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Multiple AWS Instances and Node events

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I have an implementation in node where an API when called does some processing and waits for an event from another function before returning the response. This works fine when ran locally and when running in a single instance in AWS but when multiple instances are involved there are some issues which I'm assuming is because the API is being called from one instance and the emitter is being emitted in another instance. Is there any way to keep the listeners and emitters same across all instances?

node.js amazon-web-services amazon-elastic-beanstalk

share|improve this question

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

add a comment | 

0

I have an implementation in node where an API when called does some processing and waits for an event from another function before returning the response. This works fine when ran locally and when running in a single instance in AWS but when multiple instances are involved there are some issues which I'm assuming is because the API is being called from one instance and the emitter is being emitted in another instance. Is there any way to keep the listeners and emitters same across all instances?

node.js amazon-web-services amazon-elastic-beanstalk

share|improve this question

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

add a comment | 

I have an implementation in node where an API when called does some processing and waits for an event from another function before returning the response. This works fine when ran locally and when running in a single instance in AWS but when multiple instances are involved there are some issues which I'm assuming is because the API is being called from one instance and the emitter is being emitted in another instance. Is there any way to keep the listeners and emitters same across all instances?

node.js amazon-web-services amazon-elastic-beanstalk

share|improve this question

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

share|improve this question

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

share|improve this question

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

asked Mar 22 at 4:52

VinaayakhVinaayakh

199311

1 Answer
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oldest

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0

AFAIU you think that event emitted from one process is being handled in a different process, but it never would be the case from what I know because each process has its own memory and also events would be associated with the process only.

I have added a sample code that demonstrates what I meant by it. Maybe if you post the code you are referring to, we could check what went wrong.

const cluster = require("cluster");
const EventEmitter = require("events");

if (cluster.isMaster) 
 cluster.fork();
 const myEE = new EventEmitter();
 myEE.on("foo", arg =>
 console.log("emitted from ", arg, "received in master")
 );
 setTimeout(() => 
 myEE.emit("foo", "master");
 , 1000);
 else 
 const myEE = new EventEmitter();
 myEE.on("foo", arg => console.log("emitted from", arg, "received in worker"));
 setTimeout(() => 
 myEE.emit("foo", "client");
 , 2000);

share|improve this answer

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hi Kiran, I tried this implementation but the issue I'm facing is that if an event is emitted in a fork, then all the other listeners in the other forks should also be able to receive the event and process it. Is this possible?
  
  – Vinaayakh
  Mar 29 at 6:23
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Vinaayakh I think your requirement is different from what you have stated in the question, neverthless I can suggest some solutions for your requirement. Either you can do is send a message from worker using process.send(msg); and let master resend the message to all other workers using worker.send('hi there');. or the best and preferred way is to setup a pub/sub using redis(redis.io/topics/pubsub) or node-ipc(npmjs.com/package/node-ipc). Please refer this for more idea stackoverflow.com/questions/55400905/…
  
  – Kiran Mathew Mohan
  Mar 29 at 6:34
  

  
  
  
  

add a comment | 

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0

AFAIU you think that event emitted from one process is being handled in a different process, but it never would be the case from what I know because each process has its own memory and also events would be associated with the process only.

I have added a sample code that demonstrates what I meant by it. Maybe if you post the code you are referring to, we could check what went wrong.

const cluster = require("cluster");
const EventEmitter = require("events");

if (cluster.isMaster) 
 cluster.fork();
 const myEE = new EventEmitter();
 myEE.on("foo", arg =>
 console.log("emitted from ", arg, "received in master")
 );
 setTimeout(() => 
 myEE.emit("foo", "master");
 , 1000);
 else 
 const myEE = new EventEmitter();
 myEE.on("foo", arg => console.log("emitted from", arg, "received in worker"));
 setTimeout(() => 
 myEE.emit("foo", "client");
 , 2000);

share|improve this answer

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hi Kiran, I tried this implementation but the issue I'm facing is that if an event is emitted in a fork, then all the other listeners in the other forks should also be able to receive the event and process it. Is this possible?
  
  – Vinaayakh
  Mar 29 at 6:23
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Vinaayakh I think your requirement is different from what you have stated in the question, neverthless I can suggest some solutions for your requirement. Either you can do is send a message from worker using process.send(msg); and let master resend the message to all other workers using worker.send('hi there');. or the best and preferred way is to setup a pub/sub using redis(redis.io/topics/pubsub) or node-ipc(npmjs.com/package/node-ipc). Please refer this for more idea stackoverflow.com/questions/55400905/…
  
  – Kiran Mathew Mohan
  Mar 29 at 6:34
  

  
  
  
  

add a comment | 

0

AFAIU you think that event emitted from one process is being handled in a different process, but it never would be the case from what I know because each process has its own memory and also events would be associated with the process only.

I have added a sample code that demonstrates what I meant by it. Maybe if you post the code you are referring to, we could check what went wrong.

const cluster = require("cluster");
const EventEmitter = require("events");

if (cluster.isMaster) 
 cluster.fork();
 const myEE = new EventEmitter();
 myEE.on("foo", arg =>
 console.log("emitted from ", arg, "received in master")
 );
 setTimeout(() => 
 myEE.emit("foo", "master");
 , 1000);
 else 
 const myEE = new EventEmitter();
 myEE.on("foo", arg => console.log("emitted from", arg, "received in worker"));
 setTimeout(() => 
 myEE.emit("foo", "client");
 , 2000);

share|improve this answer

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213

• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  Hi Kiran, I tried this implementation but the issue I'm facing is that if an event is emitted in a fork, then all the other listeners in the other forks should also be able to receive the event and process it. Is this possible?
  
  – Vinaayakh
  Mar 29 at 6:23
  

  
  
  
  


• 
  
  
  

  
  

  
  
  
  
  
  

  
  
  @Vinaayakh I think your requirement is different from what you have stated in the question, neverthless I can suggest some solutions for your requirement. Either you can do is send a message from worker using process.send(msg); and let master resend the message to all other workers using worker.send('hi there');. or the best and preferred way is to setup a pub/sub using redis(redis.io/topics/pubsub) or node-ipc(npmjs.com/package/node-ipc). Please refer this for more idea stackoverflow.com/questions/55400905/…
  
  – Kiran Mathew Mohan
  Mar 29 at 6:34
  

  
  
  
  

add a comment | 

AFAIU you think that event emitted from one process is being handled in a different process, but it never would be the case from what I know because each process has its own memory and also events would be associated with the process only.

I have added a sample code that demonstrates what I meant by it. Maybe if you post the code you are referring to, we could check what went wrong.

const cluster = require("cluster");
const EventEmitter = require("events");

if (cluster.isMaster) 
 cluster.fork();
 const myEE = new EventEmitter();
 myEE.on("foo", arg =>
 console.log("emitted from ", arg, "received in master")
 );
 setTimeout(() => 
 myEE.emit("foo", "master");
 , 1000);
 else 
 const myEE = new EventEmitter();
 myEE.on("foo", arg => console.log("emitted from", arg, "received in worker"));
 setTimeout(() => 
 myEE.emit("foo", "client");
 , 2000);

share|improve this answer

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213

const cluster = require("cluster");
const EventEmitter = require("events");

if (cluster.isMaster) 
 cluster.fork();
 const myEE = new EventEmitter();
 myEE.on("foo", arg =>
 console.log("emitted from ", arg, "received in master")
 );
 setTimeout(() => 
 myEE.emit("foo", "master");
 , 1000);
 else 
 const myEE = new EventEmitter();
 myEE.on("foo", arg => console.log("emitted from", arg, "received in worker"));
 setTimeout(() => 
 myEE.emit("foo", "client");
 , 2000);

share|improve this answer

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213

answered Mar 22 at 5:38

Kiran Mathew MohanKiran Mathew Mohan

573213