Create "autonag" application

[rjw57]

The autonag application provides a management command which will run daily and send the "autonag" emails. The command should be idempotent in that running it repeatedly will net affect the frequency of emails sent.

Tasks:

• Create autonag application
• Create autonag management command
• Add "new member" nag

We can add more nags as other parts of the software are implemented.

[S-Stephen]

I see at the moment the notification emails are recorded into the Email log->Emails table, unless something like settings PINAX_NOTIFICATIONS_BACKENDS=[("email", "pinax.notifications.backends.email.EmailBackend"),] is set.

Is the intention to continue to create the messages in this table then run a scheduler to send the messages later, during the night?

Another scheduler will be required to populate the email table with the nags eg you have not had any meeting with X for Y weeks etc.

[rjw57]

On 2017-02-14 16:06, StephenS wrote: I see at the moment the notification emails are recorded into the Email log->Emails table, unless something like settings PINAX_NOTIFICATIONS_BACKENDS=[("email", "pinax.notifications.backends.email.EmailBackend"),] is set. Is the intention to continue to create the messages in this table then run a scheduler to send the messages later, during the night?

I hadn't really got as far as a design for this but it seems sensible to me to make the recording of intent to send email separate to the request->render->response pipeline.

…

Another scheduler will be required to populate the email table with the nags eg you have not had any meeting with X for Y weeks etc

-- Dr Rich Wareham

[S-Stephen]

I think that it would be useful for the notification to be sent immediately in some cases for example:

• when a users registers a meeting, to avoid the other party adding the same meeting
• when a user sends or accepts an invite

However it would also be nice to have a log of these notifications, which if just sending immediately I don't think happens automatically.

For the periodic reminders then yes dong these in bulk at a particular time I think could would be helpful.

I'm slightly split, and I'm not sure if I found a clear way to dictate from the 'send()' which route a message would take (direct or via Email log).

[rjw57]

On 2017-02-14 16:16, StephenS wrote: I think that it would be useful for the notification to be sent immediately in some cases for example: - when a users registers a meeting, to avoid the other party adding the same meeting - when a user sends or accepts an invite However it would also be nice to have a log of these notifications, which if just sending immediately I don't think happens automatically. For the periodic reminders then yes dong these in bulk at a particular time I think could would be helpful. I'm slightly split, and I'm not sure if I found a clear way to dictate from the 'send()' which route a message would take (direct or via Email log).

I think I was envisaging some sort of message queue. The time between "send email" appearing in the database and the email being sent can be very low; the sending server could check every 15 seconds. I just think it should not be on the critical path for two reasons: 1. If email sending fails due to a temporary server outage then it will be re-tried automatically. 2. If we want to disable email notification temporarily, one simply stops the email sending job. When it is re-started the backlog is worked through.

…

-- Dr Rich Wareham

[S-Stephen]

Celery looks as though it logs and capture issues. Also need to find out if it can be used to temporarily disable email.

I'll take a look at Celery (http://celery.readthedocs.io) in branch REST-Celery.

(Unless there are know issues or other leads)

[S-Stephen]

Having taken a look it seems as though using mysql as the broker for Celery isn't a good idea. They suggest RabbitMQ or Redis though to install either on MWS requires a fair amount of work.

[S-Stephen]

I've used the pinax-notifications emit_notices management command. Happy to write a specific one for autonag but wasn't too sure what else it should do other than send messages and check for exceptions.

[S-Stephen]

What should happen with new member nag?

On loading a new user -> are they to get a 'congratulations' message?

Can we create another management command to search for things to nag and create the notifications (and for now keep the logic in the code; how many nags are there?)