runurl.sh

#!/bin/sh
#
# runurl - Download a URL and run as a program, passing in arguments
#
# Copyright (C) 2009 Eric Hammond <[email protected]>
#

error() { echo "$@" 1>&2; }
fail() { [ $# -eq 0 ] || error "${BNAME}:" "$1"; exit ${2:-1}; }
debug() { [ "$DEBUG" = "0" ] || error "${BNAME}:" "$@"; }
cleanup() { [ -z "${TEMP_D}" -o ! -d "${TEMP_D}" ] || rm -Rf "${TEMP_D}"; }

DEBUG="0"
TEMP_D=""
BNAME=${0##*/}

while [ $# -gt 0 ]; do
  case $1 in
    -\?|--help) pod2text "${0}"; exit 0;;
    -d|--debug) DEBUG=1;                    shift 1 ;;
    -*)         fail "Unrecognized option: $1 (try --help)";;
    *)          url="$1";                   shift 1; break ;;
  esac
done

[ -n "$url" ] || fail "Missing URL specification (try --help)"

trap cleanup 0 

TEMP_D=$(mktemp -d ${TEMPDIR:-/tmp}/${BNAME}.XXXXXX) &&
  runfile="${TEMP_D}/runfile" && wgetfile="${TEMP_D}/wget.out" ||
  fail "failed to make tempdir"

debug "downloading $url"

wget                           \
  --retry-connrefused          \
  --tries=20                   \
  "--output-document=$runfile" \
  "--output-file=$wgetfile"    \
  "$url"

wgetstatus=$?
if [ $wgetstatus != 0 ]; then
  cat $wgetfile >&2
  fail "wget failed: $wgetstatus" "${wgetstatus}"
fi

chmod 700 "${runfile}" || fail "failed to change perms of ${runfile}"

debug "running"
$runfile "$@"

exitstatus=$?

debug "exit status $exitstatus"

exit $exitstatus

#
# To read the documentation in this file use the command:
#
#   perldoc runurl
#

=head1 NAME

runurl - Download a URL and run as a program, passing in arguments

=head1 SYNOPSYS

runurl [I<OPTS>] I<URL> [I<ARGS>]...

=head1 OPTIONS

=over 8

=item B<-?> B<--help>

Debug mode

=item B<-d> B<--debug>

Debug mode

=back

=head1 ARGUMENTS

=over 8

=item B<URL>

The URL of the progran to download and run

=item B<ARGS>

Options and arguments for the downloaded program

=back

=head1 DESCRIPTION

The B<runurl> command is a simple tool that downloads a program (or
script) from the specified URL and runs it.

The first argument to the B<runurl> command is the URL of a script or
program that should be run.  Any leading "http://" may be omitted, but
"https://" or "ftp://" and the like must still be specified.

All remaining arguments listed after the URL (including ones which
look like options) are passed verbatim to the program as its own
options and arguments when it is run.

The exit code of B<runurl> is the exit code of the program, unless the
original download of the URL failed, in which case that error is
returned.

=head1 EXAMPLES

If the following content is stored at http://run.alestic.com/demo/hello

  #!/bin/bash
  echo "hello, $1"

then this command:

  runurl run.alestic.com/demo/hello world

will itself output:

  hello, world

=head1 CAVEATS

Only run content that you control or completely trust.

Just because you like the content of a URL when you look at it in your
browser does not mean that it will still look like that when B<runurl>
goes to run it.  It could change at any point to something that is
broken or even malicious unless it is under your control.

Realize that you are depending on the network for commands to succeed.
If the content is temporarily unavailable or has been moved, then the
B<runurl> command will fail.

=head1 DEPENDENCIES

This program requires that the following already be installed:

  wget

=head1 SEE ALSO

The B<runurl> project site:

  https://launchpad.net/runurl

Article about using B<runurl> for initial configuration of Amazon EC2
instances:

  http://alestic.com/2009/08/runurl

=head1 INSTALLATION

On most Ubuntu releases, the B<runurl> package can be installed
directly from the Alestic.com PPA using the following commands:

 code=$(lsb_release -cs)
 echo "deb http://ppa.launchpad.net/alestic/ppa/ubuntu $code main"|
   sudo tee /etc/apt/sources.list.d/alestic-ppa.list
 sudo apt-key adv --keyserver keyserver.ubuntu.com --recv-keys BE09C571
 sudo apt-get update
 sudo apt-get install -y runurl

=head1 BUGS

Please report bugs at https://bugs.launchpad.net/runurl

=head1 AUTHOR

Eric Hammond <[email protected]>

=head1 LICENSE

Copyright 2009 Eric Hammond <[email protected]>

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

 http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.

=cut