(PUP-11900) Notify when X-Puppet-Compiler-Name header found

This change will emit a notice when http traffic from a puppetserver
sends the `X-Puppet-Compiler-Name` header; this should help for
debugging purposes when troubleshooting compilation issues and
several compilers are behind a load balancer.

lib/puppet/http/session.rb

@@ -90,6 +90,9 @@ def process_response(response)
       site = Puppet::HTTP::Site.from_uri(response.url)
       @server_versions[site] = version
     end
+    if (compiler = response['X-Puppet-Compiler-Name'])
+      Puppet.notice("Catalog compiled by #{compiler}")
+    end
   end
 
   # Determine if a session supports a capability. Depending on the server version

spec/integration/application/agent_spec.rb

@@ -33,6 +33,19 @@ def copy_fixtures(sources, dest)
     end
   end
 
+  context 'server identification' do
+    it 'emits a notice if the server sends the X-Puppet-Compiler-Name header' do
+      server.start_server do |port|
+        Puppet[:serverport] = port
+        expect {
+          agent.command_line.args << '--test'
+          agent.run
+        }.to exit_with(0)
+               .and output(%r{Notice: Catalog compiled by test-compiler-hostname}).to_stdout
+      end
+    end
+  end
+
   context 'server_list' do
     it "uses the first server in the list" do
       Puppet[:server_list] = '127.0.0.1'

spec/lib/puppet_spec/puppetserver.rb

@@ -19,6 +19,7 @@ def do_GET request, response
   class CatalogServlet < WEBrick::HTTPServlet::AbstractServlet
     def do_POST request, response
       response['Content-Type'] = 'application/json'
+      response['X-Puppet-Compiler-Name'] = 'test-compiler-hostname'
       catalog = Puppet::Resource::Catalog.new(Puppet[:certname], 'production')
       response.body = catalog.render(:json)
     end

spec/unit/http/session_spec.rb

@@ -222,7 +222,10 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
   end
 
   context 'when retrieving capabilities' do
-    let(:response) { Puppet::HTTP::Response.new(uri, 200, 'OK') }
+    let(:response) { Puppet::HTTP::ResponseNetHTTP.new(uri,
+                                                       Net::HTTPResponse.new('http_version',
+                                                                             200,
+                                                                             "OK")) }
 
     let(:session) do
       resolver = DummyResolver.new(good_service)
@@ -244,6 +247,7 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
       end
 
       it "supports locales if the cached service's version is 5.3.4 or greater" do
+        allow(response).to receive(:[]).and_call_original
         allow(response).to receive(:[]).with('X-Puppet-Version').and_return('5.3.4')
 
         session.route_to(:puppet)
@@ -253,6 +257,7 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
       end
 
       it "does not support locales if the cached service's version is 5.3.3" do
+        allow(response).to receive(:[]).and_call_original
         allow(response).to receive(:[]).with('X-Puppet-Version').and_return('5.3.3')
 
         session.route_to(:puppet)
@@ -262,6 +267,7 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
       end
 
       it "does not support locales if the cached service's version is missing" do
+        allow(response).to receive(:[]).and_call_original
         allow(response).to receive(:[]).with('X-Puppet-Version').and_return(nil)
 
         session.route_to(:puppet)
@@ -279,6 +285,7 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
       end
 
       it "supports json if the cached service's version is 5 or greater" do
+        allow(response).to receive(:[]).and_call_original
         allow(response).to receive(:[]).with('X-Puppet-Version').and_return('5.5.12')
 
         session.route_to(:puppet)
@@ -288,6 +295,7 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
       end
 
       it "does not support json if the cached service's version is less than 5.0" do
+        allow(response).to receive(:[]).and_call_original
         allow(response).to receive(:[]).with('X-Puppet-Version').and_return('4.10.1')
 
         session.route_to(:puppet)
@@ -297,6 +305,7 @@ def resolve(session, name, ssl_context: nil, canceled_handler: nil)
       end
 
       it "supports json if the cached service's version is missing" do
+        allow(response).to receive(:[]).and_call_original
         allow(response).to receive(:[]).with('X-Puppet-Version').and_return(nil)
 
         session.route_to(:puppet)