History

Florian Klink 9748543f1c chore(tvix): drop sled compression support It's been a while since the last sled release, and that one binds to a pretty old version of zstd, requiring workarounds like cl/10090. Upstream sled main branch currently has zstd halfway patched out (it's a no-op, but the feature flag and options are still there), and it's in that state for a year. Rather than maintaining our own fork of sled, let's just stop using the compression feature in sled, dropping the version pin to zstd that way, removing the need for cl/10090. This doesn't mean we won't reintroduce per-blob compression - but we probably just won't let sled take care of the compression, but do it ourselves - which is necessary for more chunked blob storage anyways. Even though we do drop the feature flag, we still need to explicitly use use_compression(false). Change-Id: I0e4892d29e41c76653272dc1a3625180da6fee12 Reviewed-on: https://cl.tvl.fyi/c/depot/+/10257 Autosubmit: flokli <flokli@flokli.de> Reviewed-by: raitobezarius <tvl@lahfa.xyz> Tested-by: BuildkiteCI		2023-12-11 22:46:50 +00:00
..
docs	chore(tvix/castore): move data model docs to here	2023-11-02 09:08:20 +00:00
protos	refactor(tvix/*/protos): separate lint target	2023-12-11 22:35:39 +00:00
src	chore(tvix): drop sled compression support	2023-12-11 22:46:50 +00:00
build.rs	chore(tvix/[ca]store): allow building without tonic-reflection	2023-09-26 10:07:40 +00:00
Cargo.toml	chore(tvix): drop sled compression support	2023-12-11 22:46:50 +00:00
default.nix	fix(tvix/store): Remove virtiofs from default features	2023-10-07 02:34:00 +00:00
README.md	fix(tvix/store): rename Read method in Readme	2023-09-26 15:24:32 +00:00

README.md

//tvix/store

This contains the code hosting the tvix-store.

For the local store, Nix realizes files on the filesystem in /nix/store (and maintains some metadata in a SQLite database). For "remote stores", it communicates this metadata in NAR (Nix ARchive) and NARInfo format.

Compared to the Nix model, tvix-store stores data on a much more granular level than that, which provides more deduplication possibilities, and more granular copying.

However, enough information is preserved to still be able to render NAR and NARInfo when needed.

More Information

The store consists out of two different gRPC services, tvix.castore.v1 for the low-level content-addressed bits, and tvix.store.v1 for the Nix and StorePath-specific bits.

Check the protos/ subfolder both here and in castore for the definition of the exact RPC methods and messages.

Interacting with the GRPC service manually

The shell environment in //tvix provides evans, which is an interactive REPL-based gPRC client.

You can use it to connect to a tvix-store and call the various RPC methods.

$ cargo run -- daemon &
$ evans --host localhost --port 8000 -r repl
  ______
 |  ____|
 | |__    __   __   __ _   _ __    ___
 |  __|   \ \ / /  / _. | | '_ \  / __|
 | |____   \ V /  | (_| | | | | | \__ \
 |______|   \_/    \__,_| |_| |_| |___/

 more expressive universal gRPC client


localhost:8000> package tvix.castore.v1
tvix.castore.v1@localhost:8000> service BlobService

tvix.castore.v1.BlobService@localhost:8000> call Put --bytes-from-file
data (TYPE_BYTES) => /run/current-system/system
{
  "digest": "KOM3/IHEx7YfInAnlJpAElYezq0Sxn9fRz7xuClwNfA="
}

tvix.castore.v1.BlobService@localhost:8000> call Read --bytes-as-base64
digest (TYPE_BYTES) => KOM3/IHEx7YfInAnlJpAElYezq0Sxn9fRz7xuClwNfA=
{
  "data": "eDg2XzY0LWxpbnV4"
}

$ echo eDg2XzY0LWxpbnV4 | base64 -d
x86_64-linux

Thanks to tvix-store providing gRPC Server Reflection (with reflection feature), you don't need to point evans to the .proto files.