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shell-scripting-templates/scriptTemplate.sh
2021-07-30 12:53:55 -04:00

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#!/usr/bin/env bash
_mainScript_() {
info "Hello world"
} # end _mainScript_
# Set flags and default variables
# Script specific
# Common
LOGFILE="${HOME}/logs/$(basename "$0")"
QUIET=false
LOGLEVEL=ERROR
VERBOSE=false
FORCE=false
DRYRUN=false
declare -a args=()
now=$(LC_ALL=C date +"%m-%d-%Y %r") # Returns: 06-14-2015 10:34:40 PM
datestamp=$(LC_ALL=C date +%Y-%m-%d) # Returns: 2015-06-14
hourstamp=$(LC_ALL=C date +%r) # Returns: 10:34:40 PM
timestamp=$(LC_ALL=C date +%Y%m%d_%H%M%S) # Returns: 20150614_223440
longdate=$(LC_ALL=C date +"%a, %d %b %Y %H:%M:%S %z") # Returns: Sun, 10 Jan 2016 20:47:53 -0500
gmtdate=$(LC_ALL=C date -u -R | sed 's/\+0000/GMT/') # Returns: Wed, 13 Jan 2016 15:55:29 GMT
# Colors
if tput setaf 1 &>/dev/null; then
bold=$(tput bold)
white=$(tput setaf 7)
reset=$(tput sgr0)
purple=$(tput setaf 171)
red=$(tput setaf 1)
green=$(tput setaf 76)
tan=$(tput setaf 3)
yellow=$(tput setaf 3)
blue=$(tput setaf 38)
underline=$(tput sgr 0 1)
else
bold="\033[4;37m"
white="\033[0;37m"
reset="\033[0m"
purple="\033[0;35m"
red="\033[0;31m"
green="\033[1;32m"
tan="\033[0;33m"
yellow="\033[0;33m"
blue="\033[0;34m"
underline="\033[4;37m"
fi
_alert_() {
# DESC: Controls all printing of messages to log files and stdout.
# ARGS: $1 (required) - The type of alert to print
# (success, header, notice, dryrun, debug, warning, error,
# fatal, info, input)
# $2 (required) - The message to be printed to stdout and/or a log file
# $3 (optional) - Pass '${LINENO}' to print the line number where the _alert_ was triggered
# OUTS: None
# USAGE: [ALERTTYPE] "[MESSAGE]" "${LINENO}"
# NOTES: The colors of each alert type are set in this function
# For specified alert types, the funcstac will be printed
local function_name color
local alertType="${1}"
local message="${2}"
local line="${3:-}" # Optional line number
if [[ -n "${line}" && "${alertType}" =~ ^(fatal|error) && "${FUNCNAME[2]}" != "_trapCleanup_" ]]; then
message="${message} (line: ${line}) $(_functionStack_)"
elif [[ -n "${line}" && "${FUNCNAME[2]}" != "_trapCleanup_" ]]; then
message="${message} (line: ${line})"
elif [[ -z "${line}" && "${alertType}" =~ ^(fatal|error) && "${FUNCNAME[2]}" != "_trapCleanup_" ]]; then
message="${message} $(_functionStack_)"
fi
if [[ "${alertType}" =~ ^(error|fatal) ]]; then
color="${bold}${red}"
elif [ "${alertType}" = "warning" ]; then
color="${red}"
elif [ "${alertType}" = "success" ]; then
color="${green}"
elif [ "${alertType}" = "debug" ]; then
color="${purple}"
elif [ "${alertType}" = "header" ]; then
color="${bold}${tan}"
elif [[ "${alertType}" =~ ^(input|notice) ]]; then
color="${bold}"
elif [ "${alertType}" = "dryrun" ]; then
color="${blue}"
else
color=""
fi
_writeToScreen_() {
("${QUIET}") && return 0 # Print to console when script is not 'quiet'
[[ ${VERBOSE} == false && "${alertType}" =~ ^(debug|verbose) ]] && return 0
if ! [[ -t 1 ]]; then # Don't use colors on non-recognized terminals
color=""
reset=""
fi
echo -e "$(date +"%r") ${color}$(printf "[%7s]" "${alertType}") ${message}${reset}"
}
_writeToScreen_
_writeToLog_() {
[[ "${alertType}" == "input" ]] && return 0
[[ "${LOGLEVEL}" =~ (off|OFF|Off) ]] && return 0
[ -z "${LOGFILE:-}" ] && fatal "\$LOGFILE must be set"
[ ! -d "$(dirname "${LOGFILE}")" ] && mkdir -p "$(dirname "${LOGFILE}")"
[[ ! -f "${LOGFILE}" ]] && touch "${LOGFILE}"
# Don't use colors in logs
if command -v gsed &>/dev/null; then
local cleanmessage="$(echo "${message}" | gsed -E 's/(\x1b)?\[(([0-9]{1,2})(;[0-9]{1,3}){0,2})?[mGK]//g')"
else
local cleanmessage="$(echo "${message}" | sed -E 's/(\x1b)?\[(([0-9]{1,2})(;[0-9]{1,3}){0,2})?[mGK]//g')"
fi
echo -e "$(date +"%b %d %R:%S") $(printf "[%7s]" "${alertType}") [$(/bin/hostname)] ${cleanmessage}" >>"${LOGFILE}"
}
# Write specified log level data to logfile
case "${LOGLEVEL:-ERROR}" in
ALL|all|All)
_writeToLog_
;;
DEBUG|debug|Debug)
_writeToLog_
;;
INFO|info|Info)
if [[ "${alertType}" =~ ^(die|error|fatal|warning|info|notice|success) ]]; then
_writeToLog_
fi
;;
WARN|warn|Warn)
if [[ "${alertType}" =~ ^(die|error|fatal|warning) ]]; then
_writeToLog_
fi
;;
ERROR|error|Error)
if [[ "${alertType}" =~ ^(die|error|fatal) ]]; then
_writeToLog_
fi
;;
FATAL|fatal|Fatal)
if [[ "${alertType}" =~ ^(die|fatal) ]]; then
_writeToLog_
fi
;;
OFF|off)
return 0
;;
*)
if [[ "${alertType}" =~ ^(die|error|fatal) ]]; then
_writeToLog_
fi
;;
esac
} # /_alert_
error() { _alert_ error "${1}" "${2:-}"; }
warning() { _alert_ warning "${1}" "${2:-}"; }
notice() { _alert_ notice "${1}" "${2:-}"; }
info() { _alert_ info "${1}" "${2:-}"; }
success() { _alert_ success "${1}" "${2:-}"; }
dryrun() { _alert_ dryrun "${1}" "${2:-}"; }
input() { _alert_ input "${1}" "${2:-}"; }
header() { _alert_ header "== ${1} ==" "${2:-}"; }
die() { _alert_ fatal "${1}" "${2:-}"; _safeExit_ "1" ; }
fatal() { _alert_ fatal "${1}" "${2:-}"; _safeExit_ "1" ; }
debug() { _alert_ debug "${1}" "${2:-}"; }
verbose() { _alert_ debug "${1}" "${2:-}"; }
_safeExit_() {
# DESC: Cleanup and exit from a script
# ARGS: $1 (optional) - Exit code (defaults to 0)
# OUTS: None
if [[ -d "${script_lock:-}" ]]; then
if command rm -rf "${script_lock}"; then
debug "Removing script lock"
else
warning "Script lock could not be removed. Try manually deleting ${tan}'${lock_dir}'${red}"
fi
fi
if [[ -n "${tmpDir:-}" && -d "${tmpDir:-}" ]]; then
if [[ ${1:-} == 1 && -n "$(ls "${tmpDir}")" ]]; then
command rm -r "${tmpDir}"
else
command rm -r "${tmpDir}"
debug "Removing temp directory"
fi
fi
trap - INT TERM EXIT
exit ${1:-0}
}
_trapCleanup_() {
# DESC: Log errors and cleanup from script when an error is trapped
# ARGS: $1 - Line number where error was trapped
# $2 - Line number in function
# $3 - Command executing at the time of the trap
# $4 - Names of all shell functions currently in the execution call stack
# $5 - Scriptname
# $6 - $BASH_SOURCE
# OUTS: None
local line=${1:-} # LINENO
local linecallfunc=${2:-}
local command="${3:-}"
local funcstack="${4:-}"
local script="${5:-}"
local sourced="${6:-}"
funcstack="'$(echo "$funcstack" | sed -E 's/ / < /g')'"
if [[ "${script##*/}" == "${sourced##*/}" ]]; then
fatal "${7:-} command: '$command' (line: $line) [func: $(_functionStack_)]"
else
fatal "${7:-} command: '$command' (func: ${funcstack} called at line $linecallfunc of '${script##*/}') (line: $line of '${sourced##*/}') "
fi
_safeExit_ "1"
}
_makeTempDir_() {
# DESC: Creates a temp directory to house temporary files
# ARGS: $1 (Optional) - First characters/word of directory name
# OUTS: $tmpDir - Temporary directory
# USAGE: _makeTempDir_ "$(basename "$0")"
[ -d "${tmpDir:-}" ] && return 0
if [ -n "${1:-}" ]; then
tmpDir="${TMPDIR:-/tmp/}${1}.$RANDOM.$RANDOM.$$"
else
tmpDir="${TMPDIR:-/tmp/}$(basename "$0").$RANDOM.$RANDOM.$RANDOM.$$"
fi
(umask 077 && mkdir "${tmpDir}") || {
fatal "Could not create temporary directory! Exiting."
}
debug "\$tmpDir=$tmpDir"
}
_acquireScriptLock_() {
# DESC: Acquire script lock
# ARGS: $1 (optional) - Scope of script execution lock (system or user)
# OUTS: $script_lock - Path to the directory indicating we have the script lock
# NOTE: This lock implementation is extremely simple but should be reliable
# across all platforms. It does *not* support locking a script with
# symlinks or multiple hardlinks as there's no portable way of doing so.
# If the lock was acquired it's automatically released in _safeExit_()
local lock_dir
if [[ ${1:-} == 'system' ]]; then
lock_dir="${TMPDIR:-/tmp/}$(basename "$0").lock"
else
lock_dir="${TMPDIR:-/tmp/}$(basename "$0").$UID.lock"
fi
if command mkdir "${lock_dir}" 2>/dev/null; then
readonly script_lock="${lock_dir}"
debug "Acquired script lock: ${tan}${script_lock}${purple}"
else
error "Unable to acquire script lock: ${tan}${lock_dir}${red}"
fatal "If you trust the script isn't running, delete the lock dir"
fi
}
_functionStack_() {
# DESC: Prints the function stack in use
# ARGS: None
# OUTS: Prints [function]:[file]:[line]
# NOTE: Does not print functions from the alert class
local _i
funcStackResponse=()
for ((_i = 1; _i < ${#BASH_SOURCE[@]}; _i++)); do
case "${FUNCNAME[$_i]}" in "_alert_" | "_trapCleanup_" | fatal | error | warning | verbose | debug | die) continue ;; esac
funcStackResponse+=("${FUNCNAME[$_i]}:$(basename ${BASH_SOURCE[$_i]}):${BASH_LINENO[$_i - 1]}")
done
printf "( "
printf %s "${funcStackResponse[0]}"
printf ' < %s' "${funcStackResponse[@]:1}"
printf ' )\n'
}
_parseOptions_() {
# Iterate over options
# breaking -ab into -a -b when needed and --foo=bar into --foo bar
optstring=h
unset options
while (($#)); do
case $1 in
# If option is of type -ab
-[!-]?*)
# Loop over each character starting with the second
for ((i = 1; i < ${#1}; i++)); do
c=${1:i:1}
options+=("-$c") # Add current char to options
# If option takes a required argument, and it's not the last char make
# the rest of the string its argument
if [[ $optstring == *"$c:"* && ${1:i+1} ]]; then
options+=("${1:i+1}")
break
fi
done
;;
# If option is of type --foo=bar
--?*=*) options+=("${1%%=*}" "${1#*=}") ;;
# add --endopts for --
--) options+=(--endopts) ;;
# Otherwise, nothing special
*) options+=("$1") ;;
esac
shift
done
set -- "${options[@]:-}"
unset options
# Read the options and set stuff
while [[ ${1:-} == -?* ]]; do
case $1 in
-h | --help)
_usage_ >&2
_safeExit_
;;
-l | --loglevel)
shift
LOGLEVEL=${1}
;;
-L | --logfile)
shift
LOGFILE="${1}"
;;
-n | --dryrun) DRYRUN=true ;;
-v | --verbose) VERBOSE=true ;;
-q | --quiet) QUIET=true ;;
--force) FORCE=true ;;
--endopts)
shift
break
;;
*) fatal "invalid option: '$1'." ;;
esac
shift
done
args+=("$@") # Store the remaining user input as arguments.
}
_usage_() {
cat <<EOF
${bold}$(basename "$0") [OPTION]... [FILE]...${reset}
This is a script template. Edit this description to print help to users.
${bold}Options:${reset}
-h, --help Display this help and exit
-l, --loglevel One of: FATAL, ERROR, WARN, INFO, DEBUG, ALL, OFF (Default is 'ERROR')
$ $(basename "$0") --loglevel 'WARN'
-L, --logfile Full PATH to logfile. (Default is '${HOME}/logs/$(basename "$0")')
-n, --dryrun Non-destructive. Makes no permanent changes.
-q, --quiet Quiet (no output)
-v, --verbose Output more information. (Items echoed to 'verbose')
--force Skip all user interaction. Implied 'Yes' to all actions.
EOF
}
# Initialize and run the script
trap '_trapCleanup_ ${LINENO} ${BASH_LINENO} "${BASH_COMMAND}" "${FUNCNAME[*]}" "${0}" "${BASH_SOURCE[0]}"' \
EXIT INT TERM SIGINT SIGQUIT
set -o errtrace # Trap errors in subshells and functions
set -o errexit # Exit on error. Append '||true' if you expect an error
set -o pipefail # Use last non-zero exit code in a pipeline
# shopt -s nullglob globstar # Make `for f in *.txt` work when `*.txt` matches zero files
IFS=$' \n\t' # Set IFS to preferred implementation
# set -o xtrace # Run in debug mode
set -o nounset # Disallow expansion of unset variables
# [[ $# -eq 0 ]] && _parseOptions_ "-h" # Force arguments when invoking the script
_parseOptions_ "$@" # Parse arguments passed to script
# _makeTempDir_ "$(basename "$0")" # Create a temp directory '$tmpDir'
# _acquireScriptLock_ # Acquire script lock
_mainScript_ # Run the main logic script
_safeExit_ # Exit cleanly