(instead of using the id from broadcast_event)
we need every XML blob we send to have a different ID. if we're sending
different XML blobs for each provider, then each one should have a
different identifier. So, instead of taking the identifier from the
broadcast_event, take it from the broadcast_provider_message instead.
Note: We're still going to the broadcast_event for most fields, to
ensure they stay consistent between different providers. The last thing
we want is for different phone networks to get different content
at the moment only EE is enabled (this is set in app.config, but also,
only EE have a function defined for them so even if another provider was
enabled without changing the dict in cbc_proxy.py we won't trigger
anything). this commit just adds wrapper tasks that check what providers
are enabled, and invokes the send function for each provider.
The send function doesn't currently distinguish between providers for
now - as we only have EE set up. in the future we'll want to separate
the cbc_proxy_client into separate clients for separate providers.
Different providers have different lambda functions, and have different
requirements. For example, we know that the two different CBC software
solutions handle references to previous messages differently.
moved the lambda invocation to a separate function to keep DRY
asserts on exception types need to be outside of with blocks, or they
won't trip (as the exception will stop execution of the inner with
block). the asserts were also the wrong way round so fixed that.
i think it's causing havoc with my attempts to mock stuff in the
`app.clients` directory because it's also accessible at that path. the
name's super vague and doesn't explain what it is anyway
We don't retry any callbacks when it receives a 4xx status. We should
probably be aware of this happening and at the moment there is nothing
in our logs to easily identify whether the request failed and is being
retried or if it failed and is not being retried. This will enable us to
search our logs easily and figure out how much it's happening.
It's quite likely that we should in the future allow callbacks to retry
if they get a 429 http response (rate limiting) but we should do this in
a smart way (exponential backoff) and so this is a first step to being
aware of how big a problem it is in case we want to do something about
it.
Add different error message for email and text if content is too long.
Use utils version with is_message_too_long method implemented for email templates.
We want to add validation for an email that's too long, that way the user knows why the message is failing. At the moment if an email is too long it will get a technical failure, after the retries fail. This way the email post will get a validation error.
Once this: https://github.com/alphagov/notifications-utils/pull/804 is reverted, we can update the utils version.
This is causing the disk of the CBCs to fill up quickly, and their
logrotate seems a bit flakey
Reducing the rate will ensure the disks fill up less often
Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
SES rejects email messages bigger than 10485760 bytes (just over 10 MB per message (after base64 encoding)):
https://docs.aws.amazon.com/ses/latest/DeveloperGuide/quotas.html#limits-message
Base64 is apparently wasteful because we use just 64 different values per byte, whereas a byte can represent
256 different characters. That is, we use bytes (which are 8-bit words) as 6-bit words. There is
a waste of 2 bits for each 8 bits of transmission data. To send three bytes of information
(3 times 8 is 24 bits), you need to use four bytes (4 times 6 is again 24 bits). Thus the base64 version
of a file is 4/3 larger than it might be. So we use 33% more storage than we could.
https://lemire.me/blog/2019/01/30/what-is-the-space-overhead-of-base64-encoding/
That brings down our max safe size to 7.5 MB == 7500000 bytes before base64 encoding
But this is not the end! The message we send to SES is structured as follows:
"Message": {
'Subject': {
'Data': subject,
},
'Body': {'Text': {'Data': body}, 'Html': {'Data': html_body}}
},
Which means that we are sending the contents of email message twice in one request: once in plain text
and once with html tags. That means our plain text content needs to be much shorter to make sure we
fit within the limit, especially since HTML body can be much byte-heavier than plain text body.
Hence, we decided to put the limit at 1MB, which is equivalent of between 250 and 500 pages of text.
That's still an extremely long email, and should be sufficient for all normal use, while at the same
time giving us safe margin while sending the emails through Amazon SES.
depending on the notification type.
Up until now, only sms messages could get message-too-long error,
but now we also need to validate the size of email messages, so
the message content needs to be tailored to the notification type.
A BroadcastEvent knows when an event was sent and should expire
We pass through these values directly to the CBC Proxy, because
BroadcastEvent knows how they should be formatted
Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
When we ask the CBC Proxy to send a message, we should specify that we
want to send a real message, when we want a real message
We will do this by specifying the message_type which can have 4 types, 3
of which represent a real message:
| Name | Effect |
| ------ | ------------------------ |
| alert | Create an alert |
| update | Update an existing alert |
| cancel | Cancel an existing alert |
| test | Send a link test |
We will use message_type to represent the table above
Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
Co-authored-by: Richard <richard.baker@digital.cabinet-office.gov.uk>
Co-authored-by: Pea <pea.tyczynska@digital.cabinet-office.gov.uk>
