GitLab CI如何基于文件变更条件执行作业步骤？

针对你的需求，提供两种可落地的实现方式，按需选择：

方案一：拆分模板，通过规则动态选择执行逻辑 #

将原模板拆分为基础通用模板、完整流程模板、轻量测试模板，再通过rules根据文件变更情况选择继承的模板，逻辑更清晰易维护。

1. 重构模板配置 #

首先定义三个分层模板：

# 基础通用模板：包含所有不变的核心配置
.template_MWAA:DAGS:Test:Base
  stage: Test
  extends:
    - .template_MWAA
  needs: []
  variables:
    PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"
    PYTHONPATH: "$CI_PROJECT_DIR/airflow-mwaa/dags"
  cache:
    key: $CI_JOB_NAME_SLUG-python
    paths:
      - .cache/pip
  script:
    - echo "Starting .template_MWAA:DAGS:Test template"
    - cd "$CI_PROJECT_DIR/airflow-mwaa"
    - airflow db init
    - ./tests-ci.sh
  coverage: '/^TOTAL\s+\d+\s+\d+\s+(\d+%)$/'
  artifacts:
    reports:
      junit: $CI_PROJECT_DIR/airflow-mwaa/test_results/report.xml

# 完整流程模板：包含依赖安装和缓存清理环节
.template_MWAA:DAGS:Test:Full
  extends: .template_MWAA:DAGS:Test:Base
  before_script:
    - echo "Starting .install_dependencies template"
    - pip3 install -r "$CI_PROJECT_DIR/airflow-mwaa/requirements/$AIRFLOW_VERSION/requirements.txt"
  after_script:
    # remove older files from terraform providers cache
    - find "$PIP_CACHE_DIR" -mindepth 1 -mtime +14 -type f -delete
    - find "$PIP_CACHE_DIR" -mindepth 1 -mtime +14 -type d -empty -delete

# 轻量测试模板：仅执行核心测试环节，无before/after脚本
.template_MWAA:DAGS:Test:Lite
  extends: .template_MWAA:DAGS:Test:Base

2. 修改具体作业配置 #

通过rules根据文件变更动态切换继承的模板：

mwaa:dags:test:2.8.1:
  variables:
    AIRFLOW_VERSION: 2.8.1
    PYTHON_VERSION: 3.11
  rules:
    # 受保护分支：requirements目录变更时用完整流程
    - if: $CI_COMMIT_REF_PROTECTED == "true"
      changes:
        - airflow-mwaa/requirements/**/*
      extends: .template_MWAA:DAGS:Test:Full
      when: on_success
      allow_failure: false
    # 受保护分支：无requirements变更时用轻量流程
    - if: $CI_COMMIT_REF_PROTECTED == "true"
      extends: .template_MWAA:DAGS:Test:Lite
      when: on_success
      allow_failure: false
    # MR场景：dags/tests/requirements任一变更时用完整流程
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      changes:
        - airflow-mwaa/dags/**/*
        - airflow-mwaa/tests/**/*
        - airflow-mwaa/requirements/**/*
      extends: .template_MWAA:DAGS:Test:Full
      allow_failure: false
      when: on_success
    # MR场景：仅dags/tests变更且无requirements变更时用轻量流程
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      changes:
        - airflow-mwaa/dags/**/*
        - airflow-mwaa/tests/**/*
      except:
        changes:
          - airflow-mwaa/requirements/**/*
      extends: .template_MWAA:DAGS:Test:Lite
      allow_failure: false
      when: on_success
    # MR手动触发：默认用完整流程
    - if: $CI_PIPELINE_SOURCE == "merge_request_event"
      extends: .template_MWAA:DAGS:Test:Full
      when: manual
      allow_failure: true
    - when: never

方案二：在脚本内加条件判断（无需拆分模板） #

如果不想修改模板结构，可以直接在before_script和after_script中加入文件变更判断，仅当airflow-mwaa/requirements/**有变更时才执行对应逻辑。

修改原模板的before/after脚本 #

.template_MWAA:DAGS:Test
  # 保留原有其他配置（stage、variables、cache、script等）不变
  before_script:
    - |
      # 区分MR和普通分支场景，确定diff对比的基准SHA
      if [ "$CI_PIPELINE_SOURCE" = "merge_request_event" ]; then
        DIFF_BASE=$CI_MERGE_REQUEST_TARGET_BRANCH_SHA
      else
        DIFF_BASE=$CI_COMMIT_BEFORE_SHA
      fi
      # 判断requirements目录是否有变更，有则执行依赖安装
      if git diff --name-only $DIFF_BASE $CI_COMMIT_SHA | grep -q "^airflow-mwaa/requirements/"; then
        echo "Starting .install_dependencies template"
        pip3 install -r "$CI_PROJECT_DIR/airflow-mwaa/requirements/$AIRFLOW_VERSION/requirements.txt"
      else
        echo "No changes in requirements directory, skipping dependency installation"
      fi
  after_script:
    - |
      # 同before_script的基准SHA判断逻辑
      if [ "$CI_PIPELINE_SOURCE" = "merge_request_event" ]; then
        DIFF_BASE=$CI_MERGE_REQUEST_TARGET_BRANCH_SHA
      else
        DIFF_BASE=$CI_COMMIT_BEFORE_SHA
      fi
      # 判断requirements目录是否有变更，有则执行缓存清理
      if git diff --name-only $DIFF_BASE $CI_COMMIT_SHA | grep -q "^airflow-mwaa/requirements/"; then
        echo "Cleaning old pip cache files"
        find "$PIP_CACHE_DIR" -mindepth 1 -mtime +14 -type f -delete
        find "$PIP_CACHE_DIR" -mindepth 1 -mtime +14 -type d -empty -delete
      else
        echo "No changes in requirements directory, skipping cache cleanup"
      fi

具体作业配置无需修改 #

保持原作业配置即可：

mwaa:dags:test:2.8.1:
  variables:
    AIRFLOW_VERSION: 2.8.1
    PYTHON_VERSION: 3.11
  extends:
    - .template_MWAA:DAGS:Test

内容的提问来源于stack exchange，提问作者python_dev