jconsole via ssh proxy

jconsole-proxy.sh

#!/bin/bash

#/ jc -- jconsole via ssh proxy
#/ 
#/ Usage:     jc [options] HOST JMX_PORT [PROXY_PORT=JMX_PORT] [JMX_HOST=HOST]
#/ 
#/ Starts a SOCKS proxy via ssh to connect to a
#/ JVM running on a remote and protected machine.
#/ 
#/ Arguments:
#/      HOST                Host running the VM. This is a ssh host-string, so you can
#/                           specify anything that will pick out a host in ssh: [user@]host[:port]
#/      JMX_PORT            Port used by JMX on the remote JMX_HOST.
#/      PROXY_PORT=JMX_PORT      Local port to use for the SOCKs proxy. Defaults to JMX_PORT.
#/      JMX_HOST=HOST       JMX hostname, set by java.rmi.server.hostname, or defaulting
#/                           to the machine hostname.
#/ 
#/ Options:
#/      -h --help       Displays this help.
#/      -v              Verbose logging.
#/ 

VERBOSE=''


# The most important line in any shell program. (Terminate on subcommand errors)
set -e

# Utilities
log   () { [ "$VERBOSE" ] && echo -e "$*" >&2; :; }
logs  () { [ "$VERBOSE" ] && printf "%s" "$*"; :; }
fail  () { echo >&2; echo "[ERROR] $*" >&2; exit 1; }
count () { echo $#; }
nth   () { local n="$1"; shift; [ -z "$n" ] && return 1; [[ "$n" < 0 ]] && n=$(( 1 + $# + $n )); echo "${!n}"; }
join  () { local sep="$1" old="$IFS"; export IFS=\n; read -t1 out; while read -t1 line; do out="$out$sep$line"; done; echo "$out"; export IFS=$old; }
sjoin () { local sep="$1"; shift; [ -z "$*" ] && return 1; printf "$1"; shift; for a in $*; do printf "$sep$a"; done; echo; }

# Print Help
SELF="$0"
halp () { grep '^#/' <"$SELF" | cut -c4-; :; }
for opt in $*; do echo $opt | egrep -xq -e '--?h(e(lp?)?)?' && { halp; exit 0; }; done

# Parse Args
SHIFT=0
incshift () { SHIFT=$(( $SHIFT + ${1:-1} )); }
while getopts "v" opt; do
    case $opt in
        v ) VERBOSE="-v";         incshift ;;
        * ) fail "Unknown option: $OPTARG" ;;
    esac
done
shift $SHIFT


host=$1
jmx_port=$2
proxy_port=${3:-$jmx_port}
jmx_host=${4:-$host}

if [ -z "$host" -o -z "$jmx_port" ]; then
    printf "[ERROR] HOST and JMX_PORT are required!\n\n" >&2
    halp
    exit 1
fi

# start up a background ssh tunnel on the desired port
ssh -N -f -D$proxy_port $host

# if the tunnel failed to come up, fail gracefully.
[ $? -ne 0 ] && fail "ssh tunnel failed!"

ssh_pid=`ps awwwx | grep "[s]sh -N -f -D$proxy_port" | awk '{print $1}'`
log "ssh pid: $ssh_pid"

# if we can't find the ssh pid, presume something has gone wrong
[ -z "$ssh_pid" ] && fail "unable to determine ssh tunnel pid!"

# Fire up jconsole to your remote host
jconsole -J-DsocksProxyHost=localhost -J-DsocksProxyPort=$proxy_port \
    service:jmx:rmi:///jndi/rmi://${jmx_host}:${jmx_port}/jmxrmi

# tear down the tunnel
kill $ssh_pid