Quickstart

1) Download the package

Install the latest version of data_checks using pip:

pip install pydata-checks

2) Start a Data Check project

Initialize a new data_checks project by using the init command from your project directory (/Users/USERNAME/Desktop/PROJECT_NAME):

python -m data_checks.init

This will start a series of prompts that will guide you through the process of initializing a new data_checks project. For example:

$ python -m data_checks.init
Enter the relative file path of the directory where suites will be stored: my_first_data_checks_project/suites
Directory '/Users/USERNAME/Desktop/PROJECT_NAME/my_first_data_checks_project/suites' does not exist.
Would you like to create it? [y/n]: y
Enter the relative file path of the directory where checks will be stored: my_first_data_checks_project/checks
Directory '/Users/USERNAME/Desktop/PROJECT_NAME/my_first_data_checks_project/checks' does not exist.
Would you like to create it? [y/n]: y
Enter the default CRON schedule: * * * * *
Enter the database URL: database_url
Enter the alerting endpoint URL:
check_settings.py generated.
my_first_data_check.py generated.

This will create a new directory with the following structure:

PROJECT_NAME
├── my_first_data_checks_project
│   ├── __init__.py
│   ├── checks
│   │   ├── __init__.py
│   │   └── my_first_data_check.py
│   ├── suites
│   │   ├── __init__.py
├── check_settings.py

3) Set the CHECK_SETTINGS_MODULE to point to the check_settings.py file

export CHECK_SETTINGS_MODULE=check_settings

4) Run the autogenerated data check

python -m data_checks.do.run_check MyFirstDataCheck

Output:

[1/1 checks] MyFirstDataCheck
	[1/2 Rules] rule_my_first_failed_rule
This rule failed
DataCheckException(severity=1.0, exception=This rule failed, metadata={'rule': 'rule_my_first_failed_rule', 'params': {'args': (), 'kwargs': {}}})
	[2/2 Rules] rule_my_first_successful_rule
		rule_my_first_successful_rule took 0.0 seconds

5) Modify the autogenerated data check

Open up the my_first_data_checks_project/checks.my_first_data_check.py file and customize the data check to your liking. For instance, you can modify the rule_my_first_failed_rule to always pass by removing the exception:

from data_checks.classes.data_check import DataCheck


class MyFirstDataCheck(DataCheck):
    ...

    def rule_my_first_failed_rule(self):
        # This rule will now succeed
        assert True, "This rule now succeeds"

    ...

Rerun the data check:

python -m data_checks.do.run_check MyFirstDataCheck

Output:

[1/1 checks] MyFirstDataCheck
	[1/2 Rules] rule_my_first_successful_rule
		rule_my_first_successful_rule took 9.5367431640625e-07 seconds
	[2/2 Rules] rule_my_first_failed_rule
		rule_my_first_failed_rule took 9.5367431640625e-07 seconds

🎉 Congrats! 🎉 You've created and executed your first data check! See the documentation for more information on how to write more advanced checks, suites, and other features like scheduling and alerting.