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Implement method to create Cloudant client from VCAP services env
Add an additional method to parse a VCAP_SERVICES environment variable allowing easy binding of a service instance to a Cloud Foundry application. Fixes #254.
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‎requirements.txt‎

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requests >=2.7.0, <3.0.0
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‎src/cloudant/__init__.py‎

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import contextlib
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# pylint: disable=wrong-import-position
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from .client import Cloudant, CouchDB
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from ._common_util import CloudFoundryService
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@contextlib.contextmanager
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def cloudant(user, passwd, **kwargs):
@@ -61,6 +62,58 @@ def cloudant(user, passwd, **kwargs):
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yield cloudant_session
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cloudant_session.disconnect()
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@contextlib.contextmanager
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def cloudant_bluemix(bm_service_name=None, **kwargs):
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"""
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Provides a context manager to create a Cloudant session and provide access
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to databases, docs etc.
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:param str bm_service_name: Optional Bluemix service instance name. Only
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required if multiple Cloudant services are available.
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:param str encoder: Optional json Encoder object used to encode
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documents for storage. Defaults to json.JSONEncoder.
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Loads all configuration from the VCAP_SERVICES Cloud Foundry environment
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variable. The VCAP_SERVICES variable contains connection information to
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access a service instance. For example:
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.. code-block:: json
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{
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"VCAP_SERVICES": {
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"cloudantNoSQLDB": [
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{
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"credentials": {
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"username": "example",
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"password": "xxxxxxx",
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"host": "example.cloudant.com",
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"port": 443,
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"url": "https://example:[email protected]"
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},
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"syslog_drain_url": null,
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"label": "cloudantNoSQLDB",
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"provider": null,
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"plan": "Lite",
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"name": "Cloudant NoSQL DB"
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}
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]
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}
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}
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See `Cloud Foundry Environment Variables <http://docs.cloudfoundry.org/
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devguide/deploy-apps/environment-variable.html#VCAP-SERVICES>`_.
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"""
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service = CloudFoundryService(bm_service_name)
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cloudant_session = Cloudant(
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username=service.username,
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password=service.password,
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url=service.url,
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**kwargs
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)
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cloudant_session.connect()
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yield cloudant_session
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cloudant_session.disconnect()
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@contextlib.contextmanager
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def couchdb(user, passwd, **kwargs):
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"""

‎src/cloudant/_common_util.py‎

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throughout the library.
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"""
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import os
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import sys
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import platform
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from collections import Sequence
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import json
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from requests import Session
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from ._2to3 import STRTYPE, NONETYPE, UNITYPE, iteritems_, url_parse
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from .error import CloudantArgumentError
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from .error import CloudantArgumentError, CloudantException
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# Library Constants
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@@ -334,3 +335,69 @@ def request(self, method, url, **kwargs):
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resp = super(InfiniteSession, self).request(method, url, **kwargs)
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return resp
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class CloudFoundryService(object):
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""" Manages Cloud Foundry service configuration. """
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def __init__(self, name=None):
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try:
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services = json.loads(os.getenv('VCAP_SERVICES', '{}'))
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cloudant_services = services.get('cloudantNoSQLDB', [])
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# use first service if no name given and only one service present
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use_first = name is None and len(cloudant_services) == 1
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for service in cloudant_services:
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if use_first or service.get('name') == name:
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credentials = service['credentials']
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self._host = credentials['host']
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self._name = service.get('name')
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self._password = credentials['password']
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self._port = credentials.get('port', 443)
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self._username = credentials['username']
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break
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else:
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raise CloudantException('Missing service in VCAP_SERVICES')
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except KeyError as ex:
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raise CloudantException(
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"Invalid service: '{0}' missing".format(ex.args[0])
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)
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except TypeError:
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raise CloudantException(
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'Failed to decode VCAP_SERVICES service credentials'
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)
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except ValueError:
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raise CloudantException('Failed to decode VCAP_SERVICES JSON')
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@property
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def host(self):
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""" Return service host. """
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return self._host
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@property
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def name(self):
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""" Return service name. """
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return self._name
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@property
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def password(self):
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""" Return service password. """
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return self._password
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@property
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def port(self):
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""" Return service port. """
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return str(self._port)
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@property
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def url(self):
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""" Return service url. """
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return 'https://{0}:{1}'.format(self._host, self._port)
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@property
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def username(self):
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""" Return service username. """
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return self._username

‎tests/unit/cloud_foundry_tests.py‎

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#!/usr/bin/env python
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# Copyright (c) 2016 IBM. All rights reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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"""
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_cloud_foundry_tests_
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Unit tests for the CloudFoundryService class.
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"""
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import json
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import mock
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import unittest
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from cloudant._common_util import CloudFoundryService
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from cloudant.error import CloudantException
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class CloudFoundryServiceTests(unittest.TestCase):
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def __init__(self, *args, **kwargs):
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super(CloudFoundryServiceTests, self).__init__(*args, **kwargs)
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self._test_vcap_services_single = json.dumps({'cloudantNoSQLDB': [
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{
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'name': 'Cloudant NoSQL DB 1', # valid service
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'credentials': {
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'host': 'example.cloudant.com',
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'password': 'pa$$w0rd01',
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'port': 1234,
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'username': 'example'
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}
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}
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]})
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self._test_vcap_services_multiple = json.dumps({'cloudantNoSQLDB': [
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{
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'name': 'Cloudant NoSQL DB 1', # valid service
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'credentials': {
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'host': 'example.cloudant.com',
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'password': 'pa$$w0rd01',
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'port': 1234,
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'username': 'example'
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}
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},
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{
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'name': 'Cloudant NoSQL DB 2', # valid service, default port
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'credentials': {
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'host': 'example.cloudant.com',
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'password': 'pa$$w0rd01',
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'username': 'example'
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}
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},
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{
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'name': 'Cloudant NoSQL DB 3', # missing host
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'credentials': {
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'password': 'pa$$w0rd01',
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'port': 1234,
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'username': 'example'
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}
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},
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{
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'name': 'Cloudant NoSQL DB 4', # missing password
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'credentials': {
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'host': 'example.cloudant.com',
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'port': 1234,
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'username': 'example'
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}
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},
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{
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'name': 'Cloudant NoSQL DB 5', # missing username
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'credentials': {
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'host': 'example.cloudant.com',
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'password': 'pa$$w0rd01',
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'port': 1234,
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}
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},
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{
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'name': 'Cloudant NoSQL DB 6', # invalid credentials type
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'credentials': [
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'example.cloudant.com',
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'pa$$w0rd01',
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'example'
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]
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}
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]})
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@mock.patch('os.getenv')
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def test_get_vcap_service_default_success(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_single
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service = CloudFoundryService()
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self.assertEqual('Cloudant NoSQL DB 1', service.name)
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@mock.patch('os.getenv')
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def test_get_vcap_service_default_failure_multiple_services(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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with self.assertRaises(CloudantException) as cm:
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CloudFoundryService()
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self.assertEqual('Missing service in VCAP_SERVICES', str(cm.exception))
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@mock.patch('os.getenv')
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def test_get_vcap_service_instance_host(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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service = CloudFoundryService('Cloudant NoSQL DB 1')
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self.assertEqual('example.cloudant.com', service.host)
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@mock.patch('os.getenv')
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def test_get_vcap_service_instance_password(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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service = CloudFoundryService('Cloudant NoSQL DB 1')
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self.assertEqual('pa$$w0rd01', service.password)
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@mock.patch('os.getenv')
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def test_get_vcap_service_instance_port(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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service = CloudFoundryService('Cloudant NoSQL DB 1')
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self.assertEqual('1234', service.port)
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@mock.patch('os.getenv')
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def test_get_vcap_service_instance_port_default(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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service = CloudFoundryService('Cloudant NoSQL DB 2')
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self.assertEqual('443', service.port)
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@mock.patch('os.getenv')
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def test_get_vcap_service_instance_url(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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service = CloudFoundryService('Cloudant NoSQL DB 1')
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self.assertEqual('https://example.cloudant.com:1234', service.url)
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@mock.patch('os.getenv')
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def test_get_vcap_service_instance_username(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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service = CloudFoundryService('Cloudant NoSQL DB 1')
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self.assertEqual('example', service.username)
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@mock.patch('os.getenv')
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def test_raise_error_for_missing_host(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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with self.assertRaises(CloudantException):
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CloudFoundryService('Cloudant NoSQL DB 3')
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@mock.patch('os.getenv')
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def test_raise_error_for_missing_password(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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with self.assertRaises(CloudantException) as cm:
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CloudFoundryService('Cloudant NoSQL DB 4')
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self.assertEqual(
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"Invalid service: 'password' missing",
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str(cm.exception)
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)
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@mock.patch('os.getenv')
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def test_raise_error_for_missing_username(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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with self.assertRaises(CloudantException) as cm:
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CloudFoundryService('Cloudant NoSQL DB 5')
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self.assertEqual(
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"Invalid service: 'username' missing",
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str(cm.exception)
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)
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@mock.patch('os.getenv')
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def test_raise_error_for_invalid_credentials_type(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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with self.assertRaises(CloudantException) as cm:
175+
CloudFoundryService('Cloudant NoSQL DB 6')
176+
self.assertEqual(
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'Failed to decode VCAP_SERVICES service credentials',
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str(cm.exception)
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)
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@mock.patch('os.getenv')
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def test_raise_error_for_missing_service(self, m_getenv):
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m_getenv.return_value = self._test_vcap_services_multiple
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with self.assertRaises(CloudantException) as cm:
185+
CloudFoundryService('Cloudant NoSQL DB 7')
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self.assertEqual('Missing service in VCAP_SERVICES', str(cm.exception))

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