marathon-upstreams

#!/usr/bin/python

# -- stdlib --
import json
import os
import urllib2

# -- third party --
# -- own --
# -- code --
MARATHON = os.environ.get('MARATHON', 'http://mesos1:8080')

nginx_apps = set()
upstream_conf = {}


json_opener = urllib2.build_opener()
json_opener.addheaders = [('Accept', 'application/json')]

conf = json.loads(json_opener.open(MARATHON + '/v2/apps').read())['apps']

'''
{
    "labels": {
        "nginx-13001": "ip-hash;",
        "nginx-13002": "foo; bar; baz;;;",
        "nginx-default": "meh; moo; meow"
    }
}
'''
for app in conf:
    lbls = app['labels']

    for k, v in lbls.items():
        if not k.startswith('nginx-'):
            continue

        app_id = app['id'][1:]
        k = '%s-%s' % (app_id, k[6:])
        options = [i.strip() for i in v.split(';')]
        options = [i for i in options if i]
        upstream_conf[k] = ''.join(['    %s;\n' % i for i in options])
        nginx_apps.add(app_id)


def get_conf(app, srv_port):
    k = '%s-%s' % (app, srv_port)
    if k in upstream_conf:
        return upstream_conf[k]

    return upstream_conf.get('%s-default' % app, '')


for srv in urllib2.urlopen(MARATHON + '/v2/tasks').readlines():
    srv = srv.split('\t')
    srv = map(str.strip, srv)

    if len(srv) < 2:
        continue

    if not srv[1]:  # srv port
        continue

    app, port = srv[:2]

    if app not in nginx_apps:
        continue

    print "upstream %s-%s {" % (app, port)
    print get_conf(app, port)
    for task in srv[2:]:
        task = task.strip()
        if not task: continue
        print "    server %s;" % task

    print "}\n"