#!/usr/bin/env bash

# Hook to check server against list of checks specified in CHECKS file.
#
# The CHECKS file may contain empty lines, comments (lines starting with #),
# settings (NAME=VALUE) and check instructions.
#
# The format of a check instruction is a path, optionally followed by the
# expected content.  For example:
#
#   /                       My Amazing App
#   /stylesheets/index.css  .body
#   /scripts/index.js       $(function()
#   /images/logo.png
#
# To check an application that supports multiple hostnames, use relative URLs
# that include the hostname, for example:
#
#  //admin.example.com     Admin Dashboard
#  //static.example.com/logo.png
#
# You can also specify the protocol to explicitly check HTTPS requests.
#
# The default behavior is to wait for 5 seconds before running the first check,
# and timeout each check to 30 seconds.
#
# By default, checks will be retried 5 times.

# You can change these by setting WAIT, TIMEOUT and ATTEMPTS to different values, for
# example:
#
#   WAIT=30     # Wait 1/2 minute
#   TIMEOUT=60  # Timeout after a minute
#   ATTEMPTS=10  # retry checks 10 times
#

set -eo pipefail; [[ $DOKKU_TRACE ]] && set -x
source "$PLUGIN_CORE_AVAILABLE_PATH/common/functions"
source "$PLUGIN_AVAILABLE_PATH/checks/functions"
source "$PLUGIN_AVAILABLE_PATH/config/functions"

APP="$1"; DOKKU_APP_CONTAINER_ID="$2"; DOKKU_APP_CONTAINER_TYPE="$3"; DOKKU_APP_LISTEN_PORT="$4"; DOKKU_APP_LISTEN_IP="$5"
if [[ -z "$DOKKU_APP_LISTEN_PORT" ]] && [[ -f "$DOKKU_ROOT/$APP/PORT" ]]; then
  DOKKU_APP_LISTEN_PORT=$(< "$DOKKU_ROOT/$APP/PORT")
fi
if [[ -z "$DOKKU_APP_LISTEN_IP" ]] && [[ -f "$DOKKU_ROOT/$APP/IP" ]]; then
  DOKKU_APP_LISTEN_IP=$(< "$DOKKU_ROOT/$APP/IP")
fi
if [[ -z "$DOKKU_APP_CONTAINER_ID" ]]; then
  DOKKU_APP_CIDS=( $(get_app_container_ids "$APP") )
  DOKKU_APP_CONTAINER_ID=${DOKKU_APP_CIDS[0]}
fi


# source global and in-app envs to get DOKKU_CHECKS_WAIT and any other necessary vars
eval "$(config_export global)"
eval "$(config_export app "$APP")"

if [[ "$(is_app_checks_enabled "$APP")" == "false" ]];then
  dokku_log_info2_quiet "Zero downtime checks for app ($APP) have been disabled. moving on..."
  exit 0
fi

# Wait this many seconds (default 5) for server to start before running checks.
WAIT="${DOKKU_CHECKS_WAIT:-5}"
# Wait this many seconds (default 30) for each response.
TIMEOUT="${DOKKU_CHECKS_TIMEOUT:-30}"
# use this number of retries for checks
ATTEMPTS="${DOKKU_CHECKS_ATTEMPTS:-5}"

# try to copy CHECKS from container if not in APP dir & quit gracefully if it doesn't exist
# docker cp exits with status 1 when run as non-root user when it tries to chown the file
# after successfully copying the file. Thus, we suppress stderr.
# ref: https://github.com/dotcloud/docker/issues/3986
TMPDIR=$(mktemp -d /tmp/dokku_CHECKS.XXXXX)
docker cp $DOKKU_APP_CONTAINER_ID:/app/CHECKS "$TMPDIR" 2> /dev/null || true

FILENAME=${TMPDIR}/CHECKS

cleanup() {
  rm -rf "$TMPDIR"
  dokku_log_info2_quiet             "$APP container output:"
  dokku_container_log_verbose_quiet $DOKKU_APP_CONTAINER_ID
  dokku_log_info2_quiet             "end $APP container output"
}
trap cleanup EXIT

if [[ ! -s "${TMPDIR}/CHECKS" ]] || [[ "$DOKKU_APP_CONTAINER_TYPE" != "web" ]]; then
  # We allow custom check for web instances only
  if [[ "$DOKKU_APP_CONTAINER_TYPE" == "web" ]]; then
    dokku_log_verbose "For more efficient zero downtime deployments, create a file CHECKS."
    dokku_log_verbose "See http://dokku.viewdocs.io/dokku/checks-examples.md for examples"
    dokku_log_verbose "CHECKS file not found in container: Running simple container check..."
  else
    dokku_log_verbose "Non web container detected: Running default container check..."
  fi

  rm -rf "$TMPDIR"

  # simple default check to see if the container stuck around
  DOKKU_DEFAULT_CHECKS_WAIT="${DOKKU_DEFAULT_CHECKS_WAIT:-10}"
  dokku_log_info1 "Waiting for $DOKKU_DEFAULT_CHECKS_WAIT seconds ..."
  sleep "$DOKKU_DEFAULT_CHECKS_WAIT"

  ! (is_container_running $DOKKU_APP_CONTAINER_ID) && dokku_log_fail "App container failed to start!!"
  container_restarts=$(docker inspect -f "{{ .RestartCount }}" $DOKKU_APP_CONTAINER_ID)
  if [[ $container_restarts -ne 0 ]]; then
    docker stop "$DOKKU_APP_CONTAINER_ID" || true
    dokku_log_fail "App container failed to start!!"
  fi

  dokku_log_info1 "Default container check successful!" && exit 0
fi

# Reads name/value pairs, sets the WAIT and TIMEOUT variables
exec < "$FILENAME"
while read -r LINE; do
  # Name/value pair
  if [[ "$LINE" =~ ^.+= ]]; then
    TRIM=${LINE%#*}
    NAME=${TRIM%=*}
    VALUE=${TRIM#*=}
    [[ "$NAME" = "WAIT" ]] && WAIT=$VALUE
    [[ "$NAME" = "TIMEOUT" ]] && TIMEOUT=$VALUE
    [[ "$NAME" = "ATTEMPTS" ]] && ATTEMPTS=$VALUE
  fi
done

ATTEMPT=0

until [[ $SUCCESS == 1 || $ATTEMPT -ge $ATTEMPTS ]]
do
  FAILEDCHECKS=0
  ATTEMPT=$(( ATTEMPT + 1 ))
  dokku_log_info1 "Attempt $ATTEMPT/$ATTEMPTS Waiting for $WAIT seconds ..."
  sleep "$WAIT"


  # -q           do not use .curlrc (must come first)
  # --compressed Test compression handled correctly
  # --fail       Fail on server errors (4xx, 5xx)
  # --location   Follow redirects
  CURL_OPTIONS="-q --compressed --fail --location --max-time $TIMEOUT"

  # Set X-Forwarded-Proto header if TLS is enabled.
  SSL="$DOKKU_ROOT/$APP/tls"; WILDCARD_SSL="$DOKKU_ROOT/tls"
  if [[ -e "$SSL/server.crt" && -e "$SSL/server.key" ]] || [[ -e "$WILDCARD_SSL/server.crt" && -e "$WILDCARD_SSL/server.key" ]]; then
    CURL_OPTIONS+=" -H X-Forwarded-Proto:https"
  fi

  exec < "$FILENAME"
  while read -r CHECK_URL EXPECTED; do
    # Ignore empty lines and lines starting with #
    # shellcheck disable=SC1001
    [[ -z "$CHECK_URL" || "$CHECK_URL" =~ ^\# ]] && continue
    # Ignore if it's not a URL in a supported format
    # shellcheck disable=SC1001
    ! [[ "$CHECK_URL" =~ ^(http(s)?:)?\/.* ]] && continue

    if [[ "$CHECK_URL" =~ ^https?: ]]; then
      URL_PROTOCOL=${CHECK_URL%:*}
      CHECK_URL=${CHECK_URL#*:}
    else
      URL_PROTOCOL="http"
    fi

    if [[ "$CHECK_URL" =~ ^//.+ ]]; then
      # To test a URL with specific host name, we still make request to localhost,
      # but we set Host header to $SEND_HOST.
      #
      # The pattern is
      #   //SEND_HOST/PATHNAME
      UNPREFIXED=${CHECK_URL#//}
      URL_HOSTNAME=${UNPREFIXED%%/*}
      URL_PATHNAME=${UNPREFIXED#$URL_HOSTNAME}

      HEADERS="-H Host:$URL_HOSTNAME"
    else
      URL_HOSTNAME=localhost
      URL_PATHNAME=$CHECK_URL
    fi

    # This URL will show up in the messages
    LOG_URL="$URL_PROTOCOL://$URL_HOSTNAME$URL_PATHNAME"
    # And how we formulate the CURL request
    CURL_ARGS="$CURL_OPTIONS $URL_PROTOCOL://$DOKKU_APP_LISTEN_IP:$DOKKU_APP_LISTEN_PORT$URL_PATHNAME $HEADERS"

    dokku_log_verbose "CHECKS expected result:"
    dokku_log_verbose "$LOG_URL => \"$EXPECTED\""
    [[ $DOKKU_TRACE ]] && dokku_log_verbose "$ curl $CURL_ARGS"

    # Capture HTTP response or CURL error message
    # shellcheck disable=SC2086
    if OUTPUT=$(curl -# $CURL_ARGS 2>&1); then
      # OUTPUT contains the HTTP response
      if [[ ! "$OUTPUT" =~ $EXPECTED ]]; then
        dokku_log_warn "$LOG_URL: expected to but did not find: \"$EXPECTED\""
        FAILEDCHECKS=$(( FAILEDCHECKS + 1 ))
      fi
    else
      # Failed to connect/no response, OUTPUT contains error message
      dokku_log_warn "$OUTPUT"
      FAILEDCHECKS=$(( FAILEDCHECKS + 1 ))
    fi
  done

  if [[ $FAILEDCHECKS -gt 0 ]]; then
      dokku_log_warn "Check attempt $ATTEMPT/$ATTEMPTS failed."
      SUCCESS=0
  else
      SUCCESS=1
  fi
done

if [[ $FAILEDCHECKS -gt 0 ]]; then
    dokku_log_fail "Could not start due to $FAILEDCHECKS failed checks."
    exit 1
fi

dokku_log_info1 "All checks successful!"