external Durable Objects

[konsumer]

Hi, I am using a DO defined in another worker.

The way I do that is like this:

[[durable_objects.bindings]]
name = "DO_STORE"
class_name = "StoreDurableObject"
script_name = "store-production"

where store-production is the external worker that has the DO.

I realize that miniflare is all local, and that is fine (the DO is actually exposed as a http graphql server on the worker, too, so locally I can hit that, and it will be the same data.) My issue is that if I uncomment that, I get an error locally, and if I comment that, it won't be defined when I deploy this on wrangler, so it won't be bound to the real DO. I tried using cli options to force miniflare to use a separate class, instead of what is defined there, but that didn't work (I am using remix, and it had an error about using addEventListener, as DO needs ES6 modules.)

I also tried making store-production and store-production.js, because I realized that miniflare only does local DO files for script_name, not remote-worker DO like wrangler does, hoping it would do that, but I get this error:

[mf:err] DurableObjectError [ERR_SCRIPT_NOT_FOUND]: Script "store-production" for Durable Object "DO_STORE" not found
    at DurableObjectsPlugin.reload (PROJECT_DIR/node_modules/@miniflare/durable-objects/src/plugin.ts:201:17)
    at EventTarget.#runAllReloads (PROJECT_DIR/node_modules/@miniflare/core/src/index.ts:656:24)
    at EventTarget.#reload (PROJECT_DIR/node_modules/@miniflare/core/src/index.ts:797:13)
    at EventTarget.getPlugins (PROJECT_DIR/node_modules/@miniflare/core/src/index.ts:970:5)
    at createServer (PROJECT_DIR/node_modules/@miniflare/http-server/src/index.ts:332:19)
    at startServer (PROJECT_DIR/node_modules/@miniflare/http-server/src/index.ts:418:18)
    at main (PROJECT_DIR/node_modules/miniflare/src/cli.ts:96:5)

Is there a better way to make it use a mock DO class locally, but use the real DO, remotely? Do I need to give up on remix + miniflare?

[mrbbot]

Hey! 👋 I think you're looking for Miniflare's mounting feature that lets you run mutliple worker scripts in the same instance and share their Durable Object classes. See https://miniflare.dev/storage/durable-objects#using-a-class-exported-by-another-script for more details.

In your case, you'd want to mount the directory containing the store-production worker, then script_name should work as you've configured it.

That error message should probably mention mounting.

[konsumer]

I sort of tried that, but could't get it to work. That is a good tip about script_name being the name of the dir that has the worker, though. Also, that worker might not necessarily be available on the dev's system (it's a seperate repo, etc.)

I ended up solving it by using 2 wrangler.toml files. 1 is minimal, without DO, for dev, and 1 has it. Then in my code I pick the right way to get to the graphql data (DO vs HTTP query)

/* global DO_STORE, fetch, Request */
export function graphql (request, query, variables) {
  let fetchWrapped = fetch
  if (typeof DO_STORE !== 'undefined') {
    const store = DO_STORE.get(DO_STORE.idFromName(request.cf?.colo || 'PDX'))
    fetchWrapped = (url, opts) => store.fetch(new Request(new URL(url)), opts)
  }
  return fetchWrapped(URL_GRAPHQL, { method: 'POST', headers: { 'content-type': 'application/json' }, body: JSON.stringify({ query, variables }) }).then(r => r.json())
}

I kinda like it better because it's really clear that each config handles a specific use-case, so it all worked out for me. I appreciate the help and miniflare, in general. This is issue is totally closable.