Workers RPC — Lifecycle · Cloudflare Wor...

Hi all! I'm running into the following error when using Workflows:

An RPC stub was not disposed properly. You must call dispose() on all stubs in order to let the other side know that you are no longer using them. You cannot rely on the garbage collector for this because it may take arbitrarily long before actually collecting unreachable objects. As a shortcut, calling dispose() on the result of an RPC call disposes all stubs within it.

I see that step.do expects to return Rpc.Serializable<unknown>, so I did a little bit of reading about the RPC lifecycle here and found that in the context of Worker Service Bindings, you should either use the experimental using syntax, or explicitly call object[Symbol.dispose](). I'm a little confused because this error is only thrown after some calls to step.do, and not others. If someone could provide some insight as to what's going on, that would be great. Happy to provide more details also

Cloudflare Docs

Workers RPC — Lifecycle · Cloudflare Workers docs

Memory management, resource management, and the lifecycle of RPC stubs.

6 Replies

Nathan ScheeleOP•2w ago

After further debugging, it seems this error is thrown immediately after the step returns a value. Below is the step where this occurs

const orders = await step.do(
  "get orders",
  async () => {
    const orders = await getOrders();
    return orders;
  }
);

const orders = await step.do(
  "get orders",
  async () => {
    const orders = await getOrders();
    return orders;
  }
);

getOrders fetches data from an external API and returns the JSON payload

Seekerdasbatatas•2w ago

does this happen in deployed workers or just local dev?

Nathan ScheeleOP•2w ago

I haven't tried deploying it yet, I'm still working locally. Let me try deploying @Seekerdasbatatas Okay, so I don't seem to get the error once deployed. I also noticed that it only happens on the first workflow run after the local server starts or is reset

Seekerdasbatatas•2w ago

Yhep I'll try to investigate it next week

Nathan ScheeleOP•2w ago

Awesome, thanks! While I have you, is there any reference material for returning large amounts of data between steps? I'm running up against the 1MiB limit for RPC return values I've tried returning a ReadableStream from the step, but it just returns undefined

Matt Silverlock•7d ago

Break it down, or store it in R2.

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