//! This module contains glue code translating from
//! [nix_compat::derivation::Derivation] to [tvix_build::proto::BuildRequest].
use std::collections::BTreeMap;
use bytes::Bytes;
use nix_compat::{derivation::Derivation, store_path::StorePathRef};
use tvix_build::proto::{
build_request::{BuildConstraints, EnvVar},
BuildRequest,
};
use tvix_castore::proto::{NamedNode, Node};
/// These are the environment variables that Nix sets in its sandbox for every
/// build.
const NIX_ENVIRONMENT_VARS: [(&str, &str); 12] = [
("HOME", "/homeless-shelter"),
("NIX_BUILD_CORES", "0"), // TODO: make this configurable?
("NIX_BUILD_TOP", "/"),
("NIX_LOG_FD", "2"),
("NIX_STORE", "/nix/store"),
("PATH", "/path-not-set"),
("PWD", "/build"),
("TEMP", "/build"),
("TEMPDIR", "/build"),
("TERM", "xterm-256color"),
("TMP", "/build"),
("TMPDIR", "/build"),
];
/// Takes a [Derivation] and turns it into a [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 input derivations and (a subset of their) output names to
/// a castore node (`fn_input_drvs_to_node`).
#[allow(dead_code)]
fn derivation_to_build_request<FIS, FID>(
derivation: &Derivation,
fn_input_sources_to_node: FIS,
fn_input_drvs_to_node: FID,
) -> BuildRequest
where
FIS: Fn(StorePathRef) -> Node,
FID: Fn(StorePathRef, &[&str]) -> Node,
{
debug_assert!(derivation.validate(true).is_ok(), "drv must validate");
// produce command_args, which is builder and arguments in a Vec.
let mut command_args: Vec<String> = Vec::with_capacity(derivation.arguments.len() + 1);
command_args.push(derivation.builder.clone());
command_args.extend_from_slice(&derivation.arguments);
// produce output_paths, which is the basename of each output (sorted)
// since Derivation is validated, we know output paths can be parsed.
// TODO: b/264 will remove the need to parse them here
let mut outputs: Vec<String> = derivation
.outputs
.values()
.map(|output| {
let output_storepath = StorePathRef::from_absolute_path(output.path.as_bytes())
.expect("invalid output storepath");
output_storepath.to_string()
})
.collect();
// Sort the outputs. We can use sort_unstable, as these are unique strings.
outputs.sort_unstable();
// Produce environment_vars. We use a BTreeMap while producing them, so the
// resulting Vec is sorted by key.
let mut environment_vars: BTreeMap<String, Bytes> = BTreeMap::new();
// Start with some the ones that nix magically sets:
environment_vars.extend(
NIX_ENVIRONMENT_VARS
.iter()
.map(|(k, v)| (k.to_string(), Bytes::from_static(v.as_bytes()))),
);
// extend / overwrite with the keys set in the derivation environment itself.
// TODO: check if this order is correct, and environment vars set in the
// *Derivation actually* have priority.
environment_vars.extend(
derivation
.environment
.iter()
.map(|(k, v)| (k.clone(), Bytes::from(v.to_vec()))),
);
// Turn this into a sorted-by-key Vec<EnvVar>.
let environment_vars = Vec::from_iter(
environment_vars
.into_iter()
.map(|(k, v)| EnvVar { key: k, value: v }),
);
// Produce inputs. As we refer to the contents here, not just plain store path strings,
// we need to perform lookups.
// FUTUREWORK: should we also model input_derivations and input_sources with StorePath?
let mut inputs: Vec<Node> = Vec::new();
// since Derivation is validated, we know input sources can be parsed.
for input_source in derivation.input_sources.iter() {
let sp = StorePathRef::from_absolute_path(input_source.as_bytes())
.expect("invalid input source path");
let node = fn_input_sources_to_node(sp);
inputs.push(node);
}
// since Derivation is validated, we know input derivations can be parsed.
for (input_derivation, output_names) in derivation.input_derivations.iter() {
let sp = StorePathRef::from_absolute_path(input_derivation.as_bytes())
.expect("invalid input derivation path");
let output_names: Vec<&str> = output_names.iter().map(|e| e.as_str()).collect();
let node = fn_input_drvs_to_node(sp, output_names.as_slice());
inputs.push(node);
}
// validate all nodes are actually Some.
debug_assert!(
inputs.iter().all(|input| input.node.is_some()),
"input nodes must be some"
);
// sort inputs by their name
inputs.sort_by(|a, b| {
a.node
.as_ref()
.unwrap()
.get_name()
.cmp(b.node.as_ref().unwrap().get_name())
});
// Produce constraints. We currently only put platform in here.
// Maybe more things need to be added here in the future.
let constraints = Some(BuildConstraints {
system: derivation.system.clone(),
min_memory: 0,
available_ro_paths: vec![],
});
BuildRequest {
command_args,
outputs,
environment_vars,
inputs,
constraints,
}
}
#[cfg(test)]
mod test {
use bytes::Bytes;
use nix_compat::derivation::Derivation;
use tvix_build::proto::{
build_request::{BuildConstraints, EnvVar},
BuildRequest,
};
use tvix_castore::{
fixtures::DUMMY_DIGEST,
proto::{DirectoryNode, Node},
};
use crate::tvix_build::NIX_ENVIRONMENT_VARS;
use super::derivation_to_build_request;
use lazy_static::lazy_static;
lazy_static! {
static ref INPUT_NODE_FOO: Node = Node {
node: Some(tvix_castore::proto::node::Node::Directory(DirectoryNode {
name: Bytes::from("mp57d33657rf34lzvlbpfa1gjfv5gmpg-bar"),
digest: DUMMY_DIGEST.clone().into(),
size: 42,
})),
};
}
#[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 build_request = derivation_to_build_request(
&derivation,
|_| unreachable!(),
|input_drv, output_names| {
// expected to be called with ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv only
if input_drv.to_string() != "ss2p4wmxijn652haqyd7dckxwl4c7hxx-bar.drv" {
panic!("called with unexpected input_drv: {}", input_drv);
}
// expect to be called with ["out"]
if output_names != ["out"] {
panic!("called with unexpected output_names: {:?}", output_names);
}
// all good, reply with INPUT_NODE_FOO
INPUT_NODE_FOO.clone()
},
);
let mut expected_environment_vars = vec![
EnvVar {
key: "bar".to_string(),
value: Bytes::from("/nix/store/mp57d33657rf34lzvlbpfa1gjfv5gmpg-bar"),
},
EnvVar {
key: "builder".to_string(),
value: Bytes::from(":"),
},
EnvVar {
key: "name".to_string(),
value: Bytes::from("foo"),
},
EnvVar {
key: "out".to_string(),
value: Bytes::from("/nix/store/fhaj6gmwns62s6ypkcldbaj2ybvkhx3p-foo"),
},
EnvVar {
key: "system".to_string(),
value: Bytes::from(":"),
},
];
expected_environment_vars.extend(NIX_ENVIRONMENT_VARS.iter().map(|(k, v)| EnvVar {
key: k.to_string(),
value: Bytes::from_static(v.as_bytes()),
}));
expected_environment_vars.sort_unstable_by_key(|e| e.key.to_owned());
assert_eq!(
BuildRequest {
command_args: vec![":".to_string()],
outputs: vec!["fhaj6gmwns62s6ypkcldbaj2ybvkhx3p-foo".to_string()],
environment_vars: expected_environment_vars,
inputs: vec![INPUT_NODE_FOO.clone()],
constraints: Some(BuildConstraints {
system: derivation.system.clone(),
min_memory: 0,
available_ro_paths: vec![],
}),
},
build_request
);
}
}
