client.ts

// File generated from our OpenAPI spec by Stainless. See CONTRIBUTING.md for details.

import type { RequestInit, RequestInfo, BodyInit } from './internal/builtin-types';
import type { HTTPMethod, PromiseOrValue, MergedRequestInit, FinalizedRequestInit } from './internal/types';
import { uuid4 } from './internal/utils/uuid';
import { validatePositiveInteger, isAbsoluteURL, safeJSON } from './internal/utils/values';
import { sleep } from './internal/utils/sleep';
export type { Logger, LogLevel } from './internal/utils/log';
import { castToError, isAbortError } from './internal/errors';
import type { APIResponseProps } from './internal/parse';
import { getPlatformHeaders } from './internal/detect-platform';
import * as Shims from './internal/shims';
import * as Opts from './internal/request-options';
import { stringifyQuery } from './internal/utils/query';
import { VERSION } from './version';
import * as Errors from './core/error';
import * as Pagination from './core/pagination';
import { AbstractPage, type OffsetPaginationParams, OffsetPaginationResponse } from './core/pagination';
import * as Uploads from './core/uploads';
import * as API from './resources/index';
import { APIPromise } from './core/api-promise';
import { AppListParams, AppListResponse, AppListResponsesOffsetPagination, Apps } from './resources/apps';
import {
  BrowserPool,
  BrowserPoolAcquireParams,
  BrowserPoolAcquireResponse,
  BrowserPoolCreateParams,
  BrowserPoolDeleteParams,
  BrowserPoolListResponse,
  BrowserPoolReleaseParams,
  BrowserPoolUpdateParams,
  BrowserPools,
} from './resources/browser-pools';
import {
  CreateCredentialProviderRequest,
  CredentialProvider,
  CredentialProviderCreateParams,
  CredentialProviderItem,
  CredentialProviderListItemsResponse,
  CredentialProviderListResponse,
  CredentialProviderTestResult,
  CredentialProviderUpdateParams,
  CredentialProviders,
  UpdateCredentialProviderRequest,
} from './resources/credential-providers';
import {
  CreateCredentialRequest,
  Credential,
  CredentialCreateParams,
  CredentialListParams,
  CredentialTotpCodeResponse,
  CredentialUpdateParams,
  Credentials,
  CredentialsOffsetPagination,
  UpdateCredentialRequest,
} from './resources/credentials';
import {
  DeploymentCreateParams,
  DeploymentCreateResponse,
  DeploymentFollowParams,
  DeploymentFollowResponse,
  DeploymentListParams,
  DeploymentListResponse,
  DeploymentListResponsesOffsetPagination,
  DeploymentRetrieveResponse,
  DeploymentStateEvent,
  Deployments,
} from './resources/deployments';
import { KernelApp } from './core/app-framework';
import {
  ExtensionDownloadFromChromeStoreParams,
  ExtensionListResponse,
  ExtensionUploadParams,
  ExtensionUploadResponse,
  Extensions,
} from './resources/extensions';
import {
  InvocationCreateParams,
  InvocationCreateResponse,
  InvocationFollowParams,
  InvocationFollowResponse,
  InvocationListBrowsersResponse,
  InvocationListParams,
  InvocationListResponse,
  InvocationListResponsesOffsetPagination,
  InvocationRetrieveResponse,
  InvocationStateEvent,
  InvocationUpdateParams,
  InvocationUpdateResponse,
  Invocations,
} from './resources/invocations';
import { ProfileCreateParams, ProfileListParams, Profiles } from './resources/profiles';
import {
  Proxies,
  ProxyCheckResponse,
  ProxyCreateParams,
  ProxyCreateResponse,
  ProxyListResponse,
  ProxyRetrieveResponse,
} from './resources/proxies';
import { Auth } from './resources/auth/auth';
import {
  BrowserCreateParams,
  BrowserCreateResponse,
  BrowserDeleteParams,
  BrowserListParams,
  BrowserListResponse,
  BrowserListResponsesOffsetPagination,
  BrowserLoadExtensionsParams,
  BrowserPersistence,
  BrowserPoolRef,
  BrowserRetrieveParams,
  BrowserRetrieveResponse,
  BrowserUpdateParams,
  BrowserUpdateResponse,
  BrowserUsage,
  Browsers,
  Profile,
} from './resources/browsers/browsers';
import { type Fetch } from './internal/builtin-types';
import { HeadersLike, NullableHeaders, buildHeaders } from './internal/headers';
import { FinalRequestOptions, RequestOptions } from './internal/request-options';
import { readEnv } from './internal/utils/env';
import {
  type LogLevel,
  type Logger,
  formatRequestDetails,
  loggerFor,
  parseLogLevel,
} from './internal/utils/log';
import { isEmptyObj } from './internal/utils/values';

const environments = {
  production: 'https://api.onkernel.com/',
  development: 'https://localhost:3001/',
};
type Environment = keyof typeof environments;

export interface ClientOptions {
  /**
   * Defaults to process.env['KERNEL_API_KEY'].
   */
  apiKey?: string | undefined;

  /**
   * Specifies the environment to use for the API.
   *
   * Each environment maps to a different base URL:
   * - `production` corresponds to `https://api.onkernel.com/`
   * - `development` corresponds to `https://localhost:3001/`
   */
  environment?: Environment | undefined;

  /**
   * Override the default base URL for the API, e.g., "https://api.example.com/v2/"
   *
   * Defaults to process.env['KERNEL_BASE_URL'].
   */
  baseURL?: string | null | undefined;

  /**
   * The maximum amount of time (in milliseconds) that the client should wait for a response
   * from the server before timing out a single request.
   *
   * Note that request timeouts are retried by default, so in a worst-case scenario you may wait
   * much longer than this timeout before the promise succeeds or fails.
   *
   * @unit milliseconds
   */
  timeout?: number | undefined;
  /**
   * Additional `RequestInit` options to be passed to `fetch` calls.
   * Properties will be overridden by per-request `fetchOptions`.
   */
  fetchOptions?: MergedRequestInit | undefined;

  /**
   * Specify a custom `fetch` function implementation.
   *
   * If not provided, we expect that `fetch` is defined globally.
   */
  fetch?: Fetch | undefined;

  /**
   * The maximum number of times that the client will retry a request in case of a
   * temporary failure, like a network error or a 5XX error from the server.
   *
   * @default 2
   */
  maxRetries?: number | undefined;

  /**
   * Default headers to include with every request to the API.
   *
   * These can be removed in individual requests by explicitly setting the
   * header to `null` in request options.
   */
  defaultHeaders?: HeadersLike | undefined;

  /**
   * Default query parameters to include with every request to the API.
   *
   * These can be removed in individual requests by explicitly setting the
   * param to `undefined` in request options.
   */
  defaultQuery?: Record<string, string | undefined> | undefined;

  /**
   * Set the log level.
   *
   * Defaults to process.env['KERNEL_LOG'] or 'warn' if it isn't set.
   */
  logLevel?: LogLevel | undefined;

  /**
   * Set the logger.
   *
   * Defaults to globalThis.console.
   */
  logger?: Logger | undefined;
}

/**
 * API Client for interfacing with the Kernel API.
 */
export class Kernel {
  apiKey: string;

  baseURL: string;
  maxRetries: number;
  timeout: number;
  logger: Logger;
  logLevel: LogLevel | undefined;
  fetchOptions: MergedRequestInit | undefined;

  private fetch: Fetch;
  #encoder: Opts.RequestEncoder;
  protected idempotencyHeader?: string;
  private _options: ClientOptions;

  /**
   * API Client for interfacing with the Kernel API.
   *
   * @param {string | undefined} [opts.apiKey=process.env['KERNEL_API_KEY'] ?? undefined]
   * @param {Environment} [opts.environment=production] - Specifies the environment URL to use for the API.
   * @param {string} [opts.baseURL=process.env['KERNEL_BASE_URL'] ?? https://api.onkernel.com/] - Override the default base URL for the API.
   * @param {number} [opts.timeout=1 minute] - The maximum amount of time (in milliseconds) the client will wait for a response before timing out.
   * @param {MergedRequestInit} [opts.fetchOptions] - Additional `RequestInit` options to be passed to `fetch` calls.
   * @param {Fetch} [opts.fetch] - Specify a custom `fetch` function implementation.
   * @param {number} [opts.maxRetries=2] - The maximum number of times the client will retry a request.
   * @param {HeadersLike} opts.defaultHeaders - Default headers to include with every request to the API.
   * @param {Record<string, string | undefined>} opts.defaultQuery - Default query parameters to include with every request to the API.
   */
  constructor({
    baseURL = readEnv('KERNEL_BASE_URL'),
    apiKey = readEnv('KERNEL_API_KEY'),
    ...opts
  }: ClientOptions = {}) {
    // Check for Bun runtime in a way that avoids type errors if Bun is not defined
    if (
      typeof globalThis !== 'undefined' &&
      typeof (globalThis as any).Bun !== 'undefined' &&
      (globalThis as any).Bun.version &&
      !readEnv('KERNEL_SUPPRESS_BUN_WARNING')
    ) {
      loggerFor(this).warn(
        'The Bun runtime was detected. Playwright may have CDP connection issues, proceed with caution. Suppress this warning by setting the KERNEL_SUPPRESS_BUN_WARNING environment variable to true',
      );
    }

    if (apiKey === undefined) {
      throw new Errors.KernelError(
        "The KERNEL_API_KEY environment variable is missing or empty; either provide it, or instantiate the Kernel client with an apiKey option, like new Kernel({ apiKey: 'My API Key' }).",
      );
    }

    const options: ClientOptions = {
      apiKey,
      ...opts,
      baseURL,
      environment: opts.environment ?? 'production',
    };

    if (baseURL && opts.environment) {
      throw new Errors.KernelError(
        'Ambiguous URL; The `baseURL` option (or KERNEL_BASE_URL env var) and the `environment` option are given. If you want to use the environment you must pass baseURL: null',
      );
    }

    this.baseURL = options.baseURL || environments[options.environment || 'production'];
    this.timeout = options.timeout ?? Kernel.DEFAULT_TIMEOUT /* 1 minute */;
    this.logger = options.logger ?? console;
    const defaultLogLevel = 'warn';
    // Set default logLevel early so that we can log a warning in parseLogLevel.
    this.logLevel = defaultLogLevel;
    this.logLevel =
      parseLogLevel(options.logLevel, 'ClientOptions.logLevel', this) ??
      parseLogLevel(readEnv('KERNEL_LOG'), "process.env['KERNEL_LOG']", this) ??
      defaultLogLevel;
    this.fetchOptions = options.fetchOptions;
    this.maxRetries = options.maxRetries ?? 2;
    this.fetch = options.fetch ?? Shims.getDefaultFetch();
    this.#encoder = Opts.FallbackEncoder;

    this._options = options;

    this.apiKey = apiKey;
  }

  /**
   * Create a new client instance re-using the same options given to the current client with optional overriding.
   */
  withOptions(options: Partial<ClientOptions>): this {
    const client = new (this.constructor as any as new (props: ClientOptions) => typeof this)({
      ...this._options,
      environment: options.environment ? options.environment : undefined,
      baseURL: options.environment ? undefined : this.baseURL,
      maxRetries: this.maxRetries,
      timeout: this.timeout,
      logger: this.logger,
      logLevel: this.logLevel,
      fetch: this.fetch,
      fetchOptions: this.fetchOptions,
      apiKey: this.apiKey,
      ...options,
    });
    return client;
  }

  /**
   * Check whether the base URL is set to its default.
   */
  #baseURLOverridden(): boolean {
    return this.baseURL !== environments[this._options.environment || 'production'];
  }

  protected defaultQuery(): Record<string, string | undefined> | undefined {
    return this._options.defaultQuery;
  }

  protected validateHeaders({ values, nulls }: NullableHeaders) {
    return;
  }

  protected async authHeaders(opts: FinalRequestOptions): Promise<NullableHeaders | undefined> {
    return buildHeaders([{ Authorization: `Bearer ${this.apiKey}` }]);
  }

  /**
   * Basic re-implementation of `qs.stringify` for primitive types.
   */
  protected stringifyQuery(query: object | Record<string, unknown>): string {
    return stringifyQuery(query);
  }

  private getUserAgent(): string {
    return `${this.constructor.name}/JS ${VERSION}`;
  }

  protected defaultIdempotencyKey(): string {
    return `stainless-node-retry-${uuid4()}`;
  }

  protected makeStatusError(
    status: number,
    error: Object,
    message: string | undefined,
    headers: Headers,
  ): Errors.APIError {
    return Errors.APIError.generate(status, error, message, headers);
  }

  buildURL(
    path: string,
    query: Record<string, unknown> | null | undefined,
    defaultBaseURL?: string | undefined,
  ): string {
    const baseURL = (!this.#baseURLOverridden() && defaultBaseURL) || this.baseURL;
    const url =
      isAbsoluteURL(path) ?
        new URL(path)
      : new URL(baseURL + (baseURL.endsWith('/') && path.startsWith('/') ? path.slice(1) : path));

    const defaultQuery = this.defaultQuery();
    if (!isEmptyObj(defaultQuery)) {
      query = { ...defaultQuery, ...query };
    }

    if (typeof query === 'object' && query && !Array.isArray(query)) {
      url.search = this.stringifyQuery(query);
    }

    return url.toString();
  }

  /**
   * Used as a callback for mutating the given `FinalRequestOptions` object.
   */
  protected async prepareOptions(options: FinalRequestOptions): Promise<void> {}

  /**
   * Used as a callback for mutating the given `RequestInit` object.
   *
   * This is useful for cases where you want to add certain headers based off of
   * the request properties, e.g. `method` or `url`.
   */
  protected async prepareRequest(
    request: RequestInit,
    { url, options }: { url: string; options: FinalRequestOptions },
  ): Promise<void> {}

  get<Rsp>(path: string, opts?: PromiseOrValue<RequestOptions>): APIPromise<Rsp> {
    return this.methodRequest('get', path, opts);
  }

  post<Rsp>(path: string, opts?: PromiseOrValue<RequestOptions>): APIPromise<Rsp> {
    return this.methodRequest('post', path, opts);
  }

  patch<Rsp>(path: string, opts?: PromiseOrValue<RequestOptions>): APIPromise<Rsp> {
    return this.methodRequest('patch', path, opts);
  }

  put<Rsp>(path: string, opts?: PromiseOrValue<RequestOptions>): APIPromise<Rsp> {
    return this.methodRequest('put', path, opts);
  }

  delete<Rsp>(path: string, opts?: PromiseOrValue<RequestOptions>): APIPromise<Rsp> {
    return this.methodRequest('delete', path, opts);
  }

  private methodRequest<Rsp>(
    method: HTTPMethod,
    path: string,
    opts?: PromiseOrValue<RequestOptions>,
  ): APIPromise<Rsp> {
    return this.request(
      Promise.resolve(opts).then((opts) => {
        return { method, path, ...opts };
      }),
    );
  }

  request<Rsp>(
    options: PromiseOrValue<FinalRequestOptions>,
    remainingRetries: number | null = null,
  ): APIPromise<Rsp> {
    return new APIPromise(this, this.makeRequest(options, remainingRetries, undefined));
  }

  private async makeRequest(
    optionsInput: PromiseOrValue<FinalRequestOptions>,
    retriesRemaining: number | null,
    retryOfRequestLogID: string | undefined,
  ): Promise<APIResponseProps> {
    const options = await optionsInput;
    const maxRetries = options.maxRetries ?? this.maxRetries;
    if (retriesRemaining == null) {
      retriesRemaining = maxRetries;
    }

    await this.prepareOptions(options);

    const { req, url, timeout } = await this.buildRequest(options, {
      retryCount: maxRetries - retriesRemaining,
    });

    await this.prepareRequest(req, { url, options });

    /** Not an API request ID, just for correlating local log entries. */
    const requestLogID = 'log_' + ((Math.random() * (1 << 24)) | 0).toString(16).padStart(6, '0');
    const retryLogStr = retryOfRequestLogID === undefined ? '' : `, retryOf: ${retryOfRequestLogID}`;
    const startTime = Date.now();

    loggerFor(this).debug(
      `[${requestLogID}] sending request`,
      formatRequestDetails({
        retryOfRequestLogID,
        method: options.method,
        url,
        options,
        headers: req.headers,
      }),
    );

    if (options.signal?.aborted) {
      throw new Errors.APIUserAbortError();
    }

    const controller = new AbortController();
    const response = await this.fetchWithTimeout(url, req, timeout, controller).catch(castToError);
    const headersTime = Date.now();

    if (response instanceof globalThis.Error) {
      const retryMessage = `retrying, ${retriesRemaining} attempts remaining`;
      if (options.signal?.aborted) {
        throw new Errors.APIUserAbortError();
      }
      // detect native connection timeout errors
      // deno throws "TypeError: error sending request for url (https://example/): client error (Connect): tcp connect error: Operation timed out (os error 60): Operation timed out (os error 60)"
      // undici throws "TypeError: fetch failed" with cause "ConnectTimeoutError: Connect Timeout Error (attempted address: example:443, timeout: 1ms)"
      // others do not provide enough information to distinguish timeouts from other connection errors
      const isTimeout =
        isAbortError(response) ||
        /timed? ?out/i.test(String(response) + ('cause' in response ? String(response.cause) : ''));
      if (retriesRemaining) {
        loggerFor(this).info(
          `[${requestLogID}] connection ${isTimeout ? 'timed out' : 'failed'} - ${retryMessage}`,
        );
        loggerFor(this).debug(
          `[${requestLogID}] connection ${isTimeout ? 'timed out' : 'failed'} (${retryMessage})`,
          formatRequestDetails({
            retryOfRequestLogID,
            url,
            durationMs: headersTime - startTime,
            message: response.message,
          }),
        );
        return this.retryRequest(options, retriesRemaining, retryOfRequestLogID ?? requestLogID);
      }
      loggerFor(this).info(
        `[${requestLogID}] connection ${isTimeout ? 'timed out' : 'failed'} - error; no more retries left`,
      );
      loggerFor(this).debug(
        `[${requestLogID}] connection ${isTimeout ? 'timed out' : 'failed'} (error; no more retries left)`,
        formatRequestDetails({
          retryOfRequestLogID,
          url,
          durationMs: headersTime - startTime,
          message: response.message,
        }),
      );
      if (isTimeout) {
        throw new Errors.APIConnectionTimeoutError();
      }
      throw new Errors.APIConnectionError({ cause: response });
    }

    const responseInfo = `[${requestLogID}${retryLogStr}] ${req.method} ${url} ${
      response.ok ? 'succeeded' : 'failed'
    } with status ${response.status} in ${headersTime - startTime}ms`;

    if (!response.ok) {
      const shouldRetry = await this.shouldRetry(response);
      if (retriesRemaining && shouldRetry) {
        const retryMessage = `retrying, ${retriesRemaining} attempts remaining`;

        // We don't need the body of this response.
        await Shims.CancelReadableStream(response.body);
        loggerFor(this).info(`${responseInfo} - ${retryMessage}`);
        loggerFor(this).debug(
          `[${requestLogID}] response error (${retryMessage})`,
          formatRequestDetails({
            retryOfRequestLogID,
            url: response.url,
            status: response.status,
            headers: response.headers,
            durationMs: headersTime - startTime,
          }),
        );
        return this.retryRequest(
          options,
          retriesRemaining,
          retryOfRequestLogID ?? requestLogID,
          response.headers,
        );
      }

      const retryMessage = shouldRetry ? `error; no more retries left` : `error; not retryable`;

      loggerFor(this).info(`${responseInfo} - ${retryMessage}`);

      const errText = await response.text().catch((err: any) => castToError(err).message);
      const errJSON = safeJSON(errText) as any;
      const errMessage = errJSON ? undefined : errText;

      loggerFor(this).debug(
        `[${requestLogID}] response error (${retryMessage})`,
        formatRequestDetails({
          retryOfRequestLogID,
          url: response.url,
          status: response.status,
          headers: response.headers,
          message: errMessage,
          durationMs: Date.now() - startTime,
        }),
      );

      const err = this.makeStatusError(response.status, errJSON, errMessage, response.headers);
      throw err;
    }

    loggerFor(this).info(responseInfo);
    loggerFor(this).debug(
      `[${requestLogID}] response start`,
      formatRequestDetails({
        retryOfRequestLogID,
        url: response.url,
        status: response.status,
        headers: response.headers,
        durationMs: headersTime - startTime,
      }),
    );

    return { response, options, controller, requestLogID, retryOfRequestLogID, startTime };
  }

  getAPIList<Item, PageClass extends Pagination.AbstractPage<Item> = Pagination.AbstractPage<Item>>(
    path: string,
    Page: new (...args: any[]) => PageClass,
    opts?: PromiseOrValue<RequestOptions>,
  ): Pagination.PagePromise<PageClass, Item> {
    return this.requestAPIList(
      Page,
      opts && 'then' in opts ?
        opts.then((opts) => ({ method: 'get', path, ...opts }))
      : { method: 'get', path, ...opts },
    );
  }

  requestAPIList<
    Item = unknown,
    PageClass extends Pagination.AbstractPage<Item> = Pagination.AbstractPage<Item>,
  >(
    Page: new (...args: ConstructorParameters<typeof Pagination.AbstractPage>) => PageClass,
    options: PromiseOrValue<FinalRequestOptions>,
  ): Pagination.PagePromise<PageClass, Item> {
    const request = this.makeRequest(options, null, undefined);
    return new Pagination.PagePromise<PageClass, Item>(this as any as Kernel, request, Page);
  }

  async fetchWithTimeout(
    url: RequestInfo,
    init: RequestInit | undefined,
    ms: number,
    controller: AbortController,
  ): Promise<Response> {
    const { signal, method, ...options } = init || {};
    const abort = this._makeAbort(controller);
    if (signal) signal.addEventListener('abort', abort, { once: true });

    const timeout = setTimeout(abort, ms);

    const isReadableBody =
      ((globalThis as any).ReadableStream && options.body instanceof (globalThis as any).ReadableStream) ||
      (typeof options.body === 'object' && options.body !== null && Symbol.asyncIterator in options.body);

    const fetchOptions: RequestInit = {
      signal: controller.signal as any,
      ...(isReadableBody ? { duplex: 'half' } : {}),
      method: 'GET',
      ...options,
    };
    if (method) {
      // Custom methods like 'patch' need to be uppercased
      // See https://github.com/nodejs/undici/issues/2294
      fetchOptions.method = method.toUpperCase();
    }

    try {
      // use undefined this binding; fetch errors if bound to something else in browser/cloudflare
      return await this.fetch.call(undefined, url, fetchOptions);
    } finally {
      clearTimeout(timeout);
    }
  }

  private async shouldRetry(response: Response): Promise<boolean> {
    // Note this is not a standard header.
    const shouldRetryHeader = response.headers.get('x-should-retry');

    // If the server explicitly says whether or not to retry, obey.
    if (shouldRetryHeader === 'true') return true;
    if (shouldRetryHeader === 'false') return false;

    // Retry on request timeouts.
    if (response.status === 408) return true;

    // Retry on lock timeouts.
    if (response.status === 409) return true;

    // Retry on rate limits.
    if (response.status === 429) return true;

    // Retry internal errors.
    if (response.status >= 500) return true;

    return false;
  }

  private async retryRequest(
    options: FinalRequestOptions,
    retriesRemaining: number,
    requestLogID: string,
    responseHeaders?: Headers | undefined,
  ): Promise<APIResponseProps> {
    let timeoutMillis: number | undefined;

    // Note the `retry-after-ms` header may not be standard, but is a good idea and we'd like proactive support for it.
    const retryAfterMillisHeader = responseHeaders?.get('retry-after-ms');
    if (retryAfterMillisHeader) {
      const timeoutMs = parseFloat(retryAfterMillisHeader);
      if (!Number.isNaN(timeoutMs)) {
        timeoutMillis = timeoutMs;
      }
    }

    // About the Retry-After header: https://developer.mozilla.org/en-US/docs/Web/HTTP/Headers/Retry-After
    const retryAfterHeader = responseHeaders?.get('retry-after');
    if (retryAfterHeader && !timeoutMillis) {
      const timeoutSeconds = parseFloat(retryAfterHeader);
      if (!Number.isNaN(timeoutSeconds)) {
        timeoutMillis = timeoutSeconds * 1000;
      } else {
        timeoutMillis = Date.parse(retryAfterHeader) - Date.now();
      }
    }

    // If the API asks us to wait a certain amount of time (and it's a reasonable amount),
    // just do what it says, but otherwise calculate a default
    if (!(timeoutMillis && 0 <= timeoutMillis && timeoutMillis < 60 * 1000)) {
      const maxRetries = options.maxRetries ?? this.maxRetries;
      timeoutMillis = this.calculateDefaultRetryTimeoutMillis(retriesRemaining, maxRetries);
    }
    await sleep(timeoutMillis);

    return this.makeRequest(options, retriesRemaining - 1, requestLogID);
  }

  private calculateDefaultRetryTimeoutMillis(retriesRemaining: number, maxRetries: number): number {
    const initialRetryDelay = 0.5;
    const maxRetryDelay = 8.0;

    const numRetries = maxRetries - retriesRemaining;

    // Apply exponential backoff, but not more than the max.
    const sleepSeconds = Math.min(initialRetryDelay * Math.pow(2, numRetries), maxRetryDelay);

    // Apply some jitter, take up to at most 25 percent of the retry time.
    const jitter = 1 - Math.random() * 0.25;

    return sleepSeconds * jitter * 1000;
  }

  async buildRequest(
    inputOptions: FinalRequestOptions,
    { retryCount = 0 }: { retryCount?: number } = {},
  ): Promise<{ req: FinalizedRequestInit; url: string; timeout: number }> {
    const options = { ...inputOptions };
    const { method, path, query, defaultBaseURL } = options;

    const url = this.buildURL(path!, query as Record<string, unknown>, defaultBaseURL);
    if ('timeout' in options) validatePositiveInteger('timeout', options.timeout);
    options.timeout = options.timeout ?? this.timeout;
    const { bodyHeaders, body } = this.buildBody({ options });
    const reqHeaders = await this.buildHeaders({ options: inputOptions, method, bodyHeaders, retryCount });

    const req: FinalizedRequestInit = {
      method,
      headers: reqHeaders,
      ...(options.signal && { signal: options.signal }),
      ...((globalThis as any).ReadableStream &&
        body instanceof (globalThis as any).ReadableStream && { duplex: 'half' }),
      ...(body && { body }),
      ...((this.fetchOptions as any) ?? {}),
      ...((options.fetchOptions as any) ?? {}),
    };

    return { req, url, timeout: options.timeout };
  }

  private async buildHeaders({
    options,
    method,
    bodyHeaders,
    retryCount,
  }: {
    options: FinalRequestOptions;
    method: HTTPMethod;
    bodyHeaders: HeadersLike;
    retryCount: number;
  }): Promise<Headers> {
    let idempotencyHeaders: HeadersLike = {};
    if (this.idempotencyHeader && method !== 'get') {
      if (!options.idempotencyKey) options.idempotencyKey = this.defaultIdempotencyKey();
      idempotencyHeaders[this.idempotencyHeader] = options.idempotencyKey;
    }

    const headers = buildHeaders([
      idempotencyHeaders,
      {
        Accept: 'application/json',
        'User-Agent': this.getUserAgent(),
        'X-Stainless-Retry-Count': String(retryCount),
        ...(options.timeout ? { 'X-Stainless-Timeout': String(Math.trunc(options.timeout / 1000)) } : {}),
        ...getPlatformHeaders(),
      },
      await this.authHeaders(options),
      this._options.defaultHeaders,
      bodyHeaders,
      options.headers,
    ]);

    this.validateHeaders(headers);

    return headers.values;
  }

  private _makeAbort(controller: AbortController) {
    // note: we can't just inline this method inside `fetchWithTimeout()` because then the closure
    //       would capture all request options, and cause a memory leak.
    return () => controller.abort();
  }

  private buildBody({ options: { body, headers: rawHeaders } }: { options: FinalRequestOptions }): {
    bodyHeaders: HeadersLike;
    body: BodyInit | undefined;
  } {
    if (!body) {
      return { bodyHeaders: undefined, body: undefined };
    }
    const headers = buildHeaders([rawHeaders]);
    if (
      // Pass raw type verbatim
      ArrayBuffer.isView(body) ||
      body instanceof ArrayBuffer ||
      body instanceof DataView ||
      (typeof body === 'string' &&
        // Preserve legacy string encoding behavior for now
        headers.values.has('content-type')) ||
      // `Blob` is superset of `File`
      ((globalThis as any).Blob && body instanceof (globalThis as any).Blob) ||
      // `FormData` -> `multipart/form-data`
      body instanceof FormData ||
      // `URLSearchParams` -> `application/x-www-form-urlencoded`
      body instanceof URLSearchParams ||
      // Send chunked stream (each chunk has own `length`)
      ((globalThis as any).ReadableStream && body instanceof (globalThis as any).ReadableStream)
    ) {
      return { bodyHeaders: undefined, body: body as BodyInit };
    } else if (
      typeof body === 'object' &&
      (Symbol.asyncIterator in body ||
        (Symbol.iterator in body && 'next' in body && typeof body.next === 'function'))
    ) {
      return { bodyHeaders: undefined, body: Shims.ReadableStreamFrom(body as AsyncIterable<Uint8Array>) };
    } else if (
      typeof body === 'object' &&
      headers.values.get('content-type') === 'application/x-www-form-urlencoded'
    ) {
      return {
        bodyHeaders: { 'content-type': 'application/x-www-form-urlencoded' },
        body: this.stringifyQuery(body),
      };
    } else {
      return this.#encoder({ body, headers });
    }
  }

  /**
   * Create a new KernelApp instance.
   *
   * @param name - The name of the app to create.
   * @returns A new KernelApp instance you can attach actions to.
   */
  public app(name: string): KernelApp {
    return new KernelApp(name);
  }

  static Kernel = this;
  static DEFAULT_TIMEOUT = 60000; // 1 minute

  static KernelError = Errors.KernelError;
  static APIError = Errors.APIError;
  static APIConnectionError = Errors.APIConnectionError;
  static APIConnectionTimeoutError = Errors.APIConnectionTimeoutError;
  static APIUserAbortError = Errors.APIUserAbortError;
  static NotFoundError = Errors.NotFoundError;
  static ConflictError = Errors.ConflictError;
  static RateLimitError = Errors.RateLimitError;
  static BadRequestError = Errors.BadRequestError;
  static AuthenticationError = Errors.AuthenticationError;
  static InternalServerError = Errors.InternalServerError;
  static PermissionDeniedError = Errors.PermissionDeniedError;
  static UnprocessableEntityError = Errors.UnprocessableEntityError;

  static toFile = Uploads.toFile;

  deployments: API.Deployments = new API.Deployments(this);
  apps: API.Apps = new API.Apps(this);
  invocations: API.Invocations = new API.Invocations(this);
  browsers: API.Browsers = new API.Browsers(this);
  profiles: API.Profiles = new API.Profiles(this);
  auth: API.Auth = new API.Auth(this);
  proxies: API.Proxies = new API.Proxies(this);
  extensions: API.Extensions = new API.Extensions(this);
  browserPools: API.BrowserPools = new API.BrowserPools(this);
  credentials: API.Credentials = new API.Credentials(this);
  credentialProviders: API.CredentialProviders = new API.CredentialProviders(this);
}

Kernel.Deployments = Deployments;
Kernel.Apps = Apps;
Kernel.Invocations = Invocations;
Kernel.Browsers = Browsers;
Kernel.Profiles = Profiles;
Kernel.Auth = Auth;
Kernel.Proxies = Proxies;
Kernel.Extensions = Extensions;
Kernel.BrowserPools = BrowserPools;
Kernel.Credentials = Credentials;
Kernel.CredentialProviders = CredentialProviders;

export declare namespace Kernel {
  export type RequestOptions = Opts.RequestOptions;

  export import OffsetPagination = Pagination.OffsetPagination;
  export {
    type OffsetPaginationParams as OffsetPaginationParams,
    type OffsetPaginationResponse as OffsetPaginationResponse,
  };

  export {
    Deployments as Deployments,
    type DeploymentStateEvent as DeploymentStateEvent,
    type DeploymentCreateResponse as DeploymentCreateResponse,
    type DeploymentRetrieveResponse as DeploymentRetrieveResponse,
    type DeploymentListResponse as DeploymentListResponse,
    type DeploymentFollowResponse as DeploymentFollowResponse,
    type DeploymentListResponsesOffsetPagination as DeploymentListResponsesOffsetPagination,
    type DeploymentCreateParams as DeploymentCreateParams,
    type DeploymentListParams as DeploymentListParams,
    type DeploymentFollowParams as DeploymentFollowParams,
  };

  export {
    Apps as Apps,
    type AppListResponse as AppListResponse,
    type AppListResponsesOffsetPagination as AppListResponsesOffsetPagination,
    type AppListParams as AppListParams,
  };

  export {
    Invocations as Invocations,
    type InvocationStateEvent as InvocationStateEvent,
    type InvocationCreateResponse as InvocationCreateResponse,
    type InvocationRetrieveResponse as InvocationRetrieveResponse,
    type InvocationUpdateResponse as InvocationUpdateResponse,
    type InvocationListResponse as InvocationListResponse,
    type InvocationFollowResponse as InvocationFollowResponse,
    type InvocationListBrowsersResponse as InvocationListBrowsersResponse,
    type InvocationListResponsesOffsetPagination as InvocationListResponsesOffsetPagination,
    type InvocationCreateParams as InvocationCreateParams,
    type InvocationUpdateParams as InvocationUpdateParams,
    type InvocationListParams as InvocationListParams,
    type InvocationFollowParams as InvocationFollowParams,
  };

  export {
    Browsers as Browsers,
    type BrowserPersistence as BrowserPersistence,
    type BrowserPoolRef as BrowserPoolRef,
    type BrowserUsage as BrowserUsage,
    type Profile as Profile,
    type BrowserCreateResponse as BrowserCreateResponse,
    type BrowserRetrieveResponse as BrowserRetrieveResponse,
    type BrowserUpdateResponse as BrowserUpdateResponse,
    type BrowserListResponse as BrowserListResponse,
    type BrowserListResponsesOffsetPagination as BrowserListResponsesOffsetPagination,
    type BrowserCreateParams as BrowserCreateParams,
    type BrowserRetrieveParams as BrowserRetrieveParams,
    type BrowserUpdateParams as BrowserUpdateParams,
    type BrowserListParams as BrowserListParams,
    type BrowserDeleteParams as BrowserDeleteParams,
    type BrowserLoadExtensionsParams as BrowserLoadExtensionsParams,
  };

  export {
    Profiles as Profiles,
    type ProfileCreateParams as ProfileCreateParams,
    type ProfileListParams as ProfileListParams,
  };

  export { Auth as Auth };

  export {
    Proxies as Proxies,
    type ProxyCreateResponse as ProxyCreateResponse,
    type ProxyRetrieveResponse as ProxyRetrieveResponse,
    type ProxyListResponse as ProxyListResponse,
    type ProxyCheckResponse as ProxyCheckResponse,
    type ProxyCreateParams as ProxyCreateParams,
  };

  export {
    Extensions as Extensions,
    type ExtensionListResponse as ExtensionListResponse,
    type ExtensionUploadResponse as ExtensionUploadResponse,
    type ExtensionDownloadFromChromeStoreParams as ExtensionDownloadFromChromeStoreParams,
    type ExtensionUploadParams as ExtensionUploadParams,
  };

  export {
    BrowserPools as BrowserPools,
    type BrowserPool as BrowserPool,
    type BrowserPoolListResponse as BrowserPoolListResponse,
    type BrowserPoolAcquireResponse as BrowserPoolAcquireResponse,
    type BrowserPoolCreateParams as BrowserPoolCreateParams,
    type BrowserPoolUpdateParams as BrowserPoolUpdateParams,
    type BrowserPoolDeleteParams as BrowserPoolDeleteParams,
    type BrowserPoolAcquireParams as BrowserPoolAcquireParams,
    type BrowserPoolReleaseParams as BrowserPoolReleaseParams,
  };

  export {
    Credentials as Credentials,
    type CreateCredentialRequest as CreateCredentialRequest,
    type Credential as Credential,
    type UpdateCredentialRequest as UpdateCredentialRequest,
    type CredentialTotpCodeResponse as CredentialTotpCodeResponse,
    type CredentialsOffsetPagination as CredentialsOffsetPagination,
    type CredentialCreateParams as CredentialCreateParams,
    type CredentialUpdateParams as CredentialUpdateParams,
    type CredentialListParams as CredentialListParams,
  };

  export {
    CredentialProviders as CredentialProviders,
    type CreateCredentialProviderRequest as CreateCredentialProviderRequest,
    type CredentialProvider as CredentialProvider,
    type CredentialProviderItem as CredentialProviderItem,
    type CredentialProviderTestResult as CredentialProviderTestResult,
    type UpdateCredentialProviderRequest as UpdateCredentialProviderRequest,
    type CredentialProviderListResponse as CredentialProviderListResponse,
    type CredentialProviderListItemsResponse as CredentialProviderListItemsResponse,
    type CredentialProviderCreateParams as CredentialProviderCreateParams,
    type CredentialProviderUpdateParams as CredentialProviderUpdateParams,
  };

  export type AppAction = API.AppAction;
  export type BrowserExtension = API.BrowserExtension;
  export type BrowserProfile = API.BrowserProfile;
  export type BrowserViewport = API.BrowserViewport;
  export type ErrorDetail = API.ErrorDetail;
  export type ErrorEvent = API.ErrorEvent;
  export type ErrorModel = API.ErrorModel;
  export type HeartbeatEvent = API.HeartbeatEvent;
  export type LogEvent = API.LogEvent;
}