109 lines
3.8 KiB
Markdown
109 lines
3.8 KiB
Markdown
# Class: RetryHandler
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Extends: `undici.DispatcherHandlers`
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A handler class that implements the retry logic for a request.
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## `new RetryHandler(dispatchOptions, retryHandlers, [retryOptions])`
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Arguments:
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- **options** `Dispatch.DispatchOptions & RetryOptions` (required) - It is an intersection of `Dispatcher.DispatchOptions` and `RetryOptions`.
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- **retryHandlers** `RetryHandlers` (required) - Object containing the `dispatch` to be used on every retry, and `handler` for handling the `dispatch` lifecycle.
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Returns: `retryHandler`
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### Parameter: `Dispatch.DispatchOptions & RetryOptions`
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Extends: [`Dispatch.DispatchOptions`](Dispatcher.md#parameter-dispatchoptions).
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#### `RetryOptions`
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- **retry** `(err: Error, context: RetryContext, callback: (err?: Error | null) => void) => void` (optional) - Function to be called after every retry. It should pass error if no more retries should be performed.
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- **maxRetries** `number` (optional) - Maximum number of retries. Default: `5`
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- **maxTimeout** `number` (optional) - Maximum number of milliseconds to wait before retrying. Default: `30000` (30 seconds)
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- **minTimeout** `number` (optional) - Minimum number of milliseconds to wait before retrying. Default: `500` (half a second)
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- **timeoutFactor** `number` (optional) - Factor to multiply the timeout by for each retry attempt. Default: `2`
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- **retryAfter** `boolean` (optional) - It enables automatic retry after the `Retry-After` header is received. Default: `true`
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-
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- **methods** `string[]` (optional) - Array of HTTP methods to retry. Default: `['GET', 'PUT', 'HEAD', 'OPTIONS', 'DELETE']`
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- **statusCodes** `number[]` (optional) - Array of HTTP status codes to retry. Default: `[429, 500, 502, 503, 504]`
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- **errorCodes** `string[]` (optional) - Array of Error codes to retry. Default: `['ECONNRESET', 'ECONNREFUSED', 'ENOTFOUND', 'ENETDOWN','ENETUNREACH', 'EHOSTDOWN',
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**`RetryContext`**
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- `state`: `RetryState` - Current retry state. It can be mutated.
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- `opts`: `Dispatch.DispatchOptions & RetryOptions` - Options passed to the retry handler.
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### Parameter `RetryHandlers`
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- **dispatch** `(options: Dispatch.DispatchOptions, handlers: Dispatch.DispatchHandlers) => Promise<Dispatch.DispatchResponse>` (required) - Dispatch function to be called after every retry.
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- **handler** Extends [`Dispatch.DispatchHandlers`](Dispatcher.md#dispatcherdispatchoptions-handler) (required) - Handler function to be called after the request is successful or the retries are exhausted.
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Examples:
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```js
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const client = new Client(`http://localhost:${server.address().port}`);
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const chunks = [];
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const handler = new RetryHandler(
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{
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...dispatchOptions,
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retryOptions: {
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// custom retry function
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retry: function (err, state, callback) {
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counter++;
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if (err.code && err.code === "UND_ERR_DESTROYED") {
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callback(err);
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return;
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}
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if (err.statusCode === 206) {
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callback(err);
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return;
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}
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setTimeout(() => callback(null), 1000);
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},
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},
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},
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{
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dispatch: (...args) => {
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return client.dispatch(...args);
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},
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handler: {
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onConnect() {},
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onBodySent() {},
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onHeaders(status, _rawHeaders, resume, _statusMessage) {
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// do something with headers
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},
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onData(chunk) {
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chunks.push(chunk);
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return true;
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},
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onComplete() {},
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onError() {
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// handle error properly
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},
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},
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}
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);
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```
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#### Example - Basic RetryHandler with defaults
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```js
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const client = new Client(`http://localhost:${server.address().port}`);
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const handler = new RetryHandler(dispatchOptions, {
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dispatch: client.dispatch.bind(client),
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handler: {
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onConnect() {},
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onBodySent() {},
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onHeaders(status, _rawHeaders, resume, _statusMessage) {},
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onData(chunk) {},
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onComplete() {},
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onError(err) {},
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},
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});
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```
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