Configure an application to launch at start-up#

Pre-requisites#

You must already know how to install (deploy) your app on the robot. See Deploying ROS 2 packages on your robot.
We recommend you to also read about the robot’s start-up configuration.

Adding your own application to the Module Manager#

In addition to the system applications, you can easily add your own custom modules to the Module Manager. To do so, register the new module in the CMakeLists.txt of a ROS package. For example, if you have a package called hello_world, with a node called hello_world_node, you can add the following lines to the CMakeLists.txt:

find_package(pal_module_cmake QUIET)

if(pal_module_cmake_FOUND)
   pal_register_modules(
      module/hello_world.yaml
   )
endif()

The module file hello_world.yaml should be placed in the module/ directory of the package would look something like this:

hello_world:
  run: "hello_world hello_world_node"

Then, you can deploy the package to the robot as described in Deploying ROS 2 packages on your robot. After a reboot of the robot the module is available and can be started using the command pal module start hello_world.

Adding your own application to the startup sequence of the robot#

To start the module at startup a module set has to be created. To do so, register a new module set in the CMakeLists.txt of hello_world ROS package:

if(pal_module_cmake_FOUND)
   pal_register_module_sets(
      module/custom_module_set.yaml
   )
endif()

The module file custom_module_set.yaml should be placed in the module/ directory of the package would look something like this:

custom_modules:
   - hello_world

Then, you can deploy the package to the robot as described in Deploying ROS 2 packages on your robot. After a reboot of the robot the module hello_world start automatically.

Customizing an existing application in the startup sequence of the robot#

To customize an existing application in the startup sequence of the robot, you can create a new module that overwrites the existing module. To do so, first retrieve the filename of the existing module by running the command pal module info foo_module. In this example the filename is 00_foo_module.yaml.

Then, register a new module in the CMakeLists.txt of a ROS package. The new module file should be placed in the module/ directory of the package and would look something like this:

foo_module:
  run: "foo_package different_node"

The Module Manager will sort all registered modules based on their filename in lexicographical order. This means to overwrite the existing module in 00_foo_module.yaml we have to register the new module in a file with a name that comes after 00_foo_module.yaml, for example 10_foo_module.yaml.

Note

The registered modules are sorted based on the filename in lexicographical order. Take this into account when naming the file of the module. A module file named 00_foo_module.yaml will be overwritten by a module file named 10_foo_module.yaml. To overwrite the module bar_module.yaml the new module file should be named bar_module_01.yaml.

Finally, deploy the package to the robot as described in Deploying ROS 2 packages on your robot. After a reboot of the robot the updated version of the foo_module is used. To check this run the command pal module info foo_module.

Disable an existing application in the startup sequence of the robot#

To disable a module in the startup sequence of the robot, you can use the command line interface of the Module Manager.

To disable a module, run the command pal module disable foo_module.
To enable a module, run the command pal module enable foo_module.

Then, in order to apply the changes you have to restart the startup sequence of the robot by running the command pal module_manager restart.