listmonk/cmd/events.go
Kailash Nadh 414c5c0c99 Refactor the core concurrent campaign manager logic.
This commit fully refactors the core campaign manager logic.
It applies a whole new approach to campaign state and lifecycle management.

- Create a new "pipeline" abstraction on top of campaign
  for state management.
- Account for every message processed and end campaigns
  based on the actual count.
- Discard in-queue messages in the pipeline of a paused
  or cancelled campaign.
2024-01-02 14:57:04 +05:30

52 lines
1.1 KiB
Go

package main
import (
"encoding/json"
"fmt"
"log"
"time"
"github.com/labstack/echo/v4"
)
// handleEventStream serves an endpoint that never closes and pushes a
// live event stream (text/event-stream) such as a error messages.
func handleEventStream(c echo.Context) error {
var (
app = c.Get("app").(*App)
)
h := c.Response().Header()
h.Set(echo.HeaderContentType, "text/event-stream")
h.Set(echo.HeaderCacheControl, "no-store")
h.Set(echo.HeaderConnection, "keep-alive")
// Subscribe to the event stream with a random ID.
id := fmt.Sprintf("api:%v", time.Now().UnixNano())
sub, err := app.events.Subscribe(id)
if err != nil {
log.Fatalf("error subscribing to events: %v", err)
}
ctx := c.Request().Context()
for {
select {
case e := <-sub:
b, err := json.Marshal(e)
if err != nil {
app.log.Printf("error marshalling event: %v", err)
continue
}
c.Response().Write([]byte(fmt.Sprintf("retry: 3000\ndata: %s\n\n", b)))
c.Response().Flush()
case <-ctx.Done():
// On HTTP connection close, unsubscribe.
app.events.Unsubscribe(id)
return nil
}
}
return nil
}