bazel-skylib/bzl_library.bzl

110 lines
2.9 KiB
Python

# Copyright 2017 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
"""Skylib module containing a library rule for aggregating rules files."""
StarlarkLibraryInfo = provider(
"Information on contained Starlark rules.",
fields = {
"srcs": "Top level rules files.",
"transitive_srcs": "Transitive closure of rules files required for " +
"interpretation of the srcs",
},
)
def _bzl_library_impl(ctx):
deps_files = [depset(x.files, order = "postorder") for x in ctx.attr.deps]
all_files = depset(ctx.files.srcs, order = "postorder", transitive = deps_files)
return [
# All dependent files should be listed in both `files` and in `runfiles`;
# this ensures that a `bzl_library` can be referenced as `data` from
# a separate program, or from `tools` of a genrule().
DefaultInfo(
files = all_files,
runfiles = ctx.runfiles(files = list(all_files)),
),
# We also define our own provider struct, for aggregation and testing.
StarlarkLibraryInfo(
srcs = ctx.files.srcs,
transitive_srcs = all_files,
),
]
bzl_library = rule(
implementation = _bzl_library_impl,
attrs = {
"srcs": attr.label_list(
allow_files = [".bzl"],
),
"deps": attr.label_list(
allow_files = [".bzl"],
providers = [
[StarlarkLibraryInfo],
],
),
},
)
"""Creates a logical collection of Starlark .bzl files.
Args:
srcs: List of `.bzl` files that are processed to create this target.
deps: List of other `bzl_library` targets that are required by the
Starlark files listed in `srcs`.
Example:
Suppose your project has the following structure:
```
[workspace]/
WORKSPACE
BUILD
checkstyle/
BUILD
checkstyle.bzl
lua/
BUILD
lua.bzl
luarocks.bzl
```
In this case, you can have `bzl_library` targets in `checkstyle/BUILD` and
`lua/BUILD`:
`checkstyle/BUILD`:
```python
load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
bzl_library(
name = "checkstyle-rules",
srcs = ["checkstyle.bzl"],
)
```
`lua/BUILD`:
```python
load("@bazel_skylib//:bzl_library.bzl", "bzl_library")
bzl_library(
name = "lua-rules",
srcs = [
"lua.bzl",
"luarocks.bzl",
],
)
```
"""