Add --message field to the creation of ROS2 packages.

ros2pkg/ros2pkg/api/create.py

@@ -106,6 +106,8 @@ def create_package_environment(package, destination_directory):
             'package_license': package.licenses[0],
             'buildtool_dependencies': package.buildtool_depends,
             'dependencies': package.build_depends,
+            'exec_dependencies': package.exec_depends,
+            'member_of_group': package.member_of_groups,
             'test_dependencies': package.test_depends,
             'exports': package.exports,
             }
@@ -259,12 +261,14 @@ def populate_cmake(package, package_directory, cpp_node_name, cpp_library_name):
             version_config)
 
 
-def populate_ament_cmake(package, package_directory, cpp_node_name, cpp_library_name):
+def populate_ament_cmake(package, package_directory, cpp_node_name, cpp_library_name,
+                         message_names=None):
     cmakelists_config = {
             'project_name': package.name,
             'dependencies': [str(dep) for dep in package.build_depends],
             'cpp_node_name': cpp_node_name,
             'cpp_library_name': cpp_library_name,
+            'message_names': message_names or [],
             }
     _create_template_file(
             'ament_cmake',
@@ -355,3 +359,20 @@ def populate_rust_node(package, source_directory, node_name):
             source_directory,
             'main.rs',
             cargo_node_config)
+
+
+def populate_messages(package_directory: str, message_names: list) -> None:
+    """
+    Create stub message files in the msg/ subdirectory of the package.
+
+    :param package_directory: path to the package directory.
+    :param message_names: list of message names to create.
+    """
+    msg_directory = _create_folder('msg', package_directory)
+    for msg_name in message_names:
+        _create_template_file(
+                'msg',
+                'message.msg.em',
+                msg_directory,
+                msg_name + '.msg',
+                {})

ros2pkg/ros2pkg/resource/ament_cmake/CMakeLists.txt.em

@@ -10,6 +10,9 @@ find_package(ament_cmake REQUIRED)
 @[if cpp_library_name]@
 find_package(ament_cmake_ros REQUIRED)
 @[end if]@
+@[if message_names]@
+find_package(rosidl_default_generators REQUIRED)
+@[end if]@
 @[if dependencies]@
 @[  for dep in dependencies]@
 find_package(@dep REQUIRED)
@@ -19,6 +22,19 @@ find_package(@dep REQUIRED)
 # further dependencies manually.
 # find_package(<dependency> REQUIRED)
 @[end if]@
+@[if message_names]@
+
+# do not forget to find_package all dependencies of your custom messages
+# (if they were not already found earlier)
+# find_package(<msg_dependency> REQUIRED)
+
+rosidl_generate_interfaces(${PROJECT_NAME}
+@[  for msg in message_names]@
+  "msg/@(msg).msg"
+@[  end for]@
+  DEPENDENCIES  # list all package dependencies of your messages
+)
+@[end if]@
 @[if cpp_library_name]@
 
 add_library(@(cpp_library_name) src/@(cpp_library_name).cpp)

ros2pkg/ros2pkg/resource/msg/__init__.py

@@ -0,0 +1,13 @@
+# Copyright 2026 Leander Stephen Desouza
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+#     http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.

ros2pkg/ros2pkg/resource/msg/message.msg.em

@@ -0,0 +1,6 @@
+# TODO: Define the message fields here.
+# For example:
+# bool my_flag
+# string my_string
+# int32 my_number
+# if you use a non-trivial message type, do not forget to add its package to package.xml and CMakeLists.txt

ros2pkg/ros2pkg/resource/package_environment/package.xml.em

@@ -18,12 +18,24 @@
   <depend>@dep</depend>
 @[  end for]@
 
+@[end if]@
+@[if exec_dependencies]@
+@[  for dep in exec_dependencies]@
+  <exec_depend>@dep</exec_depend>
+@[  end for]@
+
 @[end if]@
 @[if test_dependencies]@
 @[  for dep in test_dependencies]@
   <test_depend>@dep</test_depend>
 @[  end for]@
 
+@[end if]@
+@[if member_of_group]@
+@[  for group in member_of_group]@
+  <member_of_group>@group</member_of_group>
+@[  end for]@
+
 @[end if]@
   <export>
 @[if exports]@

ros2pkg/ros2pkg/verb/create.py

@@ -14,6 +14,7 @@
 
 import getpass
 import os
+import re
 import shutil
 import subprocess
 import sys
@@ -33,6 +34,7 @@
 from ros2pkg.api.create import populate_cmake
 from ros2pkg.api.create import populate_cpp_library
 from ros2pkg.api.create import populate_cpp_node
+from ros2pkg.api.create import populate_messages
 from ros2pkg.api.create import populate_python_libary
 from ros2pkg.api.create import populate_python_node
 from ros2pkg.api.create import populate_rust_node
@@ -90,6 +92,12 @@ def add_arguments(self, parser, cli_name):
         parser.add_argument(
             '--library-name',
             help='name of the empty library')
+        parser.add_argument(
+            '--message',
+            nargs='+',
+            default=[],
+            metavar='MESSAGE_NAME',
+            help='name(s) of message files to create in msg/')
 
     def main(self, *, args):
 
@@ -136,12 +144,26 @@ def get_git_config(key: str) -> Optional[str]:
                 print('[WARNING] node name can not be equal to the library name', file=sys.stderr)
                 print('[WARNING] renaming node to %s' % node_name, file=sys.stderr)
 
+        if args.message:
+            if args.build_type != 'ament_cmake':
+                return "Aborted: --message is only supported with 'ament_cmake' build type."
+
+            invalid = [
+                name for name in args.message
+                if not re.match(r'^[A-Z][A-Za-z0-9]*$', name)
+            ]
+            if invalid:
+                return 'Aborted: invalid message name(s): ' + ', '.join(invalid) + \
+                    '. Message names must be CamelCase and alphanumeric (e.g. MyMsg).'
+
         buildtool_depends = []
         if args.build_type == 'ament_cmake':
             if args.library_name:
                 buildtool_depends = ['ament_cmake_ros']
             else:
                 buildtool_depends = ['ament_cmake']
+            if args.message:
+                buildtool_depends.append('rosidl_default_generators')
 
         if args.build_type == 'ament_cargo':
             buildtool_depends = ['ament_cargo']
@@ -153,6 +175,12 @@ def get_git_config(key: str) -> Optional[str]:
             test_dependencies = ['ament_copyright', 'ament_flake8', 'ament_mypy', 'ament_pep257',
                                  'ament_xmllint', 'python3-pytest']
 
+        member_of_group_depends = []
+        exec_depends = []
+        if args.message:
+            member_of_group_depends.append('rosidl_interface_packages')
+            exec_depends.append('rosidl_default_runtime')
+
         if args.build_type == 'ament_python' and args.package_name == 'test':
             # If the package name is 'test', there will be a conflict between
             # the directory the source code for the package goes in and the
@@ -169,6 +197,8 @@ def get_git_config(key: str) -> Optional[str]:
             licenses=[args.license],
             buildtool_depends=[Dependency(dep) for dep in buildtool_depends],
             build_depends=[Dependency(dep) for dep in args.dependencies],
+            exec_depends=[Dependency(dep) for dep in exec_depends],
+            member_of_groups=member_of_group_depends,
             test_depends=[Dependency(dep) for dep in test_dependencies],
             exports=[Export('build_type', content=args.build_type)]
         )
@@ -192,6 +222,8 @@ def get_git_config(key: str) -> Optional[str]:
             print('node_name:', node_name)
         if library_name:
             print('library_name:', library_name)
+        if args.message:
+            print('messages:', args.message)
 
         package_directory, source_directory, include_directory = \
             create_package_environment(package, args.destination_directory)
@@ -202,7 +234,8 @@ def get_git_config(key: str) -> Optional[str]:
             populate_cmake(package, package_directory, node_name, library_name)
 
         if args.build_type == 'ament_cmake':
-            populate_ament_cmake(package, package_directory, node_name, library_name)
+            populate_ament_cmake(package, package_directory, node_name, library_name,
+                                 message_names=args.message)
 
         if args.build_type == 'ament_cargo':
             populate_ament_cargo(package, package_directory, library_name)
@@ -239,6 +272,9 @@ def get_git_config(key: str) -> Optional[str]:
                     node_name
                     )
 
+        if args.message:
+            populate_messages(package_directory, args.message)
+
         if args.license in available_licenses:
             with open(os.path.join(package_directory, 'LICENSE'), 'w') as outfp:
                 for lic in available_licenses[args.license]:

ros2pkg/test/test_cli.py

@@ -132,7 +132,8 @@ def test_create_package(self):
                     '--maintainer-email', 'nobody@nowhere.com',
                     '--maintainer-name', 'Nobody',
                     '--node-name', 'test_node',
-                    '--library-name', 'test_library'
+                    '--library-name', 'test_library',
+                    '--message', 'MyMsg', 'OtherMsg',
                 ], cwd=tmpdir
             ) as pkg_command:
                 assert pkg_command.wait_for_shutdown(timeout=5)
@@ -151,6 +152,7 @@ def test_create_package(self):
                     "dependencies: ['ros2pkg']",
                     'node_name: test_node',
                     'library_name: test_library',
+                    "messages: ['MyMsg', 'OtherMsg']",
                     'creating folder ' + os.path.join('.', 'a_test_package'),
                     'creating ' + os.path.join('.', 'a_test_package', 'package.xml'),
                     'creating source and include folder',
@@ -171,29 +173,31 @@ def test_create_package(self):
                     'creating ' + os.path.join(
                         '.', 'a_test_package', 'include', 'a_test_package', 'visibility_control.h'
                     ),
+                    'creating folder ' + os.path.join('.', 'a_test_package', 'msg'),
+                    'creating ' + os.path.join('.', 'a_test_package', 'msg', 'MyMsg.msg'),
+                    'creating ' + os.path.join('.', 'a_test_package', 'msg', 'OtherMsg.msg'),
                 ],
                 text=pkg_command.output,
                 strict=True
             )
             # Check layout
-            assert os.path.isdir(os.path.join(tmpdir, 'a_test_package'))
-            assert os.path.isfile(os.path.join(tmpdir, 'a_test_package', 'package.xml'))
-            assert os.path.isfile(os.path.join(tmpdir, 'a_test_package', 'CMakeLists.txt'))
-            assert os.path.isfile(os.path.join(tmpdir, 'a_test_package', 'LICENSE'))
-            assert os.path.isfile(
-                os.path.join(tmpdir, 'a_test_package', 'src', 'test_node.cpp')
-            )
-            assert os.path.isfile(
-                os.path.join(tmpdir, 'a_test_package', 'src', 'test_library.cpp')
-            )
+            pkg_dir = os.path.join(tmpdir, 'a_test_package')
+            assert os.path.isdir(pkg_dir)
+            assert os.path.isfile(os.path.join(pkg_dir, 'package.xml'))
+            assert os.path.isfile(os.path.join(pkg_dir, 'CMakeLists.txt'))
+            assert os.path.isfile(os.path.join(pkg_dir, 'LICENSE'))
+            assert os.path.isfile(os.path.join(pkg_dir, 'src', 'test_node.cpp'))
+            assert os.path.isfile(os.path.join(pkg_dir, 'src', 'test_library.cpp'))
             assert os.path.isfile(os.path.join(
-                tmpdir, 'a_test_package', 'include', 'a_test_package', 'test_library.hpp'
+                pkg_dir, 'include', 'a_test_package', 'test_library.hpp'
             ))
             assert os.path.isfile(os.path.join(
-                tmpdir, 'a_test_package', 'include', 'a_test_package', 'visibility_control.h'
+                pkg_dir, 'include', 'a_test_package', 'visibility_control.h'
             ))
+            assert os.path.isfile(os.path.join(pkg_dir, 'msg', 'MyMsg.msg'))
+            assert os.path.isfile(os.path.join(pkg_dir, 'msg', 'OtherMsg.msg'))
             # Check package.xml
-            tree = ET.parse(os.path.join(tmpdir, 'a_test_package', 'package.xml'))
+            tree = ET.parse(os.path.join(pkg_dir, 'package.xml'))
             root = tree.getroot()
             assert root.tag == 'package'
             assert root.attrib['format'] == '3'
@@ -204,3 +208,18 @@ def test_create_package(self):
             assert root.find('license').text == 'Apache-2.0'
             assert root.find('depend').text == 'ros2pkg'
             assert root.find('.//build_type').text == 'ament_cmake'
+
+            # Check rosidl message dependencies
+            buildtool_deps = [e.text for e in root.findall('buildtool_depend')]
+            assert 'rosidl_default_generators' in buildtool_deps
+            exec_deps = [e.text for e in root.findall('exec_depend')]
+            assert 'rosidl_default_runtime' in exec_deps
+            assert root.find('member_of_group').text == 'rosidl_interface_packages'
+
+            # Check CMakeLists.txt
+            with open(os.path.join(pkg_dir, 'CMakeLists.txt'), 'r', encoding='utf-8') as f:
+                cmake_content = f.read()
+            assert 'find_package(rosidl_default_generators REQUIRED)' in cmake_content
+            assert 'rosidl_generate_interfaces(${PROJECT_NAME}' in cmake_content
+            assert '"msg/MyMsg.msg"' in cmake_content
+            assert '"msg/OtherMsg.msg"' in cmake_content