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Floci: Locally emulating any cloud service

210 pointsposted 2 days ago

53 Comments

thegagne

2 days ago

The cool part of this is it’s an example of what’s possible with a community of users armed with AI.

Many users, (myself included), had need to test cloud stuff locally, but had no tool to do so. Localstack exists, but it started rug pulling the free tier and they didn’t support all the features.

Meanwhile, Floci makes it easy to write your own cloud compatible test suite, then implement the feature to match. I was able to get a good enough coverage on a few features created in a weekend on the $20 tier of Claude to make it useful to me, then others picked up the work to round it out.

It’s really cool to see it grow.

theptip

13 hours ago

There’s a general concept brewing, something like “proof of work” where if enough people get together and pool their tokens, then a good thing gets built.

I think we’re in the early days of this, but for extremely verifiable domains like porting from A to B or simulators with an objective oracle, I think it’s just a matter of putting the scaffolding to enable anyone and their Claude to contribute fruitfully.

I’m hoping we can do a similar thing with shared search for vulns, though it’s a bit harder. But if eg repos give an AGENTS.md with instructions on the bar for a good reproducer, then you could start to see more helpful federation patterns (instead of drive-by CVEs which are a net drain on contributors).

Different OSS project management skills required, but I am optimistic that we can do better at onboarding non-experts to federate work via their Claude subs. Almost like Folding at Home.

didgeoridoo

2 days ago

I’d love to see this for stuff like Stripe, Twilio, etc - they’ve got sandboxes but this would be a lot easier and faster.

tough

a day ago

vercel-labs/emulate [1], has stripe and twilio (their emulators are much more shallow generally like their AWS one can't really be compared to floci here, but i've made custom ones for stuff like emulating hardware devices (airplay/google play) with much success so you can basically extend their base framework with custom emulators or their own provided ones to your needs on a fork.

1. https://github.com/vercel-labs/emulate

for modelling and testing a CI software i was working on, i had to extend their github emulator in several places for example. but it was great to already have a working base.

catlifeonmars

2 days ago

Both localstack and floci live in this weird spot where for a lot of my applications, all the cloud-vendor specific stuff is abstracted out anyway. So the only time I need to touch the cloud is for testing the abstractions and do end to end testing. The abstractions can be tested against real cloud APIs as it is generally cheap to do and provides the highest fidelity results. End to end testing includes testing against a production-like environment, so again, more bang for your buck to just test against the cloud.

I’ve definitely reached for these local cloud tools from time to time, but in a well-architected piece of software, you aren’t getting that much value from them. Either you don’t have a hard cloud dependency, or you want a high fidelity test of a specific cloud dependency.

mmarian

15 hours ago

> you want a high fidelity test of a specific cloud dependency

Reached the same conclusion. Plus it's a fair amount of effort to set them up and maintain.

microflash

2 days ago

Been using it for a while to run integration tests with Testcontainers [1]. It's very good and much more lightweight than Localstack.

[1]: https://testcontainers.com/

aeagentic

2 days ago

Would someone be interested in this but intended for production? Im already running a whole bunch of cloudflare and AWS services in my own AWS fake and it works surprisingly well! :)

dxxvi

a day ago

Could you tell us more about it? I'd love to hear about the use cases of cloudflare and AWS service combinations.

aeagentic

15 hours ago

Not really for combinations, I use almost 100% the AWS implementations but just a few days ago I found something built serverless on CF and I could deploy via the CF surface. First it was more like an experiment but I can deploy almost everything as a hybrid giving even more durability then just AWS or local alone. Also I can rune base load on cheap metal servers and load balance the rest into the cloud twin. The combination of local and cloud or beeing able to leave any time makes it powerful

danduma

6 hours ago

As a speaker of Romanian, loving the name

("floci" means "pubes")

nexo-v1

a day ago

I was never happy with how heavy LocalStack was, so I'm going to try this for my next green field cloud app.

I think having such emulator being lightweight and quick to run becomes more important in AI coding/worktree-based workflows where it's important to pre-setup the worktree with dependencies and dependent services on local ports.

bensyverson

a day ago

I've looked into developing "digital twins" of APIs that I rely on, similar to the StrongDM pattern, but the models talk me out of it every time. The rationale is that there could be subtle differences or drift between the behavior of the real service and the mocked API. So you may think you're on solid ground, but once you switch to prod, you could see show-stopping differences.

I think if I was doing evals on the way an agent interacts with a service (e.g. Slack) the digital twin could make sense, but for rapid iteration or testing, it might not be what you want.

nijave

a day ago

That makes sense for the "make sure this thing is working correctly" case but there's still "I want to run this thing locally and it requires this other thing". The second one you really only need the happy path to work and you can run your test from the first thing against it (contract test).

conception

a day ago

For a hot minute Eucalyptus https://www.eucalyptus.cloud was amazing - even matching aws bugs to keep compatibility. Wish it had rue support/resources to keep going. Maybe a viber will pick up and get it more up to date.

michaelastreiko

2 days ago

Local stubs for cloud services are a lifesaver when you're a one-person shop and don't want a surprise bill just to test a webhook path.

fduran

14 hours ago

Floci works well, we started using it at SadServers for our AWS cli scenarios :-)

mkirsten

2 days ago

This looks very cool! Is this only intended for testing and development, or as a feasible way to migrante away from e.g., GCP as well?

I’m interested in something that would allow me to over time migrante away from a GCP project that uses many services today - e.g., Datastore, FileStorage etc.

elendilm

stevekemp

2 days ago

One of the later pages mentions that the name came from "cirrocumulus floccus", the cloud formation.

adrian_b

2 days ago

In this case it is misspelled.

The Latin word is "flocci", which means hairs of wool, and it was also used to denote an insignificant thing.

English normally preserves the double consonants of Latin, and in this case it has already done this in the English words derived from "floccus", e.g. "to flocculate" and "flocculent".

In clouds, it was used due to the resemblance of those clouds with curly sheep wool.

illiac786

2 days ago

You mean like Flikr, sonarr, tumblr, Waze…?

adrian_b

a day ago

I agree that the misspelling was probably intentional, but in this case, as others have pointed, it lead to some undesirable connotations in some languages.

Even the original Latin word would be a poor choice, because, as I have said above, it was also used to designate something that is insignificant, and such a meaning is undesirable for a company, product or service.