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// 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 Protobuf Messages to a Topic
// description: Publishes a message in protobuf form to a topic with a schema.
// usage: node publishProtobufMessages.js <topic-name-or-id>
// [START pubsub_publish_proto_messages]
/**
* TODO(developer): Uncomment this variable before running the sample.
*/
// const topicNameOrId = 'YOUR_TOPIC_NAME_OR_ID';
// Imports the Google Cloud client library
const {PubSub, Encodings} = require('@google-cloud/pubsub');
// And the protobufjs library
const protobuf = require('protobufjs');
// Creates a client; cache this for further use
const pubSubClient = new PubSub();
async function publishProtobufMessages(topicNameOrId) {
// Cache topic objects (publishers) and reuse them.
const topic = pubSubClient.topic(topicNameOrId);
// Get the topic metadata to learn about its schema.
const [topicMetadata] = await topic.getMetadata();
const topicSchemaMetadata = topicMetadata.schemaSettings;
if (!topicSchemaMetadata) {
console.log(`Topic ${topicNameOrId} doesn't seem to have a schema.`);
return;
}
const schemaEncoding = topicSchemaMetadata.encoding;
// Encode the message.
const province = {
name: 'Ontario',
postAbbr: 'ON',
};
// Make an encoder using the protobufjs library.
//
// Since we're providing the test message for a specific schema here, we'll
// also code in the path to a sample proto definition.
const root = await protobuf.load('system-test/fixtures/provinces.proto');
const Province = root.lookupType('utilities.Province');
const message = Province.create(province);
let dataBuffer;
switch (schemaEncoding) {
case Encodings.Binary:
dataBuffer = Buffer.from(Province.encode(message).finish());
break;
case Encodings.Json:
dataBuffer = Buffer.from(JSON.stringify(message.toJSON()));
break;
default:
console.log(`Unknown schema encoding: ${schemaEncoding}`);
break;
}
if (!dataBuffer) {
console.log(`Invalid encoding ${schemaEncoding} on the topic.`);
return;
}
const messageId = await topic.publishMessage({data: dataBuffer});
console.log(`Protobuf message ${messageId} published.`);
}
// [END pubsub_publish_proto_messages]
function main(topicName = 'YOUR_TOPIC_NAME') {
publishProtobufMessages(topicName).catch(err => {
console.error(err.message);
process.exitCode = 1;
});
}
main(...process.argv.slice(2));