Send an e-mail from the command line using AWS SES SMTP

send-ses.sh

#!/bin/bash -e
set -o pipefail

# PREREQUISITES:
#
#   1. mailx command line utility
#   2. Firewall access to TLS SMTP port 465 on the SES server specified in SES_ENDPOINT, below.
#
# INSTRUCTIONS:
#
#   1. Create IAM user with ses:SendRawEmail permission; example policy:
#
#      {
#          "Version": "2012-10-17",
#          "Statement": [{
#              "Action": "ses:SendRawEmail",
#              "Resource": "*",
#              "Effect": "Allow"
#          }]
#      }
#
#  2. Set ACCESS_KEY_ID and SECRET_ACCESS_KEY, below, for the access key of the IAM user.
#  3. Set FROM_ADDRESS, below, to an address authorized to send from SES.
#  4. Set TO_ADDRESS, below. Note: If your SES is still sandboxed, this address first will need to be verified in SES.
#  5. Edit SUBJECT, below, as desired.
#  6. Change SES_ENDPOINT to the endpoint for your region: http://docs.aws.amazon.com/ses/latest/DeveloperGuide/smtp-connect.html

ACCESS_KEY_ID=
SECRET_ACCESS_KEY=
FROM_ADDRESS=
TO_ADDRESS=
SUBJECT=Test
SES_ENDPOINT=email-smtp.us-west-2.amazonaws.com

hmac() {
	local hexKey="$1"
	local toSign="$2"

	echo -n "$toSign" | openssl sha256 -binary -mac HMAC -macopt "hexkey:$hexKey" | od -t x1 -A n -w32 | sed 's/ //g'
}

toHex() {
	local value="$1"

	echo -n "$value" | od -t x1 -A n -w${#value} | sed 's/ //g'
}

hexToBase64() {
	local hexValue="$1"

	echo -n "$hexValue" | while read -r -n 2 byte; do printf "\\x$byte"; done | base64
}

SECRET_ACCESS_KEY_HEX=$(toHex $SECRET_ACCESS_KEY)
MESSAGE=SendRawEmail
VERSION_HEX=02
SIGNATURE_HEX=$VERSION_HEX$(hmac $SECRET_ACCESS_KEY_HEX $MESSAGE)
PASSWORD=$(hexToBase64 $SIGNATURE_HEX)

mailx \
	-r "$FROM_ADDRESS" \
	-s "$SUBJECT" \
	-S "smtp=smtps://$SES_ENDPOINT:465" \
	-S "smtp-auth-user=$ACCESS_KEY_ID" \
	-S "smtp-auth-password=$PASSWORD" \
	"$TO_ADDRESS"