docker-entrypoint

#!/usr/bin/env sh

set -e
# shellcheck disable=2039
set -o pipefail

DOCKER_SOCK=${DOCKER_SOCK:-/var/run/docker.sock}
UNIX_SOCK=""
CURL_TIMEOUT=${CURL_TIMEOUT:-60}
WEBHOOK_URL=${WEBHOOK_URL:-""}

# only use unix domain socket if no TCP endpoint is defined
case "${DOCKER_SOCK}" in
  "tcp://"*) HTTP_ENDPOINT="$(echo ${DOCKER_SOCK} | sed 's#tcp://#https://#')"
             CA="--cacert /certs/ca.pem"
             CLIENT_KEY="--key /certs/client-key.pem"
             CLIENT_CERT="--cert /certs/client-cert.pem"
             ;;
  *)         HTTP_ENDPOINT="http://localhost"
             UNIX_SOCK="--unix-socket ${DOCKER_SOCK}"
             ;;
esac

AUTOHEAL_CONTAINER_LABEL=${AUTOHEAL_CONTAINER_LABEL:-autoheal_vpn}
AUTOHEAL_START_PERIOD=${AUTOHEAL_START_PERIOD:-0}
AUTOHEAL_INTERVAL=${AUTOHEAL_INTERVAL:-20}
AUTOHEAL_DEFAULT_STOP_TIMEOUT=${AUTOHEAL_DEFAULT_STOP_TIMEOUT:-10}

log_notice() { local DATE=$(date +%d-%m-%Y" "%H:%M:%S); printf "\e[33m${DATE} [NOTICE] %s\e[0m\n" "$*"; } #yellow
log_info() { local DATE=$(date +%d-%m-%Y" "%H:%M:%S); printf "\e[32m${DATE} [INFO] %s\e[0m\n" "$*"; } #green
log_err() { local DATE=$(date +%d-%m-%Y" "%H:%M:%S); printf "\e[31m${DATE} [ERROR] %s\e[0m\n" "$*"; } #red

docker_curl() {
  curl --max-time "${CURL_TIMEOUT}" --no-buffer --silent \
  ${CA} ${CLIENT_KEY} ${CLIENT_CERT} \
  ${UNIX_SOCK} \
  "$@"
}

# shellcheck disable=2039
get_container_info() {
  local label_filter
  local url

  # Set container selector
  if [ "$AUTOHEAL_CONTAINER_LABEL" = "all" ]
  then
    label_filter=""
  else
    label_filter=",\"label\":\[\"${AUTOHEAL_CONTAINER_LABEL}=true\"\]"
  fi
  url="${HTTP_ENDPOINT}/containers/json?filters=\{\"health\":\[\"unhealthy\"\]${label_filter}\}"
  docker_curl "$url"
}


docker_start() {
  local container_id="$1"
  local timeout=90
  local api_url="${HTTP_ENDPOINT}/containers/${container_id}/start"

  (curl --silent --max-time "${timeout}" --unix-socket /var/run/docker.sock -X POST "${api_url}" \
  && log_notice "started ${container_id}") \
  || log_err "starting ${container_id} failed"
}


docker_restart() {
  local container_id="$1"
  local timeout=90
  local api_url="${HTTP_ENDPOINT}/containers/${container_id}/restart"

  (curl --silent --max-time "${timeout}" --unix-socket /var/run/docker.sock -X POST "${api_url}" \
  && log_notice "restarted ${container_id}") \
  || log_err "restarting ${container_id} failed-"
}

docker_container_status() {
  local container_id="$1"
  local api_url="${HTTP_ENDPOINT}/containers/${container_id}/json"
  curl --silent --max-time "${timeout}" --unix-socket /var/run/docker.sock -X GET "${api_url}" | jq '.State.Status'
}

docker_container_health() {
  local container_id="$1"
  local api_url="${HTTP_ENDPOINT}/containers/${container_id}/json"
  curl --silent --max-time "${timeout}" --unix-socket /var/run/docker.sock -X GET "${api_url}" | jq '.State.Health.Status'
}


# shellcheck disable=2039
restart_stack() {

  local container_id="$1"
  local timeout=90
  local DATE=$(date +%d-%m-%Y" "%H:%M:%S)
  log_info "$Restarting $container_id stack ... "


  # Check status of VPN container.
  VPN_STATUS=$(docker_container_status "${container_id}_protonvpn")

  if [ "${VPN_STATUS}" == "exited" ]
  then
   #Stopped container VPN container; Must be started first
   log_err "${container_id}_protonvpn is Not Running, Starting ${container_id}_protonvpn" 
   docker_start "${container_id}_protonvpn"
  else
   #Silent failure
   log_notice "${container_id}_protonvpn is ${VPN_STATUS}; Possible Silent Failure. Restarting ${container_id}_protonvpn"
   docker_restart "${container_id}_protonvpn"
  fi

  docker_restart "${container_id}"

}
# shellcheck disable=2039

notify_webhook() {
  local text="$@"

  if [ -n "$WEBHOOK_URL" ]
  then
    # execute webhook requests as background process to prevent healer from blocking
    curl -X POST -H "Content-type: application/json" -d "$(generate_webhook_payload $text)"  $WEBHOOK_URL
  fi
}

# https://towardsdatascience.com/proper-ways-to-pass-environment-variables-in-json-for-curl-post-f797d2698bf3
generate_webhook_payload() {
  local text="$@"
  cat <<EOF
{
  "text":"$text"
}
EOF
}

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

# shellcheck disable=2039
trap 'kill $$; term_handler' SIGTERM

if [ "$1" = "autoheal" ] && [ -e "$DOCKER_SOCK" ];then
  # Delayed startup
  if [ "$AUTOHEAL_START_PERIOD" -gt 0 ]
  then
   log_notice "Monitoring containers for unhealthy status in $AUTOHEAL_START_PERIOD second(s)"
   sleep "$AUTOHEAL_START_PERIOD"
  fi

  while true
  do
    STOP_TIMEOUT=".Labels[\"autoheal.stop.timeout\"] // $AUTOHEAL_DEFAULT_STOP_TIMEOUT"
    get_container_info | \
      jq -r "foreach .[] as \$CONTAINER([];[]; \$CONTAINER | .Id, .Names[0], .State, ${STOP_TIMEOUT})" | \
      while read -r CONTAINER_ID && read -r CONTAINER_NAME && read -r CONTAINER_STATE && read -r TIMEOUT
      do
      # shellcheck disable=2039
      CONTAINER_SHORT_ID=${CONTAINER_ID:0:12}
      DATE=$(date +%d-%m-%Y" "%H:%M:%S)

      if [ "$CONTAINER_NAME" = "null" ]
      then
       log_notice "Container name of (${CONTAINER_SHORT_ID}) is null, which implies container does not exist - don't restart" 
      elif [ "$CONTAINER_STATE" = "restarting" ]
      then
        log_notice "Container $CONTAINER_NAME (${CONTAINER_SHORT_ID}) found to be already restarting - don't restart"
      else
        #strip out leading "/"
        CONTAINER_NAME=${CONTAINER_NAME:1}
        log_err "Container $CONTAINER_NAME (${CONTAINER_SHORT_ID}) found to be unhealthy"
        if restart_stack "${CONTAINER_NAME}" 90
        then
          notify_webhook "Container ${CONTAINER_NAME} (${CONTAINER_SHORT_ID}) found to be unhealthy. Successfully restarted the container!" &
        else
          notify_webhook "Container ${CONTAINER_NAME} (${CONTAINER_SHORT_ID}) found to be unhealthy. Failed to restart the container!" &
        fi
      fi
    done
    log_info "Work Done; Checking again in ${AUTOHEAL_INTERVAL} second(s)"
    sleep "${AUTOHEAL_INTERVAL}"
  done

else
  exec "$@"
fi