144 lines
3.9 KiB
Go
144 lines
3.9 KiB
Go
// This file originally came from official Nats.io GitHub repository.
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// You can reach the original file with the following link:
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// https://github.com/nats-io/stan.go/blob/master/examples/stan-pub/main.go
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// Copyright 2016-2019 The NATS Authors
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package main
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import (
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"flag"
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"fmt"
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"log"
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"os"
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"sync"
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"time"
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nats "github.com/nats-io/nats.go"
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"github.com/nats-io/stan.go"
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)
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var usageStr = `
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Usage: stan-pub [options] <subject> <message>
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Options:
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-s, --server <url> NATS Streaming server URL(s)
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-c, --cluster <cluster name> NATS Streaming cluster name
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-id, --clientid <client ID> NATS Streaming client ID
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-a, --async Asynchronous publish mode
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-cr, --creds <credentials> NATS 2.0 Credentials
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`
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// NOTE: Use tls scheme for TLS, e.g. stan-pub -s tls://demo.nats.io:4443 foo hello
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func usage() {
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fmt.Printf("%s\n", usageStr)
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os.Exit(0)
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}
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func main() {
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var (
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clusterID string
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clientID string
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URL string
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async bool
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userCreds string
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)
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flag.StringVar(&URL, "s", stan.DefaultNatsURL, "The nats server URLs (separated by comma)")
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flag.StringVar(&URL, "server", stan.DefaultNatsURL, "The nats server URLs (separated by comma)")
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flag.StringVar(&clusterID, "c", "test-cluster", "The NATS Streaming cluster ID")
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flag.StringVar(&clusterID, "cluster", "test-cluster", "The NATS Streaming cluster ID")
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flag.StringVar(&clientID, "id", "stan-pub", "The NATS Streaming client ID to connect with")
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flag.StringVar(&clientID, "clientid", "stan-pub", "The NATS Streaming client ID to connect with")
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flag.BoolVar(&async, "a", false, "Publish asynchronously")
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flag.BoolVar(&async, "async", false, "Publish asynchronously")
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flag.StringVar(&userCreds, "cr", "", "Credentials File")
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flag.StringVar(&userCreds, "creds", "", "Credentials File")
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log.SetFlags(0)
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flag.Usage = usage
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flag.Parse()
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args := flag.Args()
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if len(args) < 1 {
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usage()
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}
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// Connect Options.
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opts := []nats.Option{nats.Name("NATS Streaming Example Publisher")}
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// Use UserCredentials
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if userCreds != "" {
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opts = append(opts, nats.UserCredentials(userCreds))
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}
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// Connect to NATS
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nc, err := nats.Connect(URL, opts...)
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if err != nil {
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log.Fatal(err)
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}
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defer nc.Close()
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sc, err := stan.Connect(clusterID, clientID, stan.NatsConn(nc))
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if err != nil {
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log.Fatalf("Can't connect: %v.\nMake sure a NATS Streaming Server is running at: %s", err, URL)
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}
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defer sc.Close()
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subj, msg := args[0], []byte(args[1])
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ch := make(chan bool)
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var glock sync.Mutex
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var guid string
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acb := func(lguid string, err error) {
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glock.Lock()
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log.Printf("Received ACK for guid %s\n", lguid)
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defer glock.Unlock()
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if err != nil {
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log.Fatalf("Error in server ack for guid %s: %v\n", lguid, err)
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}
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if lguid != guid {
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log.Fatalf("Expected a matching guid in ack callback, got %s vs %s\n", lguid, guid)
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}
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ch <- true
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}
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if !async {
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err = sc.Publish(subj, msg)
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if err != nil {
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log.Fatalf("Error during publish: %v\n", err)
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}
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log.Printf("Published [%s] : '%s'\n", subj, msg)
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} else {
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glock.Lock()
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guid, err = sc.PublishAsync(subj, msg, acb)
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if err != nil {
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log.Fatalf("Error during async publish: %v\n", err)
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}
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glock.Unlock()
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if guid == "" {
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log.Fatal("Expected non-empty guid to be returned.")
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}
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log.Printf("Published [%s] : '%s' [guid: %s]\n", subj, msg, guid)
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select {
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case <-ch:
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break
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case <-time.After(5 * time.Second):
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log.Fatal("timeout")
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}
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}
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}
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