rust/doc/rustpkg.md

% Rustpkg Reference Manual

Introduction

This document is the reference manual for the Rustpkg packaging and build tool for the Rust programming language.

Disclaimer

Rustpkg is a work in progress, as is this reference manual. If the actual behavior of rustpkg differs from the behavior described in this reference, that reflects either an incompleteness or a bug in rustpkg.

Package searching

rustpkg searches for packages using the RUST_PATH environment variable, which is a colon-separated list (semicolon-separated on Windows) of directories.

Each directory in this list is a workspace for rustpkg.

RUST_PATH implicitly contains an entry for ./.rust (as well as ../.rust, ../../.rust, and so on for every parent of . up to the filesystem root). That means that if RUST_PATH is not set, then rustpkg will still search for workspaces in ./.rust and so on. RUST_PATH also implicitly contains an entry for the system path: /usr/local or the equivalent on Windows. This entry comes after the implicit entries for ./.rust and so on. Finally, the last implicit entry in RUST_PATH is ~/.rust or the equivalent on Windows.

Each workspace may contain one or more packages.

When building code that contains one or more directives of the form extern mod P, rustpkg automatically searches for packages named P in the RUST_PATH (as described above). It builds those dependencies if necessary. Thus, when using rustpkg, there is no need for -L flags to tell the linker where to find libraries for external crates.

Package structure

A valid workspace must contain each of the following subdirectories:

• 'src/': contains one subdirectory per package. Each subdirectory contains source files for a given package.

  For example, if foo is a workspace containing the package bar, then foo/src/bar/main.rs could be the main entry point for building a bar executable.

• 'lib/': rustpkg install installs libraries into a target-specific subdirectory of this directory.

  For example, on a 64-bit machine running Mac OS X, if foo is a workspace containing the package bar, rustpkg will install libraries for bar to foo/lib/x86_64-apple-darwin/. The libraries will have names of the form foo/lib/x86_64-apple-darwin/libbar-[hash].dylib, where [hash] is a hash of the package ID.

• 'bin/': rustpkg install installs executable binaries into this directory.

  For example, rustpkg will install executables for bar to foo/bin. The executables will have names of the form foo/bin/bar.

• 'build/': rustpkg build stores temporary build artifacts in a target-specific subdirectory of this directory.

  For example, on a 64-bit machine running Mac OS X, if foo is a workspace containing the package bar and foo/src/bar/main.rs exists, then rustpkg build will create foo/build/x86_64-apple-darwin/bar/main.o.

Package identifiers

A package identifier identifies a package uniquely. A package can be stored in a workspace on the local file system, or on a remote Web server, in which case the package ID resembles a URL. For example, github.com/mozilla/rust is a package ID that would refer to the git repository browsable at http://github.com/mozilla/rust. A package ID can also specify a version, like: github.com/mozilla/rust#0.3. In this case, rustpkg will check that the repository github.com/mozilla/rust has a tag named 0.3, and report an error otherwise. A package ID can also specify a particular revision of a repository, like: github.com/mozilla/rust#release-0.7. When the refspec (portion of the package ID after the #) can't be parsed as a decimal number, rustpkg passes the refspec along to the version control system without interpreting it. rustpkg also interprets any dependencies on such a package ID literally (as opposed to versions, where a newer version satisfies a dependency on an older version). Thus, github.com/mozilla/rust#5c4cd30f80 is also a valid package ID, since git can deduce that 5c4cd30f80 refers to a revision of the desired repository.

A package identifier can name a subdirectory of another package. For example, if foo is a workspace, and foo/src/bar/lib.rs exists, as well as foo/src/bar/extras/baz/lib.rs, then both bar and bar/extras/baz are valid package identifiers in the workspace foo.

Source files

rustpkg searches for four different fixed filenames in order to determine the crates to build:

• main.rs: Assumed to be a main entry point for building an executable.
• lib.rs: Assumed to be a library crate.
• test.rs: Assumed to contain tests declared with the #[test] attribute.
• bench.rs: Assumed to contain benchmarks declared with the #[bench] attribute.

Versions

rustpkg packages do not need to declare their versions with an attribute inside one of the source files, because rustpkg infers it from the version control system. When building a package that is in a git repository, rustpkg assumes that the most recent tag specifies the current version. When building a package that is not under version control, or that has no tags, rustpkg assumes the intended version is 0.1.

Note: A future version of rustpkg will support semantic versions. Also, a future version will add the option to specify a version with a metadata attribute like #[link(vers = "3.1415")] inside the crate module, though this attribute will never be mandatory.

Dependencies

rustpkg infers dependencies from extern mod directives. Thus, there should be no need to pass a -L flag to rustpkg to tell it where to find a library. (In the future, it will also be possible to write an extern mod directive referring to a remote package.)

Custom build scripts

A file called pkg.rs at the root level in a workspace is called a package script. If a package script exists, rustpkg executes it to build the package rather than inferring crates as described previously.

Inside pkg.rs, it's possible to call back into rustpkg to finish up the build. rustpkg::api contains functions to build, install, or clean libraries and executables in the way rustpkg normally would without custom build logic.

Command reference

build

rustpkg build foo searches for a package with ID foo and builds it in any workspace(s) where it finds one. Supposing such packages are found in workspaces X, Y, and Z, the command leaves behind files in X's, Y's, and Z's build directories, but not in their lib or bin directories.

clean

rustpkg clean foo deletes the contents of foo's build directory.

install

rustpkg install foo builds the libraries and/or executables that are targets for foo. If RUST_PATH is declared as an environment variable, then rustpkg installs the libraries and executables into the lib and bin subdirectories of the first entry in RUST_PATH. Otherwise, it installs them into foo's lib and bin directories.

test

rustpkg test foo builds foo's test.rs file if necessary, then runs the resulting test executable.