This is to prepare us for where when we try and send/cancel a broadcast
we may need to invoke more than one lambda. This might happen if we call
the invoke the first lambda, we get an error and therefore we try and
invoke a failover/second lambda. Then `_invoke_lambda` will be
responsible for the call to AWS whereas `_invoke_lambda_with_failover`
will be responsible more for picking the lambda and deciding on retry
behaviour if failure cases.
This will make it impossible to create a new client without at least
having to define these properties. Which should get someone thinking
about language support…
If we’re sending non-GSM characters, we need to mark the language in the
XML as Welsh (`cy-GB` in CAP, `Welsh` in IBAG).
Currently, the CBC proxy checks the content we’re sending, and then uses
an approximation based on ASCII to determine whether we’re sending any
non-GSM characters, and if so, sets the language appropriately.
Instead, we should can functionality from the notifications-utils repo
to determine the language. If any non-GSM characters are used, then the
we can set the language to Welsh.
We’ll need to update the proxy to look at this new language flag.
In IBAG format for broadcasts, we need to give sequential number
of previous message, and it needs to be formatted as a hex padded
with zeroes to be 8 character long.
This commit adds the necessary formatting.
previously we made some incorrect assumptions about set-up on staging
and prod - they currently don't have any cbc_proxy aws creds at all.
We shoudn't be attempting canaries or link tests when there's no AWS
infrastructure to connect to.
We also shouldn't bother writing a row into the database at all for the
broadcast_provider_message since we're not even attempting to send, and
we shouldn't get confused between messages that failed and messages we
never wanted to send at all.
this is a pretty big and convoluted refactor unfortunately.
Previously:
There was one global `cbc_proxy_client` object in apps. This class has
the information about how to invoke the bt-ee lambda, and handles all
calls to lambda. This includes calls to the canary too (which is a
separate lambda).
The future:
There's one global `cbc_proxy_client`. This knows about the different
provider functions and lambdas, and you'll need to ask this client for a
proxy for your chosen provider. call cbc_proxy_client.get_proxy('ee')`
and it'll return you a proxy that knows what ee's lambda function is,
how to transform any content in a way that is exclusive to ee, and in
future how to parse any response from ee.
The present:
I also cleaned up some duplicate tests.
I'm really not sure about the names of some of these variables - in
particular `cbc_proxy_client` isn't a client - it's more of a java style
factory, where you call a function on it to get the client of your
choice.
replacing get_earlier_provider_messages. The old function returned the
previous references for earlier events for a broadcast_message. However,
these depend on the message sent to a specific provider, so the function
needs to change. It now takes in a provider, and only returns
broadcast_provider_messages sent to that provider. If there are earlier
broadcast_events without a provider_message for the chosen provider, it
raises an exception - you cannot cancel a message if all the previous
events have not been created properly (as we wouldn't know what
references to cancel).
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.
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>
The CBC Proxy is essentially a lambda function which we invoke with
various arguments.
A way in which this can fail is that the notifications-api app invoking
the function may not be able, any longer, to invoke the function.
This could be caused by, for example:
* an egress restriction preventing access to eu-west-2.lambda.amazonaws.com
* a network partition preventing access to eu-west-2.lambda.amazonaws.com
* the app's credentials have been rotated or revoked
If we invoke a simple "canary" lambda function for which the app should
have access to invoke, and check it for failures, we will know quickly
if something is likely to be broken.
This is especially important for cell broadcasts compared to email/SMS
because we always have a baseline of traffic for email/SMS, and so any
failure is observed almost immediately. This is not true for CB where we
may expect to only see one CB message every week/month/quarter/year, as
opposed to every minute or second for email/SMS.
Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
Co-authored-by: Pea <pea.tyczynska@digital.cabinet-office.gov.uk>
We are going to invoke a lambda to send a message to the CBC
We need a CBC Proxy Client to do this
The Client will be able to send/update/cancel broadcasts in the CBC
Unless we have configured the app with AWS credentials for the
CBCProxyClient, we just want to use a client that does nothing: the noop
client
The AWS access keys are separate for the CBC Proxy vs other Notify AWS
things because the CBC Proxy lives in another AWS account
Signed-off-by: Toby Lorne <toby.lornewelch-richards@digital.cabinet-office.gov.uk>
Co-authored-by: Pea <pea.tyczynska@digital.cabinet-office.gov.uk>
Co-authored-by: Katie <katie.smith@digital.cabinet-office.gov.uk>
