Bazel：如何获取生成文件的路径？

您可以通过bazel aquery查询操作图来获取此信息。

这是一个稍微丰富一点的示例，其中有一个单一规则的两个输出文件：

$ ls
BUILD  main.in  WORKSPACE
$ cat WORKSPACE
$ cat BUILD
genrule(
    name = "main",
    srcs = ["main.in"],
    outs = ["main.o1", "main.o2"],
    cmd = "cp $< $(location main.o1); cp $< $(location main.o2)",
)
$ cat main.in
hello

使用bazel aquery //:main --output=textproto查询与机器可读的输出动作图（原癌是analysis.ActionGraphContainer）：

$ bazel aquery //:main --output=textproto >aquery_result 2>/dev/null
$ cat aquery_result
artifacts {
  id: "0"
  exec_path: "main.in"
}
artifacts {
  id: "1"
  exec_path: "external/bazel_tools/tools/genrule/genrule-setup.sh"
}
artifacts {
  id: "2"
  exec_path: "bazel-out/k8-fastbuild/genfiles/main.o1"
}
artifacts {
  id: "3"
  exec_path: "bazel-out/k8-fastbuild/genfiles/main.o2"
}
actions {
  target_id: "0"
  action_key: "dd7fd759bbecce118a399c6ce7b0c4aa"
  mnemonic: "Genrule"
  configuration_id: "0"
  arguments: "/bin/bash"
  arguments: "-c"
  arguments: "source external/bazel_tools/tools/genrule/genrule-setup.sh; cp main.in bazel-out/k8-fastbuild/genfiles/main.o1; cp main.in bazel-out/k8-fastbuild/genfiles/main.o2"
  input_dep_set_ids: "0"
  output_ids: "2"
  output_ids: "3"
}
targets {
  id: "0"
  label: "//:main"
  rule_class_id: "0"
}
dep_set_of_files {
  id: "0"
  direct_artifact_ids: "0"
  direct_artifact_ids: "1"
}
configuration {
  id: "0"
  mnemonic: "k8-fastbuild"
  platform_name: "k8"
}
rule_classes {
  id: "0"
  name: "genrule"
}

数据并非完全集中在一处，但请注意：

• 与ID的伪像2和3对应于我们的两个期望的输出文件，以及列表中的那些工件作为路径上相对磁盘文件到工作区根的输出位置;
• artifacts具有目标ID的条目与0工件ID2和相关联3；和
• targetsID"0"为ID的条目与//:main标签相关联。

有了这种简单的结构，我们可以轻松地将脚本打包在一起，以列出与提供的标签相对应的所有输出文件。我找不到直接依赖Bazelanalysis.proto对外部存储库的定义或其语言绑定的方法，因此您可以将以下脚本修补到bazelbuild/bazel存储库本身：

工具/list_outputs/list_outputs.py

# Copyright 2019 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
r"""Parse an `aquery` result to list outputs created for a target.

Use this binary in conjunction with `bazel aquery` to determine the
paths on disk to output files of a target.

Example usage: first, query the action graph for the target that you
want to analyze:

    bazel aquery //path/to:target --output=textproto >/tmp/aquery_result

Then, from the Bazel repository:

    bazel run //tools/list_outputs -- \
        --aquery_result /tmp/aquery_result \
        --label //path/to:target \
        ;

This will print a list of zero or more output files emitted by the given
target, like:

    bazel-out/k8-fastbuild/foo.genfile
    bazel-out/k8-fastbuild/bar.genfile

If the provided label does not appear in the output graph, an error will
be raised.
"""
from __future__ import absolute_import
from __future__ import division
from __future__ import print_function

import sys

from absl import app
from absl import flags
from google.protobuf import text_format
from src.main.protobuf import analysis_pb2


flags.DEFINE_string(
    "aquery_result",
    None,
    "Path to file containing result of `bazel aquery ... --output=textproto`.",
)
flags.DEFINE_string(
    "label",
    None,
    "Label whose outputs to print.",
)


def die(message):
  sys.stderr.write("fatal: %s\n" % (message,))
  sys.exit(1)


def main(unused_argv):
  if flags.FLAGS.aquery_result is None:
    raise app.UsageError("Missing `--aquery_result` argument.")
  if flags.FLAGS.label is None:
    raise app.UsageError("Missing `--label` argument.")

  if flags.FLAGS.aquery_result == "-":
    aquery_result = sys.stdin.read()
  else:
    with open(flags.FLAGS.aquery_result) as infile:
      aquery_result = infile.read()
  label = flags.FLAGS.label

  action_graph_container = analysis_pb2.ActionGraphContainer()
  text_format.Merge(aquery_result, action_graph_container)

  matching_targets = [
      t for t in action_graph_container.targets
      if t.label == label
  ]
  if len(matching_targets) != 1:
    die(
        "expected exactly one target with label %r; found: %s"
        % (label, sorted(t.label for t in matching_targets))
    )
  target = matching_targets[0]

  all_artifact_ids = frozenset(
      artifact_id
      for action in action_graph_container.actions
      if action.target_id == target.id
      for artifact_id in action.output_ids
  )
  for artifact in action_graph_container.artifacts:
    if artifact.id in all_artifact_ids:
      print(artifact.exec_path)


if __name__ == "__main__":
  app.run(main)

工具/列表输出/建立

# Copyright 2019 The Bazel Authors. All rights reserved.
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#    http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.

package(default_visibility = ["//visibility:public"])

licenses(["notice"])  # Apache 2.0

filegroup(
    name = "srcs",
    srcs = glob(["**"]),
)

py_binary(
    name = "list_outputs",
    srcs = ["list_outputs.py"],
    srcs_version = "PY2AND3",
    deps = [
        "//third_party/py/abseil",
        "//src/main/protobuf:analysis_py_proto",
    ],
)

作为Git补丁，为了您的方便：https : //gist.github.com/wchargin/5e6a43a203d6c95454aae2886c5b54e4

请注意，该代码尚未经过审查或验证是否正确；我主要以它为例。如果它对您有用，那么也许这个周末我可以为此编写一些测试，并针对Bazel进行PR。