"Could not load the default credentials" - PubSub Node.js module using the Emulator

1
votes

I'm having an issue with the PubSub module for Node.js. I've created a local environment using Docker and the PubSub emulator. I'm able to publish a message and retrieve it using the asynchronous pull (as documented here: https://cloud.google.com/pubsub/docs/pull#asynchronous-pull). However when I'm trying to use the synchronous pull (https://cloud.google.com/pubsub/docs/pull#synchronous-pull) I keep having the following error:

Error: Could not load the default credentials. Browse to https://cloud.google.com/docs/authentication/getting-started for more information. at GoogleAuth. (/var/code/node_modules/google-auth-library/build/src/auth/googleauth.js:167:23) at next (native) at fulfilled (/var/code/node_modules/google-auth-library/build/src/auth/googleauth.js:19:58) at process._tickCallback (internal/process/next_tick.js:109:7) (node:493) PromiseRejectionHandledWarning: Promise rejection was handled asynchronously (rejection id: 32)

This error happens whenever I'm trying to instantiate the v1 PublisherClient or SubscriberClient:

const pubsub = require('@google-cloud/pubsub');

new pubsub.v1.PublisherClient();
new pubsub.v1.SubscriberClient();

I feel like the v1 components do not work with the emulator but connect directly to the cloud services instead. Is there a way to make these clients connect to the emulator rather than the cloud? I can't find any... Thanks !

2
node.jsgoogle-cloud-platformgoogle-cloud-pubsub

2 Answers

2
votes

I found out how to solve this issue: both PublisherClient and SubscriberClient constructors have options that set the path to the emulator. The options are servicePath and port. You also need valid credentials to pass to the sslCreds option, generated using the grpc module. Below is a sample:

const grpc = require('grpc');

const subscriber = new pubsub.v1.SubscriberClient({
  servicePath: 'path.to.your.emulator',
  port: 8080, // port your emulator is running on (default is 443)
  sslCreds: grpc.credentials.createInsecure()
});

Here is the complete answer: https://github.com/googleapis/nodejs-pubsub/issues/346

1
votes

The following TS sample seems to work for me.

import { PubSub, v1 } from "@google-cloud/pubsub";
import * as gax from "google-gax";

if (process.env.PUBSUB_EMULATOR_HOST) {
    const pieces = process.env.PUBSUB_EMULATOR_HOST.split(":");

    options = {
        servicePath: pieces[0],
        port: pieces[1],
        isEmulator: true,
        sslCreds: gax.grpc.credentials.createInsecure(),
    };
}
const subClient = new v1.SubscriberClient(options);