@google-cloud/pubsub
Version:
Cloud Pub/Sub Client Library for Node.js
115 lines • 3.85 kB
JavaScript
;
/*!
* Copyright 2017 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.Throttler = void 0;
exports.promisifySome = promisifySome;
exports.noop = noop;
exports.addToBucket = addToBucket;
exports.awaitWithTimeout = awaitWithTimeout;
const promisify_1 = require("@google-cloud/promisify");
/**
* This replaces usage of promisifyAll(), going forward. Instead of opting
* some methods out, you will need to opt methods in. Additionally, this
* function validates method names against the class using TypeScript,
* to generate compile-time failures for misspellings and changes.
*
* Future work in the library should all be Promise-first.
*
* @private
*/
function promisifySome(class_, classProto, methods, options) {
methods.forEach(methodName => {
// Do the same stream checks as promisifyAll().
const m = classProto[methodName];
classProto[methodName] = (0, promisify_1.promisify)(m, options);
});
}
function noop() { }
/**
* Provides a very simple throttling capability for tasks like error logs.
* This ensures that no task is actually completed unless N millis have passed
* since the last one.
*
* @private
*/
class Throttler {
minMillis;
lastTime;
constructor(minMillis) {
this.minMillis = minMillis;
}
/**
* Performs the task requested, if enough time has passed since the
* last successful call.
*/
doMaybe(task) {
const now = Date.now();
const doTask = !this.lastTime ||
(this.lastTime && now - this.lastTime >= this.minMillis);
if (doTask) {
task();
this.lastTime = now;
}
}
}
exports.Throttler = Throttler;
/**
* Takes care of managing a Map of buckets to the bucket arrays themselves.
*
* @private
*/
function addToBucket(map, bucket, item) {
const items = map.get(bucket) ?? [];
items.push(item);
map.set(bucket, items);
}
const timeoutToken = Symbol('pubsub promise timeout');
/**
* Awaits on Promise with a timeout. Resolves on the passed promise resolving or
* rejecting, or on timeout.
*
* @param promise An existing Promise returning type T.
* @param timeout A timeout value as a Duration; if the timeout is exceeded while
* waiting for the promise, the Promise this function returns will resolve, but
* with `timedOut` set.
* @returns A TimeoutReturn with the returned value, if applicable, an exception if
* the promise rejected, or the timedOut set to true if it timed out.
*/
async function awaitWithTimeout(promise, timeout) {
let timeoutId;
const timeoutPromise = new Promise((_, rej) => {
timeoutId = setTimeout(() => rej(timeoutToken), timeout.milliseconds);
});
try {
const value = await Promise.race([timeoutPromise, promise]);
clearTimeout(timeoutId);
return {
returnedValue: value,
timedOut: false,
};
}
catch (e) {
const err = e;
// The timeout passed or the promise rejected.
clearTimeout(timeoutId);
return {
exception: (err !== timeoutToken ? err : undefined),
timedOut: err === timeoutToken,
};
}
}
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