#!/usr/bin/env python

# Copyright 2012-2013 Amazon.com, Inc. or its affiliates. All Rights Reserved.

#

# Licensed under the Apache License, Version 2.0 (the "License"). You

# may not use this file except in compliance with the License. A copy of

# the License is located at

#

# http://aws.amazon.com/apache2.0/

#

# or in the "license" file accompanying this file. This file 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 logging

import os

import requests

import six

logger = logging.getLogger(__name__)

class ResourceLoadingError(Exception):

pass

def get_paramfile(session, path):

"""

It is possible to pass parameters to operations by referring

to files or URI's. If such a reference is detected, this

function attempts to retrieve the data from the file or URI

and returns it. If there are any errors or if the ``path``

does not appear to refer to a file or URI, a ``None`` is

returned.

"""

data = None

if isinstance(path, six.string_types):

for prefix in PrefixMap:

if path.startswith(prefix):

data = PrefixMap[prefix](session, prefix, path)

return data

def get_file(session, prefix, path):

file_path = path[len(prefix):]

file_path = os.path.expanduser(file_path)

file_path = os.path.expandvars(file_path)

if not os.path.isfile(file_path):

raise ResourceLoadingError("file does not exist: %s" % file_path)

try:

with open(file_path) as f:

return f.read()

except (OSError, IOError) as e:

raise ResourceLoadingError('Unable to load paramfile %s: %s' % (

path, e))

def get_uri(session, prefix, uri):

try:

r = requests.get(uri)

if r.status_code == 200:

return r.text

else:

raise ResourceLoadingError(

"received non 200 status code of %s" % (

r.status_code))

except Exception as e:

raise ResourceLoadingError('Unable to retrieve %s: %s' % (uri, e))

PrefixMap = {'file://': get_file,

'http://': get_uri,

'https://': get_uri}