Cloudflare Developers•4mo ago

And does anyone has thoughts about these

And does anyone has thoughts about these two options. Is there any difference between them, and if so what is the difference?

10 Replies

alex (he/him)OP•4mo ago

One follows the recommended pattern in docs: https://developers.cloudflare.com/workflows/build/rules-of-workflows/#do-not-rely-on-state-outside-of-a-step The other follows the nested step pattern often found here or on Twitter. 🤔

Matt Silverlock•4mo ago

Option A. Your results variable in OptionB breaks the rules in that doc Can you help me understand why you want OptionB here? What are you trying to achieve?

alex (he/him)OP•4mo ago

Option B, is what cf docs document, or am I mistaken here? 🤔 Code taken out of cf docs:

    // ✅ Good: imageList state is exclusively comprised of step returns - this means that in the event of
    // multiple engine lifetimes, imageList will be built accordingly
    const imageList: string[] = await Promise.all([
      step.do("get first cutest cat from KV", async () => {
        return await env.KV.get("cutest-http-cat-1");
      }),

      step.do("get second cutest cat from KV", async () => {
        return await env.KV.get("cutest-http-cat-2");
      }),
    ]);

    // ✅ Good: imageList state is exclusively comprised of step returns - this means that in the event of
    // multiple engine lifetimes, imageList will be built accordingly
    const imageList: string[] = await Promise.all([
      step.do("get first cutest cat from KV", async () => {
        return await env.KV.get("cutest-http-cat-1");
      }),

      step.do("get second cutest cat from KV", async () => {
        return await env.KV.get("cutest-http-cat-2");
      }),
    ]);

Matt Silverlock•4mo ago

I think that’s a mistake - @Seekerdasbatatas To be clear though, the “bad” here isn’t either of your options

Matt Silverlock•4mo ago

You’re ignoring that “bad” is “you have variables that are not the output of a step” -

Matt Silverlock•4mo ago

Nesting steps within a step - and having that step return state - is OK.

This means that you should not store state outside of a step

alex (he/him)OP•4mo ago

I understood that limitation, and it make sense, because it would get lost. But I think both of my options, don't have that issue. So now I'm wondering the difference between having one "wrapper" step state which returns the array of other steps states, or directly assigning the array of other step states to the variable, if there is any 🤔

Seekerdasbatatas•4mo ago

You can have state outside steps, as long it's constructed deterministically with constants or step outputs. I prefer the second approach (pMap of step.do()), because this way, the list be bigger than 1MB But assuming that you don't have this constraint, both approaches are equivalent

alex (he/him)OP•4mo ago

That's because the return value of any step.do() can be max 1MB, but combining multiple step outputs, it can exceed 1MB?

Seekerdasbatatas•4mo ago

Exactly The upper bound for the list will be the worker memory limit then

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And does anyone has thoughts about these

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