How to implement custom notifications

If you would like to implement custom notifications that include a link to Data Docs, you can access the Data Docs URL for the respective Validation Results page from your Data Context after a validation run following the steps below. This will work to get the URLs for any type of Data Docs site setup, e.g. S3 or local setup.

Prerequisites: This how-to guide assumes you have:

• Completed the Getting Started Tutorial
• Have a working installation of Great Expectations
• Set up a working deployment of Great Expectations
• Created an Expectation Suite to use for validation

1. First, this is the standard boilerplate to load a Data Context and run validation on a Batch:

   import great_expectations as ge
   
   # Load the Data Context
   context = ge.data_context.DataContext()
   
   # The batch_kwargs will differ depending on the type of Datasource,
   # see the docs for help
   batch_kwargs = {'table': 'my_table', 'datasource': 'my_datasource'}
   batch = context.get_batch(batch_kwargs, 'my_suite')
   
   # Run validation on your Batch
   results = context.run_validation_operator(
       "action_list_operator",
       assets_to_validate=[batch],
       run_id='my_run_id')

2. Next, get the list of IDs of the Validation Results. results is a list that might have multiple elements if you validate multiple Batches, so we'll have to iterate over it. In this example, we'll just grab the only element:

   validation_ids = [res for res in results['run_results']]
   validation_id = validation_ids[0]

3. Finally, use the validation_id as an argument to the Data Context's get_docs_sites_urls() method, and get the right element from the resulting list to access its site_url:

   url_dicts = context.get_docs_sites_urls(resource_identifier=validation_id)
   # The method returns a list of dictionaries like so:
   # [{'site_name': 'local_site',
   #  'site_url': 'file://validations/my_suite/my_run_id/20200811T181225.859901Z/123456.html'}]
   
   # The list will have multiple elements if you have multiple sites set up, e.g.
   # S3 and a local site. In this example, we'll just grab the only element again:
   validation_site_url = url_dicts[0]['site_url']

4. You can now include validation_site_url as a link in your custom notifications, e.g. in an email, which will allow users to jump straight to the relevant Validation Results page.