FeaturesInngest FunctionsErrors & Retries

Inngest Errors

Inngest automatically handles errors and retries for you. You can use standard errors or use included Inngest errors to control how Inngest handles errors.

Standard errors

All Error objects are handled by Inngest and retried automatically. This includes all standard errors like TypeError and custom errors that extend the Error class. You can throw errors in the function handler or within a step.

export default inngest.createFunction(
  { id: "import-item-data" },
  { event: "store/import.requested" },
  async ({ event }) => {

    // throwing a standard error
    if (!event.itemId) {
      throw new Error("Item ID is required");
    }

    // throwing an error within a step
    const item = await step.run('fetch-item', async () => {
      const response = await fetch(`https://api.ecommerce.com/items/${event.itemId}`);
      if (response.status === 500) {
        throw new Error("Failed to fetch item from ecommerce API");
      }
      // ...
    });
  }
);

NonRetriableError

Use NonRetriableError to prevent Inngest from retrying the function or step. This is useful when the type of error is not expected to be resolved by a retry, for example, when the error is caused by an invalid input or when the error is expected to occur again if retried.

import { NonRetriableError } from "inngest";

export default inngest.createFunction(
  { id: "mark-store-imported" },
  { event: "store/import.completed" },
  async ({ event }) => {
    try {
      const result = await database.updateStore(
        { id: event.data.storeId },
        { imported: true }
      );
      return result.ok === true;
    } catch (err) {
      // Passing the original error via `cause` enables you to view the error in function logs
      throw new NonRetriableError("Store not found", { cause: err });
    }
  }
);

Parameters

new NonRetriableError(message: string, options?: { cause?: Error }): NonRetriableError
  • Name
    message
    Type
    string
    Required
    required
    Description

    The error message.

  • Name
    options
    Type
    object
    Required
    optional
    Description

RetryAfterError

Use RetryAfterError to control when Inngest should retry the function or step. This is useful when you want to delay the next retry attempt for a specific period of time, for example, to more gracefully handle a race condition or backing off after hitting an API rate limit.

If RetryAfterError is not used, Inngest will use the default retry backoff policy.

inngest.createFunction(
  { id: "send-welcome-sms" },
  { event: "app/user.created" },
  async ({ event, step }) => {
    const { success, retryAfter } = await twilio.messages.create({
      to: event.data.user.phoneNumber,
      body: "Welcome to our service!",
    });

    if (!success && retryAfter) {
      throw new RetryAfterError("Hit Twilio rate limit", retryAfter);
    }
  }
);

Parameters

new RetryAfterError(
  message: string,
  retryAfter: number | string | date,
  options?: { cause?: Error }
): RetryAfterError
  • Name
    message
    Type
    string
    Required
    required
    Description

    The error message.

  • Name
    retryAfter
    Type
    number | string | date
    Required
    required
    Description

    The specified time to delay the next retry attempt. The following formats are accepted:

    • number - The number of milliseconds to delay the next retry attempt.
    • string - A time string, parsed by the ms package, such as "30m", "3 hours", or "2.5d".
    • date - A Date object.
  • Name
    options
    Type
    object
    Required
    optional
    Description

Step errors v3.12.0+

After a step exhausts all of its retries, it will throw a StepError which can be caught and handled in the function handler if desired.

inngest.createFunction(
  { id: "send-weather-forecast" },
  { event: "weather/forecast.requested" },
  async ({ event, step }) => {
    let data;

    try {
      data = await step.run('get-public-weather-data', async () => {
        return await fetch('https://api.weather.com/data');
      });
    } catch (err) {
      // err will be an instance of StepError
      // Handle the error by recovering with a different step
      data = await step.run('use-backup-weather-api', async () => {
        return await fetch('https://api.stormwaters.com/data');
      });
    }
    // ...
  }
);

Support for handling step errors is available in the Inngest TypeScript SDK starting from version 3.12.0. Prior to this version, wrapping a step in try/catch will not work correctly.

Attempt counter

The current attempt number is passed in as input to the function handler. attempt is a zero-index number that increments for each retry. The first attempt will be 0, the second 1, and so on. The number is reset after a successfully executed step.

inngest.createFunction(
  { id: "generate-summary" },
  { event: "blog/post.created" },
  async ({ attempt }) => {
    // `attempt` is the zero-index attempt number

    await step.run('call-llm', async () => {
      if (attempt < 2) {
        // Call OpenAI's API two times
      } else {
        // After two attempts to OpenAI, try a different LLM, for example, Mistral
      }
    });
  }
);

Stack traces

When calling functions that return Promises, await the Promise to ensure that the stack trace is preserved. This applies to functions executing in different cycles of the event loop, for example, when calling a database or an external API. This is especially useful when debugging errors in production.

inngest.createFunction(
  { id: "update-recent-usage" },
  { event: "app/update-recent-usage" },
  async ({ event, step }) => {
    // ...
    await step.run("update in db", () => doSomeWork(event.data));
    // ...
  }
);

Please note that immediately returning the Promise will not include a pointer to the calling function in the stack trace. Awaiting the Promise will ensure that the stack trace includes the calling function.