Allow .h files in srcs (#306) - .h files are now allowed in srcs for go_library, go_binary, and go_test. _emit_go_asm_action will include directories containing .h files. - Gazelle now adds .h files to srcs of go_library if no cgo_library is present. Fixes #303
| Bazel ≥0.4.4 | linux-x86_64 | ubuntu_15.10-x86_64 | darwin-x86_64 |
|---|---|---|---|
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The rules should be considered experimental. They support:
They currently do not support (in order of importance):
//+build comments - see here)Note: this repo requires bazel ≥ 0.4.4 to function (due to the use of BUILD.bazel files in bazelbuild/buildifier).
Decide on the name of your package, eg. github.com/joe/project. It's important to choose a name that will match where others will download your code. This will be a prefix for import paths within your project.
Add the following to your WORKSPACE file:
git_repository( name = "io_bazel_rules_go", remote = "https://github.com/bazelbuild/rules_go.git", tag = "0.4.1", ) load("@io_bazel_rules_go//go:def.bzl", "go_repositories") go_repositories()
If your project follows the structure that go build uses, you can generate your BUILD files with Gazelle. If not, read on.
Add a BUILD file to the top of your project. Declare the name of your workspace using go_prefix. This is used by Bazel to translate between build targets and import paths.
load("@io_bazel_rules_go//go:def.bzl", "go_prefix") go_prefix("github.com/joe/project")
For a library github.com/joe/project/lib, create lib/BUILD, containing a single library with the special name “go_default_library.” Using this name tells Bazel to set up the files so it can be imported in .go files as (in this example) github.com/joe/project/lib. See the FAQ below for more information on this name.
load("@io_bazel_rules_go//go:def.bzl", "go_library") go_library( name = "go_default_library", srcs = ["file.go"] )
Inside your project, you can use this library by declaring a dependency on the full Bazel name (including :go_default_library), and in the .go files, import it as shown above.
go_binary( ... deps = ["//lib:go_default_library"] )
To declare a test,
go_test( name = "mytest", srcs = ["file_test.go"], library = ":go_default_library" )
For instructions on how to depend on external libraries, see Vendoring.md.
If you project is compatible with the go tool, you can generate and update your BUILD files automatically using Gazelle, a command line tool which is part of this repository.
go install github.com/bazelbuild/rules_go/go/tools/gazelle/gazelle
gazelle -go_prefix github.com/joe/project
BUILD files later, just run gazelle.WORKSPACE file, following a certain naming convention. For example, it expects the repository for github.com/jane/utils to be named @com_github_jane_utils. If you prefer to use vendoring, run gazelle with -external vendored. See Vendoring.md.See the Gazelle README for more information.
go tool?Yes, this setup was deliberately chosen to be compatible with the go tool. Make sure your workspace appears under
$GOPATH/src/github.com/joe/project/
eg.
mkdir -p $GOPATH/src/github.com/joe/ ln -s my/bazel/workspace $GOPATH/src/github.com/joe/project
and it should work.
go_default_library name?This is used to keep import paths consistent in libraries that can be built with go build.
In order to compile and link correctly, the Go rules need to be able to translate between Bazel labels and Go import paths. Let's say your project name is github.com/joe/project, and you have a library in the foo/bar directory named bar. The Bazel label for this would be //foo/bar:bar. The Go import path for this would be github.com/joe/project/foo/bar/bar.
This is not what go build expects; it expects github.com/joe/project/foo/bar/bar to refer to a library built from .go files in the directory foo/bar/bar.
In order to avoid this conflict, you can name your library go_default_library. The full Bazel label for this library would be //foo/bar:go_default_library. The import path would be github.com/joe/project/foo/bar.
BUILD files generated with Gazelle, including those in external projects imported with go_repository, will have libraries named go_default_library automatically.
go_repositoriesgo_repositories()
Instantiates external dependencies to Go toolchain in a WORKSPACE. All the other workspace rules and build rules assume that this rule is placed in the WORKSPACE.
go_repositorygo_repository(name, importpath, remote, commit, tag)
Fetches a remote repository of a Go project, expecting it contains BUILD files. It is an analogy to git_repository but it recognizes importpath redirection of Go.
new_go_repositorynew_go_repository(name, importpath, remote, commit, tag)
Fetches a remote repository of a Go project and automatically generates BUILD files in it. It is an analogy to new_git_repository but it recognizes importpath redirection of Go.
go_prefixgo_prefix(prefix)
go_librarygo_library(name, srcs, deps, data, library, gc_goopts)
cgo_librarycgo_library(name, srcs, copts, clinkopts, cdeps, deps, data, gc_goopts)
srcs cannot contain pure-Go files, which do not have import "C". So you need to define another go_library when you build a go package with both cgo-enabled and pure-Go sources.
cgo_library( name = "cgo_enabled", srcs = ["cgo-enabled.go", "foo.cc", "bar.S", "baz.a"], ) go_library( name = "go_default_library", srcs = ["pure-go.go"], library = ":cgo_enabled", )
go_binarygo_binary(name, srcs, deps, data, library, linkstamp, x_defs, gc_goopts, gc_linkopts)
go_testgo_test(name, srcs, deps, data, library, gc_goopts, gc_linkopts)
In order for a go_test to refer to private definitions within a go_library, it must on the library's sources through the library attribute, not the deps attribute.
go_library( name = "go_default_library", srcs = glob(["*.go"], exclude=["*_test.go"]), ) go_test( name = "go_default_test", srcs = glob(["*_test.go"]), library = ":go_default_library", )
go_proto_librarygo_proto_library(name, srcs, deps, has_services)