dokku/plugins/checks/check-deploy

#!/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"

checks_check_deploy() {
  declare desc="checks check-deploy plugin trigger"
  local trigger="checks_check_deploy"
  local APP="$1"; local DOKKU_APP_CONTAINER_ID="$2"; local DOKKU_APP_CONTAINER_TYPE="$3"; local DOKKU_APP_LISTEN_PORT="$4"; local DOKKU_APP_LISTEN_IP="$5"
  if [[ -z "$DOKKU_APP_LISTEN_PORT" ]] && [[ -f "$DOKKU_ROOT/$APP/PORT" ]]; then
    local DOKKU_APP_LISTEN_PORT=$(< "$DOKKU_ROOT/$APP/PORT")
  fi
  if [[ -z "$DOKKU_APP_LISTEN_IP" ]] && [[ -f "$DOKKU_ROOT/$APP/IP" ]]; then
    local DOKKU_APP_LISTEN_IP=$(< "$DOKKU_ROOT/$APP/IP")
  fi
  if [[ -z "$DOKKU_APP_CONTAINER_ID" ]]; then
    local DOKKU_APP_CIDS=( $(get_app_container_ids "$APP") )
    local 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.
  local WAIT="${DOKKU_CHECKS_WAIT:-5}"
  # Wait this many seconds (default 30) for each response.
  local TIMEOUT="${DOKKU_CHECKS_TIMEOUT:-30}"
  # use this number of retries for checks
  local 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
  local CHECK_DEPLOY_TMP_WORK_DIR=$(mktemp -d /tmp/dokku_CHECKS.XXXXX)
  docker cp $DOKKU_APP_CONTAINER_ID:/app/CHECKS "$CHECK_DEPLOY_TMP_WORK_DIR" 2> /dev/null || true

  local FILENAME=${CHECK_DEPLOY_TMP_WORK_DIR}/CHECKS

  checks_check_deploy_cleanup() {
    declare desc="cleans up CHECK_DEPLOY_TMP_WORK_DIR and print container output"
    local id="$1"
    rm -rf "$CHECK_DEPLOY_TMP_WORK_DIR" &> /dev/null || true
    if [[ $id ]]; then
      dokku_log_info2_quiet             "$APP $DOKKU_APP_CONTAINER_TYPE container output:"
      dokku_container_log_verbose_quiet "$id"
      dokku_log_info2_quiet             "end $APP $DOKKU_APP_CONTAINER_TYPE container output"
    fi
  }
  trap 'checks_check_deploy_cleanup $DOKKU_APP_CONTAINER_ID' RETURN INT TERM EXIT

  if [[ ! -s "${CHECK_DEPLOY_TMP_WORK_DIR}/CHECKS" ]] || [[ "$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 "$CHECK_DEPLOY_TMP_WORK_DIR" &> /dev/null || true

    # simple default check to see if the container stuck around
    local 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 $DOKKU_APP_CONTAINER_ID) && dokku_log_fail "App container failed to start!!"
    local container_restarts=$(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

    trap - EXIT
    dokku_log_info1 "Default container check successful!" && exit 0
  fi

  # ensure CHECKS file has trailing newline
  if [[ "$(tail -c1 "$FILENAME")" != "" ]]; then
    echo "" >> "$FILENAME"
  fi

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

  local ATTEMPT=0

  until [[ $SUCCESS == 1 || $ATTEMPT -ge $ATTEMPTS ]]
  do
    local FAILEDCHECKS=0
    local ATTEMPT=$(( 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
    local CURL_OPTIONS="-q --compressed --fail --location --max-time $TIMEOUT"

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

    exec < "$FILENAME"
    local CHECK_URL
    local EXPECTED
    while read -r CHECK_URL EXPECTED; do
      # Ignore empty lines and lines starting with #
      # shellcheck disable=SC1001
      [[ -z "$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 [[ "$CHECK_URL" =~ ^https?: ]]; then
        local URL_PROTOCOL=${CHECK_URL%:*}
        local CHECK_URL=${CHECK_URL#*:}
      else
        local 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 $SEND_HOST.
        #
        # The pattern is
        #   //SEND_HOST/PATHNAME
        local UNPREFIXED=${CHECK_URL#//}
        local URL_HOSTNAME=${UNPREFIXED%%/*}
        local URL_PATHNAME=${UNPREFIXED#$URL_HOSTNAME}

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

      # This URL will show up in the messages
      local LOG_URL="$URL_PROTOCOL://$URL_HOSTNAME$URL_PATHNAME"
      # And how we formulate the CURL request
      local CURL_ARGS="$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: \"$EXPECTED\""
          local FAILEDCHECKS=$(( FAILEDCHECKS + 1 ))
        fi
      else
        # Failed to connect/no response, OUTPUT contains error message
        dokku_log_warn "$OUTPUT"
        local FAILEDCHECKS=$(( FAILEDCHECKS + 1 ))
      fi
    done

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

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

  trap - EXIT
  dokku_log_info1 "All checks successful!"
}

checks_check_deploy "$@"