docker-mailserver/target/scripts/helpers/log.sh

#! /bin/bash

# shellcheck disable=SC2291 # Quote repeated spaces to avoid them collapsing into one.
# shellcheck disable=SC2034 # VAR appears unused.

# Color variables for global usage
RED=$(echo -ne     '\e[0;31m')
GREEN=$(echo -ne   '\e[0;32m')
YELLOW=$(echo -ne  '\e[0;33m')
BLUE=$(echo -ne    '\e[0;34m')
PURPLE=$(echo -ne  '\e[0;35m')
CYAN=$(echo -ne    '\e[0;36m')
WHITE=$(echo -ne   '\e[0;37m')

# Light/bold variants
LRED=$(echo -ne    '\e[1;31m')
LGREEN=$(echo -ne  '\e[1;32m')
LYELLOW=$(echo -ne '\e[1;33m')
LBLUE=$(echo -ne   '\e[1;34m')
LPURPLE=$(echo -ne '\e[1;35m')
LCYAN=$(echo -ne   '\e[1;36m')
LWHITE=$(echo -ne  '\e[1;37m')

ORANGE=$(echo -ne  '\e[38;5;214m')
RESET=$(echo -ne   '\e[0m')

# ### DMS Logging Functionality
#
# This function provides the logging for scripts used by DMS.
# It adheres to the convention for log levels.
# Valid values (in order of increasing verbosity) are: `error`,
# `warn`, `info`, `debug` and `trace`. The default log level
# is `info`.
#
# #### Arguments
#
# $1 :: the log level to log the message with
# $2 :: the message
#
# #### Panics
#
# If the first argument is not set or invalid, an error
# message is logged. Likewise when the second argument
# is missing. Both failures will return with exit code '1'.
function _log
{
  if [[ -z ${1+set} ]]
  then
    echo "Call to '_log' is missing a valid log level" >&2
    return 1
  fi

  if [[ -z ${2+set} ]]
  then
    echo "Call to '_log' is missing a message to log" >&2
    return 1
  fi

  local MESSAGE LEVEL_AS_INT LOG_LEVEL_FALLBACK
  MESSAGE="${RESET}["

  if [[ -e /etc/dms-settings ]]
  then
    LOG_LEVEL_FALLBACK=$(grep "^LOG_LEVEL=" /etc/dms-settings | cut -d '=' -f 2)
    LOG_LEVEL_FALLBACK="${LOG_LEVEL_FALLBACK:1:-1}"
  else
    LOG_LEVEL_FALLBACK='info'
  fi

  case "${LOG_LEVEL:-${LOG_LEVEL_FALLBACK}}" in
    ( 'trace' ) LEVEL_AS_INT=5 ;;
    ( 'debug' ) LEVEL_AS_INT=4 ;;
    ( 'warn'  ) LEVEL_AS_INT=2 ;;
    ( 'error' ) LEVEL_AS_INT=1 ;;
    ( *       ) LEVEL_AS_INT=3 ;;
  esac

  case "${1}" in
    ( 'trace' )
      [[ ${LEVEL_AS_INT} -ge 5 ]] || return 0
      MESSAGE+="  ${LGRAY}TRACE  "
      ;;

    ( 'debug' )
      [[ ${LEVEL_AS_INT} -ge 4 ]] || return 0
      MESSAGE+="  ${LBLUE}DEBUG  "
      ;;

    ( 'info' )
      [[ ${LEVEL_AS_INT} -ge 3 ]] || return 0
      MESSAGE+="   ${BLUE}INF   "
      ;;

    ( 'warn' )
      [[ ${LEVEL_AS_INT} -ge 2 ]] || return 0
      MESSAGE+=" ${LYELLOW}WARNING "
      ;;

    ( 'error' )
      [[ ${LEVEL_AS_INT} -ge 1 ]] || return 0
      MESSAGE+="  ${RED}ERROR  " ;;

    ( * )
      echo "Call to '_log' with invalid log level argument '${1}'" >&2
      return 1
      ;;
  esac

  MESSAGE+="${RESET}]  ${2}"

  if [[ ${1} =~ ^(warn|error)$ ]]
  then
    echo -e "${MESSAGE}" >&2
  else
    echo -e "${MESSAGE}"
  fi
}

function _log_with_date { _log "${1}" "$(date '+%Y-%m-%d %H:%M:%S')  ${2}" ; }