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Clarifying the "service" terminology

There are two different entities that are called "services":

  • NAOqi services (also called "modules"), that expose an API and are registered to the ServiceDirectory. You can call them with qicli, subscribe to their signals, etc.

  • systemd services, that are standalone executables packaged in an Application Package, declared in it's manifest with a <service> tag. These are managed by ALServiceManager, who can start and stop them (they will have their own process). For clarity's sake, these are called "Executables" in this doc.

The confusion between the two is increased by the fact that a common pattern is to write an executable whose sole purpose is to run a NAOqi service, and sometimes to identify both with the same name (e.g. both are called “ALFuchsiaBallTracker”).

Ways of using them in an app:

  • Run a standalone executable during your app, possibly as the only content. This is demonstrated in the pythonapp template.

  • Run a NAOqi service during your app (packaged in an executable), but only while the app is running -> this is how service-tabletpage is built.

  • Package a NAOqi service running all the time -> this wastes resources, and risks causing hard-to-find bugs, so should only be used for system apps that really need to do so.

qi.Application

robot_runner**.init()** returns a QiApplication object, the same you would get by calling qi.Application()̀.

When your python script is packaged in an application, it should be declared in the manifest with a --qi-url parameter:

<services> <service execStart="/usr/bin/python2 scripts/main.py --qi-url [URL]" autorun="false" name="main"/> </services>

However, you can also execute that script directly, locally on your computer (python main.py), or from your favourite editor.