examples

Examples

Important

The examples are not yet functional in all languages. Check the list below to see what is already working!

Foundations of Communication in iceoryx2 Applications

In the world of iceoryx2, communication is at the core of everything. To facilitate seamless communication, we always begin by opening or creating a service, the fundamental building block of an iceoryx2 application. Services serve as the conduit through which different parts of your application interact.

The type of service you create is defined by a messaging pattern, which dictates how data flows between participants. iceoryx2 supports various messaging patterns, including:

• Publish-Subscribe: In this pattern, a publisher sends a continuous stream of data to one or more subscribers, enabling real-time data dissemination.

• Event: This pattern allows notifiers to trigger events on a listener, which waits until it receives a notification. It is the basic pattern for implementing push-notifications.

• Request-Response: (planned) This pattern enables clients to send requests to a server, which responds with the requested data or action, making it suitable for interactive, transactional communication.

• Pipeline: (planned) Borrowed from the Unix command line, this pattern involves a data source that produces data and transfers ownership to a sink, where it can be modified or processed in a pipeline-like fashion.

The service acts as a factory, creating service participants, often called "ports." These ports establish communication links between different components of your application. Each service can be customized with specific settings to meet your application's requirements.

Within the service builder, you can configure various service-specific quality of service parameters, ensuring that your communication behaves precisely as you intend. The service port factory allows you to fine-tune the settings and behavior of individual ports, giving you precise control over how they interact and exchange data.

Payload Type Restrictions

Caution

iceoryx2 stores payload data in shared memory, which imposes the restriction that the payload type must be self-contained and cannot use heap memory. Additionally, internal pointers are not allowed because the shared memory is mapped at different offsets in each process, making absolute pointers invalid and potentially leading to segmentation faults.

Furthermore, every data type must be annotated with #[repr(C)]. The Rust compiler may reorder the members of a struct, which can lead to undefined behavior if another process expects a different ordering.

To address these limitations, we provide data types that are compatible with shared memory. For Rust, we offer:

• FixedSizeByteString
• FixedSizeVec

For C++, we provide:

• iox::vector
• iox::string
• iox::list

These types are demonstrated in the complex data types example.

Overview

Name	Language	Description
complex data types	C++ Rust	Send zero-copy compatible versions of Vec and String. Introduces PlacementDefault trait for large data types to perform an in place initialization where otherwise a stack overflow would be encountered.
discovery	C C++ Rust	List all available services in a system.
docker	all	Communicate between different docker containers and the host.
domains	C C++ Rust	Establish separate domains that operate independently from one another.
event	C C++ Rust	Push notifications - send event signals to wakeup processes that are waiting for them.
event based communication	C++ Rust	Define multiple events like publisher/subscriber created or removed, send sample, received sample, deliver history etc. and react on them for a fully event driven communication setup.
event multiplexing	C C++ Rust	Wait on multiple listeners or sockets with a single call. The WaitSet demultiplexes incoming events and notifies the user.
publish subscribe	C C++ Rust	Communication between multiple processes with a publish subscribe messaging pattern.
publish subscribe dynamic data	C++ Rust	Communication between multiple processes with a publish subscribe messaging pattern and payload data that has a dynamic size.
publish subscribe with user header	C C++ Rust	Add a user header to the payload (samples) to transfer additional information.
service attributes	Rust	Creates a service with custom attributes that are available to every endpoint. If the attributes are not compatible the service will not open.