Github Actions条件满足时指定步骤未执行问题求助

我在代码仓库中运行一个用于部署应用的Github Actions工作流，包含两个核心步骤：检查远程服务器上的Docker镜像是否存在，若存在则执行镜像备份。工作流的原配置如下：

- name: Check if latest image exists
  id: check_latest_image
  uses: appleboy/ssh-action@master
  with:
    host: ${{ env.SSH_HOST }}
    username: ${{ env.SSH_USER }}
    password: ${{ env.SSH_PASSWORD }}
    key: ${{ env.SSH_PRIVATE_KEY }}
    port: ${{ env.SSH_PORT }}
    script: |
      if docker image inspect crm/api-publisher-consumer:latest &> /dev/null;
      then
        echo "::set-output name=image_exists::true"
      else  
        echo "::set-output name=image_exists::false"
      fi

- name: Backup previous state
  if: steps.check_latest_image.outputs.image_exists == 'true'
  uses: appleboy/ssh-action@master
  with:
    host: ${{ env.SSH_HOST }}
    username: ${{ env.SSH_USER }}
    password: ${{ env.SSH_PASSWORD }}
    key: ${{ env.SSH_PRIVATE_KEY }}
    port: ${{ env.SSH_PORT }}
    script: |
      cd ~/TestServer/crm/crm-api
      docker tag crm/api-publisher-consumer:latest crm/api-publisher-consumer:backup

按预期，check_latest_image步骤会设置输出参数image_exists为true，后续Backup previous state步骤会根据该条件判断是否执行。但实际运行时，尽管检查步骤的日志显示已输出image_exists的值，备份步骤始终未运行：

======CMD======
if docker image inspect crm/api-publisher-consumer:latest &> /dev/null;
then
  echo "::set-output name=image_exists::'true'"
else  
  echo "::set-output name=image_exists::'false'"
fi

======END======
out: ::set-output name=image_exists::'true'
==============================================
✅ Successfully executed commands to all host.
==============================================

问题原因 #

从日志可以看到，实际输出的image_exists值是'true'（带有单引号），而工作流中判断条件是steps.check_latest_image.outputs.image_exists == 'true'——这里比较的是不带单引号的字符串true，两者不匹配，因此条件不成立，备份步骤不会执行。

解决方案 #

修改check_latest_image步骤中的echo语句，去掉true和false两侧的单引号，确保输出的是纯字符串值：

- name: Check if latest image exists
  id: check_latest_image
  uses: appleboy/ssh-action@master
  with:
    host: ${{ env.SSH_HOST }}
    username: ${{ env.SSH_USER }}
    password: ${{ env.SSH_PASSWORD }}
    key: ${{ env.SSH_PRIVATE_KEY }}
    port: ${{ env.SSH_PORT }}
    script: |
      if docker image inspect crm/api-publisher-consumer:latest &> /dev/null;
      then
        echo "::set-output name=image_exists::true"
      else  
        echo "::set-output name=image_exists::false"
      fi

验证效果 #

修改后，检查步骤的输出会变为::set-output name=image_exists::true（不带单引号），此时判断条件steps.check_latest_image.outputs.image_exists == 'true'会正确匹配，备份步骤将按预期执行。

内容的提问来源于stack exchange，提问作者Gill Mertens