workers-wasi VS litestream

The examples seemed clear enough to read (I did not test them), but I felt than even when teaching by example there needs to be more overview and explanation. I.e., I would prefer an overview of WASM structure and use with examples, rather than just the examples. (I have some (but limited) experience using WASM.)

As for the utility of wasm, note also that Cloudflare workers can run WASM on edge servers [1], and that the Swift community has some support for compiling to wasm [2].

I've never really understood how wasm could do better than java bytecode, but I've been impressed with how much people are using lua and BPF. More generally, in a world of federated programming, we need languages client can submit that providers can run safely, without obviously leaking any secret sauce -- perhaps e.g., for model refinement or augmented lookup.

[1] https://github.com/cloudflare/workers-wasi

Those are great questions! I believe Emscripten will be required for some cases as it provides more features for targeting a Web Browser. If WASI is the only requirement for a Wasm module, then there are three possible solutions:

- Use a library that provides the WASI bindings in a browser environments: there are some OSS projects that provides WASI bindings on top of browser technologies. For example, workers-wasi from Cloudflare [1]. It could be even another Wasm module that provides the implementation for the main one. I know the people from Loophole Labs are experimenting with virtual filesystems (VFS) [2].

- Browsers provides a WASI implementation: server-oriented runtimes like NodeJS are already providing these bindings (under a experimental flag). I shouldn't have stated that as a fact, as browsers may provide it or not. However, I saw in the past the Google Chrome team experimenting with WASI and the browser FileSystem API [3]. So, I think it may happen :)

- [1] https://github.com/cloudflare/workers-wasi

- [2] https://www.youtube.com/watch?v=46jZSXVxYPw

- [3] https://github.com/GoogleChromeLabs/wasi-fs-access

Indeed, some people are doing this:

- WASI once had an official polyfill https://wasi.dev/polyfill/, now apparently succeeded by https://github.com/bjorn3/browser_wasi_shim

- wasmer-js provides a JS polyfill for WASI https://docs.wasmer.io/integrations/js/wasi

- Cloudflare has a WIP polyfill https://github.com/cloudflare/workers-wasi

I'm generally leery of non-temporary polyfills, so I'm not sure that any of these feel like a long-term viable option for me.

I think modern C++ could be perfectly viable as well. Maybe https://github.com/cloudflare/workers-wasi would be a good starting point? I'm not too knowledgeable on the subject. Exciting times though, I think WASM might be the great equalizer.

While there is a WASI implementation for Workers: cloudflare/workers-wasi, I prefer to implement each import manually - especially when there are so few and especially while I am still experimenting. This helps me to keep the full picture of what's going on.

I have not, but I keep meaning to collate everything I've learned into a set of useful defaults just to remind myself what settings I should be enabling and why.

Regarding Litestream, I learned pretty much all I know from their documentation: https://litestream.io/

This presentation is focused on the use-case of vertically scaling a single server and driving everything through that app server, which is running SQLite embedded within your application process.

This is the sweet-spot for SQLite applications, but there have been explorations and advances to running SQLite across a network of app servers. LiteFS (https://fly.io/docs/litefs/), the sibling to Litestream for backups (https://litestream.io), is aimed at precisely this use-case. Similarly, Turso (https://turso.tech) is a new-ish managed database company for running SQLite in a more traditional client-server distribution.

This post intends to help you setup replication for SQLite using Litestream.

I've been messing around with litestream. It is so cool. And, I either found a bug in the -timestamp switch or don't understand it correctly.

What I want to do is time travel into my sqlite database. I'm trying to do some forensics on why my web service returned the wrong data during a production event. Unfortunately, after the event, someone deleted records from the database and I'm unsure what the data looked like and am having trouble recreating the production issue.

Litestream has this great switch: -timestamp. If you use it (AFAICT) you can time travel into your database and go back to the database state at that moment. However, it does not seem to work as I expect it to:

https://github.com/benbjohnson/litestream/issues/564

I have the entirety of the sqlite database from the production event as well. Is there a way I could cycle through the WAL files and restore the database to the point in time before the records I need were deleted?

Will someone take sqlite and compile it into the browser using WASM so I can drag a sqlite database and WAL files into it and then using a timeline slider see all the states of the database over time? :)

We're using SQLite in production very heavily with millions of databases and fairly high operations throughput.

But we did run into some scariness around trying to use Litestream that put me off it for the time being. Litestream is really cool but it is also very much a cool hack and the risk of database corruption issues feels very real.

The scariness I ran into was related to this issue https://github.com/benbjohnson/litestream/issues/510

Litestream is a library that allows you to easily create backups. You can probably just do analytic queries on the backup data and reduce load on your server.

https://litestream.io/

One possible strategy is to have one directory/file per customer which is one SQLite file. But then as the user logs in, you have to look up first what database they should be connected to.

OR somehow derive it from the user ID/username. Keeping all the customer databases in a single directory/disk and then constantly "lite streaming" to S3.

Because each user is isolated, they'll be writing to their own database. But migrations would be a pain. They will have to be rolled out to each database separately.

One upside is, you can give users the ability to take their data with them, any time. It is just a single file.

[0]. https://litestream.io/

Upstream Kuma uses a local SQLite database to store account data, configuration for services to monitor, notification settings, and more. To make sure that our data is available across redeploys, we will bundle Uptime Kuma with Litestream, a project that implements streaming replication for SQLite databases to a remote object storage provider. Effectively, this allows us to treat the local SQLite database as if it were securely stored in a remote database.