本頁說明輸出目錄的需求和版面配置。
需求條件
輸出目錄版面配置規定：
- 如果多位使用者在同一個方塊上建構，不會發生衝突。
- 支援同時在多個工作區中建構。
- 支援在同一個工作區中，為多個目標設定建構。
- 不會與任何其他工具發生衝突。
- 方便存取。
- 可輕鬆清潔，甚至選擇性清潔。
- 即使使用者在變更至用戶端目錄時依賴符號連結，也不會造成混淆。
- 每個使用者的所有建構狀態都應位於一個目錄下 (「我想清除所有用戶端的所有 .o 檔案。」)
目前版面配置
目前採用的解決方案：
- 必須從含有存放區界線檔案的目錄或其子目錄中叫用 Bazel。換句話說，您必須從存放區內叫用 Bazel。否則會回報錯誤。
- 在 Linux 上，outputRoot 目錄預設為
${XDG_CACHE_HOME}/bazel(或~/.cache/bazel，如果未設定XDG_CACHE_HOME環境變數)；在 macOS 上，預設為/private/var/tmp；在 Windows 上，如果已設定，預設為%HOME%，否則如果已設定，預設為%USERPROFILE%，否則為呼叫SHGetKnownFolderPath()並設定FOLDERID_Profile標記的結果。如果設定了環境變數$TEST_TMPDIR(例如在測試 Bazel 本身時)，該值會覆寫預設值。 - Bazel 使用者的建構狀態位於
outputRoot/_bazel_$USER下方。這個目錄稱為 outputUserRoot。 outputUserRoot目錄下方有install目錄，其中包含installBase目錄，名稱是 Bazel 安裝資訊清單的 MD5 雜湊值。- 在
outputUserRoot目錄下方，系統也會建立outputBase目錄，其名稱是工作區根目錄路徑名稱的 MD5 雜湊值。舉例來說，如果 Bazel 在工作區根目錄/home/user/src/my-project(或連結至該目錄的目錄) 中執行，系統就會建立名為/home/user/.cache/bazel/_bazel_user/7ffd56a6e4cb724ea575aba15733d113的輸出基本目錄。您也可以在工作區根目錄中執行echo -n $(pwd) | md5sum，取得 MD5。 - 您可以使用 Bazel 的
--output_base啟動選項，覆寫預設輸出基本目錄。例如bazel --output_base=/tmp/bazel/output build x/y:z。 - 您也可以使用 Bazel 的
--output_user_root啟動選項，覆寫預設的安裝基礎和輸出基礎目錄。例如：bazel --output_user_root=/tmp/bazel build x/y:z。
「bazel-<workspace-name>」、「bazel-out」、「bazel-testlogs」和「bazel-bin」的符號連結會放在工作區目錄中；這些符號連結會指向輸出目錄中目標專屬目錄內的某些目錄。這些符號連結僅供使用者方便使用，因為 Bazel 本身不會使用這些連結。此外，只有在工作區根目錄可寫入時，才會執行這項操作。
版面配置圖
目錄結構如下：
<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
*.runfiles 目錄的版面配置詳情，請參閱 RunfilesSupport 指向的位置。
bazel clean
bazel clean 會對 outputPath 和 action_cache 目錄執行 rm -rf。也會移除工作區符號連結。--expunge 選項會清除整個 outputBase。