Path

The path object specifies the file path of the subgraph to be imported. The structure of the subgraph file should be graph object.

Format

Name	Type	Required	Description
path	string	yes	The file path of the subgraph.

Substitutions

File paths can contain substitutions like ROS 2 launch. The supported substitutions are as follows.

Substitution	Description
$(dirname)	The path of this file directory.
$(find-pkg-share <package>)	The path of the package.
$(var <name>)	The value of the variable passed from the node.

Using $(var <name>)

The $(var <name>) substitution allows you to use variables in the graph file. Variables are passed via the graph_vars parameter as a YAML map string.

Note: In launch XML, the value must be wrapped in single quotes to prevent YAML parsing.

<arg name="graph_vars" value="'{vehicle_id: vehicle1, config_dir: /path/to/config}'"/>

Then in your graph file:

files:
  - { path: $(var config_dir)/$(var vehicle_id)/module.yaml }