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diff --git a/users/flokli/presentations/2023-09-09-nixcon-tvix/presentation.md b/users/flokli/presentations/2023-09-09-nixcon-tvix/presentation.md new file mode 100644 index 0000000000..b37554e188 --- /dev/null +++ b/users/flokli/presentations/2023-09-09-nixcon-tvix/presentation.md @@ -0,0 +1,294 @@ +--- +author: +- Florian Klink +date: 2023-09-09 +title: "Tvix: Status update" +theme: moon +revealOptions: + transition: 'fade' +--- + +# Tvix: Status update + + + +2023-09-09 + +Florian Klink + +--- + +## Whoami + +- flokli +- nixpkgs contributor since 2018, maintaining systemd, nsncd and some + more stuff +- Freelance Nix/DevOps consultant +- I spend too much time on computers :-) + +--- + +## What is Tvix? + +- A new implementation of Nix +- modular +- written in Rust +- developed in the [TVL](https://tvl.fyi) monorepo +- subtree exported to [github:tvlfyi/tvix](https://github.com/tvlfyi/tvix) + +--- + +## Structure + +- strong separation between **Evaluator**, **Store** and **Builder** +- Defined interfaces between different components (Protobuf/gRPC) <!-- .element: class="fragment" --> + - Allows adding to/combining with your own components <!-- .element: class="fragment" --> +- <!-- .element: class="fragment" --> A lot of helper code for some of the Nix internals in the `nix-compat` crate + +Note: Derivation types, serializers. NAR writers, nixbase32 enc/dec, Nix Hash function, stringparsing etc. + +---- + + + +--- + +## Evaluator: Design + +- <!-- .element: class="fragment" --> + Nix code is parsed via [rnix](https://github.com/nix-community/rnix-parser) +- <!-- .element: class="fragment" --> + AST traversal, generate bytecode (with some transformations) +- <!-- .element: class="fragment" --> + Bytecode is executed by an abstract machine with a Nix-specific instruction set + +---- + +## Evaluator: Design + +- <!-- .element: class="fragment" --> + Builtins are separate from the "evaluator core" + - <!-- .element: class="fragment" --> + inject your own builtins + - <!-- .element: class="fragment" --> + this includes `builtins.derivation`! +- <!-- .element: class="fragment" --> + IO is nicely abstracted away + - <!-- .element: class="fragment" --> + We can run a Nixlang subset without IO in wasm (see [tvixbolt](https://bolt.tvix.dev/)), + or parse Nix into a config struct with `tvix-serde` + +---- + +<!-- <video class="r-stretch" src="./tvixbolt.webm"></video> --> +<a href="./tvixbolt.webm">Tvixbolt Demo</a> + +---- + +### Evaluator: Current Work + +- <!-- .element: class="fragment" --> + Current goal: **evaluate nixpkgs the same way as Nix does** +- <!-- .element: class="fragment" --> + Checked by comparing the calculated output paths, which checks correctness of all \"parent\" output paths too. +- <!-- .element: class="fragment" --> + Required implementing a lot of Nix internals in `nix-compat`, and `tvix-store` (A-Term, hash modulo, NAR writer/hasher) + +Note: Getting output hashing correct, and exposing this in a re-usable fashion took quite some iterations to get right. + +---- + +### Evaluator: Current Work (cont.) +- <!-- .element: class="fragment" --> + ๐ Already correct for (and continously checked by CI on every commit): + - <!-- .element: class="fragment" --> + `stdenv`, `hello` + - <!-- .element: class="fragment" --> + `pkgsCross.aarch64-multiplatform.stdenv`, `pkgsCross.aarch64-multiplatform.hello` +- <!-- .element: class="fragment" --> + Some work left for more complicated expressions + - <!-- .element: class="fragment" --> + infinite recursion [when inheriting from a `builtins.tryEval` multiple times](https://b.tvl.fyi/281) + - <!-- .element: class="fragment" --> + small details around file imports +- <!-- .element: class="fragment" --> + Not too much performance finetuning until we're correct first. + +---- + +### Evaluator: Demo + +[](https://asciinema.org/a/MH4tuVPLsKewJSGJUYEyIKUpj) + +--- + +## Store: Design + +- <!-- .element: class="fragment" --> + Uses a very different underlying data model: + - <!-- .element: class="fragment" --> + Nix stores on a per- `StorePath` granularity + - <!-- .element: class="fragment" --> + tvix-store uses a Merkle DAG of directories, similar to git trees, but with [BLAKE3](https://github.com/BLAKE3-team/BLAKE3) digests as pointers. + - <!-- .element: class="fragment" --> + Compat layer in front to still render/calculate NAR on demand where needed + - <!-- .element: class="fragment" --> + Substitution, caching, ... possible to describe via composition/layering + +---- + + + +---- + +### Store: Advantages + +- <!-- .element: class="fragment" --> + Less downloading of data that didn't change +- <!-- .element: class="fragment" --> + Less duplicate data on disk/storage +- <!-- .element: class="fragment" --> + Inherently content-addressed, so P2P substitution possible +- <!-- .element: class="fragment" --> + Allows doing verified blob streaming ([BAO](https://github.com/oconnor663/bao), [bao-tree](https://github.com/n0-computer/bao-tree)) +- <!-- .element: class="fragment" --> + Protocol has some \"smarter\" methods to avoid roundtrips, but could all be statically pre-rendered +- <!-- .element: class="fragment" --> + Very little data that needs to be fetched from a trusted party (or be signed) + +Note: Our way of addressing blobs by their raw blake3 digest is natively compatible with iroh, the IPFS Re-implementation in Rust + +---- + +### Store: Status + +- <!-- .element: class="fragment" --> + Whole Merkle-based store implementation (and Nix NAR compat layer) is there + - <!-- .element: class="fragment" --> + exercised by the output path CI tests, and a test suite. + - <!-- .element: class="fragment" --> + three backends (Sled, in-memory, gRPC client) + - <!-- .element: class="fragment" --> + more backends and more test suites planned. +- <!-- .element: class="fragment" --> + FUSE filesystem to expose the store (to Tvix Builders, \"appliances\") <!-- .element: class="fragment" --> + +Note: backends: RocksDB, sqlite, s3. fuse: lazy fetching of build input files | think about a minimal initrd to bring up network and mount the store, then run any closure. + +---- + +### Store: Demo + +[](https://asciinema.org/a/YFB9yycHdx0OUH9N0WdAkIYua) + +---- + +### Store: Status (cont.) +- <!-- .element: class="fragment" --> + More work on store composition needed (necessary for substition and caching) +- <!-- .element: class="fragment" --> + More work on more granular blob substititon needed. +- <!-- .element: class="fragment" --> + More work on bridges with Nix needed + - <!-- .element: class="fragment" --> + Get Nix to talk to a tvix-store + - <!-- .element: class="fragment" --> + Expose existing binary caches to tvix-store + +--- + +### Builder: Design + +- <!-- .element: class="fragment" --> + Build requests/Build protocol is less Nix-specific + - <!-- .element: class="fragment" --> + allows reusing builders for other usages (non-sandboxed builds, other build systems, playing with other addressing mechanisms) +- <!-- .element: class="fragment" --> + Distinction between a **specific build attempt** and the **general build recipe** + - <!-- .element: class="fragment" --> + allows keeping metadata about failed builds + - <!-- .element: class="fragment" --> + stats (memory/cpu consumption) + - <!-- .element: class="fragment" --> + comparing different produced binary outputs (r11y) + +---- + +### Builder: Design + +- <!-- .element: class="fragment" --> + Invididual builds can be run in your desired container/virt engine/scheduler, as long as it speaks the same Build API +- <!-- .element: class="fragment" --> + Build API composition/proxying, similar to Store composition +- <!-- .element: class="fragment" --> + allows "unattended building" (evaluate nixpkgs locally and send all build requests to a remote builder) +- <!-- .element: class="fragment" --> + allows tailing logs from currently/already running builds + +---- + +### Builder: Status + +- <!-- .element: class="fragment" --> + Dummy Builder implementation in `go-nix` (using OCI) +- <!-- .element: class="fragment" --> + Some scribble notes on the Build Protocol +- <!-- .element: class="fragment" --> + Glue code to trigger builds from inside `builtins.derivation` needs to be written +- <!-- .element: class="fragment" --> + Builder implementation (using `systemd-nspwan` or some container engine needs to be written. +- <!-- .element: class="fragment" --> + Web interface to visualize store contents and build graphs/builds/logs + +--- + +## Contributing + +- <!-- .element: class="fragment" --> + Join the IRC channel (`#tvl` on `hackint`), bridged to Matrix and XMPP +- <!-- .element: class="fragment" --> + Check our issue tracker +- <!-- .element: class="fragment" --> + Try to use it and tell us how you broke it! +- <!-- .element: class="fragment" --> + Add various Nix bits to `nix-compat` + +Note: or if you like what you seeing and want to sponsor parts, that's also cool :-) + +--- + +# Thanks to... + +- <!-- .element: class="fragment" --> + all TVL contributors (some drive-by, some long-term contributors) +- <!-- .element: class="fragment" --> + countless Nix community members for their input on the architecture and rubberducking +- <!-- .element: class="fragment" --> + NLNET and others to sponsor parts of this + +---- + +# Questions? + +<style> +.container{ + display: flex; +} +.col{ + flex: 1; +} +</style> + +<div class="container"> + +<div class="col"> +Florian Klink / <a href="https://flokli.de">flokli.de</a><br /> +<img src="qrcode-flokli.svg" /> +</div> + +<div class="col"> +Tvix / <a href="https://tvix.dev">tvix.dev</a><br /> +<img src="qrcode-tvix.svg" /> +</div> + +</div> |