socket hang in lambda wiith S3 HeadCommand

[nicolashuby]

Checkboxes for prior research

• I've gone through Developer Guide and API reference
• I've checked AWS Forums and StackOverflow.
• I've searched for previous similar issues and didn't find any solution.

Describe the bug

With "@aws-sdk/client-s3": "3.830.0" I have often a socket hangup at the first HEAD Command. There is no fucntionnal impact since the retry works well and genrally the second HEAD Command is successful.
If I downgrade the version to my previous version in production "@aws-sdk/client-s3": "3.777.0" the error is not reprodcutible.
I try several tuning with the S3 Client.
First one :

this.client = new S3Client({
     region: REGION,
     requestHandler: new NodeHttpHandler({
       httpsAgent: new Agent({ keepAlive: true, keepAliveMsecs: 2000, timeout: 10000, maxSockets: 400 }),
       connectionTimeout: 30 * 1000, // 30 seconds
       requestTimeout: 60 * 1000, // 1 minute
     }),

Second one:

this.client = new S3Client({
      region: REGION,
      requestHandler: new NodeHttpHandler({
        httpsAgent: new Agent({ keepAlive: true, keepAliveMsecs: 2000, timeout: 10000, maxSockets: 50 }),
        connectionTimeout: 30 * 1000, // 30 seconds
        requestTimeout: 60 * 1000, // 1 minute
      }),

Here the global runtime configuration

const LAMBDA_RUNTIME = 'nodejs22.x'
const DATADOG_LAYER_ARN = 'arn:aws:lambda:eu-west-3:464622532012:layer:Datadog-Node22-x:124' // See https://github.com/DataDog/datadog-lambda-js/releases
const DATADOG_LAYER_EXTENSION_ARN = 'arn:aws:lambda:eu-west-3:464622532012:layer:Datadog-Extension:77' // See https://github.com/DataDog/datadog-lambda-extension/releases

Regression Issue

• Select this option if this issue appears to be a regression.

SDK version number

"@aws-sdk/client-s3": "3.830.0"

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

node runtime 22

Reproduction Steps

How to reproduce.

• deploy a lambda with a HEAD Command which is triggered with S3 events
• Upload several Object in the bucket using the aws console

Observed Behavior

• The first HEAD Command observe 'socket hangup' error with S3 Service randomly , the second call is always succcessful

Expected Behavior

No 'socket hangup' observed

Possible Solution

I think that my S3 client is not well tuned but I did not fine how to do it.

Additional Information/Context

No response

[aBurmeseDev]

Hi @nicolashuby - thanks for checking in!

Common root causes for socket exhaustion issues are typically due to the number of socket allocation: maxSockets isn't high enough for your needs and/or when you're working with stream, you must read the stream to completion in order for the socket to close naturally or destroy the stream in Node.js.

More on that here: https://github.com/aws/aws-sdk-js-v3/blob/main/supplemental-docs/CLIENTS.md#nodejs-requesthandler

Also in your post, you mentioned the same version "@aws-sdk/client-s3": "3.830.0" as working and non-working versions. What's the version where the issue is reproducible? And what's the reason behind different maxSockets number in your code snippets "First one" and "Second one"?

[nicolashuby]

Sorry , I have just edited to 3.777.0 as the last working version tested in production.

[aBurmeseDev]

Got it! As mentioned, please consider adjusting maxSockets number and see if it changes behavior. Since the version gap is big, there might've been a lot of changes but if issue persists, please share a minimal reproducible code and error logs.

Best,
John

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