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Python

Python language recognition strategy​

By default, the platform will identify a Python project based on whether there are requirements.txt files in the source code root directory.

Platform compile and run mechanism​

  1. The pre-compilation process will detect whether the startup command configuration file Procfileis defined, if not, the default Flask/Django startup configuration file will be generated;
  2. After the pre-compilation process is completed, the Python buildpack will be selected according to the language type to compile the project. During the compilation process, the defined Python version and related Python dependencies will be installed;
  3. After the compilation is completed, it will check whether the Procfile parameter is set on the platform. If it is configured, the startup command configuration file Procfile will be rewritten.

Python project source code specification​

In this step, you need to provide a usable Python source code program for deployment on the Rainbond platform. This application must at least meet the following conditions:

  • The deployed Python program can be run normally locally
  • Projects can be hosted in git repositories
  • requirements.txt must exist in the project root directory, which is used to manage the dependencies of the Python project and is also a necessary condition for Rainbond to recognize the Python language
  • Procfile needs to be defined in the project root directory to define the program startup method
  • There is runtime.txt in the project root directory, which is used to define the Python version of the current project
requirements.txt specification​

If the program has no dependencies, you can make requirements.txt an empty file. If there is no requirements.txt , you can use the following command to generate

pip freeze > requirements.txt
Procfile specification​

If the project does not define a Procfile, the platform will generate a default Procfile by default to run the War package.

web: gunicorn app:app --log-file - --access-logfile - --error-logfile -

The above is the default Procfile, if you need to expand more startup parameters, you can customize the Procfile.

  1. web: there is a space between and gunicorn
  2. End of file cannot contain special characters

Compile and run environment settings​

Configure Python version​

It is recommended to define the Python version through the runtime.txt file in the code root directory. If not defined, Rainbond will use the python-3.6.6 version by default.

$ cat runtime.txt
python-3.6.6

Recommended python version

  • python-2.7.17
  • python-3.6.6

Default support python version

# python 2.7.x
python-2.7.9 python-2.7.17
# python 3.x
python-3.4.9
python-3.5.7
python-3.6.6 python-3.6.10

Advanced Build Options​

Enable advanced build features at build advanced settings or build source

environment variableDefaultsillustrate
BUILD_PIP_INDEX_URLhttps://pypi.tuna.tsinghua.edu.cn/simplePypi source

Django static file support​

Since Django 's static file support (CSS, images, etc.) is not very easy to configure and inconvenient to debug, here is an example：

settings.py

# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/1.7/howto/static-files/

BASE_DIR = os.path.dirname(os.path.abspath(__file__))
STATIC_ROOT = 'staticfiles'
STATIC_URL = '/static/'

STATICFILES_DIRS = (
    os.path.join(BASE_DIR, 'static'),
)

By default, the system will automatically execute the following command when building a Django application to try to detect (--dry-run) whether the static file configuration is correct：

$ python manage.py collectstatic --dry-run --noinput

If there is no error in this command, the real command will be executed to copy the static files to the STATIC_ROOT directory：

$ python manage.py collectstatic --noinput

Users can manually disable the above features, just configure the value of BUILD_DISABLE_COLLECTSTATIC to 1 in the application environment variable.

Sample demo program​

Example https://github.com/goodrain/python-demo