DB session which releases
the DB connection back to the pool.
Note, we've seen this happen in staging during load testing if our
SMS provider stub has fallen over. We've never seen it in production
and it may be less unlikely to happen as we are balancing traffic
across two providers and they generally have very good uptime.
One downside to be aware of is there could be a slight increase in
time spent to send an SMS as we will now spend a bit of extra time
closing the DB session and then reopening it again after the HTTP
request is done.
Note, there is no reason this approach couldn't be copied for our
email provider too if it appears successful.
As of 041d8b48a2
it’s not valid to call `random.choices` without giving at least one of
the options a positive weighting.
This makes sense, because giving a zero weighting is effectively saying
‘theres’s only one choice, but don’t choose it’.
In our codebase this is applicable where there’s only one international
provider, which we want to use even when it’s been de-prioritised for
domestic SMS.
This doesn’t cause a problem now, but will if we upgrade to Python
versions greater than 3.9.0.
Just looks a bit tidier and less repetitive.
I’ve only done this for the serialised service because:
- we’re only checking this in places where we’re already using the
serialised service
- if we want to check this elsewhere there’s a good chance that new code
should be using the serialised service, since it’ll itself be doing
some kind of performance optimisation
We want to start using Firetext for sending international SMS. They
require us to use a different API key for international SMS because it
requires a new code path to switch the sender ID to something that the
country will accept.
This PR does not include switching the sender of international SMS to
Firetext but sets us up to do so.
Add caching by using the SeriralisedTemplate and SerialisedService objects
Removed extra call to the database to fetch the notification after the commit by saving the created_at and key_type to a local variable. After the update to the notification to mark it as sending the db.session is committed. Any reference to the the Notification data model after that will require a query to fetch the object again because it is considered "dirty" or out of date.
Added name, sms_prefix and email branding to SerialisedService.
Refactor the get_html_options to work with the SerialisedService object.
Removed the need to validate and format the to field by using `normalised_to`, since when persisting the notification the `normalised_to` field has already had this done.
Removed the validate and format for reply_to_text for email reply_to, this has been done when the email address has been added via the frontend, no need to validate this address every time a services sends an email.
By adding SerialisedTemplate we can avoid a database call for the template. This is useful when sending many many emails/sms for the same template/version.
Remove 2 extra select queries after the update and commit. Once a transaction is committed SQLAlchemy will query for the db model if referenced after a commit.
For every email or text message we send we have to work out which
provider to send it with. Every time we do this we go and load the list
of providers from the database.
For emails, the result will always be the same.
For text messages the result is randomly chosen to balance the load
between the providers.
For international text messages the result is always the same (we only
have one international text message provider).
This commit adds an in-memory cache with a 2 second TTL so that we’re
not fetching the providers from the database every time, which should
speed things up a bit.
This does mean that, for text messages, the random choice will ‘stick’
for two seconds on each instance, before being re-chosen. I think this
is OK because it will even out to the same distribution over time.
I really don’t like having to clear the cache in the tests, so would
welcome suggestions on a better way of doing this…
