Port value is not respected when setting AWS_EC2_METADATA_SERVICE_ENDPOINT environment variable and using request with @aws-sdk/ec2-metadata-service

[BenSteenson]

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

I am currently using amazon-ec2-metadata-mock to test using IMDSv2 via the latest @aws-sdk/ec2-metadata-service from my local machine. ec2-metadata-mock sets a default URL+PORT of http://localhost:1338 which works fine for me in a browser.

When I set the environment variable AWS_EC2_METADATA_SERVICE_ENDPOINT, the URL is respected, but the port number is lost. This is because the two locations in the metadata-service code that call upon import_protocol_http.HttpRequest() do not pass through the port value;

    const request = new HttpRequest({
      method: options.method || "GET",
      headers: headers,
      hostname: endpointUrl.hostname,
      path: endpointUrl.pathname + path,
      protocol: endpointUrl.protocol,
    });

I am able to fix this manually by adding port: endpointUrl.port to the outputted CJS.

Regression Issue

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

SDK version number

@aws-sdk/ec2-metadata-service@3.876.0

Which JavaScript Runtime is this issue in?

Node.js

Details of the browser/Node.js/ReactNative version

v22.18.0

Reproduction Steps

Download and run the application from amazon-ec2-metadata-mock, then execute the below code with NodeJS (changing the endpoint URL if necessary).

const { MetadataService } = require('@aws-sdk/ec2-metadata-service')

process.env.AWS_EC2_METADATA_SERVICE_ENDPOINT = 'http://localhost:1338'

async function getMetadata() {
  try {
    const metadataService = new MetadataService()
    const instanceIdentity = JSON.parse(await metadataService.request('latest/dynamic/instance-identity/document', {}))
    process.env.INSTANCE_ID = instanceIdentity.instanceId
    process.exit()
  }
  catch (err) {
    console.error('Error getting instance id: ', err)
    process.exit(1)
  }
}

getMetadata()

Observed Behavior

The port number in the environment variable AWS_EC2_METADATA_SERVICE_ENDPOINT is ignored and he request fails because it cannot find the metadata service with the default port.

The returned error is "Error getting instance id: Error: Error making request to the metadata service: AggregateError"

Expected Behavior

The request should follow the port number as well as the URL set by the environment variable AWS_EC2_METADATA_SERVICE_ENDPOINT and see the metadata service.

Possible Solution

Replace all cases of the following code:

        const request = new HttpRequest({
            method: options.method || "GET",
            headers: headers,
            hostname: endpointUrl.hostname,
            path: endpointUrl.pathname + path,
            protocol: endpointUrl.protocol,
        });

with this code:

        const request = new HttpRequest({
            method: options.method || "GET",
            headers: headers,
            hostname: endpointUrl.hostname,
            path: endpointUrl.pathname + path,
            protocol: endpointUrl.protocol,
            port: endpointUrl.port,
        });

Additional Information/Context

No response