docker-mailserver/target/bin/dms-healthcheck

#!/bin/bash

# Verifies that all supervisor-managed services that should be running are in
# the `RUNNING` state. Returns exit code `0` if all are healthy, otherwise `1`.

# TODO: The script could also verify that service ports have listeners bound (if justified).
# Implementation approach was discussed with two examples for checking port 25 here:
# https://github.com/docker-mailserver/docker-mailserver/pull/4706#discussion_r3344258001

readonly DMS_SETTINGS='/etc/dms-settings'

# Required to proceed (ensures awareness of default enabled services):
[[ ! -f ${DMS_SETTINGS} ]] && exit 1

# shellcheck source=/dev/null
source "${DMS_SETTINGS}"

SERVICE_LIST=$(supervisorctl status | awk '{print $1}')

# Support for `IMAP IDLE` (via ENV `FETCHMAIL_PARALLEL` / `GETMAIL_PARALLEL`):
# This feature requires multiple instances of a service managed by supervisord.
# Filter the service list for a numbered suffix of the service name.
function _get_services_for() {
  local SERVICE_NAME=${1:?Service name required}
  local IS_PARALLEL="${2:-0}"

  if [[ ${IS_PARALLEL} -eq 1 ]]; then
    grep -E "^${SERVICE_NAME}-[0-9]+$" <<< "${SERVICE_LIST}"
  else
    echo "${SERVICE_NAME}"
  fi
}

# Core services that are always expected to be running:
declare -a SERVICES=(
  'cron'
  'rsyslog'
  'postfix'
  'changedetector'
)

# Conditional services based on enabled features:
[[ ${SMTP_ONLY}           -ne 1 ]] && SERVICES+=('dovecot')
[[ ${ENABLE_OPENDKIM}     -eq 1 ]] && SERVICES+=('opendkim')
[[ ${ENABLE_OPENDMARC}    -eq 1 ]] && SERVICES+=('opendmarc')
[[ ${ENABLE_AMAVIS}       -eq 1 ]] && SERVICES+=('amavis')
[[ ${ENABLE_CLAMAV}       -eq 1 ]] && SERVICES+=('clamav')
[[ ${ENABLE_FAIL2BAN}     -eq 1 ]] && SERVICES+=('fail2ban')
[[ ${ENABLE_POSTGREY}     -eq 1 ]] && SERVICES+=('postgrey')
[[ ${ENABLE_SRS}          -eq 1 ]] && SERVICES+=('postsrsd')
[[ ${ENABLE_RSPAMD_REDIS} -eq 1 ]] && SERVICES+=('rspamd-redis')
[[ ${ENABLE_RSPAMD}       -eq 1 ]] && SERVICES+=('rspamd')
[[ ${ENABLE_MTA_STS}      -eq 1 ]] && SERVICES+=('mta-sts-daemon')
[[ ${ENABLE_SASLAUTHD}    -eq 1 ]] && SERVICES+=("saslauthd_${SASLAUTHD_MECHANISMS}")

# shellcheck disable=SC2207
[[ ${ENABLE_FETCHMAIL}    -eq 1 ]] && SERVICES+=(
  $(_get_services_for 'fetchmail' "${FETCHMAIL_PARALLEL}")
)

# shellcheck disable=SC2207
[[ ${ENABLE_GETMAIL}      -eq 1 ]] && SERVICES+=(
  $(_get_services_for 'getmail' "${GETMAIL_PARALLEL}")
)

# Ensure all enabled services report a 'RUNNING' status.
# - We cannot rely upon the exit status of `supervisorctl status` (due to `STARTING`/`BACKOFF`).
# - Returns an exit status of `0` only when the 2nd column reduces to `RUNNING`.
test 'RUNNING' = "$(supervisorctl status "${SERVICES[@]}" | awk '{print $2}' | sort -u)"