Worker Bindings

import { Render, PackageManagers } from ”~/components”;

You can send records to your Pipeline directly from a Cloudflare Worker. To do so, you need to:

1. Create a Worker
2. Create a Pipeline
3. Add your Pipeline as a binding in your Workers’ wrangler.toml file
4. Write your Worker, to send records to your Pipeline

1. Create a Worker

Create a Cloudflare Worker if you don’t alreadyåhave one. This Worker will send records to your Pipeline.

To create a Worker, run:

<PackageManagers type=“create” pkg=“cloudflare@latest” args={“pipeline-worker”} />

<Render file=“c3-post-run-steps” product=“workers” params={{ one: “Hello World example”, two: “Hello World Worker”, three: “TypeScript”, }} />

This will create a new directory, which will include both a src/index.ts Worker script, and a wrangler.toml configuration file. Navigate into the newly created directory:

cd pipeline-worker

2. Create a Pipeline

Create a new Pipeline, if you don’t already have one. Follow the instructions in the (get started guide)[pipelines/get-started] if this is your first time creating a Pipeline.

By default, Worker bindings are enabled on all Pipelines. Keep track of the name you gave your Pipeline in this stage; we’ll use it in the next step.

3. Add a Binding

To connect your Worker to your Pipeline, you need to create a binding. Bindings allow you to grant specific capabilities to your Worker.

Open your newly generated wrangler.toml configuration file and add the following:

[[pipelines]]
  binding = "MY_PIPELINE"
  queue = "<MY-PIPELINE-NAME>"

Replace <MY-PIPELINE-NAME> with the name of the Pipeline you created in step 2. Next, replace MY_PIPELINE with the name you want for your binding. The binding must be a valid JavaScript variable name. This is the variable you will use to reference this queue in your Worker.

4. Write your Worker

You will now configure your Worker to send records to your Pipeline. Your Worker will:

1. Take a request it receives from the browser
2. Transform the request to JSON
3. Send the resulting record to your Pipeline

In your Worker project directory, open the src folder and add the following to your index.ts file:

export interface Env {
   <MY_PIPELINE>: Pipeline<any>;
}

export default {
  async fetch(req, env, ctx): Promise<Response> {
    let record = {
      url: req.url,
      method: req.method,
      headers: Object.fromEntries(req.headers)
    }
    await env.MY_PIPELINE.send([record]);
    return new Response('Success');
  },
} satisfies ExportedHandler<Env>;

Replace MY_PIPELINE with the name of the binding you set in Step 3. If sending the record to the Pipeline fails, your Worker will return an error (raise an exception). If sending the record succeeds, it will return Success back with a HTTP 200 status code to the browser.

In a production application, you would likely use a try...catch ↗ statement to catch the exception and handle it directly (for example, return a custom error or even retry).

Publish your Worker

With your wrangler.toml file and index.ts file configured, you are ready to publish your producer Worker. To publish your producer Worker, run:

npx wrangler deploy

You should see output that resembles the below, with a *.workers.dev URL by default.

Uploaded <YOUR-WORKER-NAME> (0.76 sec)
Published <YOUR-WORKER-NAME> (0.29 sec)
  https://<YOUR-WORKER-NAME>.<YOUR-ACCOUNT>.workers.dev

Copy your *.workers.dev subdomain and paste it into a new browser tab. Refresh the page a few times to send records to your Pipeline. Your browser should return the Success response after sending the record to your Pipeline.

5. Verify in R2

Go to the R2 bucket you created in step 2 via the Cloudflare dashboard ↗. You should see a prefix for today’s date. Click through, and you’ll find one or more files, containing the records you sent in step 4.