163 lines
4.3 KiB
Bash
Executable file
163 lines
4.3 KiB
Bash
Executable file
#!/usr/bin/env bash
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GETOPT_BIN=$IN_GETOPT_BIN
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GETOPT_BIN=${GETOPT_BIN:-getopt}
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__sleep_amount() {
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if [ -n "$constant_sleep" ]; then
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sleep_time=$constant_sleep
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else
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#TODO: check for awk
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#TODO: check if user would rather use one of the other possible dependencies: python, ruby, bc, dc
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sleep_time=`awk "BEGIN {t = $min_sleep * $(( (1<<($attempts -1)) )); print (t > $max_sleep ? $max_sleep : t)}"`
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fi
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}
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__log_out() {
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echo "$1" 1>&2
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}
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# Parameters: max_tries min_sleep max_sleep constant_sleep fail_script EXECUTION_COMMAND
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retry()
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{
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local max_tries="$1"; shift
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local min_sleep="$1"; shift
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local max_sleep="$1"; shift
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local constant_sleep="$1"; shift
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local fail_script="$1"; shift
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if [ -n "$VERBOSE" ]; then
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__log_out "Retry Parameters: max_tries=$max_tries min_sleep=$min_sleep max_sleep=$max_sleep constant_sleep=$constant_sleep"
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if [ -n "$fail_script" ]; then __log_out "Fail script: $fail_script"; fi
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__log_out ""
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__log_out "Execution Command: $*"
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__log_out ""
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fi
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local attempts=0
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local return_code=1
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while [[ $return_code -ne 0 && $attempts -le $max_tries ]]; do
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if [ $attempts -gt 0 ]; then
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__sleep_amount
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__log_out "Before retry #$attempts: sleeping $sleep_time seconds"
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sleep $sleep_time
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fi
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P="$1"
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for param in "${@:2}"; do P="$P '$param'"; done
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#TODO: replace single quotes in each arg with '"'"' ?
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export RETRY_ATTEMPT=$attempts
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bash -c "$P"
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return_code=$?
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#__log_out "Process returned $return_code on attempt $attempts"
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if [ $return_code -eq 127 ]; then
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# command not found
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exit $return_code
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elif [ $return_code -ne 0 ]; then
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attempts=$[$attempts +1]
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fi
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done
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if [ $attempts -gt $max_tries ]; then
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if [ -n "$fail_script" ]; then
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__log_out "Retries exhausted, running fail script"
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eval $fail_script
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else
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__log_out "Retries exhausted"
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fi
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fi
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exit $return_code
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}
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# If we're being sourced, don't worry about such things
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if [ "$BASH_SOURCE" == "$0" ]; then
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# Prints the help text
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help()
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{
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local retry=$(basename $0)
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cat <<EOF
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Usage: $retry [options] -- execute command
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-h, -?, --help
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-v, --verbose Verbose output
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-t, --tries=# Set max retries: Default 10
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-s, --sleep=secs Constant sleep amount (seconds)
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-m, --min=secs Exponential Backoff: minimum sleep amount (seconds): Default 0.3
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-x, --max=secs Exponential Backoff: maximum sleep amount (seconds): Default 60
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-f, --fail="script +cmds" Fail Script: run in case of final failure
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EOF
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}
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# show help for no arguments if stdin is a terminal
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if { [ -z "$1" ] && [ -t 0 ] ; } || [ "$1" == '-h' ] || [ "$1" == '-?' ] || [ "$1" == '--help' ]
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then
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help
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exit 0
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fi
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$GETOPT_BIN --test > /dev/null
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if [[ $? -ne 4 ]]; then
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echo "I’m sorry, 'getopt --test' failed in this environment. Please load GNU getopt."
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exit 1
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fi
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OPTIONS=vt:s:m:x:f:
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LONGOPTIONS=verbose,tries:,sleep:,min:,max:,fail:
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PARSED=$($GETOPT_BIN --options="$OPTIONS" --longoptions="$LONGOPTIONS" --name "$0" -- "$@")
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if [[ $? -ne 0 ]]; then
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# e.g. $? == 1
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# then getopt has complained about wrong arguments to stdout
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exit 2
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fi
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# read getopt’s output this way to handle the quoting right:
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eval set -- "$PARSED"
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max_tries=10
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min_sleep=0.3
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max_sleep=60.0
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constant_sleep=
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fail_script=
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# now enjoy the options in order and nicely split until we see --
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while true; do
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case "$1" in
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-v|--verbose)
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VERBOSE=true
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shift
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;;
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-t|--tries)
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max_tries="$2"
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shift 2
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;;
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-s|--sleep)
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constant_sleep="$2"
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shift 2
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;;
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-m|--min)
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min_sleep="$2"
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shift 2
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;;
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-x|--max)
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max_sleep="$2"
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shift 2
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;;
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-f|--fail)
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fail_script="$2"
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shift 2
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;;
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--)
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shift
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break
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;;
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*)
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echo "Programming error"
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exit 3
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;;
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esac
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done
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retry "$max_tries" "$min_sleep" "$max_sleep" "$constant_sleep" "$fail_script" "$@"
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fi
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