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module AWS
module Autoscaling
# Which host FQDN will we connect to for all API calls to AWS?
# If AS_URL is defined in the users ENV we can override the default with that.
#
# @example
# export AS_URL='http://autoscaling.amazonaws.com'
if ENV['AS_URL']
AS_URL = ENV['AS_URL']
DEFAULT_HOST = URI.parse(AS_URL).host
else
# Default US API endpoint
DEFAULT_HOST = 'autoscaling.amazonaws.com'
end
API_VERSION = '2009-05-15'
class Base < AWS::Base
def api_version
API_VERSION
end
def default_host
DEFAULT_HOST
end
# Raises the appropriate error if the specified Net::HTTPResponse object
# contains an Amazon EC2 error; returns +false+ otherwise.
def aws_error?(response)
# return false if we got a HTTP 200 code,
# otherwise there is some type of error (40x,50x) and
# we should try to raise an appropriate exception
# from one of our exception classes defined in
# exceptions.rb
return false if response.is_a?(Net::HTTPSuccess)
# parse the XML document so we can walk through it
doc = REXML::Document.new(response.body)
# Check that the Error element is in the place we would expect.
# and if not raise a generic error exception
unless doc.root.elements[1].name == "Error"
raise Error, "Unexpected error format. response.body is: #{response.body}"
end
# An valid error response looks like this:
# <?xml version="1.0"?><Response><Errors><Error><Code>InvalidParameterCombination</Code><Message>Unknown parameter: foo</Message></Error></Errors><RequestID>291cef62-3e86-414b-900e-17246eccfae8</RequestID></Response>
# AWS EC2 throws some exception codes that look like Error.SubError. Since we can't name classes this way
# we need to strip out the '.' in the error 'Code' and we name the error exceptions with this
# non '.' name as well.
error_code = doc.root.elements['//ErrorResponse/Error/Code'].text.gsub('.', '')
error_message = doc.root.elements['//ErrorResponse/Error/Message'].text
# Raise one of our specific error classes if it exists.
# otherwise, throw a generic EC2 Error with a few details.
if AWS.const_defined?(error_code)
raise AWS.const_get(error_code), error_message
else
raise AWS::Error, error_message
end
end
end
end
end
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