/
service.py
executable file
·280 lines (222 loc) · 8.77 KB
/
service.py
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
#!/usr/bin/env python
"""
Service to render pngs from vector tiles using Carto CSS.
"""
import json
from urllib.parse import quote_plus
from tornado import web, escape
from tornado.httpclient import AsyncHTTPClient, HTTPRequest
from tornado.ioloop import IOLoop
from tornado.options import define, parse_command_line, options
import mapnik # pylint: disable=import-error
import msgpack
from carto_renderer.errors import BadRequest, PayloadKeyError, ServiceError
from carto_renderer.util import get_logger, init_logging, LogWrapper
from carto_renderer.version import BUILD_TIME, SEMANTIC
__package__ = 'carto_renderer' # pylint: disable=redefined-builtin
# Variables for Vector Tiles.
BASE_ZOOM = 29
TILE_ZOOM_FACTOR = 16
TILE_SIZE = 256
def render_png(tile, _zoom, xml, overscan):
"""
Render the tile as a .png
TODO: Actually handling zoom levels.
"""
# mapnik is installed in a non-standard way.
# It confuses pylint.
# pylint: disable=no-member,too-many-locals
map_tile_size = TILE_SIZE + (overscan * 2)
logger = get_logger()
ctx = mapnik.Context()
map_tile = mapnik.Map(map_tile_size, map_tile_size)
# scale_denom = 1 << (BASE_ZOOM - int(zoom or 1))
# scale_factor = scale_denom / map_tile.scale_denominator()
# map_tile.zoom(scale_factor) # Is overriden by zoom_to_box.
mapnik.load_map_from_string(map_tile, xml)
box_min = -overscan
box_max = TILE_SIZE + overscan - 1
map_tile.zoom_to_box(mapnik.Box2d(box_min, box_min, box_max, box_max))
for (name, features) in list(tile.items()):
source = mapnik.MemoryDatasource()
map_layer = mapnik.Layer(name)
map_layer.datasource = source
for feature in features:
feat = mapnik.Feature(ctx, 0)
try:
feat.geometry = mapnik.Geometry.from_wkb(feature)
except RuntimeError:
try:
wkt = mapnik.Geometry.from_wkb(feature).to_wkt()
logger.error('Invalid feature: %s', wkt)
except RuntimeError:
logger.error('Corrupt feature: %s', feature.encode('hex'))
source.add_feature(feat)
map_layer.styles.append(name)
map_tile.layers.append(map_layer)
image = mapnik.Image(TILE_SIZE, TILE_SIZE)
# tile, image, scale, offset_x, offset_y
mapnik.render(map_tile, image, 1, overscan, overscan)
return image.tostring('png')
class BaseHandler(web.RequestHandler):
# pylint: disable=abstract-method
"""
Convert ServiceErrors to HTTP errors.
"""
def extract_body(self):
"""
Extract the body from self.request as a dictionary.
"""
logger = get_logger(self)
request_id = self.request.headers.get('x-socrata-requestid', '')
LogWrapper.ENV['X-Socrata-RequestId'] = request_id
content_type = self.request.headers.get('content-type', '').lower()
if not content_type.startswith('application/octet-stream'):
message = 'Invalid Content-Type: "{ct}"; ' + \
'expected"application/octet-stream"'
logger.warn('Invalid Content-Type: "%s"', content_type)
raise BadRequest(message.format(ct=content_type))
body = self.request.body
try:
extracted = msgpack.loads(body, raw=True)
except Exception:
logger.warn('Invalid message')
raise BadRequest('Could not parse message.', escape.to_unicode(body))
return extracted
def _handle_request_exception(self, err):
"""
Convert ServiceErrors to HTTP errors.
"""
logger = get_logger(self)
payload = {}
logger.exception(err)
if isinstance(err, ServiceError):
status_code = err.status_code
payload['message'] = err.message
if err.request_body:
payload['request_body'] = err.request_body
else:
payload['message'] = str(err)
status_code = 500
payload['resultCode'] = status_code
self.clear()
self.set_status(status_code)
self.write(json.dumps(payload))
self.finish()
class VersionHandler(BaseHandler):
# pylint: disable=abstract-method
"""
Return the version of the service, currently hardcoded.
"""
import sys
(major, minor, micro, _, _) = sys.version_info
version = {'health': 'alive',
'pythonVersion': '{}.{}.{}'.format(major, minor, micro),
'version': SEMANTIC,
'buildTime': BUILD_TIME}
def get(self):
"""
Return the version of the service, currently hardcoded.
"""
request_id = self.request.headers.get('x-socrata-requestid', '')
LogWrapper.ENV['X-Socrata-RequestId'] = request_id
logger = get_logger(self)
logger.info('Alive!')
self.write(VersionHandler.version)
self.finish()
class RenderHandler(BaseHandler):
# pylint: disable=abstract-method, arguments-differ
"""
Actually render the png.
Expects a dictionary with 'style', 'zoom', and 'tile' values.
"""
keys = [b'tile', b'zoom', b'style']
def initialize(self, http_client, style_host, style_port):
"""Magic Tornado __init__ replacement."""
self.http_client = http_client # pragma: no cover
self.style_host = style_host # pragma: no cover
self.style_port = style_port # pragma: no cover
# @web.asynchronous
async def post(self):
"""
Actually render the png.
Expects a JSON blob with 'style', 'zoom', and 'tile' values.
"""
logger = get_logger(self)
geobody = self.extract_body()
if not all([k in geobody for k in self.keys]):
logger.warn('Invalid JSON: %s', geobody)
raise PayloadKeyError(self.keys, geobody)
else:
try:
overscan = int(geobody[b'overscan'])
except:
logger.warn('Invalid JSON; overscan must be an integer: %s',
geobody)
raise BadRequest('"overscan" must be an integer',
request_body=geobody)
try:
zoom = int(geobody[b'zoom'])
except:
logger.warn('Invalid JSON; zoom must be an integer: %s',
geobody)
raise BadRequest('"zoom" must be an integer.',
request_body=geobody)
path = 'http://{host}:{port}/style?style={css}'.format(
host=self.style_host,
port=self.style_port,
css=quote_plus(geobody[b'style']))
tile = geobody[b'tile']
def handle_response(response):
"""
Process the XML returned by the style renderer.
"""
if response.body is None:
raise ServiceError(
"Failed to contact style-renderer at '{url}'".format(
url=path),
503)
xml = response.body
logger.info('zoom: %d, num features: %d, len(xml): %d',
zoom,
sum([len(layer) for layer in list(tile.values())]),
len(xml))
logger.debug('xml: %s',
LogWrapper.Lazy(lambda: xml.replace('\n', ' ')))
self.write(render_png(tile, zoom, xml, overscan))
self.finish()
headers = LogWrapper.ENV \
if LogWrapper.ENV['X-Socrata-RequestId'] is not None \
else {}
req = HTTPRequest(path, headers=headers)
resp = await self.http_client.fetch(req)
handle_response(resp)
def main(): # pragma: no cover
"""
Actually fire up the web server.
Listens on 4096.
"""
define('port', default=4096)
define('style_host', default='localhost')
define('style_port', default=4097)
define('log_level', default='INFO')
define('log_format', default='%(asctime)s %(levelname)s [%(thread)d] ' +
'[%(X-Socrata-RequestId)s] %(name)s %(message)s')
parse_command_line()
init_logging()
routes = [
web.url(r'/', web.RedirectHandler, {'url': '/version'}),
web.url(r'/version', VersionHandler),
web.url(r'/render', RenderHandler, {
'style_host': options.style_host,
'style_port': options.style_port,
'http_client': AsyncHTTPClient()
}),
]
app = web.Application(routes)
app.listen(options.port)
logger = get_logger()
logger.info('Listening on localhost:4096...')
IOLoop.instance().start()
if __name__ == '__main__': # pragma: no cover
main()