Local development
To test your Dispatch Worker, user Worker and Outbound Worker before deploying to production, you can use Wrangler for development and testing.
1. Create a user worker
$ npm create cloudflare@latest customer-worker-1
When following the interactive prompts, answer the questions as below:
- Select
no
to using TypeScript. - Select
no
to deploying your application.
Update the src/index.js
file for customer-worker-1:
src/index.jsexport default { async fetch(request) { // make a subrequest to the internet const response = await fetch('https://example.com'); return new Response(`user worker got "${await response.text()}" from fetch`); }
}
Update the wrangler.toml
file for customer-worker-1 and add the dispatch namespace:
wrangler.toml# ... other content above ...
dispatch_namespace = "my-namespace"
2. Create a dispatch worker
$ npm create cloudflare@latest dispatch-worker
When following the interactive prompts, answer the questions as below:
- Select
no
to using TypeScript. - Select
no
to deploying your application.
Update the src/index.js
file for dispatch-worker:
src/index.jsexport default { async fetch(request, env) { // get the user Worker, specifying parameters that the Outbound Worker will see when it intercepts a user worker's subrequest const customerScript = env.DISPATCH_NAMESPACE.get( "customer-worker-1", {}, { outbound: { paramCustomerName: 'customer-1' } } ); // invoke user Worker return await customerScript.fetch(request); }
}
Update the wrangler.toml
file for dispatch-worker and add the dispatch namespace binding:
wrangler.toml# ... other content above ...
[[dispatch_namespaces]]
binding = "DISPATCH_NAMESPACE"
namespace = "my-namespace"
outbound = { service = "outbound-worker", parameters = ["paramCustomerName"] }
3. Create an Outbound Worker
$ npm create cloudflare@latest outbound-worker
When following the interactive prompts, answer the questions as below:
- Select
no
to using TypeScript. - Select
no
to deploying your application.
Update the src/index.js
file for outbound-worker:
src/index.jsexport default { async fetch(request, env) { const { paramCustomerName } = env; // use the parameters passed by the dispatcher to know what this user this request is for // and return custom content back to the user worker return new Response(`intercepted a request for ${paramCustomerName} by the outbound`); }
}
4. Start local dev session for your Workers
In separate terminals, start a local dev session for each of your Workers.
For your dispatcher Worker:
$ cd dispatch-worker
$ npx wrangler@dispatch-namespaces-dev dev --port 8600
For your outbound Worker:
$ cd outbound-worker
$ npx wrangler@dispatch-namespaces-dev dev --port 8601
And for your user Worker:
$ cd customer-worker-1
$ npx wrangler@dispatch-namespaces-dev dev --port 8602
5. Test your requests
Send a request to your dispatcher Worker:
$ curl http://localhost:8600
# -> user worker got "intercepted a request for customer-1 by the outbound" from fetch