Go - Topic.Publish()

Publish an event (push based message) to a topic.

import (
  "context"
  "fmt"

  "github.com/nitrictech/go-sdk/api/events"
  "github.com/nitrictech/go-sdk/nitric"
)

func main() {
  updates, err := nitric.NewTopic("updates").Allow(nitric.TopicPublishing)
  if err != nil {
    fmt.Println(err)

    return
  }

  updates.Publish(context.TODO(), &events.Event{
    Payload: map[string]interface{}{
      "something": "amazing happened",
    },
  })

  if err := nitric.Run(); err != nil {
    fmt.Println(err)
  }
}

Parameters

  • Name
    ctx
    Required
    Required
    Type
    context
    Description

    The context of the call, used for tracing.

  • Name
    event
    Required
    Required
    Type
    Event
    Description

    The event to publish to the topic.

    • Name
      ID
      Optional
      Optional
      Type
      string
      Description

      Unique ID to apply to the event.

    • Name
      Payload
      Required
      Required
      Type
      map[string]interface{}
      Description

      Payload to send with the event.

    • Name
      PayloadType
      Optional
      Optional
      Type
      string
      Description

      A hint to the type of payload supplied.

  • Name
    opts
    Optional
    Optional
    Type
    PublishOption
    Description

    Optional function to send a message with a delay.

Examples

Publish a message

Publishing messages to a topic will push a copy of the message to each of the topic's subscribers. By default, delivery occurs without a delay.

import (
  "context"
  "fmt"

  "github.com/nitrictech/go-sdk/api/events"
  "github.com/nitrictech/go-sdk/nitric"
)

func main() {
  updates, err := nitric.NewTopic("updates").Allow(nitric.TopicPublishing)
  if err != nil {
    fmt.Println(err)

    return
  }

  err := updates.Publish(context.TODO(), &events.Event{
    Payload: map[string]interface{}{
      "something": "amazing happened",
    },
  })
  if err := nitric.Run(); err != nil {
    fmt.Println(err)
  }
}

Delaying message delivery

You can delay the delivery of messages sent to a topic. The current maximum delay is 7 days (604800 seconds).

import (
  "context"
  "fmt"
  "time"

  "github.com/nitrictech/go-sdk/api/events"
  "github.com/nitrictech/go-sdk/nitric"
)

func main() {
  updates, err := nitric.NewTopic("updates").Allow(nitric.TopicPublishing)
  if err != nil {
    fmt.Println(err)

    return
  }

  updates.Publish(context.TODO(), &events.Event{
    Payload: map[string]interface{}{
      "something": "amazing happened",
    },
  }, events.WithDelay(time.Hour))

  if err := nitric.Run(); err != nil {
    fmt.Println(err)
  }
}

Notes

  • If an id is not supplied with an event a UUID(v4) will be generated for you.
  • A function may subscribe to OR publish to a topic but not both.