🐛 BUG: Miniflare KV persistence not working in Wrangler2 --local mode

[hkochniss]

What version of Wrangler are you using?

0.0.24

What operating system are you using?

Mac OS (ARM64)

Describe the Bug

It seems as Wrangler2 uses Miniflare under the hood in --local mode, many Miniflare features should work, especially persistence around KV etc. But for some reason persistence doesn't kick in when using

[miniflare]
kv_persist = true

in wrangler.toml. Also other kv_persist options don't work, KV namespace are just empty on each change of a worker file. This really hurts productivity, I'm assuming this is unintended and should work?

Using typescript and modules, can provide a minimal reproduction case once this is confirmed as a bug.

[threepointone]

Try this cli flag: --experimental-enable-local-persistence

[hkochniss]

A bit better, but unfortunately only works for keeping KV stuff between worker changes in watch mode, does not persist to disk apparently

So once I stop wrangler 2 manually (gently via hitting X) and start again, the KV data is lost. Also I can't find anything written to disk visible, not in ./mf/kv or anywhere else, so I assume this is in-memory "persistence" for now (or I'm overlooking a secret folder somewhere, still new to the Mac ecosystem)

How is this intended to work right now? Is there any roadmap/plans around offline persistence? I feel there isn't much missing feature wise (only let Miniflare do its thing), but maybe I'm missing something

[threepointone]

We'd only just started working on this, hence the experimental flag. What the flag does, is enable persistence for kv/durable_objects/cache in miniflare https://github.com/cloudflare/wrangler2/blob/ed4f2ef00f86374ac7d1ac6ff072d939c80b6c18/packages/wrangler/src/dev/local.tsx#L163-L170
This does persist to disk. However, we use a fresh temp directory where the actual worker is bundled, and that temp directory disappears when you close wrangler dev. Instead, we should be persisting to a path relative to the working directory, so that it sticks around in a known location (and let users like you decide what to do with the generated files). I'll send a fix for this soon.

The workaround for now if you want to test persistence, is to use regular "remote" mode. But we'll fix it very soon!

[hkochniss]

Really looking forward to this, that sounds like a big improvement. Also props for the late reply, knowing your timezone is London ;)

[threepointone]

We have a fix in place, you can try it with wrangler@alpha. We will revisit it and make it better, but it should hopefully unblock it for you now. We will do a beta release soon too. Thank you for reporting!

[hkochniss]

works like a charm, thanks again