本页将介绍输出目录的要求和布局。
要求
输出目录布局要求:
- 如果多个用户在同一设备上构建,不会发生冲突。
- 支持同时在多个工作区中制作。
- 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发生碰撞。
- 使用方便。
- 易于清洁,即使有选择性。
- 明确无误,即使用户在更改为其客户端目录时依赖于符号链接也是如此。
- 每个用户的所有构建状态都应该位于一个目录下(“我想清除我的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调用 Bazel。换句话说,必须从代码库内部调用 Bazel。否则,系统会报告错误。
- outputRoot 目录默认为
${XDG_CACHE_HOME}/bazel
(如果XDG_CACHE_HOME
环境变量未设置,则默认为~/.cache/bazel
),在 macOS 上默认为/private/var/tmp
,在 Windows 上默认为%HOME%
(如果已设置),否则默认为%USERPROFILE%
,否则为设置FOLDERID_Profile
标志时调用SHGetKnownFolderPath()
的结果。如果设置了环境变量$TEST_TMPDIR
(如在 Bazel 本身的测试中),则该值会替换默认值。 - Bazel 用户的 build 状态位于
outputRoot/_bazel_$USER
下方。该目录称为 outputUserRoot 目录。 outputUserRoot
目录下有一个install
目录,其中有一个installBase
目录,其名称是 Bazel 安装清单的 MD5 哈希。- 在
outputUserRoot
目录下,还会创建一个outputBase
目录,其名称为工作区根目录的 MD5 哈希值。例如,如果 Bazel 在工作区根目录/home/user/src/my-project
(或与该目录符号连接的目录)中运行,则会创建一个名为/home/user/.cache/bazel/_bazel_user/7ffd56a6e4cb724ea575aba15733d113
的输出基础目录。您还可以在工作区根目录中运行echo -n $(pwd) | md5sum
来获取 MD5。 - 您可以使用 Bazel 的
--output_base
启动选项替换默认的输出基础目录。例如bazel --output_base=/tmp/bazel/output build x/y:z
。 - 您还可以使用 Bazel 的
--output_user_root
启动选项替换默认的安装基目录和输出基目录。例如:bazel --output_user_root=/tmp/bazel build x/y:z
。
“bazel-<workspace-name>”“bazel-out”“bazel-testlogs”和“bazel-bin”的符号链接会放在工作区目录中;这些符号链接指向输出目录中针对特定目标的目录内的一些目录。这些符号链接仅供用户使用,因为 Bazel 本身不会使用它们。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
目录的布局如下:
<workspace-name>/ <== The workspace root bazel-my-project => <...my-project> <== Symlink to execRoot bazel-out => <...bin> <== 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. action_outs/ <== Action output directory. This contains a file with the stdout/stderr for every action from the most recent bazel run that produced output. 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 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
在 RunfilesSupport 指向的位置中详细介绍了 *.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。