Damola's blog

Workers KV as a tiny (pet) db

I found a way to replace my (very small) postgres db with Cloudflare's Workers KV

September 18, 2022 | 2 min. read

Since Heroku announced deprecating their free tier - I knew I had to get off their managed Postgres, which sucks. It’s worked well for me. Especially because I was using it with Hasura - almost zero-effort. I just type into a few fields and it’d (Hasura) creates schema, index etc. and I can query without writing SQL. Nothing against sql. But why pass up auto-generated queries!

I had the goal of moving the entire site to Cloudflare pages. I went down this path and had to give it up when I found out (well, was reminded of) the fact that cloudflare workers (the equivalent of Netlify functions, which are like AWS lambdas, on Cloudflare) “runtime” doesn’t implement all nodejs apis. And I happen to be using web-push package which wouldn’t run in a worker runtime. Oh well.

I decided to just remove the hasura/heroku-postgres part of the site instead. So. I wrote up a “kv service” as a worker and use Workers KV (a key-value store) as the database. I wouldn’t even have to do this if I could access Cloudflare KV from the (Netlify) functions I currently use. Regardless, this service (I called it kvstore) was borderline trivial to write. And then I just had to update the netlify functions to write/read from the KV store instead of hasura. It was… painless.

This is a sample call to set/create a key with:test with value simple

POST / HTTP/1.1 Host: localhost:8787 Content-Type: application/json Content-Length: 69 { "op": "WRITE", "key": "with:test", "value": "simple" }

One nice trick with using a key-value database is, with prefixes, you can essentially build different “tables” from a single store. So the structure of the key can embed information about the schema. For example, A production table for number of words on a page (homepage here) could look like: prod:pages:wordcount:homepage

The namespacing helps with avoiding key-collision. And with prefix support when listing in workers KV. It’s easy to say… list all keys for word count count in dev environment with something like list(prefix='dev:pages:wordcount:')

Easy! I’ve migrated the logic for the push notification and … everything works as it always has.

And now I can rest easy again. Until cloudflare removes their free tier and I have to relocate again.

Until then.

Adedamola Shomoye

By Adedamola Shomoye

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