docker-entrypoint

#!/usr/bin/env sh

set -e
set -o pipefail

DOCKER_SOCK=${DOCKER_SOCK:-/var/run/docker.sock}
CURL_TIMEOUT=${CURL_TIMEOUT:-30}


MAIL_ENABLED=${MAIL_ENABLED:-false}
MAILHUB=${MAILHUB}
ROOT=${ROOT}
SUBJECT=${SUBJECT:-[AUTOHEAL]}
TO=${TO}
CC=${CC}
REWRITE_DOMAIN=${REWRITE_DOMAIN}
FROMLINEOVERRIDE=${FROMLINEOVERRIDE:-yes}
HOSTNAME=${HOSTNAME}
TLS_CA_FILE=${TLS_CA_FILE:-/etc/pki/tls/certs/ca-bundle.crt}
USETLS=${USETLS:-yes}
USESTARTTLS=${USESTARTTLS:-yes}
AUTHUSER=${AUTHUSER}
AUTHPASS=${AUTHPASS}


# SIGTERM-handler
term_handler() {
  exit 143; # 128 + 15 -- SIGTERM
}

docker_curl() {
  curl --max-time "${CURL_TIMEOUT}" --no-buffer -s --unix-socket "${DOCKER_SOCK}" "$@" || return 1
  return 0
}

send_mail () {
  if [ "${MAIL_ENABLED}" = 'true' ]; then
   sendmail -vit << MAIL_END
Subject: $SUBJECT
To: $TO     
CC: $CC

Hostname: $HOSTNAME
$1

MAIL_END
fi
}

trap 'kill ${!}; term_handler' SIGTERM

if [ "$1" = 'healthcheck' ]; then
  docker_curl --fail http://localhost/_ping
  exit $?
fi

if [ "${MAIL_ENABLED}" = 'true' ]; then

  cat > /etc/ssmtp/ssmtp.conf << EOF
# The user that gets all the mails (UID < 1000, usually the admin)
# The person who gets all mail for userids < 1000
# Make this empty to disable rewriting.
root=${ROOT}

# The mail server (where the mail is sent to),
# For google both port 465 or 587 should be acceptable
# See also https://support.google.com/mail/answer/78799
mailhub=${MAILHUB}

# The address where the mail appears to come from for user authentication.
rewriteDomain=${REWRITE_DOMAIN}

# The full hostname.  Must be correctly formed, fully qualified domain name or GMail will reject connection.
hostname=${HOSTNAME}

# Use SSL/TLS before starting negotiation
TLS_CA_FILE=${TLS_CA_FILE}
UseTLS=${USETLS}
UseSTARTTLS=${USESTARTTLS}

# Username/Password
AuthUser=${AUTHUSER}
AuthPass=${AUTHPASS}
AuthMethod=LOGIN

# Email 'From header's can override the default domain?
# Are users allowed to set their own From: address?
# YES - Allow the user to specify their own From: address
# NO - Use the system generated From: address
FromLineOverride=${FROMLINEOVERRIDE}
EOF

send_mail "Autoheal is running and checking your containers health!"

fi



if [ "$1" = 'autoheal' ] && [ -e ${DOCKER_SOCK} ]; then
  
  # https://docs.docker.com/engine/api/v1.25/

  # Set container selector
  if [ "$AUTOHEAL_CONTAINER_LABEL" == "all" ]; then
    labelFilter=""
  else
    labelFilter=",\"label\":\[\"${AUTOHEAL_CONTAINER_LABEL:=autoheal}=true\"\]"
  fi

  AUTOHEAL_START_PERIOD=${AUTOHEAL_START_PERIOD:=0}
  echo "Monitoring containers for unhealthy status in ${AUTOHEAL_START_PERIOD} second(s)"
  sleep ${AUTOHEAL_START_PERIOD}

  while true; do
    sleep ${AUTOHEAL_INTERVAL:=5}
    
    apiUrl="http://localhost/containers/json?filters=\{\"health\":\[\"unhealthy\"\]${labelFilter}\}"
    stopTimeout=".Labels[\"autoheal.stop.timeout\"] // ${AUTOHEAL_DEFAULT_STOP_TIMEOUT:-10}"
    docker_curl "$apiUrl" | \
    jq -r "foreach .[] as \$CONTAINER([];[]; \$CONTAINER | .Id, .Names[0], $stopTimeout )" | \
    while read -r CONTAINER_ID && read -r CONTAINER_NAME && read -r TIMEOUT; do
        CONTAINER_SHORT_ID=${CONTAINER_ID:0:12}
        DATE=$(date +%d-%m-%Y" "%H:%M:%S)
        if [ "null" = "$CONTAINER_NAME" ]; then
          MSG="$DATE Container name of ($CONTAINER_SHORT_ID) is null, which implies container does not exist - don't restart"
          echo "$MSG"
          send_mail "$MSG"
        else
          MSG="$DATE Container ${CONTAINER_NAME} ($CONTAINER_SHORT_ID) found to be unhealthy - Restarting container now with ${TIMEOUT}s timeout"
          echo "$MSG"
          send_mail "$MSG"
          docker_curl -f -XPOST "http://localhost/containers/${CONTAINER_ID}/restart?t=${TIMEOUT}" \
            || echo "$DATE Restarting container $CONTAINER_SHORT_ID failed"
        fi
    done
  done

else
  exec "$@"
fi