Lifecycle

SIL Kit provides a lifecycle service and time synchronization service, that allow to coordinate simulation execution between participants.

Coordinated required participants

This participant is in OperationMode::Coordinated, but is not among the participants that are reported to the system controller as "required".

If participants of a SIL Kit simulation want to start the simulation together as soon as all necessary participants have joined the simulation, these SIL Kit participants specify that their lifecycle service is operated in coordinated mode.

When executing such a SIL Kit Simulation, it is important to tell the SIL Kit simulation which participants are considered necessary for the coordinated start. You do this by calling sil-kit-system-controller with a whitespace separated list of participants that are necessary to start the simulation. These participants are called “required” in SIL Kit terminology.

For example:

# mark participant1, participant2 and participant3 as required
sil-kit-system-controller participant1 participant2 participant3

Attempt to instantiate a service multiple times

Tried to instantiate TimeSyncService multiple times
Tried to instantiate LifecycleService multiple times
Tried to instantiate SystemMonitor multiple times

Some services within SIL Kit can not be instantiated multiple times on the same simulation participant. If a user tries to instantiate these services a second time, an exception with the error message Tried to instantiate service multiple times is thrown. These semantics mirror the underlying implementation. No implicit caching of the service instances is performed. Since a participant can only have one lifecycle status, having multiple lifecycle services or the expectation to instantiate multiple lifecycle services are most likely a misunderstanding of the SIL Kit APIs. If you run into this problem because you want to access these services from many places in your code, you should think about introducing a singleton pattern in your code.

Required participant names are already set

Required participant names are already set.

For starting a coordinated simulation in which all participants start the simulation at the same time, it is necessary that a participant tells the simulation which participants are required for the start. Usually the sil-kit-system-controller is used to set these required participants, but the workflow configuration can also be used to set these participants through the API. Since the behavior of the simulation would be undefined if multiple different sets of required participants are specified, this exception occurs. Make sure that only one sil-kit-system-controller exists within the simulation, or that only one participant sets the workflow configuration.