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@kalefranz
Last active March 22, 2019 17:11
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mostly POSIX-compliant wait-for-it.sh; works for alpine
#!/bin/sh
# Use this script to test if a given TCP host/port are available
cmdname=$(basename "$0")
echoerr() { if [ "$QUIET" -ne 1 ]; then echo "$@" 1>&2; fi }
usage()
{
cat << USAGE >&2
Usage:
$cmdname host:port [-s] [-t timeout] [-- command args]
-h HOST | --host=HOST Host or IP under test
-p PORT | --port=PORT TCP port under test
Alternatively, you specify the host and port as host:port
-s | --strict Only execute subcommand if the test succeeds
-q | --quiet Don't output any status messages
-t TIMEOUT | --timeout=TIMEOUT
Timeout in seconds, zero for no timeout
-- COMMAND ARGS Execute command with args after the test finishes
USAGE
exit 1
}
wait_for()
{
if [ "$TIMEOUT" -gt 0 ]; then
echoerr "$cmdname: waiting $TIMEOUT seconds for $HOST:$PORT"
else
echoerr "$cmdname: waiting for $HOST:$PORT without a timeout"
fi
start_ts=$(date +%s)
while :
do
if command -v nc > /dev/null ; then
nc -z "$HOST" "$PORT"
result=$?
else
bash -c "(echo > /dev/tcp/$HOST/$PORT) >/dev/null 2>&1"
result=$?
fi
if [ $result -eq 0 ]; then
end_ts=$(date +%s)
echoerr "$cmdname: $HOST:$PORT is available after $((end_ts - start_ts)) seconds"
break
fi
sleep 1
done
return $result
}
wait_for_wrapper()
{
# In order to support SIGINT during timeout: http://unix.stackexchange.com/a/57692
if [ "$QUIET" -eq 1 ]; then
timeout "$BUSYTIMEFLAG" "$TIMEOUT" "$0" --quiet --child --host="$HOST" --port="$PORT" --timeout="$TIMEOUT" &
else
timeout "$BUSYTIMEFLAG" "$TIMEOUT" "$0" --child --host="$HOST" --port="$PORT" --timeout="$TIMEOUT" &
fi
PID=$!
trap 'kill -INT -$PID' INT
wait $PID
RESULT=$?
if [ $RESULT -ne 0 ]; then
echoerr "$cmdname: timeout occurred after waiting $TIMEOUT seconds for $HOST:$PORT"
fi
return $RESULT
}
# process arguments
while [ $# -gt 0 ]
do
case "$1" in
*:* )
HOST=${1%:*}
PORT=${1##*:}
shift 1
;;
--child)
CHILD=1
shift 1
;;
-q | --quiet)
QUIET=1
shift 1
;;
-s | --strict)
STRICT=1
shift 1
;;
-h)
HOST="$2"
if [ "$HOST" = "" ]; then break; fi
shift 2
;;
--host=*)
HOST="${1#*=}"
shift 1
;;
-p)
PORT="$2"
if [ "$PORT" = "" ]; then break; fi
shift 2
;;
--port=*)
PORT="${1#*=}"
shift 1
;;
-t)
TIMEOUT="$2"
if [ "$TIMEOUT" = "" ]; then break; fi
shift 2
;;
--timeout=*)
TIMEOUT="${1#*=}"
shift 1
;;
--)
shift
CLI="$*"
break
;;
--help)
usage
;;
*)
echoerr "Unknown argument: $1"
usage
;;
esac
done
if [ "$SKIP_WAITING" != "" ]; then
HOST="localhost"
PORT="8000"
fi
if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then
echoerr "Error: you need to provide a host and port to test."
usage
fi
TIMEOUT=${TIMEOUT:-15}
STRICT=${STRICT:-0}
CHILD=${CHILD:-0}
QUIET=${QUIET:-0}
TIMEOUT_PATH=$(realpath "$(command -v timeout)")
if echo "$TIMEOUT_PATH" | grep -q busybox ; then
BUSYTIMEFLAG="-t"
else
BUSYTIMEFLAG=""
fi
# are we skipping this entire business?
if [ "$SKIP_WAITING" != "" ]; then
RESULT=0
else
if [ "$CHILD" -gt 0 ]; then
wait_for
RESULT=$?
exit $RESULT
else
if [ "$TIMEOUT" -gt 0 ]; then
wait_for_wrapper
RESULT=$?
else
wait_for
RESULT=$?
fi
fi
fi
if [ "$CLI" != "" ]; then
if [ "$RESULT" -ne 0 ] && [ "$STRICT" -eq 1 ]; then
echoerr "$cmdname: strict mode, refusing to execute subprocess"
exit $RESULT
fi
exec "$@"
else
exit $RESULT
fi
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