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RTI Connext Go Connector Examples

Getting Started

New to RTI Connector Go? Start with the go-get-example/ - it shows the complete workflow from installation to running your first program using go get.

For users who prefer manual setup, see the main project README for library installation instructions.

Example Overview

Import the Connector library

If you want to use the Go Connector, you have to import the package.

import "github.com/rticommunity/rticonnextdds-connector-go"

Instantiate a new connector

To create a new connector you have to pass a location of an XML configuration file and a configuration name in XML. For more information on the XML format check the XML App Creation guide.

connector, err := rti.NewConnector("MyParticipantLibrary::Zero", filepath)

Delete a connector

To destroy all the DDS entities created by a connector, you should call the Delete().

connector, err := rti.NewConnector("MyParticipantLibrary::Zero", filepath)
...
...
connector.Delete()

Write a data sample

To write a data sample, you have to get a reference to the output port:

output, err := connector.GetOutput("MyPublisher::MySquareWriter")

then you have to set the fields in a sample instance:

output.Instance.SetInt("x", i)
output.Instance.SetInt("y", i*2)
output.Instance.SetInt("shapesize", 30)
output.Instance.SetString("color", "BLUE")

and then you can write:

output.Write();

Setting the fields in a sample instance:

The content of an instance can be set using a Go type that matches the original DDS type, or field by field:

  • Using a Go type with JSON encoding:
// Define a Go type for shape data
// Add an annotation (e.g. json:"color") that indicates an corresponding field in a DDS type
// The Set function uses the built-in encoding function for JSON
type Shape struct {
	Color     string `json:"color"`
	X         int    `json:"x"`
	Y         int    `json:"y"`
	Shapesize int    `json:"shapesize"`
}

var shape Shape
shape.Y = 2
output.Instance.Set(&shape)
  • Field by field:
output.Instance.SetInt("y", 2);

Nested fields can be accessed with the dot notation: "x.y.z", and array or sequences with square brakets: "x.y[1].z".

Reading/taking samples

To read/take samples first you have to get a reference to the input port:

input, err := connector.GetInput("MySubscriber::MySquareReader")

then you can call the Read() or Take() API:

input.Read();

or

input.Take();
  • Field by field: You can access each field individually like the example below. A Read() or Take() can return multiple samples. They are stored in an array. Every time you try to access a specific sample you have to specify an index (j in the example below).
input.Take()
numOfSamples := input.Samples.GetLength()
for j := 0; j < numOfSamples; j++ {
    if input.Infos.IsValid(j) {
        color := input.Samples.GetString(j, "color")
        x := input.Samples.GetInt(j, "x")
        y := input.Samples.GetInt(j, "y")
        shapesize := input.Samples.GetInt(j, "shapesize")

        log.Println("---Received Sample---")
        log.Printf("color: %s\n", color)
        log.Printf("x: %d\n", x)
        log.Printf("y: %d\n", y)
        log.Printf("shapesize: %d\n", shapesize)
}
  • Using a Go type with JSON decoding: You can access sample data in a deserialized Go type object.
// Define a Go type for shape data
// Add an annotation (e.g. json:"color") that indicates an corresponding field in a DDS type
// The Get function uses the built-in decoding function for JSON
type Shape struct {
        Color     string `json:"color"`
        X         int    `json:"x"`
        Y         int    `json:"y"`
        Shapesize int    `json:"shapesize"`
}

input.Take()
numOfSamples := input.Samples.GetLength()
for j := 0; j < numOfSamples; j++ {
    if input.Infos.IsValid(j) {
        var shape Shape
        err := input.Samples.Get(j, &shape)

        if err != nil {
            log.Println(err)
        }
        log.Println("---Received Sample---")
        log.Printf("color: %s\n", shape.Color)
        log.Printf("x: %d\n", shape.X)
        log.Printf("y: %d\n", shape.Y)
        log.Printf("shapesize: %d\n", shape.Shapesize)
}

Available Examples

Example Description Key Features
simple Basic publisher/subscriber Getting started, file-based XML configuration
go-get-example Example for go get users Inline XML, library download workflow
array Array data handling Complex data types, arrays
go_struct Go struct mapping JSON serialization, struct binding
request_reply RPC pattern Synchronous communication
security Secure communication Authentication, encryption
module Modular configuration XML organization, reusability
xml_string Inline XML configuration XML strings, no external files
sequence Sequence data types Dynamic arrays, sequences
read_and_write Combined reader/writer Single application pattern
reader_wait Blocking read pattern Waiting for data, timeouts