#!/usr/bin/env python

import requests

s = requests.Session()


def url_for(path):
    return "https://localhost/softnas/" + path


def login():
    instance_id = requests.get(
        "http://169.254.169.254/latest/meta-data/instance-id").text.strip()
    login_url = url_for("login.php")
    s.post(
        login_url,
        data={
            'username': 'softnas',
            'password': instance_id},
        verify=False)


def query(opcode, **kwargs):
    api_url = url_for("snserver/snserv.php")
    data = {'opcode': opcode}
    data.update(kwargs)
    r = s.post(api_url, data=data, verify=False)
    try:
        return r.json()['records']
    except:
        print "Error: " + r.text
        return {}


def save_metrics(metrics):
    file_path = "/var/lib/node_exporter/softnas_metrics.prom"
    with open(file_path, "w") as of:
        for m in metrics:
            if 'help' in m:
                of.write("# HELP {0} {1}\n".format(m['name'], m['help']))
            if 'type' in m:
                of.write("# TYPE {0} {1}\n".format(m['name'], m['type']))
            if 'value' in m:
                of.write("{0} {1}\n".format(m['name'], m['value']))


def volume_metrics(vol_name):
    """ Return a list of metrics for the target volume """
    vol_data = query('volumes')
    rv = []
    for vol in vol_data:
        if vol['vol_name'] != vol_name:
            continue
        for m in ('total', 'used', 'free'):
            rv.append({'name': 'volume_' + m,
                       'type': 'gauge',
                       'value': vol[m + '_numeric']})
    return rv


def perfmon_metrics():
    """ Return a list of metrics from the perfmon dataset """
    perf_data = query('perfmon')[-1]
    rv = []
    for m, val in perf_data.iteritems():
        if m.startswith('iops') or m.startswith('latency') or m == 'time':
            continue
        rv.append({'name': 'softnas_' + m,
                   'type': 'gauge',
                   'value': val})
    return rv


def snaprep_metrics():
    """ Return a list of metrics from the perfmon dataset """
    snaprep = query('snaprepcommand', command="snapreplicatestatus")
    rv = []
    rv.append({'name': 'softnas_ha_active',
               'type': 'gauge',
               'help': 'Is HA Running? 0 == no, 1 == yes',
               'value': snaprep['active']})
    return rv


def main():
    login()
    metrics = volume_metrics("volume1") + perfmon_metrics() + snaprep_metrics()
    save_metrics(metrics)

if __name__ == "__main__":
    main()