gcp-metadata

What is gcp-metadata?

The gcp-metadata npm package is a library that allows users to query Google Cloud Platform's (GCP) metadata service for information about the currently running instance and project. This can be useful for applications that need to understand their environment within GCP, such as retrieving instance attributes or project details.

What are gcp-metadata's main functionalities?

Instance Metadata

Retrieve metadata of the current GCP instance. This includes details like the instance ID, zone, and custom metadata.

const gcpMetadata = require('gcp-metadata');

async function getInstanceMetadata() {
  if (await gcpMetadata.isAvailable()) {
    const instanceMetadata = await gcpMetadata.instance();
    console.log(instanceMetadata);
  }
}
getInstanceMetadata();

Project Metadata

Fetch metadata of the current GCP project. This can include project-wide attributes like project ID and numeric project number.

const gcpMetadata = require('gcp-metadata');

async function getProjectMetadata() {
  if (await gcpMetadata.isAvailable()) {
    const projectMetadata = await gcpMetadata.project();
    console.log(projectMetadata);
  }
}
getProjectMetadata();

Check Metadata Server Availability

Determine if the GCP metadata server is available and reachable from the instance.

const gcpMetadata = require('gcp-metadata');

async function checkAvailability() {
  const isAvailable = await gcpMetadata.isAvailable();
  console.log('Metadata service available:', isAvailable);
}
checkAvailability();

Other packages similar to gcp-metadata

aws-sdk

The AWS SDK for JavaScript allows developers to interact with AWS services. It includes a module for querying the AWS EC2 instance metadata service, which is similar to what gcp-metadata does for GCP.

README

gcp-metadata

Get the metadata from a Google Cloud Platform environment.

$ npm install --save gcp-metadata

const gcpMetadata = require('gcp-metadata');

Check to see if the metadata server is available

const isAvailable = await gcpMetadata.isAvailable();

Access all metadata

const data = await gcpMetadata.instance();
console.log(data); // ... All metadata properties

Access specific properties

const data = await gcpMetadata.instance('hostname');
console.log(data) // ...Instance hostname

Access specific properties with query parameters

const data = await gcpMetadata.instance({
  property: 'tags',
  params: { alt: 'text' }
});
console.log(data) // ...Tags as newline-delimited list

Access with custom headers

await gcpMetadata.instance({
  headers: { 'no-trace': '1' }
}); // ...Request is untraced

Take care with large number valued properties

In some cases number valued properties returned by the Metadata Service may be too large to be representable as JavaScript numbers. In such cases we return those values as BigNumber objects (from the bignumber.js library). Numbers that fit within the JavaScript number range will be returned as normal number values.

const id = await gcpMetadata.instance('id');
console.log(id)  // ... BigNumber { s: 1, e: 18, c: [ 45200, 31799277581759 ] }
console.log(id.toString()) // ... 4520031799277581759

Changelog

3.1.0 (2019-10-07)

Features

• don't throw on ENETUNREACH (#250) (88f2101)