CODEWITHSUNDEEP
ruby-on-railsemailherokutimeout
piffy
piffy

Reputation: 733

Heroku/rails: error 302 while sending lots of mail

I have a send mail to all users that send one email per user.

The function works, but I get an ugly error message on the web app. On the logs i get

2012-08-28T12:08:03+00:00 heroku[router]: Error H12 (Request timeout) -> POST afternoon-spring-6294.herokuapp.com/welcome/wall dyno=web.1 queue= wait= service=30000ms status=503 bytes=0
[...]
Sent mail to [email protected] (1708ms)
2012-08-28T12:08:31+00:00 app[web.1]: Redirected to http://afternoon-spring-6294.herokuapp.com/
2012-08-28T12:08:31+00:00 app[web.1]: Completed 302 Found in 58114ms (ActiveRecord: 8.9ms)

Is there a workaround (it was triggered by only 33 emails)?

Upvotes: 1

Views: 706

Answers (1)

John Paul Ashenfelter
John Paul Ashenfelter

Reputation: 3143

Heroku reaps all process that run longer than 30s, which means almost any batch email through something like mailgun or sendgrid will get killed with the H12 error.

There's a couple of basic ways to handle, but all involve making things more asynchronous. Heroku worker processes can run indefinitely -- or at least FAR longer than 30s.

The traditional option is to use a queue -- delayed_job is dead simple and only needs a database to back it. Resque is also cool but requires Redis to be added to the mix. There are also MANY more sophisticated options but delayed_job is dead simple. Railscasts is probably your friend here to figure out how to do it.

Another option is to use a worker process to handle the email tasks directly. For example, you can use a worker to send email in batches every X minutes using a rake task. This is sort of queue without all the overhead. Let's say you need to send a batch of invitations, you write invitations with an unsent status to a table, then have a rake task pop the first one off and send it, repeat until done. You'd be basically reimplementing a simple queue but might feel more comfortable.

Personally I'd put in delayed_job until I needed something more powerful.

Upvotes: 1

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