| commit | 8d4f7612b264849b4b0d7961ab5532f6879d9239 | [log] [tgz] |
|---|---|---|
| author | László Csomor <laszlocsomor@users.noreply.github.com> | Tue Jan 08 09:04:53 2019 +0100 |
| committer | GitHub <noreply@github.com> | Tue Jan 08 09:04:53 2019 +0100 |
| tree | e49160c5a44e656daac23055033175456e8304f7 | |
| parent | 6dd0b9cbd67478e20361933a994ca01fc1758f43 [diff] |
maprule: an improved version of genrule() (#86) maprule() is an improved version of native.genrule(), with the following advantages: - Maprule can process source files in parallel, creating separate actions for each of them. - Maprule does not require declaring all output files. Instead you declare templates for the output files yielded for each source. Therefore N source files and M templates yield N*M outputs. - Maprule supports both Bash and cmd.exe syntax for its commands via the specialized rules bash_maprule and cmd_maprule. - Maprule's cmd attribute does deliberately not support $(location) expression nor Make Variables, in order to avoid issues and challenges with quoting. (In case of cmd.exe passing empty arguments is impossible). These paths can be passed as envvars instead. - Maprule's add_env attribute does support $(location) expressions (and some extra placeholders) and is the idiomatic way to pass execpaths of labels in "tools" or "srcs" (the shared sources available for all actions) to the command. See https://github.com/bazelbuild/bazel/issues/4319
Skylib is a standard library that provides functions useful for manipulating collections, file paths, and other features that are useful when writing custom build rules in Bazel.
This library is currently under early development. Be aware that the APIs in these modules may change during this time.
Each of the .bzl files in the lib directory defines a “module”—a struct that contains a set of related functions and/or other symbols that can be loaded as a single unit, for convenience.
Skylib also provides build rules under the rules directory.
WORKSPACE fileAdd the following to your WORKSPACE file to import the Skylib repository into your workspace. Replace the version number in the tag attribute with the version you wish to depend on:
git_repository( name = "bazel_skylib", remote = "https://github.com/bazelbuild/bazel-skylib.git", tag = "0.1.0", # change this to use a different release )
If you want to use lib/unittest.bzl from Skylib versions released in or after December 2018, then you also should add to the WORKSPACE file:
load("@bazel_skylib//:workspace.bzl", "bazel_skylib_workspace") bazel_skylib_workspace()
BUILD and *.bzl filesThen, in the BUILD and/or *.bzl files in your own workspace, you can load the modules (listed below) and access the symbols by dotting into those structs:
load("@bazel_skylib//lib:paths.bzl", "paths") load("@bazel_skylib//lib:shell.bzl", "shell") p = paths.basename("foo.bar") s = shell.quote(p)
new_setsSteps to add a module to Skylib:
Create a new .bzl file in the lib directory.
Write the functions or other symbols (such as constants) in that file, defining them privately (prefixed by an underscore).
Create the exported module struct, mapping the public names of the symbols to their implementations. For example, if your module was named things and had a function named manipulate, your things.bzl file would look like this:
def _manipulate(): ... things = struct( manipulate=_manipulate, )
Add unit tests for your module in the tests directory.
bzl_libraryThe bzl_library.bzl rule can be used to aggregate a set of Starlark files and its dependencies for use in test targets and documentation generation.
If you try to use unittest and you get the following error:
ERROR: While resolving toolchains for target //foo:bar: no matching toolchains found for types @bazel_skylib//toolchains:toolchain_type ERROR: Analysis of target '//foo:bar' failed; build aborted: no matching toolchains found for types @bazel_skylib//toolchains:toolchain_type
then you probably forgot to load and call bazel_skylib_workspace() in your WORKSPACE file.