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feat: warn on too many concurrent requests
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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,191 @@ | ||
| /*! | ||
| * Copyright 2020 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 | ||
| * | ||
| * 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. | ||
| */ | ||
|
|
||
| export interface TeenyStatisticsOptions { | ||
| /** | ||
| * A positive number representing when to issue a warning about the number | ||
| * of concurrent requests using teeny-request. | ||
| * Set to 0 to disable this warning. | ||
| * Corresponds to the TEENY_REQUEST_WARN_CONCURRENT_REQUESTS environment | ||
| * variable. | ||
| */ | ||
| concurrentRequests?: number; | ||
| } | ||
|
|
||
| type TeenyStatisticsConfig = Required<TeenyStatisticsOptions>; | ||
|
|
||
| /** | ||
| * TeenyStatisticsCounters is distinct from TeenyStatisticsOptions: | ||
| * Used when dumping current counters and other internal metrics. | ||
| */ | ||
| export interface TeenyStatisticsCounters { | ||
| concurrentRequests: number; | ||
| } | ||
|
|
||
| /** | ||
| * @class TeenyStatisticsWarning | ||
| * @extends Error | ||
| * @description While an error, is used for emitting warnings when | ||
| * meeting certain configured thresholds. | ||
| * @see process.emitWarning | ||
| */ | ||
| export class TeenyStatisticsWarning extends Error { | ||
| static readonly CONCURRENT_REQUESTS = 'ConcurrentRequestsExceededWarning'; | ||
|
|
||
| public threshold = 0; | ||
| public type = ''; | ||
| public value = 0; | ||
|
|
||
| /** | ||
| * @param {string} message | ||
| */ | ||
| constructor(message: string) { | ||
| super(message); | ||
| this.name = this.constructor.name; | ||
| Error.captureStackTrace(this, this.constructor); | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * @class TeenyStatistics | ||
| * @description Maintain various statistics internal to teeny-request. Tracking | ||
| * is not automatic and must be instrumented within teeny-request. | ||
| */ | ||
| export class TeenyStatistics { | ||
| /** | ||
| * @description A default threshold representing when to warn about excessive | ||
| * in-flight/concurrent requests. | ||
| * @type {number} | ||
| * @static | ||
| * @readonly | ||
| * @default 5000 | ||
| */ | ||
| static readonly DEFAULT_WARN_CONCURRENT_REQUESTS = 5e3; | ||
|
|
||
| /** | ||
| * @type {TeenyStatisticsConfig} | ||
| * @private | ||
| */ | ||
| private _options: TeenyStatisticsConfig; | ||
|
|
||
| /** | ||
| * @type {number} | ||
| * @private | ||
| * @default 0 | ||
| */ | ||
| private _concurrentRequests = 0; | ||
|
|
||
| /** | ||
| * @type {boolean} | ||
| * @private | ||
| * @default false | ||
| */ | ||
| private _didConcurrentRequestWarn = false; | ||
|
|
||
| /** | ||
| * @param {TeenyStatisticsOptions} [opts] | ||
| */ | ||
| constructor(opts?: TeenyStatisticsOptions) { | ||
| this._options = TeenyStatistics._prepareOptions(opts); | ||
| } | ||
|
|
||
| /** | ||
| * Change configured statistics options. This will not preserve unspecified | ||
| * options that were previously specified, i.e. this is a reset of options. | ||
| * @param {TeenyStatisticsOptions} [opts] | ||
| * @returns {TeenyStatisticsConfig} The previous options. | ||
| * @see _prepareOptions | ||
| */ | ||
| setOptions(opts?: TeenyStatisticsOptions): TeenyStatisticsConfig { | ||
| const oldOpts = this._options; | ||
| this._options = TeenyStatistics._prepareOptions(opts); | ||
| return oldOpts; | ||
| } | ||
|
|
||
| /** | ||
| * @readonly | ||
| * @return {TeenyStatisticsCounters} | ||
| */ | ||
| get counters(): TeenyStatisticsCounters { | ||
| return { | ||
| concurrentRequests: this._concurrentRequests, | ||
| }; | ||
| } | ||
|
|
||
| /** | ||
| * @description Should call this right before making a request. | ||
| */ | ||
| requestStarting(): void { | ||
| this._concurrentRequests++; | ||
|
|
||
| if ( | ||
| this._options.concurrentRequests > 0 && | ||
| this._concurrentRequests >= this._options.concurrentRequests && | ||
| !this._didConcurrentRequestWarn | ||
| ) { | ||
| this._didConcurrentRequestWarn = true; | ||
| const warning = new TeenyStatisticsWarning( | ||
| 'Possible excessive concurrent requests detected. ' + | ||
| this._concurrentRequests + | ||
| ' requests in-flight, which exceeds the configured threshold of ' + | ||
| this._options.concurrentRequests + | ||
| '. Use the TEENY_REQUEST_WARN_CONCURRENT_REQUESTS environment ' + | ||
| 'variable or the concurrentRequests option of teeny-request to ' + | ||
| 'increase or disable (0) this warning.' | ||
| ); | ||
| warning.type = TeenyStatisticsWarning.CONCURRENT_REQUESTS; | ||
| warning.value = this._concurrentRequests; | ||
| warning.threshold = this._options.concurrentRequests; | ||
| process.emitWarning(warning); | ||
| } | ||
| } | ||
|
|
||
| /** | ||
| * @description When using `requestStarting`, call this after the request | ||
| * has finished. | ||
| */ | ||
| requestFinished() { | ||
| // TODO negative? | ||
| this._concurrentRequests--; | ||
| } | ||
|
|
||
| /** | ||
| * Configuration Precedence: | ||
| * 1. Dependency inversion via defined option. | ||
| * 2. Global numeric environment variable. | ||
| * 3. Built-in default. | ||
| * This will not preserve unspecified options previously specified. | ||
| * @param {TeenyStatisticsOptions} [opts] | ||
| * @returns {TeenyStatisticsOptions} | ||
| * @private | ||
| */ | ||
| private static _prepareOptions({ | ||
| concurrentRequests: diConcurrentRequests, | ||
| }: TeenyStatisticsOptions = {}): TeenyStatisticsConfig { | ||
| let concurrentRequests = this.DEFAULT_WARN_CONCURRENT_REQUESTS; | ||
|
|
||
| const envConcurrentRequests = Number( | ||
| process.env.TEENY_REQUEST_WARN_CONCURRENT_REQUESTS | ||
| ); | ||
| if (diConcurrentRequests !== undefined) { | ||
| concurrentRequests = diConcurrentRequests; | ||
| } else if (!Number.isNaN(envConcurrentRequests)) { | ||
| concurrentRequests = envConcurrentRequests; | ||
| } | ||
|
|
||
| return {concurrentRequests}; | ||
| } | ||
| } |
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