本頁說明輸出目錄的相關規定和版面配置。
需求條件
輸出目錄版面配置的需求條件：
- 即使多位使用者在同一個方塊上建構，也不會發生衝突。
- 支援同時在多個工作區建構。
- 支援在同一個工作區中為多個目標設定進行建構。
- 不會與其他工具衝突。
- 方便存取。
- 清潔容易，甚至可以選擇性清潔。
- 即使使用者在變更至用戶端目錄時依賴符號連結，也能確保不含歧義。
- 每位使用者的所有建構狀態都應位於一個目錄下方 (「我想清除所有客戶的所有 .o 檔案。」)
目前的版面配置
目前實作的解決方案：
- 您必須從包含 WORKSPACE 檔案的目錄 (稱為「workspace 目錄」) 或其子目錄叫用 Bazel。如果不是，則會回報錯誤。
- 在 Linux 上，outputRoot 目錄預設為
${XDG_CACHE_HOME}/bazel(如果未設定XDG_CACHE_HOME環境變數，則為~/.cache/bazel)；在 macOS 上，預設為/private/var/tmp；在 Windows 上，如果已設定，則預設為%HOME%；如果已設定，則為%USERPROFILE%；否則為設定FOLDERID_Profile標記後呼叫SHGetKnownFolderPath()的結果。如果已設定環境變數$TEST_TMPDIR(例如在 Bazel 本身的測試中)，則該值會覆寫預設值。 - Bazel 使用者的建構狀態位於
outputRoot/_bazel_$USER下方。這就是 outputUserRoot 目錄。 outputUserRoot目錄下方有install目錄，其中的installBase目錄名稱是 Bazel 安裝資訊清單的 MD5 雜湊。- 在
outputUserRoot目錄下方也會建立outputBase目錄，名稱為工作區目錄的路徑名稱的 MD5 雜湊。舉例來說，如果 Bazel 是在工作區目錄/home/user/src/my-project(或連結至該目錄的某個目錄) 中執行，則會建立名為/home/user/.cache/bazel/_bazel_user/7ffd56a6e4cb724ea575aba15733d113的輸出基礎目錄。您也可以在 Bazel 工作區中執行echo -n $(pwd) | md5sum，取得 MD5。 - 您可以使用 Bazel 的
--output_base啟動選項，覆寫預設的輸出基礎目錄。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特定目標目錄中的某些目錄。這些符號連結只是為了方便使用者參考，因為 Bazel 本身並不會使用這類連結。此外，只有在工作區目錄可寫入時，才能執行這項操作。
版面配置圖
目錄的排列方式如下：
<workspace-name>/ <== The workspace directory
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 directory (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.
<workspace-name>/ <== 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
<workspace-name>/
...
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 所指向的位置會更詳細說明 *.runfiles 目錄的版面配置。
bazel clean
bazel clean 會對 outputPath 和 action_cache 目錄執行 rm -rf。並移除工作區的符號連結。--expunge 選項會清除整個 outputBase。