publishMessage.js

// Copyright 2019-2024 Google LLC
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     https://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

// This is a generated sample, using the typeless sample bot. Please
// look for the source TypeScript sample (.ts) for modifications.
'use strict';

/**
 * This sample demonstrates how to perform basic operations on topics with
 * the Google Cloud Pub/Sub API.
 *
 * For more information, see the README.md under /pubsub and the documentation
 * at https://cloud.google.com/pubsub/docs.
 */

// sample-metadata:
//   title: Publish Message
//   description: Publishes a message to a topic.
//   usage: node publishMessage.js <topic-name-or-id> <data>

// [START pubsub_publish_with_error_handler]
// [START pubsub_quickstart_publisher]
/**
 * TODO(developer): Uncomment these variables before running the sample.
 */
// const topicNameOrId = 'YOUR_TOPIC_NAME_OR_ID';
// const data = JSON.stringify({foo: 'bar'});

// Imports the Google Cloud client library
const {PubSub} = require('@google-cloud/pubsub');

// Creates a client; cache this for further use
const pubSubClient = new PubSub();

async function publishMessage(topicNameOrId, data) {
  // Publishes the message as a string, e.g. "Hello, world!" or JSON.stringify(someObject)
  const dataBuffer = Buffer.from(data);

  // Cache topic objects (publishers) and reuse them.
  const topic = pubSubClient.topic(topicNameOrId);

  try {
    const messageId = topic.publishMessage({data: dataBuffer});
    console.log(`Message ${messageId} published.`);
  } catch (error) {
    console.error(`Received error while publishing: ${error.message}`);
    process.exitCode = 1;
  }
}
// [END pubsub_publish_with_error_handler]
// [END pubsub_quickstart_publisher]

function main(
  topicNameOrId = 'YOUR_TOPIC_NAME_OR_ID',
  data = JSON.stringify({foo: 'bar'})
) {
  publishMessage(topicNameOrId, data).catch(err => {
    console.error(err.message);
    process.exitCode = 1;
  });
}

main(...process.argv.slice(2));