6 ms·

Curious about the authors authz implementation. Preloading authorization data into memory does not, by itself, provide the specific security guarantee (consist

by perfmode 11mo ago

Curious about the authors authz implementation. Preloading authorization data into memory does not, by itself, provide the specific security guarantee (consistency) that defines Zanzibar. The Zanzibar model is famous not just because it is fast, but because it solves the "New Enemy" problem (or causal consistency). Simple in-memory caching (preloading) often fails this test unless it is paired with complex invalidation logic that mimics Zanzibar's Zookies.

jschorr 11mo ago
It is actually slightly worse than even that: while New Enemy [1] is the primary concern, caching like this can also introduce a staleness issue from the other direction: let's say a user adds a new row or document, and immediately sends the link to their coworker... who tries to load that piece of data, but the (stale) access control dataset is cached and they are not in it... they get a "no access" error. While certainly fail safe (vs fail dangerous for New Enemy), it can be a fairly important UX concern as well. Generally, the solution is to keep a timestamp of when the data changed (Zookies as you mentioned) or you can proactively reload or recompute the cache when the underlying data changes (sometimes in very smart ways), but yeah: it adds significant complications over a "simplified" approach to Zanzibar. Disclaimer: I'm the cofounder and CTO of AuthZed and we develop the SpiceDB [2] and Materialize [3], which have quite a bit of logic around these exact problems [1]: https://authzed.com/blog/new-enemies#the-new-enemy-problem https://authzed.com/blog/new-enemies#the-new-enemy-problem [2]: https://spicedb.io https://spicedb.io [3]: https://authzed.com/docs/authzed/concepts/authzed-materialize https://authzed.com/docs/authzed/concepts/authzed-materializ...
- fud101 11mo ago
  Hi, i'd like to implement my own version for learning purposes. Do you have any recommendations?
  - jschorr 11mo ago
    I'd start with reading the Zanzibar Paper. We built an annotated version [1] that provides additional guidance on some of the denser sections and how we interpreted them. Then, I'd take a look at the history of SpiceDB [2] for how we developed the system over time. Finally, if you have any questions, feel free to jump into our Discord [3] and ask: we're happy to answer! [1]: https://zanzibar.tech/ https://zanzibar.tech/ [2]: https://spicedb.io https://spicedb.io [3]: https://discord.gg/spicedb https://discord.gg/spicedb

jschorr 11mo ago

It is actually slightly worse than even that: while New Enemy [1] is the primary concern, caching like this can also introduce a staleness issue from the other direction: let's say a user adds a new row or document, and immediately sends the link to their coworker... who tries to load that piece of data, but the (stale) access control dataset is cached and they are not in it... they get a "no access" error. While certainly fail safe (vs fail dangerous for New Enemy), it can be a fairly important UX concern as well. Generally, the solution is to keep a timestamp of when the data changed (Zookies as you mentioned) or you can proactively reload or recompute the cache when the underlying data changes (sometimes in very smart ways), but yeah: it adds significant complications over a "simplified" approach to Zanzibar. Disclaimer: I'm the cofounder and CTO of AuthZed and we develop the SpiceDB [2] and Materialize [3], which have quite a bit of logic around these exact problems [1]: https://authzed.com/blog/new-enemies#the-new-enemy-problem https://authzed.com/blog/new-enemies#the-new-enemy-problem [2]: https://spicedb.io https://spicedb.io [3]: https://authzed.com/docs/authzed/concepts/authzed-materialize https://authzed.com/docs/authzed/concepts/authzed-materializ...

fud101 11mo ago
Hi, i'd like to implement my own version for learning purposes. Do you have any recommendations?
- jschorr 11mo ago
  I'd start with reading the Zanzibar Paper. We built an annotated version [1] that provides additional guidance on some of the denser sections and how we interpreted them. Then, I'd take a look at the history of SpiceDB [2] for how we developed the system over time. Finally, if you have any questions, feel free to jump into our Discord [3] and ask: we're happy to answer! [1]: https://zanzibar.tech/ https://zanzibar.tech/ [2]: https://spicedb.io https://spicedb.io [3]: https://discord.gg/spicedb https://discord.gg/spicedb