History

Simon Hauser fa7ed39bf4 feat(tvix/tracing): correctly close otlp on exit Provide a new interface for forcing a flush of otlp traces and use this interface to shutdown otlp prior to exiting tvix-store, either if the tool was stopped with a SIGTERM or ended regularly. This also fixes an issue where traces were not even exported if for example we just imported 10 paths and never even emitted more than 256 traces. The implementation uses a mpsc channel so a flush can be done without having to wait for it to complete. If you want to wait for a flush to complete you can provide a oneshot channel which will receive a message once flushing is complete. Because of a otlp bug `force_flush` as well as `shutdown_tracer_provider` need to be executed using `spawn_blocking` otherwise the function will deadlock. See https://github.com/open-telemetry/opentelemetry-rust/issues/1395#issuecomment-1953280335 Change-Id: I0a828391adfb1f72dc8305f62ced8cba0515847c Reviewed-on: https://cl.tvl.fyi/c/depot/+/11803 Reviewed-by: flokli <flokli@flokli.de> Tested-by: BuildkiteCI Autosubmit: Simon Hauser <simon.hauser@helsinki-systems.de>		2024-06-14 09:34:51 +00:00
..
protos	refactor(tvix/*/protos): separate lint target	2023-12-11 22:35:39 +00:00
src	feat(tvix/tracing): correctly close otlp on exit	2024-06-14 09:34:51 +00:00
build.rs	fix(tvix): don't emit rerun-if-changed	2024-03-16 09:34:10 +00:00
Cargo.toml	feat(tvix/tracing): introduce common tvix-tracing crate	2024-06-10 16:35:08 +00:00
default.nix	chore(tvix/docs): move [ca]store docs to tvix/docs	2024-06-14 08:00:34 +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.