//! This module provides an implementation of EvalIO.
//!
//! It can be used by the tvix evalutator to talk to a tvix store.
use data_encoding::BASE64;
use nix_compat::{
nixhash::{HashAlgo, NixHash, NixHashWithMode},
store_path::{build_regular_ca_path, StorePath},
};
use std::{io, path::Path, path::PathBuf, sync::Arc};
use tracing::{error, instrument, warn};
use tvix_eval::{EvalIO, FileType, StdIO};
use crate::{
blobservice::BlobService,
directoryservice::{self, DirectoryService},
import,
nar::calculate_size_and_sha256,
pathinfoservice::PathInfoService,
proto::NamedNode,
B3Digest,
};
/// Implements [EvalIO], asking given [PathInfoService], [DirectoryService]
/// and [BlobService].
///
/// In case the given path does not exist in these stores, we ask StdIO.
/// This is to both cover cases of syntactically valid store paths, that exist
/// on the filesystem (still managed by Nix), as well as being able to read
/// files outside store paths.
pub struct TvixStoreIO {
blob_service: Arc<dyn BlobService>,
directory_service: Arc<dyn DirectoryService>,
path_info_service: Arc<dyn PathInfoService>,
std_io: StdIO,
}
impl TvixStoreIO {
pub fn new(
blob_service: Arc<dyn BlobService>,
directory_service: Arc<dyn DirectoryService>,
path_info_service: Arc<dyn PathInfoService>,
) -> Self {
Self {
blob_service,
directory_service,
path_info_service,
std_io: StdIO {},
}
}
/// for a given [StorePath] and additional [Path] inside the store path,
/// look up the [PathInfo], and if it exists, traverse the directory structure to
/// return the [crate::proto::node::Node] specified by `sub_path`.
#[instrument(skip(self), ret, err)]
fn store_path_to_root_node(
&self,
store_path: &StorePath,
sub_path: &Path,
) -> Result<Option<crate::proto::node::Node>, crate::Error> {
let path_info = {
match self.path_info_service.get(store_path.digest)? {
// If there's no PathInfo found, early exit
None => return Ok(None),
Some(path_info) => path_info,
}
};
let root_node = {
match path_info.node {
None => {
warn!(
"returned PathInfo {:?} node is None, this shouldn't happen.",
&path_info
);
return Ok(None);
}
Some(root_node) => match root_node.node {
None => {
warn!("node for {:?} is None, this shouldn't happen.", &root_node);
return Ok(None);
}
Some(root_node) => root_node,
},
}
};
directoryservice::traverse_to(self.directory_service.clone(), root_node, sub_path)
}
/// Imports a given path on the filesystem into the store, and returns the
/// [crate::proto::PathInfo] describing the path, that was sent to
/// [PathInfoService].
/// While not part of the [EvalIO], it's still useful for clients who
/// care about the [PathInfo].
#[instrument(skip(self), ret, err)]
pub fn import_path_with_pathinfo(
&self,
path: &std::path::Path,
) -> Result<crate::proto::PathInfo, io::Error> {
// Call [import::ingest_path], which will walk over the given path and return a root_node.
let root_node = import::ingest_path(
self.blob_service.clone(),
self.directory_service.clone(),
path,
)
.expect("error during import_path");
// Render the NAR
let (nar_size, nar_sha256) = calculate_size_and_sha256(
&root_node,
self.blob_service.clone(),
self.directory_service.clone(),
)
.expect("error during nar calculation"); // TODO: handle error
// We populate the struct directly, as we know the sha256 digest has the
// right size.
let nar_hash_with_mode = NixHashWithMode::Recursive(NixHash {
algo: HashAlgo::Sha256,
digest: nar_sha256.to_vec(),
});
let name = path
.file_name()
.expect("path must not be ..")
.to_str()
.expect("path must be valid unicode");
let output_path =
build_regular_ca_path(name, &nar_hash_with_mode, Vec::<String>::new(), false).unwrap();
// assemble a new root_node with a name that is derived from the nar hash.
let root_node = root_node.rename(output_path.to_string().into_bytes().into());
// assemble the [crate::proto::PathInfo] object.
let path_info = crate::proto::PathInfo {
node: Some(crate::proto::Node {
node: Some(root_node),
}),
// There's no reference scanning on path contents ingested like this.
references: vec![],
narinfo: Some(crate::proto::NarInfo {
nar_size,
nar_sha256: nar_sha256.to_vec().into(),
signatures: vec![],
reference_names: vec![],
// TODO: narinfo for talosctl.src contains `CA: fixed:r:sha256:1x13j5hy75221bf6kz7cpgld9vgic6bqx07w5xjs4pxnksj6lxb6`
// do we need this anywhere?
}),
};
// put into [PathInfoService], and return the PathInfo that we get back
// from there (it might contain additional signatures).
let path_info = self.path_info_service.put(path_info)?;
Ok(path_info)
}
}
/// For given NAR sha256 digest and name, return the new [StorePath] this would have.
#[instrument(skip(nar_sha256_digest), ret, fields(nar_sha256_digest=BASE64.encode(nar_sha256_digest)))]
fn calculate_nar_based_store_path(nar_sha256_digest: &[u8; 32], name: &str) -> StorePath {
// We populate the struct directly, as we know the sha256 digest has the
// right size.
let nar_hash_with_mode = NixHashWithMode::Recursive(NixHash {
algo: HashAlgo::Sha256,
digest: nar_sha256_digest.to_vec(),
});
build_regular_ca_path(name, &nar_hash_with_mode, Vec::<String>::new(), false).unwrap()
}
impl EvalIO for TvixStoreIO {
#[instrument(skip(self), ret, err)]
fn path_exists(&self, path: &Path) -> Result<bool, io::Error> {
if let Ok((store_path, sub_path)) =
StorePath::from_absolute_path_full(&path.to_string_lossy())
{
if self
.store_path_to_root_node(&store_path, &sub_path)?
.is_some()
{
Ok(true)
} else {
// As tvix-store doesn't manage /nix/store on the filesystem,
// we still need to also ask self.std_io here.
self.std_io.path_exists(path)
}
} else {
// The store path is no store path, so do regular StdIO.
self.std_io.path_exists(path)
}
}
#[instrument(skip(self), ret, err)]
fn read_to_string(&self, path: &Path) -> Result<String, io::Error> {
if let Ok((store_path, sub_path)) =
StorePath::from_absolute_path_full(&path.to_string_lossy())
{
if let Some(node) = self.store_path_to_root_node(&store_path, &sub_path)? {
// depending on the node type, treat read_to_string differently
match node {
crate::proto::node::Node::Directory(_) => {
// This would normally be a io::ErrorKind::IsADirectory (still unstable)
Err(io::Error::new(
io::ErrorKind::Unsupported,
"tried to read directory at {path} to string",
))
}
crate::proto::node::Node::File(file_node) => {
let digest: B3Digest =
file_node.digest.clone().try_into().map_err(|_e| {
error!(
file_node = ?file_node,
"invalid digest"
);
io::Error::new(
io::ErrorKind::InvalidData,
format!("invalid digest length in file node: {:?}", file_node),
)
})?;
let reader = {
let resp = self.blob_service.open_read(&digest)?;
match resp {
Some(blob_reader) => blob_reader,
None => {
error!(
blob.digest = %digest,
"blob not found",
);
Err(io::Error::new(
io::ErrorKind::NotFound,
format!("blob {} not found", &digest),
))?
}
}
};
io::read_to_string(reader)
}
crate::proto::node::Node::Symlink(_symlink_node) => Err(io::Error::new(
io::ErrorKind::Unsupported,
"read_to_string for symlinks is unsupported",
))?,
}
} else {
// As tvix-store doesn't manage /nix/store on the filesystem,
// we still need to also ask self.std_io here.
self.std_io.read_to_string(path)
}
} else {
// The store path is no store path, so do regular StdIO.
self.std_io.read_to_string(path)
}
}
#[instrument(skip(self), ret, err)]
fn read_dir(&self, path: &Path) -> Result<Vec<(bytes::Bytes, FileType)>, io::Error> {
if let Ok((store_path, sub_path)) =
StorePath::from_absolute_path_full(&path.to_string_lossy())
{
if let Some(node) = self.store_path_to_root_node(&store_path, &sub_path)? {
match node {
crate::proto::node::Node::Directory(directory_node) => {
// fetch the Directory itself.
let digest = directory_node.digest.clone().try_into().map_err(|_e| {
io::Error::new(
io::ErrorKind::InvalidData,
format!(
"invalid digest length in directory node: {:?}",
directory_node
),
)
})?;
if let Some(directory) = self.directory_service.get(&digest)? {
let mut children: Vec<(bytes::Bytes, FileType)> = Vec::new();
for node in directory.nodes() {
children.push(match node {
crate::proto::node::Node::Directory(e) => {
(e.name, FileType::Directory)
}
crate::proto::node::Node::File(e) => {
(e.name, FileType::Regular)
}
crate::proto::node::Node::Symlink(e) => {
(e.name, FileType::Symlink)
}
})
}
Ok(children)
} else {
// If we didn't get the directory node that's linked, that's a store inconsistency!
error!(
directory.digest = %digest,
path = ?path,
"directory not found",
);
Err(io::Error::new(
io::ErrorKind::NotFound,
format!("directory {digest} does not exist"),
))?
}
}
crate::proto::node::Node::File(_file_node) => {
// This would normally be a io::ErrorKind::NotADirectory (still unstable)
Err(io::Error::new(
io::ErrorKind::Unsupported,
"tried to readdir path {:?}, which is a file",
))?
}
crate::proto::node::Node::Symlink(_symlink_node) => Err(io::Error::new(
io::ErrorKind::Unsupported,
"read_dir for symlinks is unsupported",
))?,
}
} else {
self.std_io.read_dir(path)
}
} else {
self.std_io.read_dir(path)
}
}
#[instrument(skip(self), ret, err)]
fn import_path(&self, path: &std::path::Path) -> Result<PathBuf, std::io::Error> {
let path_info = self.import_path_with_pathinfo(path)?;
// from the [PathInfo], extract the store path (as string).
Ok({
let mut path = PathBuf::from(nix_compat::store_path::STORE_DIR_WITH_SLASH);
let root_node_name = path_info.node.unwrap().node.unwrap().get_name().to_vec();
// This must be a string, otherwise it would have failed validation.
let root_node_name = String::from_utf8(root_node_name).unwrap();
// append to the PathBuf
path.push(root_node_name);
// and return it
path
})
}
#[instrument(skip(self), ret)]
fn store_dir(&self) -> Option<String> {
Some("/nix/store".to_string())
}
}
