bazel系列之初识芳容
下载安装:wget https://github.com/bazelbuild/bazel/releases/download/0.18.0/bazel-0.18.0-installer-linux-x86_64.sh
常见的库用bazel编译的例子
https://github.com/bazelment/trunk
可以顺序看下来
- https://docs.bazel.build/versions/master/getting-started.html
- https://docs.bazel.build/versions/master/tutorial/cpp.html
- https://docs.bazel.build/versions/master/cpp-use-cases.html
- https://docs.bazel.build/versions/master/external.html
- https://docs.bazel.build/versions/master/rules.html
- https://docs.bazel.build/versions/master/bazel-and-cpp.html
- https://docs.bazel.build/versions/master/be/overview.html
- https://docs.bazel.build/versions/master/command-line-reference.html
- https://docs.bazel.build/versions/master/skylark/testing.html
- https://docs.bazel.build/versions/master/be/general.html
- https://docs.bazel.build/versions/master/best-practices.html
有心人的学习笔记(中文版)
https://blog.gmem.cc/bazel-study-note
package: A directory within the workspace that contains a BUILD file is a package.
package_group: Package groups are sets of packages whose purpose is to limit accessibility of certain rules.
label: All targets belong to exactly one package. The name of a target is called its label, every label uniquely identifies a target.
label syntax: //path/to/package:target-name
If the target is a rule target, then path/to/package is the path to the directory containing the BUILD file, and target-name is what you named the target in the BUILD file (the name attribute). If the target is a file target, then path/to/package is the path to the root of the package, and target-name is the name of the target file, including its full path.
When referencing targets within the same package, you can skip the package path and just use //:target-name. When referencing targets within the same BUILD file, you can even skip the // workspace root identifier and just use :target-name.
Labels start with "//", but package names never do, thus "my/app" is the package containing "//my/app".
内容
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定义
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链接
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Bazel概念(workspace、package、target) |
workspace: package: A directory within the workspace that contains a target: Each instance of a build rule in the |
https://docs.bazel.build/versions/0.27.0/build-ref.html |
Bazel命令行参数 | https://docs.bazel.build/versions/0.27.0/guide.html | |
Bazel外部依赖 |
https://docs.bazel.build/versions/0.27.0/external.html https://docs.bazel.build/versions/0.27.0/best-practices.html#depending-on-binaries |
查看依赖图
bazel query --noimplicit_deps 'deps(//main:hello-world)' --output graph
sudo apt update && sudo apt install graphviz xdot
xdot <(bazel query --noimplicit_deps 'deps(//main:hello-world)' --output graph)
常见规则
cc_binary
cc_library
cc_proto_library
其他规则
filegroup 给一个target集合取一个方便的名字
config_setting ??? https://docs.bazel.build/versions/master/be/general.html#config_setting
规则里的常见属性
srcs: 指定源文件,也可以加二进制文件
outs:
hdrs: 指定头文件
copts: 指定编译选项,如 "-I<include-paths>"
linkopts: 指定链接选项,如“-pthread”
visibility: 指定target的可见性,默认是同一个BUILD file里的target是可见的
strip_prefix: 去掉前缀
deps: 依赖
固定套路,加载bazel扩展
load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")
load("@bazel_tools//tools/build_defs/repo:git.bzl", "git_repository")
load("@bazel_tools//tools/build_defs/repo:git.bzl", "new_git_repository")
事实依赖和声明依赖之间的关系
A target X is actually dependent on target Y if and only if Y must be present, built and up-to-date in order for X to be built correctly. "Built" could mean generated, processed, compiled, linked, archived, compressed, executed, or any of the other kinds of tasks that routinely occur during a build.
A target X has a declared dependency on target Y if and only if there is a dependency edge from X to Y in the package of X.
For correct builds, the graph of actual dependencies A must be a subgraph of the graph of declared dependencies D.
三种常见依赖
srcs: Files consumed directly by the rule or rules that output source files.
deps: Rule pointing to separately-compiled modules providing header files, symbols, libraries, data, etc.
data: 比如单元测试需要用到的数据等
为保证增量build的正确性,最好让bazel掌握输入文件的完整集合,而不是目录。
可以使用glob函数,方便使用,“**”可以强制其递归。
data = glob(["testdata/**"]) # use this instead
目录label只可能使用在data依赖中,其他依赖类型不允许。
修改bazel的cache目录
bazel --output_user_root=/path/to/directory build //foo:bar
bazelrc
https://docs.bazel.build/versions/master/best-practices.html#bazelrc
https://docs.bazel.build/versions/master/guide.html#bazelrc
bazel编译可调试版本
bazel build xxx -c dbg