wait-for

#!/bin/sh

# The MIT License (MIT)
#
# Copyright (c) 2017 Eficode Oy
#
# Permission is hereby granted, free of charge, to any person obtaining a copy
# of this software and associated documentation files (the "Software"), to deal
# in the Software without restriction, including without limitation the rights
# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
# copies of the Software, and to permit persons to whom the Software is
# furnished to do so, subject to the following conditions:
#
# The above copyright notice and this permission notice shall be included in all
# copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
# SOFTWARE.

VERSION="2.2.3"

set -- "$@" -- "$TIMEOUT" "$QUIET" "$PROTOCOL" "$HOST" "$PORT" "$result"
TIMEOUT=15
QUIET=0
# The protocol to make the request with, either "tcp" or "http"
PROTOCOL="tcp"

echoerr() {
    if [ "$QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi
}

usage() {
    exitcode="$1"
    cat <<USAGE >&2
Usage:
  $0 host:port|url [-t timeout] [-- command args]
  -q | --quiet                        Do not output any status messages
  -t TIMEOUT | --timeout=timeout      Timeout in seconds, zero for no timeout
  -v | --version                      Show the version of this tool
  -- COMMAND ARGS                     Execute command with args after the test finishes
USAGE
    exit "$exitcode"
}

wait_for() {
    case "$PROTOCOL" in
    tcp)
        if ! command -v nc >/dev/null; then
            echoerr 'nc command is missing!'
            exit 1
        fi
        ;;
    http)
        if ! command -v wget >/dev/null; then
            echoerr 'wget command is missing!'
            exit 1
        fi
        ;;
    esac

    TIMEOUT_END=$(($(date +%s) + TIMEOUT))

    while :; do
        case "$PROTOCOL" in
        tcp)
            nc -w 1 -z "$HOST" "$PORT" >/dev/null 2>&1
            ;;
        http)
            wget --timeout=1 -q "$HOST" -O /dev/null >/dev/null 2>&1
            ;;
        *)
            echoerr "Unknown protocol '$PROTOCOL'"
            exit 1
            ;;
        esac

        result=$?

        if [ $result -eq 0 ]; then
            if [ $# -gt 7 ]; then
                for result in $(seq $(($# - 7))); do
                    result=$1
                    shift
                    set -- "$@" "$result"
                done

                TIMEOUT=$2 QUIET=$3 PROTOCOL=$4 HOST=$5 PORT=$6 result=$7
                shift 7
                exec "$@"
            fi
            exit 0
        fi

        if [ $TIMEOUT -ne 0 -a $(date +%s) -ge $TIMEOUT_END ]; then
            echo "Operation timed out" >&2
            exit 1
        fi

        sleep 1
    done
}

while :; do
    case "$1" in
    http://* | https://*)
        HOST="$1"
        PROTOCOL="http"
        shift 1
        ;;
    *:*)
        HOST=$(printf "%s\n" "$1" | cut -d : -f 1)
        PORT=$(printf "%s\n" "$1" | cut -d : -f 2)
        shift 1
        ;;
    -v | --version)
        echo $VERSION
        exit
        ;;
    -q | --quiet)
        QUIET=1
        shift 1
        ;;
    -q-*)
        QUIET=0
        echoerr "Unknown option: $1"
        usage 1
        ;;
    -q*)
        QUIET=1
        result=$1
        shift 1
        set -- -"${result#-q}" "$@"
        ;;
    -t | --timeout)
        TIMEOUT="$2"
        shift 2
        ;;
    -t*)
        TIMEOUT="${1#-t}"
        shift 1
        ;;
    --timeout=*)
        TIMEOUT="${1#*=}"
        shift 1
        ;;
    --)
        shift
        break
        ;;
    --help)
        usage 0
        ;;
    -*)
        QUIET=0
        echoerr "Unknown option: $1"
        usage 1
        ;;
    *)
        QUIET=0
        echoerr "Unknown argument: $1"
        usage 1
        ;;
    esac
done

if ! [ "$TIMEOUT" -ge 0 ] 2>/dev/null; then
    echoerr "Error: invalid timeout '$TIMEOUT'"
    usage 3
fi

case "$PROTOCOL" in
tcp)
    if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then
        echoerr "Error: you need to provide a host and port to test."
        usage 2
    fi
    ;;
http)
    if [ "$HOST" = "" ]; then
        echoerr "Error: you need to provide a host to test."
        usage 2
    fi
    ;;
esac

wait_for "$@"