Hello World: Integration and Testing With F´ Deployments

This section will walk new users through creating a new F´ deployment. This deployment will build a topology containing the standard F´ stack of components and a single HelloWorld component instance. The HelloWorld was created in the last section. The tutorial will close by testing the deployment and HelloWorld component through the fprime-gds.

Prerequisites:

• Hello World: F´ Hello World Component

Tutorial Steps:

• Creating A New Deployment
• Adding The Hello World Component
• Running With fprime-gds
• Conclusion

Creating A New Deployment

F´ deployments represent one flight software executable. All the components we develop for F´ run within a deployment. The deployment created here will contain the standard command and data handling stack. This stack enables ground control and data collection of the deployment.

To create a deployment, run the following commands:

# In: MyProject
fprime-util new --deployment

This command will ask for some input. Respond with the following answers:

Deployment name [MyDeployment]: HelloWorldDeployment

For any other questions, select the default response.

At this point, the HelloWorldDeployment has been created, but our HelloWorld component has not been added to the deployment.

Adding The Hello World Component

In this section the HelloWorld component will be added to the HelloWorldDeployment deployment. This can be done by adding the component to the topology defined in HelloWorldDeployment/Top.

Topologies instantiate all the components in a running system and link them together. For some port types, like the commanding, event, and telemetry ports used by HelloWorld, the connections are made automatically. In addition, the topology specifies how to construct the component instance. This is also done automatically unless the component has specific configuration.

In order to add a component to the topology, it must be added to the topology model. An instance definition and an instance initializer must both be added.

To add an instance definition, add instance helloWorld to the instance definition list in the topology HelloWorldDeployment section of HelloWorldDeployment/Top/topology.fpp. This is shown below.

Edit HelloWorldDeployment/Top/topology.fpp:

...
    topology HelloWorldDeployment {
        # ----------------------------------------------------------------------
        # Instances used in the topology
        # ----------------------------------------------------------------------
        
        instance ...
        instance ...
        instance helloWorld

Be careful to not remove any other instances from the list.

helloWorld is the name of the component instance. Like variable names, component instance names should be descriptive and are typically named in camel or snake case.

Next, an instance initializer must be added to topology instances defined in MyDeploymment/Top/instances.fpp file. Since the HelloWorld component is an active component it should be added to the active components section and should define a priority and queue depth options. This is shown below.

Add to MyDeploymment/Top/instances.fpp:

...
  # ----------------------------------------------------------------------
  # Active component instances
  # ----------------------------------------------------------------------
  instance ...
    ...
    ...
    ...
    
  instance ...
  
  instance helloWorld: Components.HelloWorld base id 0x0F00 \
    queue size Default.QUEUE_SIZE \
    stack size Default.STACK_SIZE \
    priority 50

The user must ensure that the base id (0x0F00) does not conflict with any other base ids in the topology. 0x0F00 should be safe for deployments created with fprime-util new --deployment.

Make sure to use the same instance name (i.e. helloWorld) as defined in the instance definition just added to topology.fpp.

Finally, our new telemetry channel should be added to our telemetry packet specification. For this tutorial the channel can be ignored as the deployment will not use the telemetry packetizer. Add the following to the ignore section of HelloWorldDeployment/Top/HelloWorldDeploymentPackets.xml.

Update HelloWorldDeployment/Top/HelloWorldDeploymentPackets.xml:

    <ignore>
        ...
        <channel name="helloWorld.GreetingCount"/>
    </ignore>

Since this component has no custom ports nor does it require special configuration, our addition to the topology is completed. The deployment can now be set up and built using the following commands:

# In: MyProject/HelloWorldDeployment
fprime-util build -j4

Resolve any errors that occur before continuing to the running section.

Running With fprime-gds

It is now time to test the HelloWorld component by running the deployment created in this section. This can be accomplished by running the fprime-gds command in the deployment, verifying connection, sending the new SEND_HELLO command and verifying that the Hello event and GreetingCount channel appears.

To start the deployment with default settings, run:

fprime-gds

The F´ GDS control page should open up in your web browser. If it does not open up, navigate to http://127.0.0.1:5000.

Once the F´ GDS page is visible, look for a green circle icon in the upper right corner. This shows that the flight software deployment has connected to the GDS system. If a red X appears instead, navigate to the Logs tab and look for errors in the various logs.

Now that communication is verified, navigate to the “Commanding” tab and select helloWorld.SAY_HELLO from the dropdown list. Type a greeting into the argument input box and click the button “Send Command”. If the argument has validated successfully the command will send. Resolve all errors and ensure the command has sent.

Notice commands are instance specific. Had several HelloWorld component instances been used, there would be multiple SAY_HELLO listings, one for each component instance.

Now that the command has sent, navigate to the “Events” tab. Ensure that the event list contains the Hello event with the text entered when sending the command.

Lastly, navigate to the “Channels” tab. Look for “helloWorld.GreetingCount” in the channel list. Ensure it has recorded the number of times a helloWorld.SAY_HELLO was sent.

Congratulations, you have now set up a project, component, and deployment in F´.

Conclusion

This concludes both the adding deployment section of the Hello World tutorial and the tutorial itself. The user has been able to perform the following actions:

1. Create a new blank F´ projects
2. Create a new F´ components
3. Create a new F´ deployments and add components it

To explore components more in-depth and see how components communicate with one another, see the Math Component Tutorial.

Next: Math Component Tutorial