在 nodejs 中创建大量 google pubsub 订阅者的推荐方法是什么？

Question

我需要收听大约 40 个订阅（未来几天不会增加）。

如果那时只有一个订阅，我会做以下事情，

const subName = 'mysubscription'
const pubSubClient = new PubSub()
const startVidsubscription = pubSubClient.subscription(subName)
startVidsubscription.on('message', messageHandler)

const messageHandler = async(message) => {
// do stuff

}

但是，当我有几十个订阅时，我不能这样做。所以，我正在尝试如下所示：

// the name is the name of each subscription and the variable is the variable name in which I will be holding the subscription object. 
var subscriptionDetails = [
    {'name': 'M10057-sub-cam1Api', 'variable': 'M10057Subscription'},
    {'name': 'M10058-sub-cam1Api', 'variable': 'M10058Subscription'},
    {'name': 'M10059-sub-cam1Api', 'variable': 'M10059Subscription'},
]

for(const subscription of subscriptionDetails){
        var subscription.variable = pubSubClient.subscription(subscription.name)
        subscription.variable.on('message', messageHandler)
    }

但这给了我像 Unexpected token, expected ; 这样的错误。

有没有大佬告诉我在nodejs中收听大量订阅的推荐方法

Answer 1

您的一般方法应该有效。您可能运行在将订阅对象分配给 subscription.variable 时遇到问题，该对象已定义为字符串。

像下面这样的东西会起作用：

const {PubSub} = require('@google-cloud/pubsub');

const pubSubClient = new PubSub();
const messageHandler = async(message) => {
  // ... handle message ...
};

var subscriptionDetails = [
  {'name': 'M10057-sub-cam1Api'},
  {'name': 'M10058-sub-cam1Api'},
  {'name': 'M10059-sub-cam1Api'},
];

for (const subscription of subscriptionDetails) {
  subscription.variable = pubSubClient.subscription(subscription.name);
  subscription.variable.on('message', messageHandler);
}

然后您可以使用 subscriptionDetails 中的 variable 字段引用订阅对象。

如果您想通过名称 'M10057Subscription' 引用订阅对象，您可以创建订阅对象映射：

var subscriptionDetails = [
  {'name': 'M10057-sub-cam1Api', 'variable': 'M10057Subscription'},
  {'name': 'M10058-sub-cam1Api', 'variable': 'M10058Subscription'},
  {'name': 'M10059-sub-cam1Api', 'variable': 'M10059Subscription'},
];

var subscriptionObjects = {};

for (const subscription of subscriptionDetails) {
  subscriptionObjects[subscription.variable] = pubSubClient.subscription(subscription.name);
  subscriptionObjects[subscription.variable].on('message', messageHandler);
}

// subscriptionObjects['M10057Subscription'] is a subscription object

在 nodejs 中创建大量 google pubsub 订阅者的推荐方法是什么？

What's the recommended way of creating a large no of google pubsub subscribers in nodejs?

publish-subscribe

node.js

google-cloud-platform

google-cloud-pubsub