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.
Get the metadata from a Google Cloud Platform environment
A comprehensive list of changes in each version may be found in
the CHANGELOG.
Read more about the client libraries for Cloud APIs, including the older
Google APIs Client Libraries, in Client Libraries Explained.
Table of contents:
Quickstart
Installing the client library
npm install gcp-metadata
Using the client library
const gcpMetadata = require('gcp-metadata');
async function quickstart() {
const isAvailable = await gcpMetadata.isAvailable();
console.log(`Is available: ${isAvailable}`);
if (isAvailable) {
const instanceMetadata = await gcpMetadata.instance();
console.log('Instance metadata:');
console.log(instanceMetadata);
const projectMetadata = await gcpMetadata.project();
console.log('Project metadata:');
console.log(projectMetadata);
}
}
quickstart();
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);
Access specific properties
const data = await gcpMetadata.instance('hostname');
console.log(data);
const projectId = await gcpMetadata.project('project-id');
console.log(projectId);
Access nested properties with the relative path
const data = await gcpMetadata.instance('service-accounts/default/email');
console.log(data);
Access specific properties with query parameters
const data = await gcpMetadata.instance({
property: 'tags',
params: { alt: 'text' }
});
console.log(data)
await gcpMetadata.instance({
headers: { 'no-trace': '1' }
});
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)
console.log(id.toString())
Environment variables
- GCE_METADATA_HOST: provide an alternate host or IP to perform lookup against (useful, for example, you're connecting through a custom proxy server).
For example:
export GCE_METADATA_HOST = '169.254.169.254'
- DETECT_GCP_RETRIES: number representing number of retries that should be attempted on metadata lookup.
Samples
Samples are in the samples/
directory. Each sample's README.md
has instructions for running its sample.
The GCP Metadata Node.js Client API Reference documentation
also contains samples.
Supported Node.js Versions
Our client libraries follow the Node.js release schedule.
Libraries are compatible with all current active and maintenance versions of
Node.js.
Client libraries targeting some end-of-life versions of Node.js are available, and
can be installed via npm dist-tags.
The dist-tags follow the naming convention legacy-(version)
.
Legacy Node.js versions are supported as a best effort:
- Legacy versions will not be tested in continuous integration.
- Some security patches may not be able to be backported.
- Dependencies will not be kept up-to-date, and features will not be backported.
Legacy tags available
legacy-8
: install client libraries from this dist-tag for versions
compatible with Node.js 8.
Versioning
This library follows Semantic Versioning.
This library is considered to be General Availability (GA). This means it
is stable; the code surface will not change in backwards-incompatible ways
unless absolutely necessary (e.g. because of critical security issues) or with
an extensive deprecation period. Issues and requests against GA libraries
are addressed with the highest priority.
More Information: Google Cloud Platform Launch Stages
Contributing
Contributions welcome! See the Contributing Guide.
Please note that this README.md
, the samples/README.md
,
and a variety of configuration files in this repository (including .nycrc
and tsconfig.json
)
are generated from a central template. To edit one of these files, make an edit
to its template in this
directory.
License
Apache Version 2.0
See LICENSE