diff --git a/retry b/retry new file mode 100755 index 0000000..48d964b --- /dev/null +++ b/retry @@ -0,0 +1,153 @@ +#!/usr/bin/env bash + +__sleep_amount() { + if [ -n "$constant_sleep" ]; then + sleep_time=$constant_sleep + else + sleep_time=`awk "BEGIN {t = $min_sleep * $(( (1<<($attempts -1)) )); print (t > $max_sleep ? $max_sleep : t)}"` + fi +} + +__log_out() { + echo "$1" 1>&2 +} + +# Paramters: max_tries min_sleep max_sleep constant_sleep fail_script EXECUTION_COMMAND +retry() +{ + local max_tries="$1"; shift + local min_sleep="$1"; shift + local max_sleep="$1"; shift + local constant_sleep="$1"; shift + local fail_script="$1"; shift + if [ -n "$VERBOSE" ]; then + __log_out "Retry Parameters: max_tries=$max_tries min_sleep=$min_sleep max_sleep=$max_sleep constant_sleep=$constant_sleep" + if [ -n "$fail_script" ]; then __log_out "Fail script: $fail_script"; fi + __log_out "" + __log_out "Execution Command: $*" + __log_out "" + fi + + local attempts=0 + local return_code=1 + + + while [[ $return_code -ne 0 && $attempts -le $max_tries ]]; do + if [ $attempts -gt 0 ]; then + __sleep_amount + __log_out "Before retry #$attempts: sleeping $sleep_time seconds" + sleep $sleep_time + fi + eval $* + return_code=$? + #__log_out "Process returned $return_code on attempt $attempts" + if [ $return_code -eq 127 ]; then + # command not found + exit $return_code + else + attempts=$[$attempts +1] + fi + done + + if [ $attempts -gt $max_tries ]; then + if [ -n "$fail_script" ]; then + __log_out "Retries exhausted, running fail script" + eval $fail_script + else + __log_out "Retries exhausted" + fi + fi + + exit $return_code +} + +# If we're being sourced, don't worry about such things +if [ "$BASH_SOURCE" == "$0" ]; then + # Prints the help text + help() + { + local retry=$(basename $0) + cat < /dev/null + if [[ $? -ne 4 ]]; then + echo "I’m sorry, 'getopt --test' failed in this environment. Please load GNU getopt." + exit 1 + fi + + OPTIONS=vt:s:m:x:f: + LONGOPTIONS=verbose,tries:,sleep:,min:,max:,fail: + + PARSED=$(getopt --options="$OPTIONS" --longoptions="$LONGOPTIONS" --name "$0" -- "$@") + if [[ $? -ne 0 ]]; then + # e.g. $? == 1 + # then getopt has complained about wrong arguments to stdout + exit 2 + fi + # read getopt’s output this way to handle the quoting right: + eval set -- "$PARSED" + + max_tries=10 + min_sleep=0.3 + max_sleep=60.0 + constant_sleep= + fail_script= + + # now enjoy the options in order and nicely split until we see -- + while true; do + case "$1" in + -v|--verbose) + VERBOSE=true + shift + ;; + -t|--tries) + max_tries="$2" + shift 2 + ;; + -s|--sleep) + constant_sleep="$2" + shift 2 + ;; + -m|--min) + min_sleep="$2" + shift 2 + ;; + -x|--max) + max_sleep="$2" + shift 2 + ;; + -f|--fail) + fail_script="$2" + shift 2 + ;; + --) + shift + break + ;; + *) + echo "Programming error" + exit 3 + ;; + esac + done + + retry "$max_tries" "$min_sleep" "$max_sleep" "$constant_sleep" "$fail_script" $* + +fi