Toolchains

A toolchain wraps three things: installing the runtime, warming the dependency cache, and the common build/test/lint commands. You call one factory, then attach the actions you want. Each action forks off the shared install step, so adding a check costs you the action — never the install.

Rust

hm.rust.toolchain() installs the toolchain; the action methods build, test, lint, and format.

rust.toolchain(*, path='.', version='stable', image=None, components=('clippy', 'rustfmt'), base=None) -> RustToolchain

Parameter	Type	Default	Description
`path`	`str`	`'.'`	Path to the crate or workspace root.
`version`	`str`	`'stable'`	rustup channel name (``"stable"``) or a pinned version (``"1.81.0"``).
`image`	`str \| None`	`None`	Local-mode Docker base image override.
`components`	`tuple[str, ...]`	`('clippy', 'rustfmt')`	rustup components to install alongside the toolchain. Defaults to ``("clippy", "rustfmt")``.
`base`	`Step \| None`	`None`	Existing ``Step`` to attach the toolchain install to instead of emitting a fresh apt-base step. Use to share one apt-base across multiple toolchains.

import harmont as hm

@hm.pipeline("ci")
def ci() -> tuple[hm.Step, ...]:
    project = hm.rust.toolchain(path=".")
    return (project.build(), project.test(), project.clippy(), project.fmt())

import { pipeline, type PipelineDefinition } from "@harmont/hm";
import { rust } from "@harmont/hm/toolchains";

const project = rust.toolchain({ path: "." });

const pipelines: PipelineDefinition[] = [
  { slug: "ci", pipeline: pipeline([project.build(), project.test(), project.clippy(), project.fmt()]) },
];
export default pipelines;

CMake (C / C++)

hm.cmake() configures and builds with CMake. Pass compiler, defines, a generator, or a preset; the action methods run CTest, clang-format, and clang-tidy.

cmake(*, path='.', lang='c', image=None, base=None) -> CMakeProject

Parameter	Type	Default	Description
`path`	`str`	`'.'`	Path to the project root (where ``CMakeLists.txt`` lives).
`lang`	`str`	`'c'`	Language tag, either ``"c"`` or ``"cpp"``. Affects label prefixes only; the cmake commands are identical.
`image`	`str \| None`	`None`	Local-mode Docker base image override.
`base`	`Step \| None`	`None`	Existing ``Step`` to attach to instead of emitting a fresh apt-base step.

import harmont as hm

@hm.pipeline("ci")
def ci() -> tuple[hm.Step, ...]:
    project = hm.cmake(
        path=".",
        compiler="clang-18",
        defines={"CMAKE_BUILD_TYPE": "Release", "CMAKE_CXX_STANDARD": "20"},
    )
    return (project.test(), project.lint(), project.fmt())

import { pipeline, type PipelineDefinition } from "@harmont/hm";
import { cmake } from "@harmont/hm/toolchains";

const project = cmake({
  path: ".",
  compiler: "clang-18",
  defines: { CMAKE_BUILD_TYPE: "Release", CMAKE_CXX_STANDARD: "20" },
});

const pipelines: PipelineDefinition[] = [
  { slug: "ci", pipeline: pipeline([project.test(), project.lint(), project.fmt()]) },
];
export default pipelines;

Every toolchain

Harmont ships toolchains for Rust, Python, Go, JavaScript/TypeScript (js/ts, with npm, pnpm, yarn, and Bun), CMake (C/C++), Elixir, and Zig. Each one's full method list lives in the toolchains reference.

Rust

CMake (C / C++)

Every toolchain

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