provisioners/ansible: show ansible-playbook in use

Motivation:
By printing out the ansible command used behind the scene, we can ease
the support effort to very quickly identify whether a problem is due to
Vagrant provisioner or Ansible itself.

plugins/provisioners/ansible/provisioner.rb

@@ -66,6 +66,8 @@ module VagrantPlugins
         # Support Multiple SSH keys and SSH forwarding:
         env["ANSIBLE_SSH_ARGS"] = ansible_ssh_args unless ansible_ssh_args.empty?
 
+        show_ansible_playbook_command(env, command) if config.verbose
+
         # Write stdout and stderr data, since it's the regular Ansible output
         command << {
           :env => env,
@@ -213,6 +215,30 @@ module VagrantPlugins
       def as_array(v)
         v.kind_of?(Array) ? v : [v]
       end
+
+      def show_ansible_playbook_command(env, command)
+        shell_command = ''
+        env.each_pair do |k, v|
+          if k == 'ANSIBLE_SSH_ARGS'
+            shell_command += "#{k}='#{v}' "
+          else
+            shell_command += "#{k}=#{v} "
+          end
+        end
+
+        shell_arg = []
+        command.each do |arg|
+          if arg =~ /(--start-at-task|--limit)=(.+)/
+            shell_arg << "#{$1}='#{$2}'"
+          else
+            shell_arg << arg
+          end
+        end
+
+        shell_command += shell_arg.join(' ')
+
+        @machine.env.ui.detail(shell_command)
+      end
     end
   end
 end

test/unit/plugins/provisioners/ansible/provisioner_test.rb

@@ -226,6 +226,12 @@ VF
           expect(args.length).to be > 0
         }
       end
+
+      it "does not show the ansible-playbook command" do
+        expect(machine.env.ui).not_to receive(:detail).with { |full_command|
+          expect(full_command).to include("ansible-playbook")
+        }
+      end
     end
 
     describe "with groups option" do
@@ -459,11 +465,30 @@ VF
       end
     end
 
+    describe "with verbose option" do
+      before do
+        config.verbose = 'v'
+      end
+
+      it_should_set_arguments_and_environment_variables 6
+      it_should_set_optional_arguments({ "verbose" => "-v" })
+
+      it "shows the ansible-playbook command" do
+        expect(machine.env.ui).to receive(:detail).with { |full_command|
+          expect(full_command).to eq("ANSIBLE_FORCE_COLOR=true ANSIBLE_HOST_KEY_CHECKING=false PYTHONUNBUFFERED=1 ansible-playbook --private-key=/path/to/my/key --user=testuser --limit='machine1' --inventory-file=#{generated_inventory_dir} -v playbook.yml")
+        }
+      end
+    end
+
     # Note:
     # The Vagrant Ansible provisioner does not validate the coherency of argument combinations,
     # and let ansible-playbook complain.
     describe "with a maximum of options" do
       before do
+        # vagrant general options
+        ssh_info[:forward_agent] = true
+        ssh_info[:private_key_path] = ['/my/key1', '/my/key2']
+
         # command line arguments
         config.extra_vars = "@#{existing_file}"
         config.sudo = true
@@ -505,6 +530,12 @@ VF
           expect(args).to include("--why-not")
         }
       end
+
+      it "shows the ansible-playbook command, with additional quotes when required" do
+        expect(machine.env.ui).to receive(:detail).with { |full_command|
+          expect(full_command).to eq("ANSIBLE_FORCE_COLOR=true ANSIBLE_HOST_KEY_CHECKING=true PYTHONUNBUFFERED=1 ANSIBLE_SSH_ARGS='-o IdentityFile=/my/key2 -o ForwardAgent=yes -o ControlMaster=no -o ControlMaster=auto -o ControlPersist=60s' ansible-playbook --private-key=/my/key1 --user=testuser --connection=ssh --why-not --su-user=foot --ask-su-pass --limit='all' --inventory-file=#{generated_inventory_dir} --extra-vars=@#{File.expand_path(__FILE__)} --sudo --sudo-user=deployer -vvv --ask-sudo-pass --ask-vault-pass --vault-password-file=#{File.expand_path(__FILE__)} --tags=db,www --skip-tags=foo,bar --limit='machine*:&vagrant:!that_one' --start-at-task='an awesome task' playbook.yml")
+        }
+      end
     end
 
   end