tvl-depot/tvix/store
Connor Brewster e7be342256 feat(tvix/store): concurrently upload small blobs during nar ingestion
Currently all blobs are uploaded serially when ingesting NARs. If a NAR
contains many, small blobs, ingestion may become slow if there is a lot
of round-trip latency to the blob service.

This makes the NAR ingester use the ConcurrentBlobUploader which allows
for buffering small blobs in memory so they can be uploaded concurrently
to the blob service without blocking further deserialization.

Change-Id: I093a73770232df12d9a11e5d901b99c08505c3cb
Reviewed-on: https://cl.tvl.fyi/c/depot/+/11694
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
2024-05-20 15:21:51 +00:00
..
docs chore(tvix/nar-bridge): move to nar-bridge-go 2024-05-15 21:31:36 +00:00
protos refactor(tvix/*/protos): separate lint target 2023-12-11 22:35:39 +00:00
src feat(tvix/store): concurrently upload small blobs during nar ingestion 2024-05-20 15:21:51 +00:00
build.rs fix(tvix): don't emit rerun-if-changed 2024-03-16 09:34:10 +00:00
Cargo.toml chore(tvix): drop json feature for tracing-subscriber 2024-05-16 21:05:51 +00:00
default.nix test(tvix/[ca]store): enable bigtable only with "integration" feature 2024-05-03 08:53:09 +00:00
README.md fix(tvix/store): rename Read method in Readme 2023-09-26 15:24:32 +00:00

//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.