blob: 8d25d4218fe3d28211081f1681f7af77e27fda03 [file] [log] [blame]
#!/usr/bin/env python
#
# Copyright 2007 Google Inc.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
#
"""HTTP utils for devappserver."""
import contextlib
import httplib
import socket
import time
class Error(Exception):
"""Base class for errors in this module."""
class HostNotReachable(Error):
"""Raised if host can't be reached at given port."""
def wait_for_connection(host, port, retries=1):
"""Tries to connect to the given host and port.
Retries until success or number of retires is used up.
Args:
host: str, Host to connect to.
port: int, Port to connect to.
retries: int, Number of connection retries.
Raises:
HostNotReachable: if host:port can't be reached after given number of
retries.
"""
def ping():
connection = httplib.HTTPConnection(host, port)
with contextlib.closing(connection):
try:
connection.connect()
except (socket.error, httplib.HTTPException):
return False
else:
return True
while not ping() and retries > 0:
retries -= 1
if not retries:
raise HostNotReachable(
'Cannot connect to the instance on {host}:{port}'.format(
host=host, port=port))
time.sleep(1)