@google-cloud/pubsub/build/src/publisher/message-queues.js

"use strict";
/*!
 * Copyright 2019 Google Inc. All Rights Reserved.
 *
 * 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
 *
 *      http://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.
 */
Object.defineProperty(exports, "__esModule", { value: true });
exports.OrderedQueue = exports.Queue = exports.MessageQueue = void 0;
const events_1 = require("events");
const message_batch_1 = require("./message-batch");
const publish_error_1 = require("./publish-error");
/**
 * Queues are used to manage publishing batches of messages.
 *
 * @private
 *
 * @param {Publisher} publisher The parent publisher.
 */
class MessageQueue extends events_1.EventEmitter {
    constructor(publisher) {
        super();
        this.publisher = publisher;
        this.batchOptions = publisher.settings.batching;
    }
    /**
     * Forces the queue to update its options from the publisher.
     * The specific queue will need to do a bit more to pass the new
     * values down into any MessageBatch.
     *
     * This is only for use by {@link Publisher}.
     *
     * @private
     */
    updateOptions() {
        this.batchOptions = this.publisher.settings.batching;
    }
    /**
     * Accepts a batch of messages and publishes them to the API.
     *
     * @param {object[]} messages The messages to publish.
     * @param {PublishCallback[]} callbacks The corresponding callback functions.
     * @param {function} [callback] Callback to be fired when publish is done.
     */
    _publish(messages, callbacks, callback) {
        const { topic, settings } = this.publisher;
        const reqOpts = {
            topic: topic.name,
            messages,
        };
        if (messages.length === 0) {
            if (typeof callback === 'function') {
                callback(null);
            }
            return;
        }
        topic.request({
            client: 'PublisherClient',
            method: 'publish',
            reqOpts,
            gaxOpts: settings.gaxOpts,
        }, (err, resp) => {
            const messageIds = (resp && resp.messageIds) || [];
            callbacks.forEach((callback, i) => callback(err, messageIds[i]));
            if (typeof callback === 'function') {
                callback(err);
            }
        });
    }
}
exports.MessageQueue = MessageQueue;
/**
 * Standard message queue used for publishing messages.
 *
 * @private
 * @extends MessageQueue
 *
 * @param {Publisher} publisher The publisher.
 */
class Queue extends MessageQueue {
    constructor(publisher) {
        super(publisher);
        this.batch = new message_batch_1.MessageBatch(this.batchOptions);
    }
    // This needs to update our existing message batch.
    updateOptions() {
        super.updateOptions();
        this.batch.setOptions(this.batchOptions);
    }
    /**
     * Adds a message to the queue.
     *
     * @param {PubsubMessage} message The message to publish.
     * @param {PublishCallback} callback The publish callback.
     */
    add(message, callback) {
        if (!this.batch.canFit(message)) {
            this.publish();
        }
        this.batch.add(message, callback);
        if (this.batch.isFull()) {
            this.publish();
        }
        else if (!this.pending) {
            const { maxMilliseconds } = this.batchOptions;
            this.pending = setTimeout(() => this.publish(), maxMilliseconds);
        }
    }
    /**
     * Cancels any pending publishes and calls _publish immediately.
     */
    publish(callback) {
        const { messages, callbacks } = this.batch;
        this.batch = new message_batch_1.MessageBatch(this.batchOptions);
        if (this.pending) {
            clearTimeout(this.pending);
            delete this.pending;
        }
        this._publish(messages, callbacks, callback);
    }
}
exports.Queue = Queue;
/**
 * Queue for handling ordered messages. Unlike the standard queue, this
 * ensures that batches are published one at a time and throws an exception in
 * the event that any batch fails to publish.
 *
 * @private
 * @extends MessageQueue
 *
 * @param {Publisher} publisher The publisher.
 * @param {string} key The key used to order the messages.
 */
class OrderedQueue extends MessageQueue {
    constructor(publisher, key) {
        super(publisher);
        this.batches = [];
        this.inFlight = false;
        this.key = key;
    }
    // This needs to update our existing message batches.
    updateOptions() {
        super.updateOptions();
        this.batches.forEach(b => b.setOptions(this.batchOptions));
    }
    /**
     * Reference to the batch we're currently filling.
     * @returns {MessageBatch}
     */
    get currentBatch() {
        if (!this.batches.length) {
            this.batches.push(this.createBatch());
        }
        return this.batches[0];
    }
    /**
     * Adds a message to a batch, creating a new batch if need be.
     *
     * @param {object} message The message to publish.
     * @param {PublishCallback} callback The publish callback.
     */
    add(message, callback) {
        if (this.error) {
            callback(this.error);
            return;
        }
        if (this.inFlight) {
            // in the event that a batch is currently in flight, we can overfill
            // the next batch as long as it hasn't hit the API limit
            if (this.currentBatch.isAtMax()) {
                this.batches.unshift(this.createBatch());
            }
            this.currentBatch.add(message, callback);
            return;
        }
        if (!this.currentBatch.canFit(message)) {
            this.publish();
        }
        this.currentBatch.add(message, callback);
        // it is possible that we triggered a publish earlier, so we'll need to
        // check again here
        if (!this.inFlight) {
            if (this.currentBatch.isFull()) {
                this.publish();
            }
            else if (!this.pending) {
                this.beginNextPublish();
            }
        }
    }
    /**
     * Starts a timeout to publish any pending messages.
     */
    beginNextPublish() {
        const maxMilliseconds = this.batchOptions.maxMilliseconds;
        const timeWaiting = Date.now() - this.currentBatch.created;
        const delay = Math.max(0, maxMilliseconds - timeWaiting);
        this.pending = setTimeout(() => this.publish(), delay);
    }
    /**
     * Creates a new {@link MessageBatch} instance.
     *
     * @returns {MessageBatch}
     */
    createBatch() {
        return new message_batch_1.MessageBatch(this.batchOptions);
    }
    /**
     * In the event of a publish failure, we need to cache the error in question
     * and reject all pending publish calls, prompting the user to call
     * {@link OrderedQueue#resumePublishing}.
     *
     * @param {Error} err The publishing error.
     */
    handlePublishFailure(err) {
        this.error = new publish_error_1.PublishError(this.key, err);
        // reject all pending publishes
        while (this.batches.length) {
            const { callbacks } = this.batches.pop();
            callbacks.forEach(callback => callback(err));
        }
    }
    /**
     * Publishes the messages. If successful it will prepare the next batch to be
     * published immediately after. If an error occurs, it will reject all
     * pending messages. In the event that no pending messages/batches are left,
     * a "drain" event will be fired, indicating to the publisher that it is
     * safe to delete this queue.
     *
     * @fires OrderedQueue#drain
     */
    publish(callback) {
        const definedCallback = callback || (() => { });
        this.inFlight = true;
        if (this.pending) {
            clearTimeout(this.pending);
            delete this.pending;
        }
        const { messages, callbacks } = this.batches.pop();
        this._publish(messages, callbacks, (err) => {
            this.inFlight = false;
            if (err) {
                this.handlePublishFailure(err);
                definedCallback(err);
            }
            else if (this.batches.length) {
                this.beginNextPublish();
            }
            else {
                this.emit('drain');
                definedCallback(null);
            }
        });
    }
    /**
     * Tells the queue it is ok to continue publishing messages.
     */
    resumePublishing() {
        delete this.error;
        // once this is called, we'll make this object eligible for garbage
        // collection. by wrapping in nextTick() we'll give users an opportunity
        // to use it again instead of deleting instantly and then creating a new
        // instance.
        process.nextTick(() => {
            if (!this.batches.length) {
                this.emit('drain');
            }
        });
    }
}
exports.OrderedQueue = OrderedQueue;
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