Comment by pcl | Hacker News Reader

Comment by pcl | Hacker News Reader

Cool stuff!

What do you suggest is the sweet spot for document size and "hotness"? Your cookbook [0] says "We suspect that an Automerge document is best suited to being a unit of collaboration between two people or a small group." Does that mean tens of kilobytes? Hundreds? More? And how much concurrent contention is viable? And is the "atom of contention" the document as a whole, or do you have any plans for merging of sub-parts?

Also, do you have support for juggling multiple transports, either concurrently or back-to-back? In particular, I'm thinking about synchronizing via the cloud when connected, and falling back to peer-to-peer when offline. In that peer-to-peer case, how many peers can I have, and can my peer network behave as a mesh, or must it stick together to some degree?

And finally, it looks like your tutorial [1] doesn't actually exist! You refer to it in a blog post [2], but it's a dead link.

[0] https://automerge.org/docs/cookbook/modeling-data/

[1] https://automerge.org/docs/tutorial/introduction/

[2] https://automerge.org/blog/automerge-2/

The way I think about it is that if the data should always travel together it should be in one document. For example -- if your TODO list always goes as a unit, then make it an array of objects in a single Automerge document. On the other hand, if you want to build an issue tracker and to be able to link to individual issues or share them individually then a document each is the way to go. Does that help?

As for network transports you can indeed have multiple at once. I usually have a mix of in-browser transports (MessageChannels) and WebSocket connections. I suspect we'll need to do a little adjusting to account for prioritization once people really start to push on this with things like mDNS vs relay server connections but the design should accommodate that just fine.

As for the docs, my apologies. The "tutorial" was merged into the quickstart as part of extensive documentation upgrades over the last few months. We should update the link in the old blog post accordingly.

Here's a link to save you the effort: https://automerge.org/docs/quickstart/

Cool, thanks for the details.

So if I smoosh everything in my sorta “collaboration context” together into one document, are there any provisions for delta updates on the wire? Your browser-side storage format sounds like it’s compatible with that approach, but what about clients that are far apart version-wise? Are you storing full relay history and also a snapshot?

I see in your format docs [0] that you store change chunks. Are these exposed in the API for atomicity at all? Are there any atomicity guaranties?

And you discuss backends, but I don’t see any pointers to an S3 or Postgres implementation. Is that something you’re keeping closed source for your business model, or am I just missing something?

I haven’t found anything about authorization. Have you done any work there? I quite like the Firebase model in which you can write simple validation rules that can evaluate against the document itself —- “only allow users who are listed in path `members` to write to this document” or whatever.

[0] https://automerge.org/automerge-binary-format-spec/#chunk-co...

The sync protocol does indeed calculate the delta between peers and efficiently catches both sides up.

The backends you see are the ones I use, but the API is a binary blob key value store with range queries: supporting other stores should be straightforward.

Authentication isn’t exactly left as an exercise to the reader but is an area of active work. I would say securing access to a URL via whatever mechanism you’re used to should be fine for client server applications and peer to peer folk seem to mostly have their own ideas.

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