loadbalancer

scripts/loadbalancer/loadbalancer.py

@@ -0,0 +1,74 @@
+#!/usr/bin/env python3
+
+import json
+
+import click
+import requests
+from loadbalancer_lib.curl import pycurl_get, pycurl_status
+
+
+AREAS = ['planet', 'monaco']
+
+
+@click.group()
+def cli():
+    """
+    Manages load-balancing of Round-Robin DNS records
+    """
+
+
+@cli.command()
+def run():
+    """
+    Runs load-balancing job (triggered by cron every minute)
+    """
+
+    with open('/data/ofm/config/loadbalancer.json') as fp:
+        c = json.load(fp)
+    print(c)
+
+    for area in AREAS:
+        results = run_area(c, area)
+        print(results)
+
+
+def run_area(c, area):
+    deployed_version = get_deployed_version(area)
+
+    print(f'deployed version: {area}: {deployed_version}')
+
+    results = dict()
+
+    for host_ip in c['load_balance_host_list']:
+        try:
+            check_host(c['domain_ledns'], host_ip, area, deployed_version)
+            results[host_ip] = True
+        except Exception:
+            results[host_ip] = False
+
+    return results
+
+
+def check_host(domain, host_ip, area, version):
+    # check TileJSON first
+    url = f'https://{domain}/{area}'
+    tilejson_str = pycurl_get(url, domain, host_ip)
+    tilejson = json.loads(tilejson_str)
+    tiles_url = tilejson['tiles'][0]
+    version_in_tilejson = tiles_url.split('/')[4]
+    assert version_in_tilejson == version
+
+    # check actual vector tile
+    url = f'https://{domain}/{area}/{version}/14/8529/5975.pbf'
+    assert pycurl_status(url, domain, host_ip) == 200
+
+
+def get_deployed_version(area):
+    url = f'https://assets.openfreemap.com/versions/deployed_{area}.txt'
+    response = requests.get(url)
+    response.raise_for_status()
+    return response.text.strip()
+
+
+if __name__ == '__main__':
+    cli()

scripts/loadbalancer/loadbalancer_lib/curl.py

@@ -0,0 +1,43 @@
+from io import BytesIO
+
+import pycurl
+
+
+def pycurl_status(url, domain, host_ip):
+    """
+    Uses pycurl to make a HTTPS HEAD request using custom resolving,
+    checks if the status code is 200
+    """
+
+    c = pycurl.Curl()
+    c.setopt(c.URL, url)
+    c.setopt(c.CAINFO, '/etc/ssl/certs/ca-certificates.crt')
+    c.setopt(c.RESOLVE, [f'{domain}:443:{host_ip}'])
+    c.setopt(c.NOBODY, True)
+    c.perform()
+    status_code = c.getinfo(c.RESPONSE_CODE)
+    c.close()
+
+    return status_code
+
+
+def pycurl_get(url, domain, host_ip):
+    """
+    Uses pycurl to make a HTTPS GET request using custom resolving,
+    checks if the status code is 200, and returns the content.
+    """
+
+    buffer = BytesIO()
+    c = pycurl.Curl()
+    c.setopt(c.URL, url)
+    c.setopt(c.CAINFO, '/etc/ssl/certs/ca-certificates.crt')
+    c.setopt(c.RESOLVE, [f'{domain}:443:{host_ip}'])
+    c.setopt(c.WRITEDATA, buffer)
+    c.perform()
+    status_code = c.getinfo(c.RESPONSE_CODE)
+    c.close()
+
+    if status_code != 200:
+        raise ValueError('non-200')
+
+    return buffer.getvalue().decode('utf8')

scripts/loadbalancer/setup.py

@@ -3,6 +3,8 @@ from setuptools import find_packages, setup
 
 requirements = [
     'click',
+    'requests',
+    'pycurl',
 ]