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| 1 | +#!/usr/bin/env bash |
| 2 | + |
| 3 | +GETOPT_BIN=$IN_GETOPT_BIN |
| 4 | +GETOPT_BIN=${GETOPT_BIN:-getopt} |
| 5 | + |
| 6 | +__sleep_amount() { |
| 7 | + if [ -n "$constant_sleep" ]; then |
| 8 | + sleep_time=$constant_sleep |
| 9 | + else |
| 10 | + #TODO: check for awk |
| 11 | + #TODO: check if user would rather use one of the other possible dependencies: python, ruby, bc, dc |
| 12 | + sleep_time=`awk "BEGIN {t = $min_sleep * $(( (1<<($attempts -1)) )); print (t > $max_sleep ? $max_sleep : t)}"` |
| 13 | + fi |
| 14 | +} |
| 15 | + |
| 16 | +__log_out() { |
| 17 | + echo "$1" 1>&2 |
| 18 | +} |
| 19 | + |
| 20 | +# Paramters: max_tries min_sleep max_sleep constant_sleep fail_script EXECUTION_COMMAND |
| 21 | +retry() |
| 22 | +{ |
| 23 | + local max_tries="$1"; shift |
| 24 | + local min_sleep="$1"; shift |
| 25 | + local max_sleep="$1"; shift |
| 26 | + local constant_sleep="$1"; shift |
| 27 | + local fail_script="$1"; shift |
| 28 | + if [ -n "$VERBOSE" ]; then |
| 29 | + __log_out "Retry Parameters: max_tries=$max_tries min_sleep=$min_sleep max_sleep=$max_sleep constant_sleep=$constant_sleep" |
| 30 | + if [ -n "$fail_script" ]; then __log_out "Fail script: $fail_script"; fi |
| 31 | + __log_out "" |
| 32 | + __log_out "Execution Command: $*" |
| 33 | + __log_out "" |
| 34 | + fi |
| 35 | + |
| 36 | + local attempts=0 |
| 37 | + local return_code=1 |
| 38 | + |
| 39 | + |
| 40 | + while [[ $return_code -ne 0 && $attempts -le $max_tries ]]; do |
| 41 | + if [ $attempts -gt 0 ]; then |
| 42 | + __sleep_amount |
| 43 | + __log_out "Before retry #$attempts: sleeping $sleep_time seconds" |
| 44 | + sleep $sleep_time |
| 45 | + fi |
| 46 | + |
| 47 | + P="$1" |
| 48 | + for param in "${@:2}"; do P="$P '$param'"; done |
| 49 | + #TODO: replace single quotes in each arg with '"'"' ? |
| 50 | + export RETRY_ATTEMPT=$attempts |
| 51 | + bash -c "$P" |
| 52 | + return_code=$? |
| 53 | + #__log_out "Process returned $return_code on attempt $attempts" |
| 54 | + if [ $return_code -eq 127 ]; then |
| 55 | + # command not found |
| 56 | + exit $return_code |
| 57 | + elif [ $return_code -ne 0 ]; then |
| 58 | + attempts=$[$attempts +1] |
| 59 | + fi |
| 60 | + done |
| 61 | + |
| 62 | + if [ $attempts -gt $max_tries ]; then |
| 63 | + if [ -n "$fail_script" ]; then |
| 64 | + __log_out "Retries exhausted, running fail script" |
| 65 | + eval $fail_script |
| 66 | + else |
| 67 | + __log_out "Retries exhausted" |
| 68 | + fi |
| 69 | + fi |
| 70 | + |
| 71 | + exit $return_code |
| 72 | +} |
| 73 | + |
| 74 | +# If we're being sourced, don't worry about such things |
| 75 | +if [ "$BASH_SOURCE" == "$0" ]; then |
| 76 | + # Prints the help text |
| 77 | + help() |
| 78 | + { |
| 79 | + local retry=$(basename $0) |
| 80 | + cat <<EOF |
| 81 | +Usage: $retry [options] -- execute command |
| 82 | + -h, -?, --help |
| 83 | + -v, --verbose Verbose output |
| 84 | + -t, --tries=# Set max retries: Default 10 |
| 85 | + -s, --sleep=secs Constant sleep amount (seconds) |
| 86 | + -m, --min=secs Exponenetial Backoff: minimum sleep amount (seconds): Default 0.3 |
| 87 | + -x, --max=secs Exponenetial Backoff: maximum sleep amount (seconds): Default 60 |
| 88 | + -f, --fail="script +cmds" Fail Script: run in case of final failure |
| 89 | +EOF |
| 90 | + } |
| 91 | + |
| 92 | + # show help for no arguments if stdin is a terminal |
| 93 | + if { [ -z "$1" ] && [ -t 0 ] ; } || [ "$1" == '-h' ] || [ "$1" == '-?' ] || [ "$1" == '--help' ] |
| 94 | + then |
| 95 | + help |
| 96 | + exit 0 |
| 97 | + fi |
| 98 | + |
| 99 | + $GETOPT_BIN --test > /dev/null |
| 100 | + if [[ $? -ne 4 ]]; then |
| 101 | + echo "I’m sorry, 'getopt --test' failed in this environment. Please load GNU getopt." |
| 102 | + exit 1 |
| 103 | + fi |
| 104 | + |
| 105 | + OPTIONS=vt:s:m:x:f: |
| 106 | + LONGOPTIONS=verbose,tries:,sleep:,min:,max:,fail: |
| 107 | + |
| 108 | + PARSED=$($GETOPT_BIN --options="$OPTIONS" --longoptions="$LONGOPTIONS" --name "$0" -- "$@") |
| 109 | + if [[ $? -ne 0 ]]; then |
| 110 | + # e.g. $? == 1 |
| 111 | + # then getopt has complained about wrong arguments to stdout |
| 112 | + exit 2 |
| 113 | + fi |
| 114 | + # read getopt’s output this way to handle the quoting right: |
| 115 | + eval set -- "$PARSED" |
| 116 | + |
| 117 | + max_tries=10 |
| 118 | + min_sleep=0.3 |
| 119 | + max_sleep=60.0 |
| 120 | + constant_sleep= |
| 121 | + fail_script= |
| 122 | + |
| 123 | + # now enjoy the options in order and nicely split until we see -- |
| 124 | + while true; do |
| 125 | + case "$1" in |
| 126 | + -v|--verbose) |
| 127 | + VERBOSE=true |
| 128 | + shift |
| 129 | + ;; |
| 130 | + -t|--tries) |
| 131 | + max_tries="$2" |
| 132 | + shift 2 |
| 133 | + ;; |
| 134 | + -s|--sleep) |
| 135 | + constant_sleep="$2" |
| 136 | + shift 2 |
| 137 | + ;; |
| 138 | + -m|--min) |
| 139 | + min_sleep="$2" |
| 140 | + shift 2 |
| 141 | + ;; |
| 142 | + -x|--max) |
| 143 | + max_sleep="$2" |
| 144 | + shift 2 |
| 145 | + ;; |
| 146 | + -f|--fail) |
| 147 | + fail_script="$2" |
| 148 | + shift 2 |
| 149 | + ;; |
| 150 | + --) |
| 151 | + shift |
| 152 | + break |
| 153 | + ;; |
| 154 | + *) |
| 155 | + echo "Programming error" |
| 156 | + exit 3 |
| 157 | + ;; |
| 158 | + esac |
| 159 | + done |
| 160 | + |
| 161 | + retry "$max_tries" "$min_sleep" "$max_sleep" "$constant_sleep" "$fail_script" "$@" |
| 162 | + |
| 163 | +fi |
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