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Josh jokajak
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#!/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 1.0.0
#
# Authors:
# - Kevin van Zonneveld (http://kvz.io)
#
# Usage:
# LOG_LEVEL=7 ./main.sh -f /tmp/x -d
#
# Licensed under MIT
# Copyright (c) 2013 Kevin van Zonneveld (http://kvz.io)
### Configuration
#####################################################################
# Environment variables and their defaults
LOG_LEVEL="${LOG_LEVEL:-6}" # 7 = debug -> 0 = emergency
# Commandline options. This defines the usage page, and is used to parse cli
# opts & defaults from. The parsing is unforgiving so be precise in your syntax
read -r -d '' usage <<-'EOF'
-f [arg] Filename to process. Required.
-t [arg] Location of tempfile. Default="/tmp/bar"
-d Enables debug mode
-h This page
EOF
# Set magic variables for current FILE & DIR
__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
### Functions
#####################################################################
function _fmt () {
local color_ok="\x1b[32m"
local color_bad="\x1b[31m"
local color="${color_bad}"
if [ "${1}" = "debug" ] || [ "${1}" = "info" ] || [ "${1}" = "notice" ]; then
color="${color_ok}"
fi
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 $arg_<flag> defaults
while read line; do
opt="$(echo "${line}" |awk '{print $1}' |sed -e 's#^-##')"
if ! echo "${line}" |egrep '\[.*\]' >/dev/null 2>&1; then
init="0" # it's a flag. init with 0
else
opt="${opt}:" # add : if opt has arg
init="" # it has an arg. init with ""
fi
opts="${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}"
# 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
line="$(echo "${usage}" |grep "\-${opt}")"
[ "${opt}" = "?" ] && help "Invalid use of script: ${@} "
varname="arg_${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
# 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 is required"
[ -z "${LOG_LEVEL}" ] && emergency "Cannot continue without LOG_LEVEL. "
### Runtime
#####################################################################
# Exit on error. Append ||true if you expect an error.
# set -e is safer than #!/bin/bash -e because that is neutralised if
# someone runs your script like `bash yourscript.sh`
set -o errexit
set -o nounset
# Bash will remember & return the highest exitcode in a chain of pipes.
# This way you can catch the error in case mysqldump fails in `mysqldump |gzip`
set -o pipefail
if [[ "${OSTYPE}" == "darwin"* ]]; then
info "You are on OSX"
fi
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."
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