Fixed #28 -- Added a command for generating a basic LXDock file (#32)

* Fixed #28 -- Added a command for generating a basic LXDock file

* Removed uneccessary usage of codecs.open and mocked os.getcwd instead of os.path.exists

contrib/completion/bash/lxdock

@@ -20,7 +20,7 @@ ___lxdock_container_names() {
 _lxdock_complete () {
   local cur cmd commands
 
-  commands='config destroy halt help provision shell status up'
+  commands='config destroy halt help init provision shell status up'
 
   cur=${COMP_WORDS[COMP_CWORD]}
   cmd=${COMP_WORDS[1]}
@@ -56,6 +56,12 @@ _lxdock_complete () {
           containers="$(___lxdock_container_names)"
           COMPREPLY=($(compgen -W "$containers" -- ${cur}))
           ;;
+        init)
+          case "${cur}" in
+            -*)
+              COMPREPLY=($(compgen -W "-f --force --image --project" -- ${cur})) ;;
+          esac
+          ;;
         provision)
           containers="$(___lxdock_container_names)"
           COMPREPLY=($(compgen -W "$containers" -- ${cur}))

docs/cli/index.rst

@@ -29,6 +29,7 @@ help for a specifc subcommand. For example:
   destroy
   halt
   help
+  init
   provision
   shell
   status

docs/cli/init.rst

@@ -0,0 +1,24 @@
+lxdock init
+===========
+
+**Command:** ``lxdock init``
+
+This command can be used to generate a LXDock file containing highlights regarding some useful
+options.
+
+Options
+-------
+
+* ``--image`` - this option allows to use a specific container image in the generated configuration
+* ``--project`` - this option allows to define the name of the project that will appear in the LXDock file
+* ``--force`` or ``-f`` - this option allows to overwrite an exsting LXDock file if any
+
+Examples
+--------
+
+.. code-block:: console
+
+  $ lxdock init                          # generates a basic LXDock file
+  $ lxdock init --image debian/jessie    # generates a LXDock file defining a debian/jessie container
+  $ lxdock init --project myproject      # generates a basic LXDock file defining a "myproject" project
+  $ lxdock init --force                  # overwrite an existing LXDock file if applicable

lxdock/cli/constants.py

@@ -0,0 +1,32 @@
+# TEMPLATES
+# --
+
+INIT_LXDOCK_FILE_CONTENT = """# This is a basic configuration file for LXDock.
+# All configuration is done through this YML file that should be placed at the root of your project.
+# The file define a basic LXDock project containing a single container with highlights regarding
+# some other useful options.
+name: {project_name}
+image: {image}
+
+# By default LXDock creates a single "default" container if you don't specify a "containers" option.
+# But you need the "containers" option if you have more than one container.
+
+# containers:
+#   - name: {project_name}01
+#   - name: {project_name}02
+#   - name: {project_name}02
+#     Most of the options can be redefined for each container definition, eg. the "image" option:
+#     image: archlinux
+
+# You can use the "provisioning" option to define provisioning tools that should be used to
+# provision your containers. For example, you could use Ansible as follows:
+# provisioning:
+#   - type: ansible
+#     playbook: deploy/site.yml
+
+# A common need is to access your project folder in your containers. To do this you can use the
+# "shares" option:
+# shares:
+#   - source: .
+#     dest: /myshare
+"""

lxdock/cli/main.py

@@ -56,6 +56,16 @@ def __init__(self, argv=None):
                         'subcommand.')
         self._parsers['help'].add_argument('subcommand', nargs='?', help='Subcommand name.')
 
+        # Creates the 'init' action.
+        self._parsers['init'] = subparsers.add_parser(
+            'init', help='Generate a LXDock file.',
+            description='Generate a LXDock file defining a single container and highlighting '
+                        'useful options.')
+        self._parsers['init'].add_argument(
+            '-f', '--force', action='store_true', help='Overwrite existing LXDock file')
+        self._parsers['init'].add_argument('--image', help='Container image to use')
+        self._parsers['init'].add_argument('--project', help='Project name to use')
+
         # Creates the 'provision' action.
         self._parsers['provision'] = subparsers.add_parser(
             'provision', help='Provision containers.',
@@ -163,6 +173,28 @@ def help(self, args):
             # args.subcommand is not a valid subcommand!
             raise CLIError('No such command: {}'.format(args.subcommand))
 
+    def init(self, args):
+        import os
+        from ..conf.constants import ALLOWED_FILENAMES
+        from .constants import INIT_LXDOCK_FILE_CONTENT
+        cwd = os.getcwd()
+        project_name = args.project or os.path.split(cwd)[1]
+
+        # Check if an existing config file is already present in the current working directory.
+        existing_config = [
+            filename for filename in ALLOWED_FILENAMES
+            if os.path.exists(os.path.join(cwd, filename))]
+        if existing_config and not args.force:
+            raise CLIError(
+                'An existing LXDock file is already present in this directory! Using "lxdock init" '
+                'could overwrite this file. Use the -f/--force to overwrite existing LXDock files.')
+
+        # Compute the content of the LXDock file to write and write it to a lxdock.yml file.
+        init_filecontent = INIT_LXDOCK_FILE_CONTENT.format(
+            project_name=project_name, image=args.image or 'ubuntu/xenial')
+        with open('lxdock.yml', mode='w', encoding='utf-8') as fd:
+            fd.write(init_filecontent)
+
     def provision(self, args):
         self.project.provision(container_names=args.name)
 

tests/unit/cli/test_main.py

@@ -3,6 +3,7 @@
 
 import pytest
 
+from lxdock.cli.constants import INIT_LXDOCK_FILE_CONTENT
 from lxdock.cli.main import LXDock, main
 from lxdock.cli.project import get_project
 from lxdock.conf.config import Config
@@ -252,3 +253,60 @@ def test_project_property_works(
         project1, project2 = n.project, n.project
         assert project1 == project2
         assert from_config_mock.call_count == 1
+
+    @unittest.mock.patch('builtins.open')
+    def test_can_generate_a_basic_lxdock_file(self, mock_open):
+        fd_mock = unittest.mock.Mock()
+        mock_open.return_value.__enter__.return_value = fd_mock
+        LXDock(['init', ])
+        assert mock_open.call_count == 1
+        assert mock_open.call_args[0] == ('lxdock.yml', )
+        assert fd_mock.write.call_count == 1
+        assert fd_mock.write.call_args[0][0] == INIT_LXDOCK_FILE_CONTENT.format(
+            project_name=os.path.split(os.getcwd())[1], image='ubuntu/xenial')
+
+    @unittest.mock.patch('builtins.open')
+    @unittest.mock.patch('os.getcwd')
+    def test_cannot_generate_a_lxdock_file_if_there_is_already_an_existing_lxdock_file(
+            self, mock_getcwd, mock_open):
+        mock_getcwd.return_value = os.path.join(FIXTURE_ROOT, 'project01')
+        fd_mock = unittest.mock.Mock()
+        mock_open.return_value.__enter__.return_value = fd_mock
+        with pytest.raises(SystemExit):
+            LXDock(['init', ])
+
+    @unittest.mock.patch('builtins.open')
+    @unittest.mock.patch('os.getcwd')
+    def test_can_generate_a_lxdock_file_by_overwritting_an_existing_file_with_the_force_option(
+            self, mock_getcwd, mock_open):
+        mock_getcwd.return_value = os.path.join(FIXTURE_ROOT, 'project01')
+        fd_mock = unittest.mock.Mock()
+        mock_open.return_value.__enter__.return_value = fd_mock
+        LXDock(['init', '--force'])
+        assert mock_open.call_count == 1
+        assert mock_open.call_args[0] == ('lxdock.yml', )
+        assert fd_mock.write.call_count == 1
+        assert fd_mock.write.call_args[0][0] == INIT_LXDOCK_FILE_CONTENT.format(
+            project_name=os.path.split(os.getcwd())[1], image='ubuntu/xenial')
+
+    @unittest.mock.patch('builtins.open')
+    def test_can_generate_a_lxdock_file_with_a_custom_image(self, mock_open):
+        fd_mock = unittest.mock.Mock()
+        mock_open.return_value.__enter__.return_value = fd_mock
+        LXDock(['init', '--image', 'debian/jessie', ])
+        assert mock_open.call_count == 1
+        assert mock_open.call_args[0] == ('lxdock.yml', )
+        assert fd_mock.write.call_count == 1
+        assert fd_mock.write.call_args[0][0] == INIT_LXDOCK_FILE_CONTENT.format(
+            project_name=os.path.split(os.getcwd())[1], image='debian/jessie')
+
+    @unittest.mock.patch('builtins.open')
+    def test_can_generate_a_lxdock_file_with_a_custom_project_name(self, mock_open):
+        fd_mock = unittest.mock.Mock()
+        mock_open.return_value.__enter__.return_value = fd_mock
+        LXDock(['init', '--project', 'customproject', ])
+        assert mock_open.call_count == 1
+        assert mock_open.call_args[0] == ('lxdock.yml', )
+        assert fd_mock.write.call_count == 1
+        assert fd_mock.write.call_args[0][0] == INIT_LXDOCK_FILE_CONTENT.format(
+            project_name='customproject', image='ubuntu/xenial')