channels.md

Channel APIs

Channel APIs take the work of sending to a Producer, or receiving from a Consumer, and simplify the approach down to using Go Channels. In order to use these APIs, you'd call the Receive method on a Consumer, or the Send method on a Producer. For example:

package main

import (
    "fmt"

    "github.com/caravan/essentials"
    "github.com/caravan/essentials/topic/config"
)

func main() {
    top := essentials.NewTopic[string](config.Permanent)

    // Send some stuff to the topic via its channel
    go func() {
        p := top.NewProducer()
        for i := 0; i < 10; i++ {
            p.Send() <- fmt.Sprintf("Message %d", i)
        }
        p.Close()
    }()

    // Receive some stuff from the topic via its channel
    go func() {
        c := top.NewConsumer()
        for i := 0; i < 10; i++ {
            fmt.Println(<-c.Receive())
        }
        c.Close()
    }()

    <- make(chan bool) // hit ctrl-c
}

One difference between normal channel use in Go and the Channel API in Caravan is that you still have to explicitly call Close on the Producer or Consumer. The reason for this is that a Topic manages a set of subscriber resources under the hood that can't be automatically garbage collected if the channel is closed.