To make our package understand action definitions and aid in their usage, we need to modify our package.xml and CMakeLists.txt files. In the package.xml file, ensure the following lines of code are available to call the action package. If not, please add them:

<build_depend>actionlib_msgs</build_depend>
<exec_depend>actionlib_msgs</exec_depend>

In the CMakeLists.txt file, add the action files to the add_action_files() call:

add_action_files(
DIRECTORY action
FILES battery_sim.action
)

Indicate the dependencies in the generate_messages() call:

generate_messages(
DEPENDENCIES
actionlib_msgs
std_msgs
)

Indicate the dependencies in the catkin_package() call:

catkin_package(
CATKIN_DEPENDS
actionlib_msgs
)

Now that the package has been configured, let's compile the workspace:

$ cd ~/chapter_4_ws
$ catkin_make

You should see the following list of files:

We will use these files in our code as a message structure. Now, let's define the server and client.