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// Copyright 2012-2022 The NATS Authors
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package main
import (
"flag"
"log"
"os"
"time"
"github.com/nats-io/nats.go"
)
// NOTE: Can test with demo servers.
// nats-req -s demo.nats.io <subject> <msg>
func usage() {
log.Printf("Usage: nats-req [-s server] [-creds file] [-nkey file] <subject> <msg>\n")
flag.PrintDefaults()
}
func showUsageAndExit(exitcode int) {
usage()
os.Exit(exitcode)
}
func main() {
var urls = flag.String("s", nats.DefaultURL, "The nats server URLs (separated by comma)")
var userCreds = flag.String("creds", "", "User Credentials File")
var nkeyFile = flag.String("nkey", "", "NKey Seed File")
var showHelp = flag.Bool("h", false, "Show help message")
log.SetFlags(0)
flag.Usage = usage
flag.Parse()
if *showHelp {
showUsageAndExit(0)
}
args := flag.Args()
if len(args) < 2 {
showUsageAndExit(1)
}
// Connect Options.
opts := []nats.Option{nats.Name("NATS Sample Requestor")}
if *userCreds != "" && *nkeyFile != "" {
log.Fatal("specify -seed or -creds")
}
// Use UserCredentials
if *userCreds != "" {
opts = append(opts, nats.UserCredentials(*userCreds))
}
// Use Nkey authentication.
if *nkeyFile != "" {
opt, err := nats.NkeyOptionFromSeed(*nkeyFile)
if err != nil {
log.Fatal(err)
}
opts = append(opts, opt)
}
// Connect to NATS
nc, err := nats.Connect(*urls, opts...)
if err != nil {
log.Fatal(err)
}
defer nc.Close()
subj, payload := args[0], []byte(args[1])
msg, err := nc.Request(subj, payload, 2*time.Second)
if err != nil {
if nc.LastError() != nil {
log.Fatalf("%v for request", nc.LastError())
}
log.Fatalf("%v for request", err)
}
log.Printf("Published [%s] : '%s'", subj, payload)
log.Printf("Received [%v] : '%s'", msg.Subject, string(msg.Data))
}
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