switched to wait for it to avoid external deps

scripts/wait-for.sh

@@ -1,56 +1,115 @@
-#!/bin/sh
+#!/usr/bin/env bash
+#   Use this script to test if a given TCP host/port are available
 
-TIMEOUT=15
+cmdname=$(basename $0)
-QUIET=0
 
-echoerr() {
+echoerr() { if [[ $QUIET -ne 1 ]]; then echo "$@" 1>&2; fi }
-  if [ "$QUIET" -ne 1 ]; then printf "%s\n" "$*" 1>&2; fi
-}
 
-usage() {
+usage()
-  exitcode="$1"
+{
     cat << USAGE >&2
 Usage:
-  $0 host:port [-t timeout] [-- command args]
+    $cmdname host:port [-s] [-t timeout] [-- command args]
-  -q | --quiet                        Do not output any status messages
+    -h HOST | --host=HOST       Host or IP under test
-  -t TIMEOUT | --timeout=timeout      Timeout in seconds, zero for no timeout
+    -p PORT | --port=PORT       TCP port under test
+                                Alternatively, you specify the host and port as host:port
+    -s | --strict               Only execute subcommand if the test succeeds
+    -q | --quiet                Don't output any status messages
+    -t TIMEOUT | --timeout=TIMEOUT
+                                Timeout in seconds, zero for no timeout
     -- COMMAND ARGS             Execute command with args after the test finishes
 USAGE
-  exit "$exitcode"
-}
-
-wait_for() {
-  for _ in $(seq $TIMEOUT) ; do
-    nc -z "$HOST" "$PORT" > /dev/null 2>&1
-
-    result=$?
-    if [ $result -eq 0 ] ; then
-      if [ $# -gt 0 ] ; then
-        exec "$@"
-      fi
-      exit 0
-    fi
-    sleep 1
-  done
-  echo "Operation timed out" >&2
     exit 1
 }
 
-while [ $# -gt 0 ]
+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 [[ $ISBUSY -eq 1 ]]; then
+            nc -z $HOST $PORT
+            result=$?
+        else
+            (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 "$1" in
         *:* )
-    HOST=$(printf "%s\n" "$1"| cut -d : -f 1)
+        hostport=(${1//:/ })
-    PORT=$(printf "%s\n" "$1"| cut -d : -f 2)
+        HOST=${hostport[0]}
+        PORT=${hostport[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
+        if [[ $TIMEOUT == "" ]]; then break; fi
         shift 2
         ;;
         --timeout=*)
@@ -59,21 +118,60 @@ do
         ;;
         --)
         shift
+        CLI=("$@")
         break
         ;;
         --help)
-    usage 0
+        usage
         ;;
         *)
         echoerr "Unknown argument: $1"
-    usage 1
+        usage
         ;;
     esac
 done
 
-if [ "$HOST" = "" ] || [ "$PORT" = "" ]; then
+if [[ "$HOST" == "" || "$PORT" == "" ]]; then
     echoerr "Error: you need to provide a host and port to test."
-  usage 2
+    usage
 fi
 
-wait_for "$@"
+TIMEOUT=${TIMEOUT:-15}
+STRICT=${STRICT:-0}
+CHILD=${CHILD:-0}
+QUIET=${QUIET:-0}
+
+# check to see if timeout is from busybox?
+# check to see if timeout is from busybox?
+TIMEOUT_PATH=$(realpath $(which timeout))
+if [[ $TIMEOUT_PATH =~ "busybox" ]]; then
+        ISBUSY=1
+        BUSYTIMEFLAG="-t"
+else
+        ISBUSY=0
+        BUSYTIMEFLAG=""
+fi
+
+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
+
+if [[ $CLI != "" ]]; then
+    if [[ $RESULT -ne 0 && $STRICT -eq 1 ]]; then
+        echoerr "$cmdname: strict mode, refusing to execute subprocess"
+        exit $RESULT
+    fi
+    exec "${CLI[@]}"
+else
+    exit $RESULT
+fi