Allow cloud metadata to ignore proxy settings

Prior to this commit, if the http_proxy environment variable was set for
Net::HTTP, cloud resolvers (ec2, GCE, Azure) would fail to resolve
metadata.

This commit adds a new positional argument to
Facter::Util::Resolvers::Http.get_request and #put_request to allow
those resolvers to disable proxy settings.

.rubocop_todo.yml

@@ -42,3 +42,11 @@ Style/Documentation:
     - 'spec_integration/**/*'
     - 'scripts/*'
     - 'install.rb'
+
+# While it would be preferable to use a keyword argument for the proxy setting in #get_request and #put_request, if we
+# add keyword arguments to those methods Ruby < 3 misinterprets earlier positional arguments as a keyword arguments.
+# This is because those positional arguments are hashes that use symbols as keys.
+# TODO: revisit this after we drop Ruby < 3 support.
+Style/OptionalBooleanParameter:
+  Exclude:
+    - 'lib/facter/util/resolvers/http.rb'

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 }, false)
         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 }, false)
         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, false))
           parse_instance(gce_data)
 
           gce_data.empty? ? nil : gce_data

lib/facter/util/resolvers/http.rb

@@ -17,28 +17,30 @@ class << self
           #   Defaults to an empty hash.
           # @param timeouts [Hash] Values for the session and connection
           #   timeouts.
+          # @param proxy [Boolean] Whether to use proxy settings when calling
+          #   Net::HTTP.new. Defaults to true.
           # @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 = {})
-            make_request(url, headers, timeouts, 'GET')
+          def get_request(url, headers = {}, timeouts = {}, proxy = true)
+            make_request(url, headers, timeouts, 'GET', proxy)
           end
 
           # Makes a PUT HTTP request and returns its response
           # @param (see #get_request)
           # @return (see #get_request)
-          def put_request(url, headers = {}, timeouts = {})
-            make_request(url, headers, timeouts, 'PUT')
+          def put_request(url, headers = {}, timeouts = {}, proxy = true)
+            make_request(url, headers, timeouts, 'PUT', proxy)
           end
 
           private
 
-          def make_request(url, headers, timeouts, request_type)
+          def make_request(url, headers, timeouts, request_type, proxy)
             require 'net/http'
 
             uri = URI.parse(url)
-            http = http_obj(uri, timeouts)
+            http = http_obj(uri, timeouts, proxy)
             request = request_obj(headers, uri, request_type)
 
             # The Windows implementation of sockets does not respect net/http
@@ -57,8 +59,16 @@ def make_request(url, headers, timeouts, request_type)
             ''
           end
 
-          def http_obj(parsed_url, timeouts)
-            http = Net::HTTP.new(parsed_url.host)
+          def http_obj(parsed_url, timeouts, proxy)
+            # If get_request or put_request are called and set proxy to false,
+            # manually set Net::HTTP.new's p_addr (proxy address) positional
+            # argument to nil to override anywhere else a proxy may be set
+            # (e.g. the http_proxy environment variable).
+            http = if proxy
+                     Net::HTTP.new(parsed_url.host)
+                   else
+                     Net::HTTP.new(parsed_url.host, 80, nil)
+                   end
             http.read_timeout = timeouts[:session] || SESSION_TIMEOUT
             http.open_timeout = timeouts[:connection] || CONNECTION_TIMEOUT
 

spec/facter/resolvers/az_spec.rb

@@ -8,7 +8,7 @@
 
   before do
     allow(Facter::Util::Resolvers::Http).to receive(:get_request)
-      .with(uri, { Metadata: 'true' }, { session: 5 }).and_return(output)
+      .with(uri, { Metadata: 'true' }, { session: 5 }, false).and_return(output)
     az.instance_variable_set(:@log, log_spy)
   end
 
@@ -24,6 +24,18 @@
     end
   end
 
+  context "when a proxy is set with ENV['http_proxy']" do
+    before do
+      stub_const('ENV', { 'http_proxy' => 'http://example.com' })
+    end
+
+    let(:output) { '{"azEnvironment":"AzurePublicCloud"}' }
+
+    it 'returns az metadata' do
+      expect(az.resolve(:metadata)).to eq({ 'azEnvironment' => 'AzurePublicCloud' })
+    end
+  end
+
   context 'when an exception is thrown' do
     let(:output) { '' }
 

spec/facter/resolvers/ec2_spec.rb

@@ -158,4 +158,16 @@
       expect(ec2.resolve(:userdata)).to eql(expected_str)
     end
   end
+
+  context "when a proxy is set with ENV['http_proxy']" do
+    before do
+      stub_const('ENV', { 'http_proxy' => 'http://example.com' })
+      stub_request(:put, token_uri).to_return(status: 200, body: token)
+    end
+
+    let(:headers) { { 'Accept' => '*/*' } }
+    let(:token) { 'v2_token' }
+
+    it_behaves_like 'ec2'
+  end
 end