nrstan

Overview ¶

Package nrstan instruments https://github.com/nats-io/stan.go.

This package can be used to simplify instrumenting NATS Streaming subscribers. Currently due to the nature of the NATS Streaming framework we are limited to two integration points: `StartPublishSegment` for publishers, and `SubWrapper` for subscribers.

NATS Streaming subscribers ¶

`nrstan.StreamingSubWrapper` can be used to wrap the function for STREAMING stan.Subscribe and stan.QueueSubscribe (https://godoc.org/github.com/nats-io/stan.go#Conn) If the `newrelic.Application` parameter is non-nil, it will create a `newrelic.Transaction` and end the transaction when the passed function is complete. Example:

sc, err := stan.Connect(clusterName, clientName)
if err != nil {
	t.Fatal("Couldn't connect to server", err)
}
defer sc.Close()
app := createTestApp(t)  // newrelic.Application
sc.Subscribe(subject, StreamingSubWrapper(app, myMessageHandler)

NATS Streaming publishers ¶

You can use `nrnats.StartPublishSegment` from the `nrnats` package (https://godoc.org/github.com/newrelic/go-agent/_integrations/nrnats/#StartPublishSegment) to start an external segment when doing a streaming publish, which must be ended after publishing is complete. Example:

sc, err := stan.Connect(clusterName, clientName)
if err != nil {
	t.Fatal("Couldn't connect to server", err)
}
txn := currentTransaction()  // current newrelic.Transaction
seg := nrnats.StartPublishSegment(txn, sc.NatsConn(), subj)
sc.Publish(subj, []byte("Hello World"))
seg.End()

Full Publisher/Subscriber example: https://github.com/newrelic/go-agent/blob/master/_integrations/nrstan/examples/main.go