本页将介绍输出目录的要求和布局。
要求
输出目录布局的要求:
- 如果多个用户在同一盒上进行构建,不会发生冲突。
- 支持同时在多个工作区中进行构建。
- 支持在同一工作区中针对多个目标配置进行构建。
- 不会与任何其他工具冲突。
- 易于访问。
- 易于清理,甚至可以选择性地清理。
- 明确,即使用户在切换到客户端目录时依靠符号链接,也是如此。
- 每个用户的所有 build 状态都应位于一个目录下(“我想清除所有客户端中的所有 .o 文件。”)
当前布局
目前实现的解决方案:
- 必须从包含代码库边界文件的目录或其子目录中调用 Bazel。换言之,必须从代码库内部调用 Bazel。否则,会报告错误。
- outputRoot 目录在 Linux 上默认为
${XDG_CACHE_HOME}/bazel
(如果未设置XDG_CACHE_HOME
环境变量,则默认为~/.cache/bazel
)、在 macOS 上为/private/var/tmp
、在 Windows 上默认为%HOME%
(如果已设置),否则为%USERPROFILE%
(如果已设置),否则为设置了FOLDERID_Profile
标志的调用SHGetKnownFolderPath()
的结果。如果设置了环境变量$TEST_TMPDIR
(如对 Bazel 本身的测试),则该值会替换默认值。 - Bazel 用户的构建状态位于
outputRoot/_bazel_$USER
下方。这称为 outputUserRoot 目录。 outputUserRoot
目录下面是install
目录,而installBase
目录的名称是 Bazel 安装清单的 MD5 哈希。- 在
outputUserRoot
目录下,还会创建一个outputBase
目录,其名称是工作区根目录的路径名称的 MD5 哈希值。例如,如果 Bazel 在工作区根目录/home/user/src/my-project
(或链接到该目录的符号链接)中运行,则会创建一个名为/home/user/.cache/bazel/_bazel_user/7ffd56a6e4cb724ea575aba15733d113
的输出基本目录。您也可以在工作区根目录中运行echo -n $(pwd) | md5sum
以获取 MD5。 - 您可以使用 Bazel 的
--output_base
启动选项替换默认输出基本目录。例如bazel --output_base=/tmp/bazel/output build x/y:z
。 - 您还可以使用 Bazel 的
--output_user_root
启动选项来替换默认安装基准和输出基本目录。例如:bazel --output_user_root=/tmp/bazel build x/y:z
。
“bazel-<workspace-name>”“bazel-out”“bazel-testlogs”和“bazel-bin”的符号链接位于工作区目录中;这些符号链接指向输出目录中某个目标特定目录内的某些目录。这些符号链接只是为了方便用户,因为 Bazel 本身并不使用它们。此外,仅当工作区根目录可写入时,系统才会执行此操作。
布局图
目录布局如下:
<workspace-name>/ <== The workspace root bazel-my-project => <..._main> <== Symlink to execRoot bazel-out => <...bazel-out> <== Convenience symlink to outputPath bazel-bin => <...bin> <== Convenience symlink to most recent written bin dir $(BINDIR) bazel-testlogs => <...testlogs> <== Convenience symlink to the test logs directory /home/user/.cache/bazel/ <== Root for all Bazel output on a machine: outputRoot _bazel_$USER/ <== Top level directory for a given user depends on the user name: outputUserRoot install/ fba9a2c87ee9589d72889caf082f1029/ <== Hash of the Bazel install manifest: installBase _embedded_binaries/ <== Contains binaries and scripts unpacked from the data section of the bazel executable on first run (such as helper scripts and the main Java file BazelServer_deploy.jar) 7ffd56a6e4cb724ea575aba15733d113/ <== Hash of the client's workspace root (such as /home/user/src/my-project): outputBase action_cache/ <== Action cache directory hierarchy This contains the persistent record of the file metadata (timestamps, and perhaps eventually also MD5 sums) used by the FilesystemValueChecker. command.log <== A copy of the stdout/stderr output from the most recent bazel command. external/ <== The directory that remote repositories are downloaded/symlinked into. server/ <== The Bazel server puts all server-related files (such as socket file, logs, etc) here. jvm.out <== The debugging output for the server. execroot/ <== The working directory for all actions. For special cases such as sandboxing and remote execution, the actions run in a directory that mimics execroot. Implementation details, such as where the directories are created, are intentionally hidden from the action. Every action can access its inputs and outputs relative to the execroot directory. _main/ <== Working tree for the Bazel build & root of symlink forest: execRoot _bin/ <== Helper tools are linked from or copied to here. bazel-out/ <== All actual output of the build is under here: outputPath _tmp/actions/ <== Action output directory. This contains a file with the stdout/stderr for every action from the most recent bazel run that produced output. local_linux-fastbuild/ <== one subdirectory per unique target BuildConfiguration instance; this is currently encoded bin/ <== Bazel outputs binaries for target configuration here: $(BINDIR) foo/bar/_objs/baz/ <== Object files for a cc_* rule named //foo/bar:baz foo/bar/baz1.o <== Object files from source //foo/bar:baz1.cc other_package/other.o <== Object files from source //other_package:other.cc foo/bar/baz <== foo/bar/baz might be the artifact generated by a cc_binary named //foo/bar:baz foo/bar/baz.runfiles/ <== The runfiles symlink farm for the //foo/bar:baz executable. MANIFEST _main/ ... genfiles/ <== Bazel puts generated source for the target configuration here: $(GENDIR) foo/bar.h such as foo/bar.h might be a headerfile generated by //foo:bargen testlogs/ <== Bazel internal test runner puts test log files here foo/bartest.log such as foo/bar.log might be an output of the //foo:bartest test with foo/bartest.status foo/bartest.status containing exit status of the test (such as PASSED or FAILED (Exit 1), etc) include/ <== a tree with include symlinks, generated as needed. The bazel-include symlinks point to here. This is used for linkstamp stuff, etc. host/ <== BuildConfiguration for build host (user's workstation), for building prerequisite tools, that will be used in later stages of the build (ex: Protocol Compiler) <packages>/ <== Packages referenced in the build appear as if under a regular workspace
RunfilesSupport 指向的位置更详细地记录了 *.runfiles 目录的布局。
bazel clean
bazel clean
会对 outputPath
和 action_cache
目录执行 rm -rf
。它还会移除工作区符号链接。--expunge
选项将清理整个 outputBase。