Add Repository

This skill guides you through adding a new Git repository to the zenoh_ros2_sdk/_repositories.py file to enable automatic message type loading.

When to Use

• User wants to add support for message types from a new ROS2 repository
• User asks to support a specific repository (e.g., "support geometry2", "add tf2_msgs")
• Message types are not found because the repository isn't registered
• Adding support for new message packages

1. Discover Repository Structure

First, identify the repository URL and explore its structure to find message packages.

A. Get Repository URL

The user may provide:

• Full GitHub URL (e.g., https://github.com/ros2/geometry2.git)
• Repository name (e.g., geometry2)
• Package name (e.g., tf2_msgs)

B. Explore Repository Contents

Use curl to check the repository structure:

# List all directories in the repository
curl -s https://api.github.com/repos/ros2/geometry2/contents | \
  python3 -c "import sys, json; data = json.load(sys.stdin); \
  dirs = [item['name'] for item in data if item['type'] == 'dir']; \
  print('\n'.join(sorted(dirs)))"

C. Find Message Packages

Check which directories contain message definitions:

# Check if a package has a msg directory
curl -s https://api.github.com/repos/ros2/geometry2/contents/tf2_msgs | \
  python3 -c "import sys, json; data = json.load(sys.stdin); \
  print('\n'.join([item['name'] for item in data if item['type'] == 'dir']))"

D. List Available Messages

Check what messages are in a package:

# List .msg files in a package
curl -s https://api.github.com/repos/ros2/geometry2/contents/tf2_msgs/msg | \
  python3 -c "import sys, json; data = json.load(sys.stdin); \
  msgs = [item['name'] for item in data if item['name'].endswith('.msg')]; \
  print('\n'.join(sorted(msgs)))"

2. Determine Repository Structure

Identify the repository layout pattern:

Pattern A: Meta-Repository (Multiple Packages)

Structure: <repo_root>/<package>/msg/<message>.msg

• Example: common_interfaces, rcl_interfaces, geometry2
• Contains multiple packages in subdirectories
• Each package has its own msg/ directory

Pattern B: Single Package Repository

Structure: <repo_root>/msg/<message>.msg or <repo_root>/<package>/msg/<message>.msg

• Example: example_interfaces
• Single package, messages at repo root or in package subdirectory

3. Determine Commit/Tag

Choose an appropriate commit or tag:

• Recommended: Use stable ROS2 distribution tags (e.g., jazzy, iron, humble) for consistency with other repositories
• Default: Use jazzy to match existing repositories (rcl_interfaces, common_interfaces, example_interfaces, geometry2)
• Rolling: Use rolling branch only if you need latest development features
• Specific version: Use commit SHA or version tag for reproducibility

Check available tags:

curl -s https://api.github.com/repos/ros2/geometry2/tags | \
  python3 -c "import sys, json; data = json.load(sys.stdin); \
  print('\n'.join([tag['name'] for tag in data[:10]]))"

4. Add Repository Entry

Edit zenoh_ros2_sdk/_repositories.py and add a new entry to MESSAGE_REPOSITORIES:

Template for Meta-Repository

# Repository name (descriptive, matches repo name)
"repository_name": MessageRepository(
    url="https://github.com/ros2/repository_name.git",
    commit="jazzy",  # Use jazzy for consistency with other repositories
    cache_path="repository_name",  # Local cache directory name
    msg_path="",  # Empty for standard structure: <package>/msg/<message>.msg
    packages=[
        "package1",  # List all message packages in this repository
        "package2",
        # ... more packages
    ],
),

Template for Single Package Repository

"package_name": MessageRepository(
    url="https://github.com/ros2/package_name.git",
    commit="jazzy",  # Use jazzy for consistency, or specific tag/commit
    cache_path="package_name",
    msg_path="",  # Adjust if messages are at repo root vs package subdirectory
    packages=[
        "package_name",  # Single package
    ],
),

Example: Adding geometry2

# Geometry2 (contains tf2_msgs and other TF2-related packages)
# This repository contains TF2 transform message definitions
# Reference: https://github.com/ros2/geometry2
"geometry2": MessageRepository(
    url="https://github.com/ros2/geometry2.git",
    commit="jazzy",  # Use specific commit/tag for reproducibility
    cache_path="geometry2",
    msg_path="",  # Messages are at <package>/msg/<message>.msg
    packages=[
        "tf2_msgs",  # Contains TFMessage, TF2Error messages
    ],
),

5. Verify Package Mapping

The PACKAGE_TO_REPOSITORY mapping is automatically generated at the bottom of the file. Verify it includes your new packages:

# Mapping from message package namespace to repository name
PACKAGE_TO_REPOSITORY: Dict[str, str] = {}
for repo_name, repo in MESSAGE_REPOSITORIES.items():
    for package in repo.packages:
        PACKAGE_TO_REPOSITORY[package] = repo_name

This ensures packages like tf2_msgs map to geometry2 repository.

6. Check for Linting Errors

Run linting to ensure code quality:

# Check for linting errors
# (The linter will automatically check when you edit the file)

7. Test Message Loading (Optional)

Verify the repository works by testing message loading:

from zenoh_ros2_sdk import load_message_type, get_message_class

# Load a message type from the new repository
load_message_type("tf2_msgs/msg/TFMessage")
TFMessage = get_message_class("tf2_msgs/msg/TFMessage")

if TFMessage:
    print("Successfully loaded message from new repository!")

Common Repositories

Already Supported

• rcl_interfaces - Core ROS2 interfaces (builtin_interfaces, action_msgs, etc.)
• common_interfaces - Standard messages (std_msgs, geometry_msgs, sensor_msgs, etc.)
• example_interfaces - Example messages and services
• geometry2 - TF2 messages (tf2_msgs)

Potential Additions

• ros2_interfaces - Additional ROS2 interfaces
• rosidl_defaults - Default message definitions
• Custom repositories with message definitions

Notes

• Cache Location: Repositories are cached in ~/.cache/zenoh_ros2_sdk/ (or $ZENOH_ROS2_SDK_CACHE)
• Automatic Download: Messages are downloaded automatically when first requested
• Dependencies: Message dependencies are resolved automatically
• Consistency: Use jazzy as the default commit tag to match existing repositories for consistency and reproducibility