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feat(snix/glue): Transitively propagate drv inputs.

Browse source 
Previously drv's were fed into the build as opposed to their
dependencies.

Additionally this change refactors input propagation in a way that
ensures both:

* We only construct inputs *once* and use for both build inputs and
  refscan needles
* Inputs and refscan needles have consistent ordering and fixes #89

Change-Id: Id53701cea48598a0f73c6abd01293a02b71fb2d8
Reviewed-on: https://cl.snix.dev/c/snix/+/30240
Tested-by: besadii
Reviewed-by: Florian Klink <flokli@flokli.de>
This commit is contained in:
Vova Kryachko 2025-03-21 17:37:01 +00:00
parent 683458d604
commit 74492e9d6e
2 changed files with 180 additions and 134 deletions
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183
snix/glue/src/snix_build.rs
View file

@ -1,7 +1,7 @@
//! This module contains glue code translating from
//! [nix_compat::derivation::Derivation] to [snix_build::buildservice::BuildRequest].
use std::collections::{BTreeMap, HashSet};
use std::collections::{BTreeMap, HashSet, VecDeque};
use std::path::PathBuf;
use bytes::Bytes;
@ -10,6 +10,8 @@ use sha2::{Digest, Sha256};
use snix_build::buildservice::{AdditionalFile, BuildConstraints, BuildRequest, EnvVar};
use snix_castore::Node;
use crate::known_paths::KnownPaths;
/// These are the environment variables that Nix sets in its sandbox for every
/// build.
const NIX_ENVIRONMENT_VARS: [(&str, &str); 12] = [
@ -27,30 +29,115 @@ const NIX_ENVIRONMENT_VARS: [(&str, &str); 12] = [
("TMPDIR", "/build"),
];
/// Get an iterator of store paths whose nixbase32 hashes will be the needles for refscanning
/// Importantly, the returned order will match the one used by [derivation_to_build_request]
/// so users may use this function to map back from the found needles to a store path
pub(crate) fn get_refscan_needles(
derivation: &Derivation,
) -> impl Iterator<Item = &StorePath<String>> {
derivation
.outputs
.values()
.filter_map(|output| output.path.as_ref())
.chain(derivation.input_sources.iter())
.chain(derivation.input_derivations.keys())
/// Bfs queue needs to track both leaf store paths as well as
/// input derivation outputs.
#[derive(Eq, Hash, PartialEq, Clone)]
enum DerivationQueueItem<'a> {
/// Leaf input of a derivation
InputSource(&'a StorePath<String>),
/// Derivation input that can transitively produce more paths
/// that are needed for a given output.
InputDerivation {
drv_path: &'a StorePath<String>,
output: &'a String,
},
}
/// Iterator that yields store paths in a breadth-first order.
/// It is used to get all inputs for a derivation and the needles for refscanning.
struct BfsDerivationInputs<'a> {
queue: VecDeque<DerivationQueueItem<'a>>,
visited: HashSet<DerivationQueueItem<'a>>,
known_paths: &'a KnownPaths,
}
impl<'a> Iterator for BfsDerivationInputs<'a> {
type Item = &'a StorePath<String>;
fn next(&mut self) -> Option<Self::Item> {
while let Some(item) = self.queue.pop_front() {
if !self.visited.insert(item.clone()) {
continue;
}
match item {
DerivationQueueItem::InputSource(path) => {
return Some(path);
}
DerivationQueueItem::InputDerivation { drv_path, output } => {
let drv = self
.known_paths
.get_drv_by_drvpath(drv_path)
.expect("drv Bug!!!");
let output_path = drv
.outputs
.get(output)
.expect("No output bug!")
.path
.as_ref()
.expect("output has no store path");
if self
.visited
.insert(DerivationQueueItem::InputSource(output_path))
{
self.queue.extend(
drv.input_sources
.iter()
.map(DerivationQueueItem::InputSource)
.chain(drv.input_derivations.iter().flat_map(
|(drv_path, outs)| {
outs.iter().map(move |output| {
DerivationQueueItem::InputDerivation {
drv_path,
output,
}
})
},
)),
);
}
return Some(output_path);
}
}
}
None
}
}
/// Get an iterator of a transitive input closure for a derivation.
/// It's used for input propagation into the build and nixbase32 needle propagation
/// for build output refscanning.
pub(crate) fn get_all_inputs<'a>(
derivation: &'a Derivation,
known_paths: &'a KnownPaths,
) -> impl Iterator<Item = &'a StorePath<String>> {
BfsDerivationInputs {
queue: derivation
.input_sources
.iter()
.map(DerivationQueueItem::InputSource)
.chain(
derivation
.input_derivations
.iter()
.flat_map(|(drv_path, outs)| {
outs.iter()
.map(move |output| DerivationQueueItem::InputDerivation {
drv_path,
output,
})
}),
)
.collect(),
visited: HashSet::new(),
known_paths,
}
}
/// Takes a [Derivation] and turns it into a [buildservice::BuildRequest].
/// It assumes the Derivation has been validated.
/// It needs two lookup functions:
/// - one translating input sources to a castore node
/// (`fn_input_sources_to_node`)
/// - one translating a tuple of drv path and (a subset of their) output names to
/// castore nodes of the selected outpus (`fn_input_drvs_to_output_nodes`).
/// It assumes the Derivation has been validated, and all referenced output paths are present in `inputs`.
pub(crate) fn derivation_to_build_request(
derivation: &Derivation,
inputs: BTreeMap<StorePath<String>, Node>,
inputs: &BTreeMap<StorePath<String>, Node>,
) -> std::io::Result<BuildRequest> {
debug_assert!(derivation.validate(true).is_ok(), "drv must validate");
@ -105,23 +192,20 @@ pub(crate) fn derivation_to_build_request(
Ok(BuildRequest {
// Importantly, this must match the order of get_refscan_needles, since users may use that
// function to map back from the found needles to a store path
refscan_needles: get_refscan_needles(derivation)
refscan_needles: derivation
.outputs
.values()
.filter_map(|output| output.path.as_ref())
.map(|path| nixbase32::encode(path.digest()))
.chain(inputs.keys().map(|path| nixbase32::encode(path.digest())))
.collect(),
command_args,
outputs: {
// produce output_paths, which is the absolute path of each output (sorted)
let mut output_paths: Vec<PathBuf> = derivation
.outputs
.values()
.map(|e| PathBuf::from(e.path_str()[1..].to_owned()))
.collect();
// Sort the outputs. We can use sort_unstable, as these are unique strings.
output_paths.sort_unstable();
output_paths
},
outputs: derivation
.outputs
.values()
.map(|e| PathBuf::from(e.path_str()[1..].to_owned()))
.collect(),
// Turn this into a sorted-by-key Vec<EnvVar>.
environment_vars: environment_vars
@ -129,14 +213,14 @@ pub(crate) fn derivation_to_build_request(
.map(|(key, value)| EnvVar { key, value })
.collect(),
inputs: inputs
.into_iter()
.iter()
.map(|(path, node)| {
(
path.to_string()
.as_str()
.try_into()
.expect("Snix bug: unable to convert store path basename to PathComponent"),
node,
node.clone(),
)
})
.collect(),
@ -223,6 +307,7 @@ mod test {
use snix_build::buildservice::{AdditionalFile, BuildConstraints, BuildRequest, EnvVar};
use crate::known_paths::KnownPaths;
use crate::snix_build::NIX_ENVIRONMENT_VARS;
use super::derivation_to_build_request;
@ -239,11 +324,25 @@ mod test {
fn test_derivation_to_build_request() {
let aterm_bytes = include_bytes!("tests/ch49594n9avinrf8ip0aslidkc4lxkqv-foo.drv");
let derivation = Derivation::from_aterm_bytes(aterm_bytes).expect("must parse");
let dep_drv_bytes = include_bytes!("tests/ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv");
let derivation1 = Derivation::from_aterm_bytes(aterm_bytes).expect("drv1 must parse");
let drv_path1 =
StorePath::<String>::from_bytes("ch49594n9avinrf8ip0aslidkc4lxkqv-foo.drv".as_bytes())
.expect("drv path1 must parse");
let derivation2 = Derivation::from_aterm_bytes(dep_drv_bytes).expect("drv2 must parse");
let drv_path2 =
StorePath::<String>::from_bytes("ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv".as_bytes())
.expect("drv path2 must parse");
let mut known_paths = KnownPaths::default();
known_paths.add_derivation(drv_path2, derivation2);
known_paths.add_derivation(drv_path1, derivation1.clone());
let build_request = derivation_to_build_request(
&derivation,
BTreeMap::from([(
&derivation1,
&BTreeMap::from([(
StorePath::<String>::from_bytes(&INPUT_NODE_FOO_NAME.clone()).unwrap(),
INPUT_NODE_FOO.clone(),
)]),
@ -291,7 +390,7 @@ mod test {
)]),
inputs_dir: "nix/store".into(),
constraints: HashSet::from([
BuildConstraints::System(derivation.system.clone()),
BuildConstraints::System(derivation1.system.clone()),
BuildConstraints::ProvideBinSh
]),
additional_files: vec![],
@ -299,7 +398,7 @@ mod test {
scratch_paths: vec!["build".into(), "nix/store".into()],
refscan_needles: vec![
"fhaj6gmwns62s6ypkcldbaj2ybvkhx3p".into(),
"ss2p4wmxijn652haqyd7dckxwl4c7hxx".into()
"mp57d33657rf34lzvlbpfa1gjfv5gmpg".into()
],
},
build_request
@ -313,7 +412,7 @@ mod test {
let derivation = Derivation::from_aterm_bytes(aterm_bytes).expect("must parse");
let build_request =
derivation_to_build_request(&derivation, BTreeMap::from([])).expect("must succeed");
derivation_to_build_request(&derivation, &BTreeMap::from([])).expect("must succeed");
let mut expected_environment_vars = vec![
EnvVar {
@ -382,7 +481,7 @@ mod test {
let derivation = Derivation::from_aterm_bytes(aterm_bytes).expect("must parse");
let build_request =
derivation_to_build_request(&derivation, BTreeMap::from([])).expect("must succeed");
derivation_to_build_request(&derivation, &BTreeMap::from([])).expect("must succeed");
let mut expected_environment_vars = vec![
// Note how bar and baz are not present in the env anymore,

131
snix/glue/src/snix_store_io.rs
View file

@ -177,70 +177,19 @@ impl SnixStoreIO {
span.pb_set_style(&snix_tracing::PB_SPINNER_STYLE);
span.pb_set_message(&format!("⏳Waiting for inputs {}", &store_path));
// Maps from the index in refscan_needles to the full store path
// Used to map back to the actual store path from the found needles
// Importantly, this must match the order of the needles generated in derivation_to_build_request
let inputs =
crate::snix_build::get_all_inputs(&drv, &self.known_paths.borrow())
.map(StorePath::to_owned)
.collect::<Vec<_>>();
// derivation_to_build_request needs castore nodes for all inputs.
// Provide them, which means, here is where we recursively build
// all dependencies.
let mut inputs: BTreeMap<StorePath<String>, Node> =
futures::stream::iter(drv.input_derivations.iter())
.map(|(input_drv_path, output_names)| {
// look up the derivation object
let input_drv = {
let known_paths = self.known_paths.borrow();
known_paths
.get_drv_by_drvpath(input_drv_path)
.unwrap_or_else(|| {
panic!("{} not found", input_drv_path)
})
.to_owned()
};
// convert output names to actual paths
let output_paths: Vec<StorePath<String>> = output_names
.iter()
.map(|output_name| {
input_drv
.outputs
.get(output_name)
.expect("missing output_name")
.path
.as_ref()
.expect("missing output path")
.clone()
})
.collect();
// For each output, ask for the castore node.
// We're in a per-derivation context, so if they're
// not built yet they'll all get built together.
// If they don't need to build, we can however still
// substitute all in parallel (if they don't need to
// be built) - so we turn this into a stream of streams.
// It's up to the builder to deduplicate same build requests.
futures::stream::iter(output_paths.into_iter()).map(
|output_path| async move {
let node = self
.store_path_to_node(&output_path, Path::new(""))
.await?;
if let Some(node) = node {
Ok((output_path, node))
} else {
Err(io::Error::other("no node produced"))
}
},
)
})
.flatten()
.buffer_unordered(
1, /* TODO: increase again once we prevent redundant fetches */
) // TODO: make configurable
.try_collect()
.await?;
// FUTUREWORK: merge these who things together
// add input sources
let input_sources: BTreeMap<_, _> =
futures::stream::iter(drv.input_sources.iter())
let resolved_inputs: BTreeMap<StorePath<String>, Node> =
futures::stream::iter(inputs.iter())
.then(|input_source| {
Box::pin({
let input_source = input_source.clone();
@ -259,16 +208,10 @@ impl SnixStoreIO {
.try_collect()
.await?;
inputs.extend(input_sources);
span.pb_set_message(&format!("🔨Building {}", &store_path));
// TODO: check if input sources are sufficiently dealth with,
// I think yes, they must be imported into the store by other
// operations, so dealt with in the Some(…) match arm
// synthesize the build request.
let build_request = derivation_to_build_request(&drv, inputs)?;
let build_request = derivation_to_build_request(&drv, &resolved_inputs)?;
// create a build
let build_result = self
@ -278,16 +221,13 @@ impl SnixStoreIO {
.await
.map_err(|e| std::io::Error::new(io::ErrorKind::Other, e))?;
// Maps from the index in refscan_needles to the full store path
// Used to map back to the actual store path from the found needles
// Importantly, this must match the order of the needles generated in derivation_to_build_request
let refscan_needles =
crate::snix_build::get_refscan_needles(&drv).collect::<Vec<_>>();
// For each output, insert a PathInfo.
for ((output, output_needles), drv_output) in build_result
.outputs
.iter()
// Important: build outputs must match drv outputs order,
// otherwise the outputs will be mixed up
// see https://git.snix.dev/snix/snix/issues/89
.zip(build_result.outputs_needles.iter())
.zip(drv.outputs.iter())
{
@ -296,20 +236,6 @@ impl SnixStoreIO {
.try_into_name_and_node()
.expect("invalid node");
let output_needles: Vec<_> = output_needles
.needles
.iter()
// Map each output needle index back to the refscan_needle
.map(|idx| {
refscan_needles
.get(*idx as usize)
.ok_or(std::io::Error::new(
std::io::ErrorKind::Other,
"invalid build response",
))
})
.collect::<Result<_, std::io::Error>>()?;
// calculate the nar representation
let (nar_size, nar_sha256) = self
.nar_calculation_service
@ -328,10 +254,31 @@ impl SnixStoreIO {
))?
.to_owned(),
node: output_node,
references: output_needles
.iter()
.map(|s| (**s).to_owned())
.collect(),
references: {
let all_possible_refs: Vec<_> = drv
.outputs
.values()
.filter_map(|output| output.path.as_ref())
.chain(resolved_inputs.keys())
.collect();
let mut references: Vec<_> = output_needles
.needles
.iter()
// Map each output needle index back to the refscan_needle
.map(|idx| {
all_possible_refs
.get(*idx as usize)
.map(|it| (*it).clone())
.ok_or(std::io::Error::new(
std::io::ErrorKind::Other,
"invalid build response",
))
})
.collect::<Result<_, std::io::Error>>()?;
// Produce references sorted by name for consistency with nix narinfos
references.sort();
references
},
nar_size,
nar_sha256,
signatures: vec![],