GitLab CI容器内无法访问本地Flask应用的问题咨询与解决

相关配置文件 #

.gitlab-ci.yml内容如下：

image: python:3.8

variables:
  PIP_CACHE_DIR: "$CI_PROJECT_DIR/.cache/pip"

cache:
  paths:
    - .cache/pip
    - venv/

before_script:
  - python -V  # Print out python version for debugging
  - pip install --upgrade pip
  - pip install virtualenv
  - virtualenv venv
  - source venv/bin/activate
  - pip install -r requirements.txt
  - cp properties_ci properties
  - apt-get update
  - apt-get install net-tools

stages:
  - build
  - test
  - security
  - leanix

include:
  - ...

test:unit:
  stage: ...

test:integration:
    stage: test
    script:
        - echo "0"
        - python app.py &
        - curl 127.0.0.1:8126
        - py.test tests/integration/test_integration.py
    services:
        - name: cassandra:3.11

应用启动日志 #

执行python app.py启动Flask应用时，日志显示Cassandra连接及初始化正常，服务启动在http://127.0.0.1:8126：

$ python app.py
WARNING:cassandra.cluster:Cluster.__init__ called with contact_points specified, but no load_balancing_policy. In the next major version, this will raise an error; please specify a load-balancing policy. (contact_points = ['cassandra'], lbp = None)
WARNING:cassandra.connection:An authentication challenge was not sent, this is suspicious because the driver expects authentication (configured authenticator = PlainTextAuthenticator)
WARNING:cassandra.connection:An authentication challenge was not sent, this is suspicious because the driver expects authentication (configured authenticator = PlainTextAuthenticator)
Creating keyspace if not exist...
Creating tables if not exist...
 * Serving Flask app 'src' (lazy loading)
 * Environment: production
   WARNING: This is a development server. Do not use it in a production deployment.
   Use a production WSGI server instead.
 * Debug mode: off
INFO:werkzeug:WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on http://127.0.0.1:8126

集成测试报错信息 #

但集成测试执行时，访问http://127.0.0.1:8126出现连接拒绝错误：

Creating keyspace if not exist...
=========================== short test summary info ============================
ERROR tests/integration/test_integration.py - requests.exceptions.ConnectionError: HTTPConnectionPool(host='localhost', port=8126): Max retries exceeded with url: /getCSRFToken (Caused by NewConnectionError('<urllib3.connection.HTTPConnection object at 0x7f316d3df700>: Failed to establish a new connection: [Errno 111] Connection refused'))
!!!!!!!!!!!!!!!!!!!! Interrupted: 1 error during collection !!!!!!!!!!!!!!!!!!!!
=============================== 1 error in 3.05s =============================== 

补充测试脚本代码（编辑1） #

测试脚本test_integration.py中访问应用的相关代码：

...
url = "http://localhost:8126/series/"

import zipfile
with zipfile.ZipFile("tests/integration/20230323.zip", mode="r") as archive:
  #Iterate through files in zip file
  for zipfilename in archive.filelist:
    txtdata = archive.read(zipfilename)
    if (zipfilename.filename == 'OP_lastchange_CRUDE_2023-03-23.json'):
      payload2 = json.dumps(json.loads(txtdata))
      response = requests.request("POST", url, headers=headers, data=payload2)
      assert response.status_code == 204, "Santa Claus is not coming this year !"
      
... 

解决方案（编辑2） #

修改test:integration的script步骤，在后台启动应用后添加等待时间，确保应用完成初始化再执行测试：

test:integration:
    stage: test
    script:
        - echo "0"
        - python app.py &
        - sleep 5  # 等待应用完成Cassandra连接、表创建等初始化操作
        - curl 127.0.0.1:8126  # 验证服务已就绪
        - py.test tests/integration/test_integration.py
    services:
        - name: cassandra:3.11

原因：Flask应用启动后需要时间完成Cassandra连接、键空间/表创建等初始化工作，直接紧接着执行测试会因服务未完全就绪导致连接拒绝，添加等待时间让应用完成初始化后再执行测试即可解决问题。

内容的提问来源于stack exchange，提问作者R13mus