import collectd,os,subprocess

# https://www.programcreek.com/python/example/106897/collectd.register_read

PATHS = []
INTERVAL = 60 * 60 * 24

def du(path):
    return subprocess.check_output(['du','-Dsb', path]).split()[0].decode('utf-8')

def init():
    global PATHS
    collectd.info('custom du plugin initialized with %s' % PATHS)

# configure is called for each module block
def configure(config):
    global PATHS

    for node in config.children:
        key = node.key

        if key == 'Path':
            PATHS.append({ 'name': node.values[0], 'path': node.values[1] })
            collectd.info('du plugin: monitoring %s' % node.values[1])
        else:
            collectd.info('du plugin: Unknown config key "%s"' % key)

def read():
    for p in PATHS:
        path = p['path']
        collectd.info('computing size of %s' % path)
        size = du(path)
        collectd.info('du plugin: size of %s is %s' % (path, size))

        # type comes from https://github.com/collectd/collectd/blob/master/src/types.db
        val = collectd.Values(type='capacity', plugin='du', plugin_instance=p['name'])

        val.dispatch(values=[size], type_instance='usage')

collectd.register_init(init)
collectd.register_config(configure)
collectd.register_read(read, INTERVAL)