diff options
| -rw-r--r-- | fietsboek/views/tileproxy.py | 21 |
1 files changed, 20 insertions, 1 deletions
diff --git a/fietsboek/views/tileproxy.py b/fietsboek/views/tileproxy.py index 01dc9a9..5195c91 100644 --- a/fietsboek/views/tileproxy.py +++ b/fietsboek/views/tileproxy.py @@ -39,7 +39,16 @@ TILE_SOURCES = { } TTL = datetime.timedelta(days=7) +"""Time to live of cached tiles.""" + TIMEOUT = datetime.timedelta(seconds=1.5) +"""Timeout when requesting new tiles from a source server.""" + +PUNISHMENT_TTL = datetime.timedelta(minutes=10) +"""Block-out period after too many requests of a server have timed out.""" + +PUNISHMENT_THRESHOLD = 10 +"""Block a provider after that many requests have timed out.""" @view_config(route_name='tile-proxy', http_cache=3600) @@ -57,13 +66,21 @@ def tile_proxy(request): x, y, z = (int(request.matchdict['x']), int(request.matchdict['y']), int(request.matchdict['z'])) - cache_key = f"tile-{provider}-{x}-{y}-{z}" + cache_key = f"tile:{provider}-{x}-{y}-{z}" content_type = "image/png" cached = request.redis.get(cache_key) if cached is not None: return Response(cached, content_type=content_type) + timeout_tracker = f"provider-timeout:{provider}" + previous_timeouts = int(request.redis.get(timeout_tracker) or "0") + if previous_timeouts > PUNISHMENT_THRESHOLD: + # We've gotten too many timeouts from this provider recently, so avoid + # contacting it in the first place. + LOGGER.debug("Aborted attempt to contact %s due to previous timeouts", provider) + return HTTPGatewayTimeout(f"Avoiding request to {provider}") + url = TILE_SOURCES[provider].format(x=x, y=y, z=z, s=random.choice("abc")) headers = { "user-agent": f"Fietsboek-Tile-Proxy/{__VERSION__}", @@ -76,6 +93,8 @@ def tile_proxy(request): resp = requests.get(url, headers=headers, timeout=TIMEOUT.total_seconds()) except ReadTimeout: LOGGER.debug("Proxy timeout when accessing %r", url) + request.redis.incr(timeout_tracker) + request.redis.expire(timeout_tracker, PUNISHMENT_TTL) return HTTPGatewayTimeout(f"No response in time from {url}") else: request.redis.set(cache_key, resp.content, ex=TTL) |