dockyard / courier Goto Github PK

There are instances when you want emails to do nothing. A null adapter would be useful.

Use case

Let's say you send out 10,000 e-mails advertising your latest shiny product. It would be extremely beneficial to know how many of those e-mails bounced for tracking purposes in third party tooling.

An e-mail can bounce in 2 ways, a soft and hard bounce. SendGrid has a nice article articulating the difference between the 2 https://sendgrid.com/blog/email-bounce-management/.

Feature

In the response of the sent message call, include if it was a success, soft bounce, hard bounce and perhaps other forms of failure that I haven't thought of but are common.

I know this is probably something really stupid that I'm overlooking...

I am able to send email when running my app locally, but not after deploying.

This is the error I get:

01:22:12.077 [error] Process #PID<0.6419.0> raised an exception
** (FunctionClauseError) no function clause matching in :base64.encode/1
    (stdlib) base64.erl:64: :base64.encode(nil)
    src/gen_smtp_client.erl:375: :gen_smtp_client.do_AUTH_each/4
    src/gen_smtp_client.erl:322: :gen_smtp_client.try_AUTH/3
    src/gen_smtp_client.erl:203: :gen_smtp_client.do_smtp_session/3
    src/gen_smtp_client.erl:142: :gen_smtp_client.try_smtp_sessions/4
    src/gen_smtp_client.erl:109: :gen_smtp_client.send_it_nonblock/3
** (EXIT from #PID<0.1695.0>) an exception was raised:
    ** (FunctionClauseError) no function clause matching in :base64.encode/1
        (stdlib) base64.erl:64: :base64.encode(nil)
        src/gen_smtp_client.erl:375: :gen_smtp_client.do_AUTH_each/4
        src/gen_smtp_client.erl:322: :gen_smtp_client.try_AUTH/3
        src/gen_smtp_client.erl:203: :gen_smtp_client.do_smtp_session/3
        src/gen_smtp_client.erl:142: :gen_smtp_client.try_smtp_sessions/4
        src/gen_smtp_client.erl:109: :gen_smtp_client.send_it_nonblock/3

This is my `config/confix.exs':

config :drip_emails, DripEmails.Mailer,
  adapter: Courier.Adapters.SMTP,
  relay: "email-smtp.us-east-1.amazonaws.com",
  port: 587,
  username: System.get_env("AWS_SMTP_USER"),
  password: System.get_env("AWS_SMTP_PASS")

This is my mix.lock for Courier:

 "courier": {:hex, :courier, "0.0.3", "a01a42d3c06b08989bc1003acd5a58db1c652b4c6ecb414286f70b8ca62a67ec", [:mix], [{:gen_smtp, "0.9.0", [hex: :gen_smtp, optional: false]}, {:mail, "~> 0.0.4", [hex: :mail, optional: false]}]}

The way I'm reading these errors, its as if :gen_smtp can't parse the username / password because they aren't set. But when I inspect the values of those AWS_SMTP_*** env vars, they are clearly set.

Again, everything works fine locally, but not after deploying on Heroku.

Any thoughts?

Use case

You have a mailing list with 500,000 people and mailing back-ends such as Amazon SES and SendGrid enforce limits such as 10 mails per second or 50 mails per second.

This increases the total send time for a "campaign" and is most definitely the biggest bottleneck when it comes to sending out a lot of e-mails in bulk.

Feature

It would be really nice if you could configure something to load balance multiple adapters that are configured. The first implementation could be a round robin balancer which simply alternates sending e-mails out to each adapter.

Down the line (or now if it's not difficult?) it would be interesting if you could supply your limit to the adapter in the form of e-mails per second and then introduce an algorithm that determines the fastest way to deliver all of your e-mails.