executable runner (only linux)

runner.sh

#!/usr/bin/env bash

# @TODO cut off to variable runargs before getopts
set -e

host="s3.amazonaws.com"
bucket="BUCKET"
filepath="DIRECTORY/FILE_NAME"
type="s3"
directory=$(pwd)
curl=`which curl`

# environment vars
key=${AWS_ACCESS_KEY_ID="xxxx"}
secret=${AWS_SECRET_ACCESS_KEY="xxxxxx"}
region=${AWS_DEFAULT_REGION="us-east-1"}

HELP="\t-H <host> \t\t\t host to download executable from (default: $host)
\t-f <filepath> \t\t\t executable file path (default: $filepath)
\t-d <directory_path> \t\t directory where to safe downloaded file (default: $directory)
\t-t <s3|basicauth> \t\t host type, available types \"s3\" and \"basicauth\" (default: $type)

\t---------- s3 options ----------
\t-k <AWS_ACCESS_KEY_ID> \t\t AWS access key (default: environment variable or blank)
\t-s <AWS_SECRET_ACCESS_KEY> \t AWS secret key (default: environment variable or blank)
\t-r <AWS_DEFAULT_REGION> \t AWS region (default: environment variable or $region)
\t-b <bucket> \t\t\t s3 bucket to download executable from (default: $bucket)

\t------ Basic Auth options ------
\t-l <username> \t\t\t login/username (default: blank)
\t-p <password> \t\t\t password (default: blank)
"

trim() {
    local var="$*"
    # remove leading whitespace characters
    var="${var#"${var%%[![:space:]]*}"}"
    # remove trailing whitespace characters
    var="${var%"${var##*[![:space:]]}"}"
    echo -n "$var"
}

usage() { printf >&2 "$HELP"; exit 1; }
err_usage() { printf >&2 "Invalid option \"-$OPTARG\" available options:\n$HELP"; exit 1; }
full_help() { printf >&2 "Download and run executable from Amazon S3 and/or BasicAuth URL and then run it\n$HELP"; exit 1; }

if [ -z "$*" ]; then full_help; fi
while getopts ":H:b:f:t:k:s:r:l:p:d:a:" opt; do
  case ${opt} in
    H) host=$(trim $OPTARG)
    ;;
    b) bucket=$(trim $OPTARG)
    ;;
    f) filepath=$(trim $OPTARG)
    ;;
    t) type=$(trim $OPTARG)
    ([ "$type" == "s3" ] || [ "$type" == "basicauth" ]) || usage
    ;;
    k) key=$(trim $OPTARG)
    ;;
    s) secret=$(trim $OPTARG)
    ;;
    r) region=$(trim $OPTARG)
    ;;
    l) login=$(trim $OPTARG)
    ;;
    p) password=$(trim $OPTARG)
    ;;
    d) directory=$(trim $OPTARG)
    ([ ! -d ${directory} ]) && (printf "Directory does not exists.\n"; usage; )
    ;;
    a) runargs=$(trim $OPTARG)
    ;;
    *) err_usage
    ;;
  esac
done

#shift $((OPTIND-1))
filename=${filepath##*/}
path="$directory/$filename"

function download_s3 {
    hmac_sha256() { echo -n "$2" | openssl dgst -sha256 -mac HMAC -macopt "$1" | sed 's/^.* //'; }

    resource="/${bucket}/${filepath}"
    hashedPayload="e3b0c44298fc1c149afbf4c8996fb92427ae41e4649b934ca495991b7852b855"
    timestamp=`TZ=GMT date +'%Y%m%dT%H%M%SZ'`
    date=`TZ=GMT date +'%Y%m%d'`
    canonicalRequest="GET\n${resource}\n\nhost:${host}\nx-amz-content-sha256:${hashedPayload}\nx-amz-date:${timestamp}\n\nhost;x-amz-content-sha256;x-amz-date\n${hashedPayload}"

    canonicalRequestHash=$(/bin/echo -en ${canonicalRequest} | openssl dgst -sha256 -binary | xxd -p -c256)
    stringToSign="AWS4-HMAC-SHA256\n${timestamp}\n${date}/${region}/$type/aws4_request\n${canonicalRequestHash}"

    dateKey=$(hmac_sha256 key:"AWS4$secret" ${date})
    dateRegionKey=$(hmac_sha256 hexkey:${dateKey} ${region})
    dateRegionServiceKey=$(hmac_sha256 hexkey:${dateRegionKey} ${type})
    signingKey=$(hmac_sha256 hexkey:${dateRegionServiceKey} "aws4_request")
    signature=$(/bin/echo -en ${stringToSign} | openssl dgst -sha256 -mac HMAC -macopt hexkey:${signingKey} -binary | xxd -p -c256)

    curl \
    --silent \
    -H "Host: ${host}" \
    -H "Authorization: AWS4-HMAC-SHA256 \
        Credential=${key}/${date}/${region}/$type/aws4_request, \
        SignedHeaders=host;x-amz-content-sha256;x-amz-date, \
        Signature=${signature}" \
    -H "X-Amz-Content-Sha256: ${hashedPayload}" \
    -H "X-Amz-Date: ${timestamp}" \
    -o ${path} \
    "https://$host$resource"
}

function download_basicauth {
    curl \
    --silent \
    --basic \
    -L \
    -u "$login:$password" \
    -o ${path} \
    "https://$host/${filepath}"
}

exec $("download_$type")
([ ! -f ${path} ]) && (printf "File error or not found.\n"; exit 1; )
chmod +x ${path}

set -- ${path} ${runargs:1:-1}
exec "$@"