SES Forwarder Terraform

Lambda function source: https://github.com/arithmetric/aws-lambda-ses-forwarder

Architecture

Source: https://aws.amazon.com/blogs/messaging-and-targeting/forward-incoming-email-to-an-external-destination/

Source: https://medium.com/@ashan.fernando/forwarding-emails-to-your-inbox-using-amazon-ses-2d261d60e417

Prerequisites

• You have a domain in AWS
• You have a verified your domain in AWS SES (including DKIM)
• If you have not configured inbound email handling, create a new Rule Set. Otherwise, you can use an existing one.
• You have configured the DNS MX record for your domain to point to the email receiving SES endpoint e.g. inbound-smtp.us-west-2.amazonaws.com
• Know what Terraform is
• Know what all the components are in the diagrams above (ish)

How to Use

1. Create a Terraform backend S3 bucket to store your state files
2. Copy and paste the example folder somewhere on your computer
3. Configure backend.tf to point at the S3 bucket you just created
4. Configure terraform.tfvars as per the input descriptions in inputs.tf
5. Run terraform init && terraform apply

• The steps above will set up a serverless mailbox for one email. You can copy and paste the example folder and repeat the steps to create multiple mailboxes (make sure your change the Terraform backend key).
• The sns_email_address variable is the email where error notifications will be sent to, so if you're administering several mailboxes you would keep this address the same for each one.
• You will need to confirm SNS subscription notifications will work.

Tests

Currently using terraform validate + terraform-compliance:

./test/test.sh

Requirements

Name	Version
aws	~> 3.0

Inputs

Name	Description	Type	Default	Required
account_id	The AWS account ID	string	n/a	yes
bucket_name	The name of the S3 bucket where emails will be stored	string	n/a	yes
cloudwatch_alarm	The name of the CloudWatch alarm monitoring the Lambda function	string	n/a	yes
cloudwatch_metric	The name of the metric used for detecting Lambda runtime errors	string	n/a	yes
lambda_name	The name of the Lambda function	string	n/a	yes
lambda_recipient	Where the Lambda function will send/forward the sent mail to	string	n/a	yes
lambda_role_name	The name of the IAM role used by the Lambda function	string	n/a	yes
mail_s3_prefix	Folder prefix where emails will be stored e.g. /mail	string	n/a	yes
region	Must be either us-west-2, us-east-1 or eu-west-1 (where SES receiving is)	string	"us-west-2"	no
ses_mail_recipient	The email address that the sender used	string	n/a	yes
ses_rule_name	The name of the SES rule that invokes the Lambda function	string	n/a	yes
ses_set_name	The name of the active Rule Set in SES which you have already configured	string	n/a	yes
sns_display_name	The friendly name of the SNS topic	string	n/a	yes
sns_email_address	The email address used to send error notifications to	string	n/a	yes
sns_protocol	The SNS protocol	string	"email"	no

Limitations

• SES only allows receiving email sent to addresses within verified domains: http://docs.aws.amazon.com/ses/latest/DeveloperGuide/verify-domains.html

• SES only allows sending emails up to 10 MB in size (including attachments after encoding): https://docs.aws.amazon.com/ses/latest/DeveloperGuide/limits.html

• Initially SES users are in a sandbox environment that has a number of limitations: http://docs.aws.amazon.com/ses/latest/DeveloperGuide/limits.html

Source: https://github.com/arithmetric/aws-lambda-ses-forwarder

Other Documentation

• https://github.com/arithmetric/aws-lambda-ses-forwarder
• https://aws.amazon.com/blogs/messaging-and-targeting/forward-incoming-email-to-an-external-destination/
• https://medium.com/@ashan.fernando/forwarding-emails-to-your-inbox-using-amazon-ses-2d261d60e417
• https://github.com/cloudposse/terraform-aws-ses-lambda-forwarder