swarm - another parallel ssh wrapper

swarm.sh

#!/bin/bash

## Run commands on a set of hosts

WAIT="%%"

while getopts 'w' OPTION; do
    case $OPTION in
        w) WAIT="" ;;
        ?) usage; exit ;;
    esac
done
shift $[OPTIND - 1]

declare -A tags
declare -a cmds
declare -a hosts
declare -a local_cmds


# Parse host args: [user@]hostname[=tag]:cmd
for i in "$@"; do
    prefix=${i%%:*}
    cmd=${i#$prefix:}

    if [ "$cmd" = "$i" ]; then
        echo "Failed to parse $i"
        exit -1
    fi

    userhost=${prefix%=*}
    hostname=${userhost#*@}
    tag=${prefix#*=}

    if [ "$hostname" = "local" ]; then
        local_cmds+=("$cmd")
    else
        if [ "$tag" != "$prefix" ]; then
            tags[$tag]=$hostname
        fi

        cmds+=("$userhost $cmd")
    fi
done

# Munch cmds and replace %tag% with its expansion.
for h in "${!cmds[@]}"; do
    for t in "${!tags[@]}"; do
        r=${tags[$t]}
        cmds[$h]=${cmds[$h]//%$t%/$r}
    done
done

#trap 'kill -- -`ps -o pgid= $$ | tr -d " "`' EXIT
trap 'kill `jobs -p` &> /dev/null' EXIT

for c in "${cmds[@]}"; do
    ssh -tt \
        -o ForwardX11=no -o ForwardX11Trusted=no \
        -o StrictHostKeyChecking=no -o BatchMode=yes \
        $c </dev/null &
done

for c in "${local_cmds[@]}"; do
    $c &
done

wait $WAIT