Action Retrier

Pre-requisite: Convex

You'll need an existing Convex project to use the component. Convex is a hosted backend platform, including a database, serverless functions, and a ton more you can learn about here.

Run npm create convex or follow any of the quickstarts to set one up.

Installation

First, add @convex-dev/action-retrier as an NPM dependency:

npm install @convex-dev/action-retrier

Then, install the component into your Convex project within the convex/convex.config.ts configuration file:

// convex/convex.config.ts
import { defineApp } from "convex/server";
import actionRetrier from "@convex-dev/action-retrier/convex.config";

const app = defineApp();
app.use(actionRetrier);
export default app;

Finally, create a new ActionRetrier within your Convex project, and point it to the installed component:

// convex/index.ts
import { ActionRetrier } from "@convex-dev/action-retrier";
import { components } from "./_generated/api";

export const retrier = new ActionRetrier(components.actionRetrier);

You can optionally configure the retrier's backoff behavior in the ActionRetrier constructor.

const retrier = new ActionRetrier(components.actionRetrier, {
  initialBackoffMs: 10000,
  base: 10,
  maxFailures: 4,
});

initialBackoffMs is the initial delay after a failure before retrying (default: 250).
base is the base for the exponential backoff (default: 2).
maxFailures is the maximum number of times to retry the action (default: 4).

API

Starting a run

After installing the component, use the run method from either a mutation or action to kick off an action.

export const kickoffExampleAction = mutation({
  handler: async (ctx) => {
    const runId = await retrier.run(ctx, internal.index.exampleAction, {
      foo: "bar",
    });
    // ... optionally persist or pass along the runId
  },
});

export const exampleAction = internalAction({
  args: { foo: v.string() },
  handler: async (ctx, args) => {
    return operationThatMightFail(args);
  },
});

The return value of retrier.run is not the result of the action, but rather an ID that you can use to query its status or cancel it. The action's return value is saved along with the status, when it succeeds.

You can optionally specify overrides to the backoff parameters in an options argument.

export const kickoffExampleAction = action(async (ctx) => {
  const runId = await retrier.run(
    ctx,
    internal.index.exampleAction,
    { failureRate: 0.8 },
    {
      initialBackoffMs: 125,
      base: 2.71,
      maxFailures: 3,
    },
  );
});

You can specify an onComplete mutation callback in the options argument as well. This mutation is guaranteed to eventually run exactly once.

// convex/index.ts

import { runResultValidator } from "@convex-dev/action-retrier";

export const kickoffExampleAction = action(async (ctx) => {
  const runId = await retrier.run(
    ctx,
    internal.index.exampleAction,
    { failureRate: 0.8 },
    {
      onComplete: internal.index.exampleCallback,
    },
  );
});

export const exampleCallback = internalMutation({
  args: { result: runResultValidator },
  handler: async (ctx, args) => {
    if (args.result.type === "success") {
      console.log(
        "Action succeeded with return value:",
        args.result.returnValue,
      );
    } else if (args.result.type === "failed") {
      console.log("Action failed with error:", args.result.error);
    } else if (args.result.type === "canceled") {
      console.log("Action was canceled.");
    }
  },
});

Run status

The run method returns a RunId, which can then be used for querying a run's status.

export const kickoffExampleAction = action(async (ctx) => {
  const runId = await retrier.run(ctx, internal.index.exampleAction, {
    failureRate: 0.8,
  });
  while (true) {
    const status = await retrier.status(ctx, runId);
    if (status.type === "inProgress") {
      await new Promise((resolve) => setTimeout(resolve, 1000));
      continue;
    } else {
      console.log("Run completed with result:", status.result);
      break;
    }
  }
});

Canceling a run

You can cancel a run using the cancel method.

export const kickoffExampleAction = action(async (ctx) => {
  const runId = await retrier.run(ctx, internal.index.exampleAction, {
    failureRate: 0.8,
  });
  await new Promise((resolve) => setTimeout(resolve, 1000));
  await retrier.cancel(ctx, runId);
});

Runs that are currently executing will be canceled best effort, so they may still continue to execute. A succcesful call to cancel, however, does guarantee that subsequent status calls will indicate cancelation.

Cleaning up completed runs

Runs take up space in the database, since they store their return values. After a run completes, you can immediately clean up its storage by using retrier.cleanup(ctx, runId). The system will automatically cleanup completed runs after 7 days.

export const kickoffExampleAction = action(async (ctx) => {
  const runId = await retrier.run(ctx, internal.index.exampleAction, {
    failureRate: 0.8,
  });
  try {
    while (true) {
      const status = await retrier.status(ctx, runId);
      if (status.type === "inProgress") {
        await new Promise((resolve) => setTimeout(resolve, 1000));
        continue;
      } else {
        console.log("Run completed with result:", status.result);
        break;
      }
    }
  } finally {
    await retrier.cleanup(ctx, runId);
  }
});

Logging

You can set the ACTION_RETRIER_LOG_LEVEL to DEBUG to have the retrier log out more of its internal information, which you can then view on the Convex dashboard.

npx convex env set ACTION_RETRIER_LOG_LEVEL DEBUG

The default log level is INFO, but you can also set it to ERROR for even fewer logs.