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# -------------------------------------------------------------------------
# Copyright (c) 2015-2017 AT&T Intellectual Property
#
# 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.
#
# -------------------------------------------------------------------------
#
import requests
from osdf.utils.data_types import list_like
from osdf.operation.exceptions import MessageBusConfigurationException
class MessageRouterClient(object):
def __init__(self,
dmaap_url=None,
mr_host_base_urls=None,
topic=None,
consumer_group=None, consumer_id=None,
timeout_ms=15000, fetch_limit=1000,
userid=None, passwd=None):
"""
:param dmaap_url: protocol, host and port; mostly for UEB
(e.g. https://dcae-msrt-ftl.homer.att.com:3905/)
:param mr_host_base_urls: for DMaaP, we get a topic URL (base_url + events/topic_name)
(e.g. https://dcae-msrt-ftl.homer.att.com:3905/events/com.att.dcae.dmaap.FTL.SNIRO-CM-SCHEDULER-RESPONSE)
:param consumer_group: DMaaP/UEB consumer group (unique for each subscriber; required for GET)
:param consumer_id: DMaaP/UEB consumer ID (unique for each thread/process for a subscriber; required for GET)
:param timeout_ms: (optional, default 15 seconds or 15,000 ms) server-side timeout for GET request
:param fetch_limit: (optional, default 1000 messages per request for GET), ignored for "POST"
:param userid: (optional, userid for HTTP basic authentication)
:param passwd: (optional, password for HTTP basic authentication)
"""
mr_error = MessageBusConfigurationException
if dmaap_url is None: # definitely not DMaaP, so use UEB mode
self.is_dmaap = False
if not (mr_host_base_urls and list_like(mr_host_base_urls)):
raise mr_error("Not a DMaaP or UEB configuration")
if not topic:
raise mr_error("Invalid topic: '{}'",format(topic))
self.topic_urls = ["{}/events/{}".format(base_url, topic) for base_url in mr_host_base_urls]
else:
self.is_dmaap = True
self.topic_urls = [dmaap_url]
self.timeout_ms = timeout_ms
self.fetch_limit = fetch_limit
self.auth = (userid, passwd) if userid and passwd else None
self.consumer_group = consumer_group
self.consumer_id = consumer_id
def get(self, outputjson=True):
"""Fetch messages from message router (DMaaP or UEB)
:param outputjson: (optional, specifies if response is expected to be in json format), ignored for "POST"
:return: response as a json object (if outputjson is True) or as a string
"""
url_fmt = "{topic_url}/{cgroup}/{cid}?timeout={timeout_ms}&limit={limit}"
urls = [url_fmt.format(topic_url=x, timeout_ms=self.timeout_ms, limit=self.fetch_limit,
cgroup=self.consumer_group, cid=self.consumer_id) for x in self.topic_urls]
for url in urls[:-1]:
try:
return self.http_request(method='GET', url=url, outputjson=outputjson)
except:
pass
return self.http_request(method='GET', url=urls[-1], outputjson=outputjson)
def post(self, msg, inputjson=True):
for url in self.topic_urls[:-1]:
try:
return self.http_request(method='POST', url=url, inputjson=inputjson, msg=msg)
except:
pass
return self.http_request(method='POST', url=self.topic_urls[-1], inputjson=inputjson, msg=msg)
def http_request(self, url, method, inputjson=True, outputjson=True, msg=None, **kwargs):
"""
Perform the actual URL request (GET or POST), and do error handling
:param url: full URL (including topic, limit, timeout, etc.)
:param method: GET or POST
:param inputjson: Specify whether input is in json format (valid only for POST)
:param outputjson: Is response expected in a json format
:param msg: content to be posted (valid only for POST)
:return: response as a json object (if outputjson or POST) or as a string; None if error
"""
res = requests.request(url=url, method=method, auth=self.auth, **kwargs)
if res.status_code == requests.codes.ok:
return res.json() if outputjson or method == "POST" else res.content
else:
raise Exception("HTTP Response Error: code {}; headers:{}, content: {}".format(
res.status_code, res.headers, res.content))
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