https://github.com/jayconrod/rules_go_simple/tree/v1 这是一个为一个新语言写 Bazel rules 的 最小样例。
.
├── BUILD.bazel
├── def.bzl
├── deps.bzl
├── internal
│ ├── actions.bzl
│ ├── BUILD.bazel
│ └── rules.bzl
├── LICENSE.txt
├── README.md
├── tests
│ ├── BUILD.bazel
│ ├── hello.go
│ ├── hello_test.sh
│ └── message.go
└── WORKSPACEWORKSPACE
workspace(name = "rules_go_simple")
load("//:deps.bzl", "go_rules_dependencies")
go_rules_dependencies()上面的WORKSPACE调用下面的deps.bzl，在deps.bzl用内置的方法http_archive引入bazel基础库Skylib依赖
deps.bzl
"""Macro for declaring repository dependencies."""
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
def go_rules_dependencies():
"""Declares external repositories that rules_go_simple depends on.
This function should be loaded and called from WORKSPACE of any project
that uses rules_go_simple.
"""
# bazel_skylib is a set of libraries that are useful for writing
# Bazel rules. We use it to handle quoting arguments in shell commands.
_maybe(
http_archive,
name = "bazel_skylib",
urls = [
"https://mirror.bazel.build/github.com/bazelbuild/bazel-skylib/releases/download/1.0.2/bazel-skylib-1.0.2.tar.gz",
"https://github.com/bazelbuild/bazel-skylib/releases/download/1.0.2/bazel-skylib-1.0.2.tar.gz",
],
sha256 = "97e70364e9249702246c0e9444bccdc4b847bed1eb03c5a3ece4f83dfe6abc44",
)
def _maybe(rule, name, **kwargs):
"""Declares an external repository if it hasn't been declared already."""
if name not in native.existing_rules():
rule(name = name, **kwargs)tests/BUILD.bazel
load("//:def.bzl", "go_binary")
sh_test(
name = "hello_test",
srcs = ["hello_test.sh"],
args = ["$(location :hello)"],
data = [":hello"],
)
go_binary(
name = "hello",
srcs = [
"hello.go",
"message.go",
],
)BUILD.bazel调用了项目根目录下的def.bzl，def.bzl又调用了internal目录的rules.bzl的go_binary方法。
def.bzl
load("//internal:rules.bzl", _go_binary = "go_binary")
go_binary = _go_binaryinternal/rules.bzl
load(":actions.bzl", "go_compile", "go_link")
def _go_binary_impl(ctx):
# Declare an output file for the main package and compile it from srcs. All
# our output files will start with a prefix to avoid conflicting with
# other rules.
prefix = ctx.label.name + "%/"
main_archive = ctx.actions.declare_file(prefix + "main.a")
go_compile(
ctx,
srcs = ctx.files.srcs,
out = main_archive,
)
# Declare an output file for the executable and link it. Note that output
# files may not have the same name as the rule, so we still need to use the
# prefix here.
executable = ctx.actions.declare_file(prefix + ctx.label.name)
go_link(
ctx,
main = main_archive,
out = executable,
)
# Return the DefaultInfo provider. This tells Bazel what files should be
# built when someone asks to build a go_binary rules. It also says which
# one is executable (in this case, there's only one).
return [DefaultInfo(
files = depset([executable]),
executable = executable,
)]
# Declare the go_binary rule. This statement is evaluated during the loading
# phase when this file is loaded. The function body above is evaluated only
# during the analysis phase.
go_binary = rule(
_go_binary_impl,
attrs = {
"srcs": attr.label_list(
allow_files = [".go"],
doc = "Source files to compile for the main package of this binary",
),
},
doc = "Builds an executable program from Go source code",
executable = True,
)上面的代码构造ctx上下文内容，调用了internal/actions.bzl的go_compile（go tool compile）和go_link（go tool link）方法
internal/actions.bzl
load("@bazel_skylib//lib:shell.bzl", "shell")
def go_compile(ctx, srcs, out):
"""Compiles a single Go package from sources.
Args:
ctx: analysis context.
srcs: list of source Files to be compiled.
out: output .a file. Should have the importpath as a suffix,
for example, library "example.com/foo" should have the path
"somedir/example.com/foo.a".
"""
cmd = "go tool compile -o {out} -- {srcs}".format(
out = shell.quote(out.path),
srcs = " ".join([shell.quote(src.path) for src in srcs]),
)
ctx.actions.run_shell(
outputs = [out],
inputs = srcs,
command = cmd,
mnemonic = "GoCompile",
use_default_shell_env = True,
)
def go_link(ctx, out, main):
"""Links a Go executable.
Args:
ctx: analysis context.
out: output executable file.
main: archive file for the main package.
"""
cmd = "go tool link -o {out} -- {main}".format(
out = shell.quote(out.path),
main = shell.quote(main.path),
)
ctx.actions.run_shell(
outputs = [out],
inputs = [main],
command = cmd,
mnemonic = "GoLink",
use_default_shell_env = True,
)运行 bazel build/run/test
[root@localhost rules_go_simple]# bazel build //tests:hello
INFO: Analyzed target //tests:hello (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
Target //tests:hello up-to-date:
bazel-bin/tests/hello%/hello
INFO: Elapsed time: 0.121s, Critical Path: 0.00s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action
[root@localhost rules_go_simple]# bazel run //tests:hello
INFO: Analyzed target //tests:hello (0 packages loaded, 0 targets configured).
INFO: Found 1 target...
Target //tests:hello up-to-date:
bazel-bin/tests/hello%/hello
INFO: Elapsed time: 0.118s, Critical Path: 0.00s
INFO: 1 process: 1 internal.
INFO: Build completed successfully, 1 total action
INFO: Build completed successfully, 1 total action
Hello, world!
[root@localhost rules_go_simple]# bazel test //tests:hello_test
INFO: Analyzed target //tests:hello_test (0 packages loaded, 0 targets configured).
INFO: Found 1 test target...
Target //tests:hello_test up-to-date:
bazel-bin/tests/hello_test
INFO: Elapsed time: 0.179s, Critical Path: 0.05s
INFO: 2 processes: 2 linux-sandbox.
INFO: Build completed successfully, 2 total actions
//tests:hello_test PASSED in 0.0s
Executed 1 out of 1 test: 1 test passes.
INFO: Build completed successfully, 2 total actions转载请注明来源，欢迎指出任何有错误或不够清晰的表达。可以邮件至 backendcloud@gmail.com
