使用Bazel运行Python二进制文件时遇仓库解析错误求助

执行bazel run projects/my-python-app/...运行Python二进制文件时出现错误：

ERROR: /private/var/tmp/_bazel_justin/84cef48b5ae183d272bc73733d19e8e1/external/python_deps_pypi__flask/BUILD.bazel:11:11: no such package '@python_deps_pypi__itsdangerous//': The repository '@python_deps_pypi__itsdangerous' could not be resolved: Repository '@python_deps_pypi__itsdangerous' is not defined and referenced by '@python_deps_pypi__flask//:pkg'
ERROR: Analysis of target '//projects/my-python-app:main' failed; build aborted:

相关配置文件如下：

WORKSPACE 文件 #

load("@bazel_tools//tools/build_defs/repo:http.bzl", "http_archive")

rules_python_version = "740825b7f74930c62f44af95c9a4c1bd428d2c53" # Latest @ 2021-06-23

http_archive(
    name = "rules_python",
    # Bazel will print the proper value to add here during the first build.
    # sha256 = "FIXME",
    strip_prefix = "rules_python-{}".format(rules_python_version),
    url = "https://github.com/bazelbuild/rules_python/archive/{}.zip".format(rules_python_version),
)

load("@rules_python//python:pip.bzl", "pip_parse")

# Create a central repo that knows about the dependencies needed from
# requirements_lock.txt.
pip_parse(
   name = "python_deps",
   requirements_lock = "//third_party:requirements_lock.txt",
)
# Load the starlark macro which will define your dependencies.
load("@python_deps//:requirements.bzl", "install_deps")
# Call it to define repos for your requirements.
install_deps()

requirements_lock.txt 文件 #

Flask==2.0.2

BUILD 文件 #

load("@python_deps//:requirements.bzl", "requirement")

py_binary(
    name = "main",
    srcs = ["main.py"],
    deps = [
        "//projects/calculator:calculator",
        requirement("Flask"),
    ],
)

用户按rules_python的README操作，询问错误原因。

这个错误的核心是**requirements_lock.txt仅声明了Flask直接依赖，未包含其所有间接依赖（比如itsdangerous）**。pip_parse需要完整的锁定文件，涵盖所有直接和间接依赖包，否则Bazel无法解析这些缺失依赖对应的仓库。

解决步骤：

• 生成完整的锁定文件：在本地Python环境中执行命令，生成包含所有依赖的requirements_lock.txt

  # 方法1：用pip freeze生成
  pip freeze --all > third_party/requirements_lock.txt
  
  # 方法2：用pip-tools生成（推荐，可生成带哈希的锁定文件）
  pip-compile --generate-hashes requirements.in
  

  生成后的文件应包含Flask及其所有依赖（如itsdangerous、Werkzeug、Jinja2等）。

• 清理缓存并重新构建：执行以下命令清除Bazel旧缓存，避免残留配置干扰

  bazel clean --expunge
  bazel run projects/my-python-app/...
  

补充说明：pip_parse会根据锁定文件中的每个包创建对应的Bazel仓库。如果仅指定Flask，Bazel处理Flask的BUILD配置时，找不到其依赖包的仓库定义，就会抛出上述错误。

内容的提问来源于stack exchange，提问作者jlcv