WALinuxAgent/azurelinuxagent/utils/restutil.py

# Microsoft Azure Linux Agent
#
# Copyright 2014 Microsoft Corporation
#
# 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.
#
# Requires Python 2.4+ and Openssl 1.0+
#

import time
import platform
import os
import subprocess
import azurelinuxagent.logger as logger
import azurelinuxagent.conf as conf
from azurelinuxagent.future import httpclient, urlparse

"""
REST api util functions
"""

RETRY_WAITING_INTERVAL = 10

class HttpError(Exception):
    pass

def _parse_url(url):
    o = urlparse(url)
    rel_uri = o.path
    if o.fragment:
        rel_uri = "{0}#{1}".format(rel_uri, o.fragment)
    if o.query:
        rel_uri = "{0}?{1}".format(rel_uri, o.query)
    secure = False
    if o.scheme.lower() == "https":
        secure = True
    return o.hostname, o.port, secure, rel_uri

def get_http_proxy():
    """
    Get http_proxy and https_proxy from environment variables.
    Username and password is not supported now.
    """
    host = conf.get("HttpProxy.Host", None)
    port = conf.get("HttpProxy.Port", None)
    return (host, port)

def _http_request(method, host, rel_uri, port=None, data=None, secure=False,
                 headers=None, proxy_host=None, proxy_port=None):
    url, conn = None, None
    if secure:
        port = 443 if port is None else port
        if proxy_host is not None and proxy_port is not None:
            conn = httpclient.HTTPSConnection(proxy_host, proxy_port)
            conn.set_tunnel(host, port)
            #If proxy is used, full url is needed.
            url = "https://{0}:{1}{2}".format(host, port, rel_uri)
        else:
            conn = httpclient.HTTPSConnection(host, port, timeout=10)
            url = rel_uri
    else:
        port = 80 if port is None else port
        if proxy_host is not None and proxy_port is not None:
            conn = httpclient.HTTPConnection(proxy_host, proxy_port)
            #If proxy is used, full url is needed.
            url = "http://{0}:{1}{2}".format(host, port, rel_uri)
        else:
            conn = httpclient.HTTPConnection(host, port, timeout=10)
            url = rel_uri
    if headers == None:
        conn.request(method, url, data)
    else:
        conn.request(method, url, data, headers)
    resp = conn.getresponse()
    return resp

def http_request(method, url, data, headers=None, max_retry=3, chk_proxy=False):
    """
    Sending http request to server
    On error, sleep 10 and retry max_retry times.
    """
    logger.verb("HTTP Req: {0} {1}", method, url)
    logger.verb("    Data={0}", data)
    logger.verb("    Header={0}", headers)
    host, port, secure, rel_uri = _parse_url(url)

    #Check proxy
    proxy_host, proxy_port = (None, None)
    if chk_proxy:
        proxy_host, proxy_port = get_http_proxy()

    #If httplib module is not built with ssl support. Fallback to http
    if secure and not hasattr(httpclient, "HTTPSConnection"):
        logger.warn("httplib is not built with ssl support")
        secure = False

    #If httplib module doesn't support https tunnelling. Fallback to http
    if secure and \
            proxy_host is not None and \
            proxy_port is not None and \
            not hasattr(httpclient.HTTPSConnection, "set_tunnel"):
        logger.warn("httplib doesn't support https tunnelling(new in python 2.7)")
        secure = False

    for retry in range(0, max_retry):
        try:
            resp = _http_request(method, host, rel_uri, port=port, data=data, 
                                 secure=secure, headers=headers, 
                                 proxy_host=proxy_host, proxy_port=proxy_port)
            logger.verb("HTTP Resp: Status={0}", resp.status)
            logger.verb("    Header={0}", resp.getheaders())
            return resp
        except httpclient.HTTPException as e:
            logger.warn('HTTPException {0}, args:{1}', e, repr(e.args))
        except IOError as e:
            logger.warn('Socket IOError {0}, args:{1}', e, repr(e.args))

        if retry < max_retry - 1:
            logger.info("Retry={0}, {1} {2}", retry, method, url)
            time.sleep(RETRY_WAITING_INTERVAL)

    raise HttpError("HTTP Err: {0} {1}".format(method, url))

def http_get(url, headers=None, max_retry=3, chk_proxy=False):
    return http_request("GET", url, data=None, headers=headers, 
                        max_retry=max_retry, chk_proxy=chk_proxy)

def http_head(url, headers=None, max_retry=3, chk_proxy=False):
    return http_request("HEAD", url, None, headers=headers, 
                        max_retry=max_retry, chk_proxy=chk_proxy)

def http_post(url, data, headers=None, max_retry=3, chk_proxy=False):
    return http_request("POST", url, data, headers=headers, 
                        max_retry=max_retry, chk_proxy=chk_proxy)

def http_put(url, data, headers=None, max_retry=3, chk_proxy=False):
    return http_request("PUT", url, data, headers=headers, 
                        max_retry=max_retry, chk_proxy=chk_proxy)

def http_delete(url, headers=None, max_retry=3, chk_proxy=False):
    return http_request("DELETE", url, None, headers=headers, 
                        max_retry=max_retry, chk_proxy=chk_proxy)

#End REST api util functions