python-3.x - 为什么 `exec bash` 在 CI 管道中不起作用？

Question

我已经写了一个 github 工作流文件。我想在 github 操作中运行一个 python 程序来验证一些更改。我有一个 environment.yml 文件，其中包含该程序所需的所有 conda 环境依赖项。问题是，实际程序根本没有运行，我的工作流程已成功完成。

以下是workflow.yml文件的作业部分

jobs:
  build-linux:
    runs-on: ubuntu-latest

    steps:
      - name: Checkout repository
        uses: actions/checkout@v2
        with:
          ref: refs/pull/${{ github.event.pull_request.number }}/merge

      - name: Set up Python 3.8
        uses: actions/setup-python@v2
        with:
          python-version: 3.8

      - name: Cache conda
        uses: actions/cache@v2
        env:
          # Increase this value to reset cache if etc/example-environment.yml has not changed
          CACHE_NUMBER: 0
        with:
          path: ~/conda_pkgs_dir
          key:
            ${{ runner.os }}-conda-${{ env.CACHE_NUMBER }}-${{hashFiles('**/environment.yml') }}

      - uses: conda-incubator/setup-miniconda@v2
        with:
          activate-environment: test-env
          environment-file: environment.yml
          use-only-tar-bz2: true # IMPORTANT: This needs to be set for caching to work properly!

      - name: Test
        run: |
          export PATH="./:$PATH"
          conda init bash
          exec bash
          conda activate test-env
          echo "Conda prefix: $CONDA_PREFIX"
          python test.py
        shell: bash

我也尝试在最后一步中删除 shell:bash ，但这也给了我同样的结果。最后一步中的日志如下所示:

Run export PATH="./:$PATH"
  export PATH="./:$PATH"
  conda init bash
  exec bash
  conda activate test-env
  echo "Conda prefix: $CONDA_PREFIX"
  python test.py
  shell: /usr/bin/bash --noprofile --norc -e -o pipefail {0}
  env:
    pythonLocation: /opt/hostedtoolcache/Python/3.8.11/x64
    LD_LIBRARY_PATH: /opt/hostedtoolcache/Python/3.8.11/x64/lib
    CONDA_PKGS_DIR: /home/runner/conda_pkgs_dir
no change     /usr/share/miniconda/condabin/conda
no change     /usr/share/miniconda/bin/conda
no change     /usr/share/miniconda/bin/conda-env
no change     /usr/share/miniconda/bin/activate
no change     /usr/share/miniconda/bin/deactivate
no change     /usr/share/miniconda/etc/profile.d/conda.sh
no change     /usr/share/miniconda/etc/fish/conf.d/conda.fish
no change     /usr/share/miniconda/shell/condabin/Conda.psm1
no change     /usr/share/miniconda/shell/condabin/conda-hook.ps1
no change     /usr/share/miniconda/lib/python3.9/site-packages/xontrib/conda.xsh
no change     /usr/share/miniconda/etc/profile.d/conda.csh
modified      /home/runner/.bashrc

==> For changes to take effect, close and re-open your current shell. <==

我们可以清楚地看到，行 echo "Conda prefix: $CONDA_PREFIX" 根本没有被执行，工作流成功终止。我们应该期望它要么运行要么失败，但什么也没有发生。工作流只是忽略这些命令并将工作流标记为成功。

Answer 1

您的 CI 脚本包含以下行:

exec bash

当这一行被执行时，shell进程被一个新进程替换，新的shell进程不知道它应该继续执行前一个进程的脚本:所有的执行状态都丢失了。 GitHub Actions 将要执行的脚本作为命令行参数传递给初始 shell 进程，并将标准输入设置为 /dev/null；由于新的 shell 进程以空命令行和标准输入上的空文件启动，因此它会立即退出。这在交互式 shell 中运行良好这一事实是一个幸运的巧合。

安装程序指示您重新启动 shell 的原因是应用添加到 shell 初始化文件的环境变量更改。因此，将 exec bash 行替换为

可能就足够了

source "$HOME/.bashrc"

然而，即使使用这一行，环境修改也不会应用于后续步骤，因为 the documentation of the setup-miniconda action warns :

• Bash shells do not use ~/.profile or ~/.bashrc so these shells need to beexplicitely declared as shell: bash -l {0} on steps that need to be properlyactivated (or use a default shell). This is because bash shells are executedwith bash --noprofile --norc -eo pipefail {0} thus ignoring updated on bashprofile files made by conda init bash. SeeGithub Actions Documentationandthread.

根据这个建议，我认为最好的做法是在放置 exec bash 的位置结束操作步骤，然后应用 shell:设置所有进一步的步骤(或至少那些实际需要它的步骤):

      - name: Set up Conda environment
        run: |
          export PATH="./:$PATH"
          conda init bash
      - name: Perform Conda tests
        shell: bash -l {0}
        run: |
          export PATH="./:$PATH"
          conda activate test-env
          echo "Conda prefix: $CONDA_PREFIX"
          python test.py