systemd-mailer-script.j2

#!/usr/bin/env bash

to="${1}"
service="${2}"

if systemctl is-active --quiet "${service}"; then
    # The service running is again, a new timer should have start it
    # Prepare output message
    message="A new execution of ${service} is ongoing...\n\n"
    message+="Previous execution logs :\n"
    # There is no way of extracting logs of a previous execution, so we extract it manually
    # See : https://github.com/systemd/systemd/issues/1942
    # Timestamp when unit transitioned from inactive to active
    until=$(systemctl show -p InactiveExitTimestamp "${service}" | cut -d'=' -f2-)
    until=${until:-now}
    # add jounal to message, use reverse + tac to make output faster
    message+="$(journalctl --until "${until}" --unit "${service}" --reverse | head -n20 | tac)"
else
    # add current status to message
    message="$(systemctl status --full "${service}" -n 20)"
fi

sendmail -t <<ERRMAIL
To: ${to}
From: {{ vault_email_from }}
Subject: ({{ ansible_fqdn }}) ${service} status
Content-Transfer-Encoding: 8bit
Content-Type: text/plain; charset=UTF-8

$(echo -e "${message}")
ERRMAIL