They are defined using the task() function and can be triggered from your backend or inside another task. Like all tasks they don’t have timeouts, they should be placed inside a /trigger folder, and you can configure them.

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Example tasks

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A task that does an OpenAI call with retrying

Sometimes OpenAI calls can take a long time to complete, or they can fail. This task will retry if the API call fails completely or if the response is empty.
/trigger/openai.ts
import { task } from "@trigger.dev/sdk";
import OpenAI from "openai";

const openai = new OpenAI({
  apiKey: process.env.OPENAI_API_KEY,
});

export const openaiTask = task({
  id: "openai-task",
  //specifying retry options overrides the defaults defined in your trigger.config file
  retry: {
    maxAttempts: 10,
    factor: 1.8,
    minTimeoutInMs: 500,
    maxTimeoutInMs: 30_000,
    randomize: false,
  },
  run: async (payload: { prompt: string }) => {
    //if this fails, it will throw an error and retry
    const chatCompletion = await openai.chat.completions.create({
      messages: [{ role: "user", content: payload.prompt }],
      model: "gpt-3.5-turbo",
    });

    if (chatCompletion.choices[0]?.message.content === undefined) {
      //sometimes OpenAI returns an empty response, let's retry by throwing an error
      throw new Error("OpenAI call failed");
    }

    return chatCompletion.choices[0].message.content;
  },
});

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A Task that sends emails in a sequence with delays in between

This example uses Resend to send a sequence of emails over several days. Each email is wrapped in retry.onThrow. This will retry the block of code if an error is thrown. This is useful when you don’t want to retry the whole task, but just a part of it. The entire task will use the default retrying, so can also retry. Additionally this task uses wait.for to wait for a certain amount of time before sending the next email. During the waiting time, the task will be paused and will not consume any resources.
/trigger/email-sequence.ts
import { Resend } from "resend";

const resend = new Resend(process.env.RESEND_ASP_KEY);

export const emailSequence = task({
  id: "email-sequence",
  run: async (payload: { userId: string; email: string; name: string }) => {
    console.log(`Start email sequence for user ${payload.userId}`, payload);

    //send the first email immediately
    const firstEmailResult = await retry.onThrow(
      async ({ attempt }) => {
        const { data, error } = await resend.emails.send({
          from: "hello@trigger.dev",
          to: payload.email,
          subject: "Welcome to Trigger.dev",
          html: `<p>Hello ${payload.name},</p><p>Welcome to Trigger.dev</p>`,
        });

        if (error) {
          //throwing an error will trigger a retry of this block
          throw error;
        }

        return data;
      },
      { maxAttempts: 3 }
    );

    //then wait 3 days
    await wait.for({ days: 3 });

    //send the second email
    const secondEmailResult = await retry.onThrow(
      async ({ attempt }) => {
        const { data, error } = await resend.emails.send({
          from: "hello@trigger.dev",
          to: payload.email,
          subject: "Some tips for you",
          html: `<p>Hello ${payload.name},</p><p>Here are some tips for you…</p>`,
        });

        if (error) {
          //throwing an error will trigger a retry of this block
          throw error;
        }

        return data;
      },
      { maxAttempts: 3 }
    );

    //etc...
  },
});