provisioners/ansible_local: Optimize SSH commands

With this change, the same remote command is used to:
- verify that ansible is available
- gather the ansible version details

plugins/provisioners/ansible/provisioner/base.rb

@@ -52,7 +52,7 @@ module VagrantPlugins
           @gathered_version = nil
         end
 
-        def set_compatibility_mode
+        def set_and_check_compatibility_mode
           begin
             set_gathered_ansible_version(gather_ansible_version)
           rescue Exception => e

plugins/provisioners/ansible/provisioner/guest.rb

@@ -15,9 +15,8 @@ module VagrantPlugins
         end
 
         def provision
-          check_and_install_ansible
           check_files_existence
-          set_compatibility_mode
+          check_and_install_ansible
 
           execute_ansible_galaxy_on_guest if config.galaxy_role_file
           execute_ansible_playbook_on_guest
@@ -28,6 +27,8 @@ module VagrantPlugins
         #
         # This handles verifying the Ansible installation, installing it if it was
         # requested, and so on. This method will raise exceptions if things are wrong.
+        # The compatibility mode checks are also performed here in order to fetch the
+        # Ansible version information only once.
         #
         # Current limitations:
         #   - The installation of a specific Ansible version is only supported by
@@ -53,17 +54,13 @@ module VagrantPlugins
             @machine.guest.capability(:ansible_install, config.install_mode, config.version, config.pip_args)
           end
 
-          # Check that Ansible Playbook command is available on the guest
-          @machine.communicate.execute(
-            "test -x \"$(command -v #{config.playbook_command})\"",
-            error_class: Ansible::Errors::AnsibleNotFoundOnGuest,
-            error_key: :ansible_not_found_on_guest
-          )
+          # This step will also fetch the Ansible version data into related instance variables
+          set_and_check_compatibility_mode
 
           # Check if requested ansible version is available
           if (!config.version.empty? &&
               config.version.to_s.to_sym != :latest &&
-              !@machine.guest.capability(:ansible_installed, config.version))
+              config.version != @gathered_version)
             raise Ansible::Errors::AnsibleVersionMismatch,
               system: @control_machine,
               required_version: config.version,
@@ -73,14 +70,20 @@ module VagrantPlugins
 
         def gather_ansible_version
           raw_output = ""
-          result = @machine.communicate.execute("ansible --version", error_check: false) do |type, output|
+
+          result = @machine.communicate.execute(
+            "ansible --version",
+            error_class: Ansible::Errors::AnsibleNotFoundOnGuest,
+            error_key: :ansible_not_found_on_guest) do |type, output|
             if type == :stdout && output.lines[0]
               raw_output = output.lines[0]
             end
           end
+
           if result != 0
             raw_output = ""
           end
+
           raw_output
         end
 

plugins/provisioners/ansible/provisioner/host.rb

@@ -21,8 +21,7 @@ module VagrantPlugins
 
           warn_for_unsupported_platform
           check_files_existence
-          set_compatibility_mode
-          check_required_ansible_version
+          check_ansible_version_and_compatibility
 
           execute_ansible_galaxy_from_host if config.galaxy_role_file
           execute_ansible_playbook_from_host
@@ -38,7 +37,10 @@ module VagrantPlugins
           end
         end
 
-        def check_required_ansible_version
+        def check_ansible_version_and_compatibility
+          # This step will also fetch the Ansible version data into related instance variables
+          set_and_check_compatibility_mode
+
           # Skip this check when not required, nor possible
           if !@gathered_version || config.version.empty? || config.version.to_s.to_sym == :latest
             return