wait-for

#!/usr/bin/env bash
# wait-for
#
# @author Jon Pugh
#
# Runs any command over and over again until it passes, hiding all output but printing a character every time it runs.
#
# Use Environment variables for options:
#
# SLEEP: Length of time to wait in-between running the command.
# CHAR: The character to print after every command run.
# OUTPUT: Set to 'all' to print all output, set to 'out' to print just stdOut, set to "err" to print just stdErr.
# TIMEOUT: Default: 30. Exit with an error if process doesn't pass within this time.
# SILENT: Set to 1 to not print any output except the timeout exceeded error. Useful when running from other scripts. See wait-mysql
#

# Document usage
usage() {
  cat <<<EOF
Usage:
  wait-for any-command any-arguments --any-options
EOF
}

# Set Environment
set -e
DIR="$( cd "$( dirname "${BASH_SOURCE[0]}" )" >/dev/null 2>&1 && pwd )"
PATH="$DIR:$PATH"

# Prepare arguments and options.
COMMAND=$@

# Environment Variables
SLEEP=${SLEEP:-1}
CHAR=${CHAR:-.}
OUTPUT=${OUTPUT:-}
TIMEOUT=${TIMEOUT:-30}
SILENT=${SILENT:-""}

# Check for required variables
if [ -z "${COMMAND}" ]; then
  usage
  exit 1
fi

runCommand() {

    # If $OUTPUT=out, hide errors.
    if [ "${OUTPUT}" == "out" ]; then
      $COMMAND 2> /dev/null

    # If $OUTPUT=err, print only errors
    elif [ "${OUTPUT}" == "err" ]; then
      $COMMAND > /dev/null

    # If $OUTPUT=all, just print
    elif [ "${OUTPUT}" == "all" ]; then
      $COMMAND

    # Otherwise, hide output and errors
    else
      $COMMAND > /dev/null 2>&1
    fi
}

if [ -z "${SILENT}" ]; then
    devshop-log "Running command until it succeeds: $COMMAND"
fi

while ! (runCommand)
do
    # Exit with an error if timeout is reached.
    [ "$SECONDS" -gt "$TIMEOUT" ] && echo "Timeout exceeded. Command did not succeed in $SECONDS seconds." && exit 1

    # Pause for $SLEEP seconds.
    sleep $SLEEP

    # Print $CHAR without a new line.
    echo -n "$CHAR"
done

if [ -z "${SILENT}" ]; then
  echo "Done in $SECONDS seconds!"
fi