Cloudflare Developers•8mo ago

What is the downside of using this flag? It seems like it should be a default, what would it break…?

Ddave What is the downside of using this flag? It seems like it should be a default, w...

Chaika•5/26/25, 4:29 PM

It would break every worker on a route fetching through to the origin

Chaika•5/26/25, 4:30 PM

or any worker depending on it not being challenged/blocked. I have an Astro SSR site which fetches the API on the same zone, wouldn't want it being challenged or blocked in anyway

CChaika It would break every worker on a route fetching through to the origin

daveOP•5/26/25, 4:30 PM

ahhh, I think I have almost zero Workers do that do that pattern.

Chaika•5/26/25, 4:31 PM

yea I think it's kind of rarer these days, was like the #1 use case when Workers first launched though, and still a good example/use

CChaika It would break every worker on a route fetching through to the origin

daveOP•5/26/25, 4:40 PM

How does the flag interact with service bindings?

Ddave How does the flag interact with service bindings?

Chaika•5/26/25, 4:42 PM

in what way? I would assume this changes nothing with calling/fetching them since that's all seperate and magical, I haven't tested though

CChaika in what way? I would assume this changes nothing with calling/fetching them sinc...

daveOP•5/26/25, 4:43 PM

like if it would change any behaviour at all.

I think you're right that it's all seperate and doesn't impact, but yeah I don't know 100%.

daveOP•5/26/25, 10:56 PM

How is it possible that I exceeded the CPU time with only 11ms?

Walshy•5/26/25, 11:13 PM

Cron triggers have a wall time limit, you exceeded that

Walshy•5/26/25, 11:13 PM

(The reporting for that isn't great I know - sorry for that)

Walshy•5/26/25, 11:15 PM

https://developers.cloudflare.com/workers/platform/limits/#worker-limits

WWalshy (The reporting for that isn't great I know - sorry for that)

daveOP•5/26/25, 11:19 PM

ah yeah it's just the reporting that's the issue

Trojan•5/27/25, 12:48 PM

Is it beneficial to ping workers at the beginning of a request to “pre-warm” them if you know you’ll make requests to them?

WWalshy Cron triggers have a wall time limit, you exceeded that

daveOP•5/27/25, 1:21 PM

Why do normal Workers have no limit, but Cron Workers do? Feels backwards.

Walshy•5/27/25, 1:22 PM

well, cron triggers are a bit different than normal invocations. don't really want to run a worker every minute and let it run for 6 hours

TTrojan Is it beneficial to ping workers at the beginning of a request to “pre-warm” the...

daveOP•5/27/25, 1:22 PM

Workers are so fast that I don’t really see a need to do that. The max startup time is 400ms, so I think you’d always be looking at <1 second at worst for a cold start.

WWalshy well, cron triggers are a bit different than normal invocations. don't really wa...

daveOP•5/27/25, 1:22 PM

That’s exactly what I want though.

Walshy•5/27/25, 1:22 PM

also we already pre-warm https://blog.cloudflare.com/eliminating-cold-starts-with-cloudflare-workers/

Ddave That’s exactly what I want though. 😅

Walshy•5/27/25, 1:23 PM

haha, then your best bet is DO Alarms

WWalshy also we already pre-warm <https://blog.cloudflare.com/eliminating-cold-starts-wi...

daveOP•5/27/25, 1:24 PM

For now, this is only available for Workers that are deployed to a “root” hostname like “example.com” and not specific paths like “example.com/path/to/something.” We plan to introduce more optimizations in the future that can preload specific paths.

Is this still the case, or did that optimization land for custom routes (i.e. non-custom domain routes)?

WWalshy haha, then your best bet is DO Alarms

daveOP•5/27/25, 1:25 PM

A Worker can have up to three Cron Triggers configured at once

https://developers.cloudflare.com/durable-objects/api/alarms/#background

I’m like 75% sure this is wrong, since I use waaaaay more than three Cron schedules in many of my Workers.

Cloudflare Docs

Alarms

Durable Objects alarms allow you to schedule the Durable Object to be woken up at a time in the future. When the alarm's scheduled time comes, the alarm() handler method will be called. Alarms are modified using the Storage API, and alarm operations follow the same rules as other storage operations.

Ddave > For now, this is only available for Workers that are deployed to a “root” host...

Walshy•5/27/25, 1:28 PM

still root, it's hard to figure out the right path early

WWalshy also we already pre-warm <https://blog.cloudflare.com/eliminating-cold-starts-wi...

Trojan•5/27/25, 1:28 PM

how about for subrequests? those can’t be known ahead of time right?

Ddave > A Worker can have up to three Cron Triggers configured at once https://develo...

Walshy•5/27/25, 1:29 PM

hmm yeah, i think the limit is like 10/15

TTrojan how about for subrequests? those can’t be known ahead of time right?

Walshy•5/27/25, 1:29 PM

no, this doesn't help subrequests

Walshy•5/27/25, 1:29 PM

but also worth noting that workers are fast anyway :)

Trojan•5/27/25, 1:29 PM

maybe premature optimization, but fun to think about

Trojan•5/27/25, 1:31 PM

what’s the wind down period? maybe i can time prewarming by a kv value

Walshy•5/27/25, 1:31 PM

also worth remembering that workers don't shut down right away

Walshy•5/27/25, 1:31 PM

they stay around for a while (there is no set duration)

Trojan•5/27/25, 1:32 PM

ahhh darn

WWalshy also worth remembering that workers don't shut down right away

daveOP•5/27/25, 1:43 PM

Are you allowed to do a fetch with FinalizationRegistry? Was thinking you could make a Worker fetch itself as soon as it's being cleaned up.

https://developers.cloudflare.com/workers/configuration/compatibility-flags/#enable-finalizationregistry-and-weakref

Walshy•5/27/25, 1:44 PM

FinalizationRegistry is only on gc cleanup, i don't know if you'll be able to get that reliably on worker shut down - i doubt it

Walshy•5/27/25, 1:45 PM

i'm not aware of it blocking fetch though so you can try it

Ddave Are you allowed to do a fetch with FinalizationRegistry? Was thinking you could ...

Trojan•5/27/25, 2:04 PM

that’s terrifying lol

Trojan•5/27/25, 2:07 PM

how about regional durable object replicas which ping their counterparts on the opposite side of the globe to stay warmed and consume wall time over cpu time

Trojan•5/27/25, 2:07 PM

well i guess you can’t concretely set their placement

GilDev•5/27/25, 3:49 PM

Hi!
Is there a way to rate-limit my Worker so that requests are not even counted by Cloudflare toward my daily request limit? It seems like the rate limit API only limits inside the Worker, but the initial call will still increment the request counter, right?

GGilDev Hi! Is there a way to rate-limit my Worker so that requests are not even counted...

Chaika•5/27/25, 4:05 PM

yes, rate limit rules and using Worker Custom Domains

Chaika•5/27/25, 4:06 PM

https://developers.cloudflare.com/waf/rate-limiting-rules/

Cloudflare Docs

Rate limiting rules

Rate limiting rules allow you to define rate limits for requests matching an expression, and the action to perform when those rate limits are reached.

izak•5/27/25, 4:13 PM

Anyone else having issues with worker builds atm?

Iizak Anyone else having issues with worker builds atm?

MadDog•5/27/25, 4:19 PM

yes. Can't deploy a worker I have.

Walshy•5/27/25, 4:27 PM

Workers builds is having issues - status page coming up

Walshy•5/27/25, 4:29 PM

https://www.cloudflarestatus.com/incidents/y1h2xdfxbkb9

Workers Builds Issues

izak•5/27/25, 4:36 PM

Cool it's deploying again, thanks for the quick fix

CChaika yes, rate limit rules and using Worker Custom Domains

GilDev•5/27/25, 6:45 PM

Thanks!

MadDog•5/27/25, 8:06 PM

Are workers slower than pages? A Hugo project which takes less than 90 seconds on pages is now taking over 200 seconds on workers.

MMadDog Are workers slower than pages? A Hugo project which takes less than 90 seconds o...

Chaika•5/27/25, 8:10 PM

Build Environment wise? Yes, it's been my experience the Workers Builds are slower
Production wise? It's all the same tech, Pages Functions are Workers, and both Pages Assets and Workers Static Assets are based off the same stuff, both use KV for storage and such, Workers Custom Domains are faster then Pages Custom Domains by a solid ~20ms tho

Trojan•5/27/25, 8:29 PM

does cloudflare snippets block waituntil?

Trojan•5/27/25, 8:37 PM

nvm

What is the downside of using this flag? It seems like it should be a default, what would it break…?

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