diff options
Diffstat (limited to 'tvix/build/src/buildservice/build_request.rs')
| -rw-r--r-- | tvix/build/src/buildservice/build_request.rs | 131 |
1 files changed, 131 insertions, 0 deletions
diff --git a/tvix/build/src/buildservice/build_request.rs b/tvix/build/src/buildservice/build_request.rs new file mode 100644 index 000000000000..a93fef5b393c --- /dev/null +++ b/tvix/build/src/buildservice/build_request.rs @@ -0,0 +1,131 @@ +use std::collections::{BTreeMap, HashSet}; +use std::path::PathBuf; + +use bytes::Bytes; +use tvix_castore::{Node, PathComponent}; +/// A BuildRequest describes the request of something to be run on the builder. +/// It is distinct from an actual \[Build\] that has already happened, or might be +/// currently ongoing. +/// +/// A BuildRequest can be seen as a more normalized version of a Derivation +/// (parsed from A-Term), "writing out" some of the Nix-internal details about +/// how e.g. environment variables in the build are set. +/// +/// Nix has some impurities when building a Derivation, for example the --cores option +/// ends up as an environment variable in the build, that's not part of the ATerm. +/// +/// As of now, we serialize this into the BuildRequest, so builders can stay dumb. +/// This might change in the future. +/// +/// There's also a big difference when it comes to how inputs are modelled: +/// +/// * Nix only uses store path (strings) to describe the inputs. +/// As store paths can be input-addressed, a certain store path can contain +/// different contents (as not all store paths are binary reproducible). +/// This requires that for every input-addressed input, the builder has access +/// to either the input's deriver (and needs to build it) or else a trusted +/// source for the built input. +/// to upload input-addressed paths, requiring the trusted users concept. +/// * tvix-build records a list of tvix.castore.v1.Node as inputs. +/// These map from the store path base name to their contents, relieving the +/// builder from having to "trust" any input-addressed paths, contrary to Nix. +/// +/// While this approach gives a better hermeticity, it has one downside: +/// A BuildRequest can only be sent once the contents of all its inputs are known. +/// +/// As of now, we're okay to accept this, but it prevents uploading an +/// entirely-non-IFD subgraph of BuildRequests eagerly. +#[derive(Clone, PartialEq)] +pub struct BuildRequest { + /// The list of all root nodes that should be visible in `inputs_dir` at the + /// time of the build. + /// As all references are content-addressed, no additional signatures are + /// needed to substitute / make these available in the build environment. + pub inputs: BTreeMap<PathComponent, Node>, + /// The command (and its args) executed as the build script. + /// In the case of a Nix derivation, this is usually + /// \["/path/to/some-bash/bin/bash", "-e", "/path/to/some/builder.sh"\]. + pub command_args: Vec<String>, + /// The working dir of the command, relative to the build root. + /// "build", in the case of Nix. + /// This MUST be a clean relative path, without any ".", "..", or superfluous + /// slashes. + pub working_dir: PathBuf, + /// A list of "scratch" paths, relative to the build root. + /// These will be write-able during the build. + /// \[build, nix/store\] in the case of Nix. + /// These MUST be clean relative paths, without any ".", "..", or superfluous + /// slashes, and sorted. + pub scratch_paths: Vec<PathBuf>, + /// The path where the castore input nodes will be located at, + /// "nix/store" in case of Nix. + /// Builds might also write into here (Nix builds do that). + /// This MUST be a clean relative path, without any ".", "..", or superfluous + /// slashes. + pub inputs_dir: PathBuf, + /// The list of output paths the build is expected to produce, + /// relative to the root. + /// If the path is not produced, the build is considered to have failed. + /// These MUST be clean relative paths, without any ".", "..", or superfluous + /// slashes, and sorted. + pub outputs: Vec<PathBuf>, + /// The list of environment variables and their values that should be set + /// inside the build environment. + /// This includes both environment vars set inside the derivation, as well as + /// more "ephemeral" ones like NIX_BUILD_CORES, controlled by the `--cores` + /// CLI option of `nix-build`. + /// For now, we consume this as an option when turning a Derivation into a BuildRequest, + /// similar to how Nix has a `--cores` option. + /// We don't want to bleed these very nix-specific sandbox impl details into + /// (dumber) builders if we don't have to. + /// Environment variables are sorted by their keys. + pub environment_vars: Vec<EnvVar>, + /// A set of constraints that need to be satisfied on a build host before a + /// Build can be started. + pub constraints: HashSet<BuildConstraints>, + /// Additional (small) files and their contents that should be placed into the + /// build environment, but outside inputs_dir. + /// Used for passAsFile and structuredAttrs in Nix. + pub additional_files: Vec<AdditionalFile>, + /// If this is an non-empty list, all paths in `outputs` are scanned for these. + /// For Nix, `refscan_needles` would be populated with the nixbase32 hash parts of + /// every input store path and output store path. The latter is necessary to scan + /// for references between multi-output derivations. + pub refscan_needles: Vec<String>, +} + +#[derive(Clone, PartialEq)] +pub struct EnvVar { + /// name of the environment variable. Must not contain =. + pub key: String, + pub value: Bytes, +} +/// BuildConstraints represents certain conditions that must be fulfilled +/// inside the build environment to be able to build this. +/// Constraints can be things like required architecture and minimum amount of memory. +/// The required input paths are *not* represented in here, because it +/// wouldn't be hermetic enough - see the comment around inputs too. +#[derive(Clone, PartialEq, Eq, Hash)] +pub enum BuildConstraints { + /// The system that's needed to execute the build. + /// Must not be empty. + System(String), + /// The amount of memory required to be available for the build, in bytes. + MinMemory(u64), + /// An absolute path that need to be available in the build + /// environment, like `/dev/kvm`. + /// This is distinct from the castore nodes in inputs. + /// These MUST be clean absolute paths, without any ".", "..", or superfluous + /// slashes, and sorted. + AvailableReadOnlyPath(PathBuf), + /// Whether the build should be able to access the network. + NetworkAccess, + /// Whether to provide a /bin/sh inside the build environment, usually a static bash. + ProvideBinSh, +} + +#[derive(Clone, PartialEq)] +pub struct AdditionalFile { + pub path: PathBuf, + pub contents: Bytes, +} |