How to Setup Action Mailbox with Postfix [Part 2]

This is the second part of a 2 series tutorial to setup action mailbox with postfix. In this part, we will configure postfix in production server to forward incoming emails to our rails app so action mailbox can process it.

If you haven't read the first part where we setup action mailbox and test it in development, you can read it here

You should have

• Postfix configured in production server (same server as your rails app)
• Existing app built with rails 6
• Ruby with rbenv setup
• Patience

Steps

Login to your production server first and then;

Step 1: Create bash script

Create a script inside

/usr/local/bin/

shell
$ nano email_forwarder.sh

Add following to the script

shell
#!/bin/sh
export HOME=YOUR_HOME_PATH
export PATH=YOUR_PATH
export RBENV_ROOT=YOUR_RBENV_PATH

cd /path/to/your/project && bin/rails action_mailbox:ingress:postfix URL='https://truemark.com.np/rails/action_mailbox/relay/inbound_emails' INGRESS_PASSWORD='YOUR_INGRESS_PASSWORD'

Replace value of

HOME

PATH

RBENV_ROOT

URL

INGRESS_PASSWORD 

• Copy your home directory for

  HOME

cd

pwd

shell
$ cd
$ pwd

• Copy what you get from

  $PATH

  and

  which rbenv

  command for

  PATH

  and

  RBENV_PATH

  respectively

shell
$ $PATH
$ which rbenv

• Copy the password you added to

  credentials

  or your

  ENV

  |

  application.yml

  file for

  INGRESS_PASSWORD

For

URL

https://example.com

bin/rails action_mailbox:ingress:postfix URL=https://example.com/rails/action_mailbox/relay/inbound_emails INGRESS_PASSWORD=YOUR_STRONG_PASSWORD

Step 2: Configure Postfix to Pipe Incoming emails to script

We will follow steps as described here.

Create

/etc/postfix/virtual_aliases

file
# /etc/postfix/virtual_aliases
@mydomain.tld   localuser@mydomain.tld

• Create `/etc/postfix/transport` to add a transport mapping. "forward_to_rails" can be whatever you want; it will be used later in `master.cf`

file
# /etc/postfix/transport
mydomain.tld    forward_to_rails:

• Next, both transport and virtual_aliases need to be compiled into berkeley db files:

shell
$ sudo postmap /etc/postfix/virtual_aliases
$ sudo postmap /etc/postfix/transport

• Add the transport to

  /etc/postfix/master.cf

file
# /etc/postfix/master.cf
forward_to_rails   unix  -       n       n       -       -       pipe
  flags=Xhq user=deploy:deploy argv=/usr/local/bin/email_forwarder.sh
  ${nexthop} ${user}

We should specify user so script is run by that user and not postfix or nobody.

user=deploy:deploy` ~ `user=user:group

• Add following in

  /etc/postfix/main.cf

file
# /etc/postfix/main.cf
  transport_maps = hash:/etc/postfix/transport
  virtual_alias_maps = hash:/etc/postfix/virtual_aliases

You can view postfix log with

tail -f /var/log/mail.log

You must have everything now to receive email in your rails app. Test it with any of your email provider; just send the email to

[email protected]

References

• https://guides.rubyonrails.org/action_mailbox_basics.html
• https://serverfault.com/questions/258469/how-to-configure-postfix-to-pipe-all-incoming-email-to-a-script

Previously published at https://thedevpost.com/blog/setup-action-mailbox-with-postfix-part-2/