Groovy Script to total active sessions from one or more Tomcat contexts with option to stall until zero sessions

tomcatsessions.groovy

#!/usr/bin/env groovy
package devops

Authenticator.setDefault(new Authenticator() {
    protected PasswordAuthentication getPasswordAuthentication() {
        return new PasswordAuthentication("list", "**********".toCharArray());
    }
})

servers = []
context = ''

list = false
wait = false

def cli = new CliBuilder(usage: 'tomcatsessions [options] -c context {server}...')

cli.w('wait for zero sessions')
cli.c(args: 1, "context")
cli.l('list')
cli.h('help')
def options = cli.parse(args)

if (options.h) {
    cli.usage()
    System.exit(0)
}

if (options.w) {
    wait = true
} else {
    list = true
}

if (options.l) { list = true }

if (options.arguments()) {
    servers = options.arguments().collect { it.trim() }
}

if (options.c) {
    context = options.c
}

def total = getTotal()
while (wait && total) {
    println "waiting for sessions on $servers$context: $total remaining"
    Thread.sleep(10 * 1000)
    total = getTotal()
}

def getTotal() {
    def counts = getSessionCounts()
    if (list) {
        println "session counts for $context:\n "
        counts.each { k, v ->
            println String.format("%20s:%4d", k, v)
        }
        println String.format("\n%20s:%4d", "Total", counts.collect { it.value }.sum(0))
    }
    return counts.collect { it.value }.sum(0)
}

def getSessionCounts() {
    servers.collectEntries { s ->

        def lines = "http://${s}:8080/manager/text/sessions?path=${context}".toURL().readLines()
        if (!lines[0].startsWith('OK')) {
            return [(s): "failed: " + lines.join('\n')]
        }

        [(s): lines.findAll { it.contains(":") }.collect { it.split(':')[1].trim().split(' ')[0].toInteger() }.sum(0)]
    }
}