team-3/src/c3nav/tileserver/wsgi.py
2017-12-23 21:03:14 +01:00

239 lines
9.3 KiB
Python

import base64
import logging
import multiprocessing
import os
import pickle
import re
import threading
import time
from datetime import datetime
from email.utils import formatdate
from io import BytesIO
import pylibmc
import requests
from c3nav.mapdata.utils.cache import CachePackage
from c3nav.mapdata.utils.tiles import (build_access_cache_key, build_base_cache_key, build_tile_etag, get_tile_bounds,
parse_tile_access_cookie)
logging.basicConfig(level=logging.DEBUG if os.environ.get('C3NAV_DEBUG') else logging.INFO,
format='[%(asctime)s] [%(process)s] [%(levelname)s] %(name)s: %(message)s',
datefmt='%Y-%m-%d %H:%M:%S %z')
logger = logging.getLogger('c3nav')
class TileServer:
def __init__(self):
self.path_regex = re.compile(r'^/(\d+)/(-?\d+)/(-?\d+)/(-?\d+).png$')
self.cookie_regex = re.compile(r'(^| )c3nav_tile_access="?([^;" ]+)"?')
try:
self.upstream_base = os.environ['C3NAV_UPSTREAM_BASE'].strip('/')
except KeyError:
raise Exception('C3NAV_UPSTREAM_BASE needs to be set.')
try:
self.data_dir = os.environ.get('C3NAV_DATA_DIR', 'data')
except KeyError:
raise Exception('C3NAV_DATA_DIR needs to be set.')
if not os.path.exists(self.data_dir):
os.mkdir(self.data_dir)
self.tile_secret = os.environ.get('C3NAV_TILE_SECRET', None)
if not self.tile_secret:
tile_secret_file = None
try:
tile_secret_file = os.environ['C3NAV_TILE_SECRET_FILE']
self.tile_secret = open(tile_secret_file).read().strip()
except KeyError:
raise Exception('C3NAV_TILE_SECRET or C3NAV_TILE_SECRET_FILE need to be set.')
except FileNotFoundError:
raise Exception('The C3NAV_TILE_SECRET_FILE (%s) does not exist.' % tile_secret_file)
self.reload_interval = int(os.environ.get('C3NAV_RELOAD_INTERVAL', 60))
self.auth_headers = {'X-Tile-Secret': base64.b64encode(self.tile_secret.encode())}
self.cache_package = None
self.cache_package_etag = None
self.cache_package_filename = None
self.cache = self.get_cache_client()
wait = 1
while True:
success = self.load_cache_package(cache=self.cache)
if success:
logger.info('Cache package successfully loaded.')
break
logger.info('Retrying after %s seconds...' % wait)
time.sleep(wait)
wait = min(10, wait*2)
threading.Thread(target=self.update_cache_package_thread, daemon=True).start()
@staticmethod
def get_cache_client():
return pylibmc.Client(["127.0.0.1"], binary=True, behaviors={"tcp_nodelay": True, "ketama": True})
def update_cache_package_thread(self):
cache = self.get_cache_client() # different thread → different client!
while True:
time.sleep(self.reload_interval)
self.load_cache_package(cache=cache)
def get_date_header(self):
return 'Date', formatdate(timeval=time.time(), localtime=False, usegmt=True)
def load_cache_package(self, cache):
logger.debug('Downloading cache package from upstream...')
try:
headers = self.auth_headers.copy()
if self.cache_package_etag is not None:
headers['If-None-Match'] = self.cache_package_etag
r = requests.get(self.upstream_base+'/map/cache/package.tar.xz', headers=headers)
if r.status_code == 403:
logger.error('Rejected cache package download with Error 403. Tile secret is probably incorrect.')
return False
if r.status_code == 304:
if self.cache_package is not None:
logger.debug('Not modified.')
cache['cache_package_filename'] = self.cache_package_filename
return True
logger.error('Unexpected not modified.')
return False
r.raise_for_status()
except Exception as e:
logger.error('Cache package download failed: %s' % e)
return False
try:
self.cache_package = CachePackage.read(BytesIO(r.content))
self.cache_package_etag = r.headers.get('ETag', None)
except Exception as e:
logger.error('Cache package parsing failed: %s' % e)
return False
try:
self.cache_package_filename = os.path.join(
self.data_dir,
datetime.now().strftime('%Y-%m-%d_%H-%M-%S-%f')+'.pickle'
)
with open(self.cache_package_filename, 'wb') as f:
pickle.dump(self.cache_package, f)
cache.set('cache_package_filename', self.cache_package_filename)
except Exception as e:
self.cache_package_etag = None
logger.error('Saving pickled package failed: %s' % e)
return False
return True
def not_found(self, start_response, text):
start_response('404 Not Found', [self.get_date_header(),
('Content-Type', 'text/plain'),
('Content-Length', str(len(text)))])
return [text]
def deliver_tile(self, start_response, etag, data):
start_response('200 OK', [self.get_date_header(),
('Content-Type', 'image/png'),
('Content-Length', str(len(data))),
('Cache-Control', 'no-cache'),
('ETag', etag)])
return [data]
def get_cache_package(self):
cache_package_filename = self.cache.get('cache_package_filename')
if cache_package_filename is None:
logger.warning('cache_package_filename went missing.')
return self.cache_package
if self.cache_package_filename != cache_package_filename:
logger.debug('Loading new cache package in worker.')
self.cache_package_filename = cache_package_filename
with open(self.cache_package_filename, 'rb') as f:
self.cache_package = pickle.load(f)
return self.cache_package
cache_lock = multiprocessing.Lock()
def __call__(self, env, start_response):
path_info = env['PATH_INFO']
match = self.path_regex.match(path_info)
if match is None:
return self.not_found(start_response, b'invalid tile path.')
level, zoom, x, y = match.groups()
zoom = int(zoom)
if not (-2 <= zoom <= 5):
return self.not_found(start_response, b'zoom out of bounds.')
# do this to be thread safe
cache_package = self.get_cache_package()
# check if bounds are valid
x = int(x)
y = int(y)
minx, miny, maxx, maxy = get_tile_bounds(zoom, x, y)
if not cache_package.bounds_valid(minx, miny, maxx, maxy):
return self.not_found(start_response, b'coordinates out of bounds.')
# get level
level = int(level)
level_data = cache_package.levels.get(level)
if level_data is None:
return self.not_found(start_response, b'invalid level.')
# build cache keys
last_update = level_data.history.last_update(minx, miny, maxx, maxy)
base_cache_key = build_base_cache_key(last_update)
# decode access permissions
access_permissions = set()
access_cache_key = '0'
cookie = env.get('HTTP_COOKIE', None)
if cookie:
cookie = self.cookie_regex.search(cookie)
if cookie:
cookie = cookie.group(2)
access_permissions = (parse_tile_access_cookie(cookie, self.tile_secret) &
set(level_data.restrictions[minx:maxx, miny:maxy]))
access_cache_key = build_access_cache_key(access_permissions)
# check browser cache
if_none_match = env.get('HTTP_IF_NONE_MATCH')
tile_etag = build_tile_etag(level, zoom, x, y, base_cache_key, access_cache_key, self.tile_secret)
if if_none_match == tile_etag:
start_response('304 Not Modified', [self.get_date_header(),
('Content-Length', '0'),
('ETag', tile_etag)])
return [b'']
cache_key = path_info+'_'+tile_etag
cached_result = self.cache.get(cache_key)
if cached_result is not None:
return self.deliver_tile(start_response, tile_etag, cached_result)
r = requests.get('%s/map/%d/%d/%d/%d/%s.png' % (self.upstream_base, level, zoom, x, y, access_cache_key),
headers=self.auth_headers)
if r.status_code == 200 and r.headers['Content-Type'] == 'image/png':
self.cache.set(cache_key, r.content)
return self.deliver_tile(start_response, tile_etag, r.content)
start_response('%d %s' % (r.status_code, r.reason), [
self.get_date_header(),
('Content-Length', len(r.content)),
('Content-Type', r.headers.get('Content-Type', 'text/plain'))
])
return [r.content]
application = TileServer()