Show something meaningful to the user in case the container already exists [GH-132]

lib/vagrant-lxc/driver/cli.rb

@@ -58,6 +58,12 @@ module Vagrant
               '--name',     @name,
               *(config_opts),
               *extra
+        rescue Errors::ExecuteError => e
+          if e.stderr =~ /already exists/i
+            raise Errors::ContainerAlreadyExists, name: @name
+          else
+            raise
+          end
         end
 
         def destroy

lib/vagrant-lxc/errors.rb

@@ -5,7 +5,16 @@ module Vagrant
     module Errors
       class ExecuteError < Vagrant::Errors::VagrantError
         error_key(:lxc_execute_error)
+        attr_reader :stderr, :stdout
+        def initialize(message, *args)
+          super
+          if message.is_a?(Hash)
+            @stderr = message[:stderr]
+            @stdout = message[:stdout]
           end
+        end
+      end
+
       class NamespacesNotSupported < Vagrant::Errors::VagrantError
       end
 
@@ -13,6 +22,10 @@ module Vagrant
         error_key(:lxc_not_installed)
       end
 
+      class ContainerAlreadyExists < Vagrant::Errors::VagrantError
+        error_key(:lxc_container_already_exists)
+      end
+
       # Box related errors
       class TemplateFileMissing < Vagrant::Errors::VagrantError
         error_key(:lxc_template_file_missing)

lib/vagrant-lxc/sudo_wrapper.rb

@@ -51,7 +51,8 @@ module Vagrant
             if @interrupted
               @logger.info("Exit code != 0, but interrupted. Ignoring.")
             else
-              raise LXC::Errors::ExecuteError, :command => command.inspect
+              raise LXC::Errors::ExecuteError,
+                command: command.inspect, stderr: r.stderr, stdout: r.stdout
             end
           end
         end

locales/en.yml

@@ -60,3 +60,8 @@ en:
 
       lxc_redir_not_installed: |-
         `redir` is not installed or is not accessible on the PATH.
+
+      lxc_container_already_exists: |-
+        There is container on your system with the same name you've specified
+        on your Vagrantfile (%{name}), please choose a different one or
+        run `lxc-destroy --name %{name}` and try again.

spec/unit/driver/cli_spec.rb

@@ -49,10 +49,10 @@ describe Vagrant::LXC::Driver::CLI do
 
     before do
       subject.stub(:run) { |*args| @run_args = args }
-      subject.create(template, config_file, template_args)
     end
 
     it 'issues a lxc-create with provided template, container name and hash of arguments' do
+      subject.create(template, config_file, template_args)
       subject.should have_received(:run).with(
         :create,
         '--template', template,
@@ -63,6 +63,13 @@ describe Vagrant::LXC::Driver::CLI do
         '--other',       'value'
       )
     end
+
+    it 'wraps a low level error into something more meaningful in case the container already exists' do
+      subject.stub(:run) { raise Vagrant::LXC::Errors::ExecuteError, stderr: 'alreAdy Exists' }
+      expect {
+        subject.create(template, config_file, template_args)
+      }.to raise_error(Vagrant::LXC::Errors::ContainerAlreadyExists)
+    end
   end
 
   describe 'destroy' do