A year ago, my co-founder launched Desktop Docs here on HN. It's a Mac app we built with Electron that uses CLIP embeddings to search photos and videos locally with natural language. We got positive feedback from HN and our first paying customers, but the app was almost 1GB and clunky to use.

TLDR; rebuilding in Rust was the right move.

So we rewrote the app with Rust and Tauri and here are the results:

- App size is 83% smaller: 1GB → 172MB - DMG Installer is 70% smaller: 232MB → 69.5MB - Indexing files is faster: A 38-minute video now indexes in ~3 minutes instead of 10-14 minutes - Overall more stability (old app used to randomly crash)

The original version worked, but it didn't perform well when you tried indexing thousands of images or large videos. We lost a lot of time struggling to optimize Electron’s main-renderer process communication and ended up with a complex worker system to process large batches of media files.

For months we wrestled with indecision about continuing to optimize the Electron app vs. starting a full rebuild in Swift or Rust. The main thing holding us back was that we hadn’t coded in Swift in almost 10 years and we didn’t know Rust very well.

What finally broke us was when users complained the app crashed their video calls just running in background. I guess that’s what happens when you ship an app with Chromium that takes up 200mb before any application code.

Today the app still uses CLIP for embeddings and Redis for vector storage and search, except Rust now handles the image and video processing pipeline and all the file I/O to let users browse their entire machine, not just indexed files.

For the UI, we decided to rebuild it from scratch instead of porting over the old UI. This turned out well because it resulted in a cleaner, simpler UI after living with the complexity of the old version.

The trickiest part of the migration was learning Rust. LLMs definitely help, but the Rust/Tauri community just isn’t as mature compared to Electron. Bundling Redis into the app was a permissioning nightmare, but I think our solution with Rust handles this better than what we had with Electron.

All in, the rebuild took about two months and still needs some more work to be at total parity with its Electron version, but the core functionality of indexing and searching files is way more performant than before and that made it worth the time. Sometimes you gotta throw away working code to build the right thing.

AMA about Rust/Tauri migration, Redis bundling nightmares, how CLIP embeddings work for local semantic search, or why Electron isn't always the answer.

user:	backendEngineer
created:	March 4, 2023
karma:	3