Ignore proxy for cloud metadata retrieval

lib/facter/resolvers/az.rb

@@ -26,7 +26,7 @@ def read_facts(fact_name)
 
         def get_data_from(url)
           headers = { Metadata: 'true' }
-          Facter::Util::Resolvers::Http.get_request(url, headers, { session: determine_session_timeout })
+          Facter::Util::Resolvers::Http.get_request(url, headers, { session: determine_session_timeout }, http_port: nil, proxy_addr: nil)
         end
 
         def determine_session_timeout

lib/facter/resolvers/ec2.rb

@@ -52,7 +52,7 @@ def build_path_component(line)
         def get_data_from(url)
           headers = {}
           headers['X-aws-ec2-metadata-token'] = v2_token if v2_token
-          Facter::Util::Resolvers::Http.get_request(url, headers, { session: determine_session_timeout })
+          Facter::Util::Resolvers::Http.get_request(url, headers, { session: determine_session_timeout }, http_port: nil, proxy_addr: nil)
         end
 
         def determine_session_timeout

lib/facter/resolvers/gce.rb

@@ -22,7 +22,7 @@ def read_facts(fact_name)
         end
 
         def query_for_metadata
-          gce_data = extract_to_hash(Facter::Util::Resolvers::Http.get_request(METADATA_URL, HEADERS))
+          gce_data = extract_to_hash(Facter::Util::Resolvers::Http.get_request(METADATA_URL, HEADERS, http_port: nil, proxy_addr: nil))
           parse_instance(gce_data)
 
           gce_data.empty? ? nil : gce_data

lib/facter/util/resolvers/http.rb

@@ -9,35 +9,45 @@ module Http
         class << self
           CONNECTION_TIMEOUT = 0.6
           SESSION_TIMEOUT = 5
+          DEFAULT_HOST = Object.new.freeze
 
-          # Makes a GET http request and returns its response.
+          # Makes a GET HTTP request and returns its response.
           #
-          # Params:
-          # url: String which contains the address to which the request will be made
-          # headers: Hash which contains the headers you need to add to your request.
-          #          Default headers is an empty hash
-          #          Example: { "Accept": 'application/json' }
-          # timeouts: Hash that includes the values for the session and connection timeouts.
-          #          Example: { session: 2.4. connection: 5 }
-          #
-          # Return value:
-          # is a string with the response body if the response code is 200.
-          # If the response code is not 200, an empty string is returned.
-          def get_request(url, headers = {}, timeouts = {})
-            make_request(url, headers, timeouts, 'GET')
+          # @note This method uses an empty DEFAULT_HOST constant to provide a
+          #   way to override the http_proxy environment variable without
+          #   interfering with other behaviors (such as connecting to a
+          #   loopback address or using the no_proxy environment variable).
+          # @param url [String] the address to which the request will be made.
+          # @param headers [Hash] the headers you need to add to your request.
+          #   Defaults to an empty hash.
+          # @param timesouts [Hash] Values for the session and connection
+          #   timeouts.
+          # @param http_port [Integer] The port number used to make the
+          #   request. Defaults to 80.
+          # @param proxy_addr [String] The address of a proxy host.
+          # @returns [String] the response body if the response code is 200.
+          #   If the response code is not 200, an empty string is returned.
+          # @example
+          #   get_request('https://example.com', { "Accept": 'application/json' }, { session: 2.4, connection: 5 })
+          def get_request(url, headers = {}, timeouts = {}, http_port: 80, proxy_addr: DEFAULT_HOST)
+            make_request(url, headers, timeouts, 'GET', http_port, proxy_addr)
           end
 
-          def put_request(url, headers = {}, timeouts = {})
-            make_request(url, headers, timeouts, 'PUT')
+          # Makes a PUT HTTP request and returns its response
+          # @param (see #get_request)
+          # @return (see #get_request)
+          def put_request(url, headers = {}, timeouts = {}, http_port: 80, proxy_addr: DEFAULT_HOST)
+            make_request(url, headers, timeouts, 'PUT', http_port, proxy_addr)
           end
 
           private
 
-          def make_request(url, headers, timeouts, request_type)
+          # rubocop:disable Metrics/ParameterLists
+          def make_request(url, headers, timeouts, request_type, http_port, proxy_addr)
             require 'net/http'
 
             uri = URI.parse(url)
-            http = http_obj(uri, timeouts)
+            http = http_obj(uri, timeouts, http_port, proxy_addr)
             request = request_obj(headers, uri, request_type)
 
             # The Windows implementation of sockets does not respect net/http
@@ -55,9 +65,14 @@ def make_request(url, headers, timeouts, request_type)
             @log.debug("Trying to connect to #{url} but got: #{e.message}")
             ''
           end
-
-          def http_obj(parsed_url, timeouts)
-            http = Net::HTTP.new(parsed_url.host)
+          # rubocop:enable Metrics/ParameterLists
+
+          def http_obj(parsed_url, timeouts, http_port, proxy_addr)
+            http = if proxy_addr == DEFAULT_HOST
+                     Net::HTTP.new(parsed_url.host)
+                   else
+                     Net::HTTP.new(parsed_url.host, http_port, proxy_addr)
+                   end
             http.read_timeout = timeouts[:session] || SESSION_TIMEOUT
             http.open_timeout = timeouts[:connection] || CONNECTION_TIMEOUT