apartment-application-service

Apartment application service

Development with Docker

1. Copy the contents of .env.example to .env and modify it if needed.

2. Run docker-compose up

The project is now running at localhost:8081

Development without Docker

Prerequisites:

• PostgreSQL 12
• Python 3.8

Installing Python requirements

• Run pip install -r requirements.txt
• Run pip install -r requirements-dev.txt (development requirements)

Database

To setup a database compatible with default database settings:

Create user and database

sudo -u postgres createuser -P -R -S apartment-application  # use password `apartment-application`
sudo -u postgres createdb -O apartment-application apartment-application

Allow user to create test database

sudo -u postgres psql -c 'ALTER USER "apartment-application" CREATEDB;'

Database encryption

Some model fields are encrypted using pgcrypto, which requires a PGP keypair. For instructions on how to generate the keys, see the pgcrypto documentation:

Use the PostgreSQL preferred key type ("DSA and Elgamal") and at least 2048 bits as the key size.

To convert the multi-line PEM key into a single line (for .env), you can use this snippet:

cat your-key-file | awk '{print}' ORS='\\n'

For local development, you can use the example keys in .env.example. Do not use these example keys in production!

Daily running

• Create .env file: touch .env
• Set the DEBUG environment variable to 1.
• Run python manage.py migrate
• Run python manage.py runserver 0:8081

The project is now running at localhost:8081

Makefile targets

If you have the make command available, you can use the following commands to run certain common tasks:

• make check - Run all checks (linting, Django checks, tests)
• make lint - Run linters (flake8, black, isort)
• make test - Run tests
• make fix - Run code formmitng fixes (isort, black)
• make requirements - Update all requirements *.txt files from their corresponding *.in files
• make deploy - Run the deployment tasks (migrate, compilemessages, collectstatic)

Keeping Python requirements up to date

This project uses pip-tools to manage the Python requirements. It works with two kind of files: *.in and *.txt. The *.in files are the source files, which list the directly required packages and their version constraints. The *.txt files are generated from the *.in files and they list the exact versions of the packages that are installed.

1. pip-tools is installed from requirements-dev.txt:

   • pip install -r requirements-dev.txt

2. Add new packages to requirements.in or requirements-dev.in

3. Update .txt file for the changed requirements file:

   • pip-compile requirements.in
   • pip-compile requirements-dev.in
   • There is also a Makefile target for updating all requirement files: make requirements

4. If you want to update dependencies to their newest versions, run:

   • pip-compile --upgrade requirements.in

5. To install Python requirements run:

   • pip-sync requirements*.txt

Code Formatting and Linting

This project uses black, flake8 and isort for code formatting and quality checking. Project follows the basic black config, without any modifications.

Basic black commands:

• To let black do its magic: black .
• To see which files black would change: black --check .

There is also make lint and make fix commands for code style checking and fixing.

For Django, this project mostly follows the styleguide defined in Django-Styleguide.

SAP Integration

To be able to send installments to SAP, the following settings need to be set:

SAP_SFTP_SEND_USERNAME
SAP_SFTP_SEND_PASSWORD
SAP_SFTP_SEND_HOST
SAP_SFTP_SEND_PORT

Also,

python manage.py send_installments_to_sap

needs to be run periodically.

For fetching payments from SAP, the following settings need to be set:

SAP_SFTP_FETCH_USERNAME
SAP_SFTP_FETCH_PASSWORD
SAP_SFTP_FETCH_HOST
SAP_SFTP_FETCH_PORT

Also,

python manage.py fetch_payments_from_sap

needs to be run periodically.

You may also use variables named SAP_SFTP_USERNAME, SAP_SFTP_PASSWORD, SAP_SFTP_HOST and SAP_SFTP_PORT to set default values for the corresponding send/fetch settings.

Testing / exceptional situations

There are also two other management commands, which should not be needed for normal usage, but can be useful for testing purposes and exceptional situations:

• Generating an XML file of given installments

python manage.py create_sap_xml [reference numbers]

• Sending an XML file to the SAP SFTP server

python manage.py send_sap_xml <filename>

Cronjobs

There are few commands that are needed to be run periodically to get full functionality of some features. The easiest way to do this should be using cron.

• to get SAP invoices actually sent to the SFTP server

  python manage.py send_pending_installments_to_sap
  

  once a day during night at some point.

• to get reservation states updated based on expired offers

  python manage.py update_reservations_based_on_offer_expiration
  

  once a day as close to midnight as possible, but must be after it.