Ta-Ching ChenandSoam Vasani
e4fe007838
Adds support for message queue triggers based on the NATS-Streaming message queue. This lets the user map a queue topic to a function, and optionally send the function's response into another queue topic. The message queue trigger manager is designed to be message queue independent, so we should be able add support for more queues by adding implementations for the relatively simple mqtrigger.MessageQueue interface.
113 lines
2.9 KiB
Go
113 lines
2.9 KiB
Go
// This file originally came from official Nats.io GitHub repository.
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// You can reach original file with the following link:
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// https://github.com/nats-io/go-nats-streaming/tree/master/examples
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// Copyright 2012-2016 Apcera Inc. All rights reserved.
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// +build ignore
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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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"github.com/nats-io/go-nats-streaming"
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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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`
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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 clusterID string
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var clientID string
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var async bool
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var URL string
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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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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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sc, err := stan.Connect(clusterID, clientID, stan.NatsURL(URL))
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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 != true {
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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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