mirror of
https://github.com/kvz/bash3boilerplate.git
synced 2024-12-18 22:27:51 +00:00
245 lines
8.5 KiB
Bash
Executable File
245 lines
8.5 KiB
Bash
Executable File
#!/usr/bin/env bash
|
|
# BASH3 Boilerplate
|
|
#
|
|
# This file:
|
|
# - Is a template to write better bash scripts
|
|
# - Is delete-key friendly, in case you don't need e.g. command line option parsing
|
|
#
|
|
# More info:
|
|
# - https://github.com/kvz/bash3boilerplate
|
|
# - http://kvz.io/blog/2013/02/26/introducing-bash3boilerplate/
|
|
#
|
|
# Version 1.1.0
|
|
#
|
|
# Authors:
|
|
# - Kevin van Zonneveld (http://kvz.io)
|
|
# - Izaak Beekman (https://izaakbeekman.com/)
|
|
# - Alexander Rathai (Alexander.Rathai@gmail.com)
|
|
#
|
|
# Usage:
|
|
# LOG_LEVEL=7 ./main.sh -f /tmp/x -d
|
|
#
|
|
# Licensed under MIT
|
|
# Copyright (c) 2013 Kevin van Zonneveld (http://kvz.io)
|
|
|
|
|
|
### Configuration
|
|
#####################################################################
|
|
|
|
# Exit on error. Append ||true if you expect an error.
|
|
# `set` is safer than relying on a shebang like `#!/bin/bash -e` because that is neutralized
|
|
# when someone runs your script as `bash yourscript.sh`
|
|
set -o errexit
|
|
set -o nounset
|
|
|
|
# Bash will remember & return the highest exitcode in a chain of pipes.
|
|
# This way you can catch the error in case mysqldump fails in `mysqldump |gzip`
|
|
set -o pipefail
|
|
# set -o xtrace
|
|
|
|
# Environment variables and their defaults
|
|
LOG_LEVEL="${LOG_LEVEL:-6}" # 7 = debug -> 0 = emergency
|
|
|
|
# Commandline options. This defines the usage page, and is used to parse cli
|
|
# opts & defaults from. The parsing is unforgiving so be precise in your syntax
|
|
# - A short option must be preset for every long option; but every short option
|
|
# need not have a long option
|
|
# - `--` is respected as the separator between options and arguments
|
|
read -r -d '' usage <<-'EOF' || true # exits non-zero when EOF encountered
|
|
-f --file [arg] Filename to process. Required.
|
|
-t --temp [arg] Location of tempfile. Default="/tmp/bar"
|
|
-v Enable verbose mode, print script as it is executed
|
|
-d --debug Enables debug mode
|
|
-h --help This page
|
|
EOF
|
|
|
|
# Set magic variables for current file and its directory.
|
|
# BASH_SOURCE[0] is used so we can display the current file even if it is sourced by a parent script.
|
|
# If you need the script that was executed, consider using $0 instead.
|
|
__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
|
|
__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
|
|
__base="$(basename ${__file} .sh)"
|
|
__os="Linux"
|
|
if [[ "${OSTYPE:-}" == "darwin"* ]]; then
|
|
__os="OSX"
|
|
fi
|
|
|
|
### Functions
|
|
#####################################################################
|
|
|
|
function _fmt () {
|
|
local color_debug="\x1b[35m"
|
|
local color_info="\x1b[32m"
|
|
local color_notice="\x1b[34m"
|
|
local color_warning="\x1b[33m"
|
|
local color_error="\x1b[31m"
|
|
local color_critical="\x1b[1;31m"
|
|
local color_alert="\x1b[1;33;41m"
|
|
local color_emergency="\x1b[1;4;5;33;41m"
|
|
local colorvar=color_$1
|
|
|
|
local color="${!colorvar:-$color_error}"
|
|
local color_reset="\x1b[0m"
|
|
if [[ "${TERM:-}" != "xterm"* ]] || [ -t 1 ]; then
|
|
# Don't use colors on pipes or non-recognized terminals
|
|
color=""; color_reset=""
|
|
fi
|
|
echo -e "$(date -u +"%Y-%m-%d %H:%M:%S UTC") ${color}$(printf "[%9s]" ${1})${color_reset}";
|
|
}
|
|
function emergency () { echo "$(_fmt emergency) ${@}" 1>&2 || true; exit 1; }
|
|
function alert () { [ "${LOG_LEVEL}" -ge 1 ] && echo "$(_fmt alert) ${@}" 1>&2 || true; }
|
|
function critical () { [ "${LOG_LEVEL}" -ge 2 ] && echo "$(_fmt critical) ${@}" 1>&2 || true; }
|
|
function error () { [ "${LOG_LEVEL}" -ge 3 ] && echo "$(_fmt error) ${@}" 1>&2 || true; }
|
|
function warning () { [ "${LOG_LEVEL}" -ge 4 ] && echo "$(_fmt warning) ${@}" 1>&2 || true; }
|
|
function notice () { [ "${LOG_LEVEL}" -ge 5 ] && echo "$(_fmt notice) ${@}" 1>&2 || true; }
|
|
function info () { [ "${LOG_LEVEL}" -ge 6 ] && echo "$(_fmt info) ${@}" 1>&2 || true; }
|
|
function debug () { [ "${LOG_LEVEL}" -ge 7 ] && echo "$(_fmt debug) ${@}" 1>&2 || true; }
|
|
|
|
function help () {
|
|
echo "" 1>&2
|
|
echo " ${@}" 1>&2
|
|
echo "" 1>&2
|
|
echo " ${usage}" 1>&2
|
|
echo "" 1>&2
|
|
exit 1
|
|
}
|
|
|
|
function cleanup_before_exit () {
|
|
info "Cleaning up. Done"
|
|
}
|
|
trap cleanup_before_exit EXIT
|
|
|
|
|
|
### Parse commandline options
|
|
#####################################################################
|
|
|
|
# Translate usage string -> getopts arguments, and set $arg_<flag> defaults
|
|
while read line; do
|
|
# fetch single character version of option sting
|
|
opt="$(echo "${line}" |awk '{print $1}' |sed -e 's#^-##')"
|
|
|
|
# fetch long version if present
|
|
long_opt="$(echo "${line}" |awk '/\-\-/ {print $2}' |sed -e 's#^--##')"
|
|
|
|
# map long name back to short name
|
|
varname="short_opt_${long_opt}"
|
|
eval "${varname}=\"${opt}\""
|
|
|
|
# check if option takes an argument
|
|
varname="has_arg_${opt}"
|
|
if ! echo "${line}" |egrep '\[.*\]' >/dev/null 2>&1; then
|
|
init="0" # it's a flag. init with 0
|
|
eval "${varname}=0"
|
|
else
|
|
opt="${opt}:" # add : if opt has arg
|
|
init="" # it has an arg. init with ""
|
|
eval "${varname}=1"
|
|
fi
|
|
opts="${opts:-}${opt}"
|
|
|
|
varname="arg_${opt:0:1}"
|
|
if ! echo "${line}" |egrep '\. Default=' >/dev/null 2>&1; then
|
|
eval "${varname}=\"${init}\""
|
|
else
|
|
match="$(echo "${line}" |sed 's#^.*Default=\(\)#\1#g')"
|
|
eval "${varname}=\"${match}\""
|
|
fi
|
|
done <<< "${usage}"
|
|
|
|
# Allow long options like --this
|
|
opts="${opts}-:"
|
|
|
|
# Reset in case getopts has been used previously in the shell.
|
|
OPTIND=1
|
|
|
|
# Overwrite $arg_<flag> defaults with the actual CLI options
|
|
while getopts "${opts}" opt; do
|
|
[ "${opt}" = "?" ] && help "Invalid use of script: ${@} "
|
|
|
|
if [ "${opt}" = "-" ]; then
|
|
# OPTARG is long-option-name or long-option=value
|
|
if [[ "${OPTARG}" =~ .*=.* ]]; then
|
|
# --key=value format
|
|
long=${OPTARG/=*/}
|
|
# Set opt to the short option corresponding to the long option
|
|
eval "opt=\"\${short_opt_${long}}\""
|
|
OPTARG=${OPTARG#*=}
|
|
else
|
|
# --key value format
|
|
# Map long name to short version of option
|
|
eval "opt=\"\${short_opt_${OPTARG}}\""
|
|
# Only assign OPTARG if option takes an argument
|
|
eval "OPTARG=\"\${@:OPTIND:\${has_arg_${opt}}}\""
|
|
# shift over the argument if argument is expected
|
|
((OPTIND+=has_arg_${opt}))
|
|
fi
|
|
# we have set opt/OPTARG to the short value and the argument as OPTARG if it exists
|
|
fi
|
|
varname="arg_${opt:0:1}"
|
|
default="${!varname}"
|
|
|
|
value="${OPTARG:-}"
|
|
if [ -z "${OPTARG:-}" ] && [ "${default}" = "0" ]; then
|
|
value="1"
|
|
fi
|
|
|
|
eval "${varname}=\"${value}\""
|
|
debug "cli arg ${varname} = ($default) -> ${!varname}"
|
|
done
|
|
|
|
shift $((OPTIND-1))
|
|
|
|
[ "${1:-}" = "--" ] && shift
|
|
|
|
|
|
### Switches (like -d for debugmode, -h for showing helppage)
|
|
#####################################################################
|
|
|
|
# debug mode
|
|
if [ "${arg_d}" = "1" ]; then
|
|
set -o xtrace
|
|
LOG_LEVEL="7"
|
|
fi
|
|
|
|
# verbose mode
|
|
if [ "${arg_v}" = "1" ]; then
|
|
set -o verbose
|
|
fi
|
|
|
|
# help mode
|
|
if [ "${arg_h}" = "1" ]; then
|
|
# Help exists with code 1
|
|
help "Help using ${0}"
|
|
fi
|
|
|
|
|
|
### Validation (decide what's required for running your script and error out)
|
|
#####################################################################
|
|
|
|
[ -z "${arg_f:-}" ] && help "Setting a filename with -f or --file is required"
|
|
[ -z "${LOG_LEVEL:-}" ] && emergency "Cannot continue without LOG_LEVEL. "
|
|
|
|
|
|
### Runtime
|
|
#####################################################################
|
|
|
|
info "__file: ${__file}"
|
|
info "__dir: ${__dir}"
|
|
info "__base: ${__base}"
|
|
info "__os: ${__os}"
|
|
|
|
info "arg_f: ${arg_f}"
|
|
info "arg_d: ${arg_d}"
|
|
info "arg_v: ${arg_v}"
|
|
info "arg_h: ${arg_h}"
|
|
|
|
# All of these go to STDERR, so you can use STDOUT for piping machine readable information to other software
|
|
debug "Info useful to developers for debugging the application, not useful during operations."
|
|
info "Normal operational messages - may be harvested for reporting, measuring throughput, etc. - no action required."
|
|
notice "Events that are unusual but not error conditions - might be summarized in an email to developers or admins to spot potential problems - no immediate action required."
|
|
warning "Warning messages, not an error, but indication that an error will occur if action is not taken, e.g. file system 85% full - each item must be resolved within a given time. This is a debug message"
|
|
error "Non-urgent failures, these should be relayed to developers or admins; each item must be resolved within a given time."
|
|
critical "Should be corrected immediately, but indicates failure in a primary system, an example is a loss of a backup ISP connection."
|
|
alert "Should be corrected immediately, therefore notify staff who can fix the problem. An example would be the loss of a primary ISP connection."
|
|
emergency "A \"panic\" condition usually affecting multiple apps/servers/sites. At this level it would usually notify all tech staff on call."
|