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// Copyright 2020 New Relic Corporation. All rights reserved.
// SPDX-License-Identifier: Apache-2.0
package main
import (
"fmt"
"os"
"sync"
"time"
"github.com/nats-io/nats.go"
newrelic "github.com/newrelic/go-agent"
"github.com/newrelic/go-agent/_integrations/nrnats"
)
var app newrelic.Application
func doAsync(nc *nats.Conn, txn newrelic.Transaction) {
wg := sync.WaitGroup{}
subj := "async"
// Simple Async Subscriber
// Use the nrnats.SubWrapper to wrap the nats.MsgHandler and create a
// newrelic.Transaction with each processed nats.Msg
_, err := nc.Subscribe(subj, nrnats.SubWrapper(app, func(m *nats.Msg) {
defer wg.Done()
fmt.Println("Received async message:", string(m.Data))
}))
if nil != err {
panic(err)
}
// Simple Publisher
wg.Add(1)
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Publish
seg := nrnats.StartPublishSegment(txn, nc, subj)
err = nc.Publish(subj, []byte("Hello World"))
seg.End()
if nil != err {
panic(err)
}
wg.Wait()
}
func doQueue(nc *nats.Conn, txn newrelic.Transaction) {
wg := sync.WaitGroup{}
subj := "queue"
// Queue Subscriber
// Use the nrnats.SubWrapper to wrap the nats.MsgHandler and create a
// newrelic.Transaction with each processed nats.Msg
_, err := nc.QueueSubscribe(subj, "myQueueName", nrnats.SubWrapper(app, func(m *nats.Msg) {
defer wg.Done()
fmt.Println("Received queue message:", string(m.Data))
}))
if nil != err {
panic(err)
}
wg.Add(1)
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Publish
seg := nrnats.StartPublishSegment(txn, nc, subj)
err = nc.Publish(subj, []byte("Hello World"))
seg.End()
if nil != err {
panic(err)
}
wg.Wait()
}
func doSync(nc *nats.Conn, txn newrelic.Transaction) {
subj := "sync"
// Simple Sync Subscriber
sub, err := nc.SubscribeSync(subj)
if nil != err {
panic(err)
}
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Publish
seg := nrnats.StartPublishSegment(txn, nc, subj)
err = nc.Publish(subj, []byte("Hello World"))
seg.End()
if nil != err {
panic(err)
}
m, err := sub.NextMsg(time.Second)
if nil != err {
panic(err)
}
fmt.Println("Received sync message:", string(m.Data))
}
func doChan(nc *nats.Conn, txn newrelic.Transaction) {
subj := "chan"
// Channel Subscriber
ch := make(chan *nats.Msg)
_, err := nc.ChanSubscribe(subj, ch)
if nil != err {
panic(err)
}
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Publish
seg := nrnats.StartPublishSegment(txn, nc, subj)
err = nc.Publish(subj, []byte("Hello World"))
seg.End()
if nil != err {
panic(err)
}
m := <-ch
fmt.Println("Received chan message:", string(m.Data))
}
func doReply(nc *nats.Conn, txn newrelic.Transaction) {
subj := "reply"
// Replies
nc.Subscribe(subj, func(m *nats.Msg) {
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Publish
seg := nrnats.StartPublishSegment(txn, nc, m.Reply)
nc.Publish(m.Reply, []byte("Hello World"))
seg.End()
})
// Requests
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Request
seg := nrnats.StartPublishSegment(txn, nc, subj)
m, err := nc.Request(subj, []byte("request"), time.Second)
seg.End()
if nil != err {
panic(err)
}
fmt.Println("Received reply message:", string(m.Data))
}
func doRespond(nc *nats.Conn, txn newrelic.Transaction) {
subj := "respond"
// Respond
nc.Subscribe(subj, func(m *nats.Msg) {
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to m.Respond
seg := nrnats.StartPublishSegment(txn, nc, m.Reply)
m.Respond([]byte("Hello World"))
seg.End()
})
// Requests
// Use nrnats.StartPublishSegment to create a
// newrelic.MessageProducerSegment for the call to nc.Request
seg := nrnats.StartPublishSegment(txn, nc, subj)
m, err := nc.Request(subj, []byte("request"), time.Second)
seg.End()
if nil != err {
panic(err)
}
fmt.Println("Received respond message:", string(m.Data))
}
func mustGetEnv(key string) string {
if val := os.Getenv(key); "" != val {
return val
}
panic(fmt.Sprintf("environment variable %s unset", key))
}
func main() {
// Initialize agent
cfg := newrelic.NewConfig("NATS App", mustGetEnv("NEW_RELIC_LICENSE_KEY"))
cfg.Logger = newrelic.NewDebugLogger(os.Stdout)
var err error
app, err = newrelic.NewApplication(cfg)
if nil != err {
panic(err)
}
defer app.Shutdown(10 * time.Second)
err = app.WaitForConnection(5 * time.Second)
if nil != err {
panic(err)
}
txn := app.StartTransaction("main", nil, nil)
defer txn.End()
// Connect to a server
nc, err := nats.Connect(nats.DefaultURL)
if nil != err {
panic(err)
}
defer nc.Drain()
doAsync(nc, txn)
doQueue(nc, txn)
doSync(nc, txn)
doChan(nc, txn)
doReply(nc, txn)
doRespond(nc, txn)
}
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