LG-15559: Add support for A/B tests daily reporting

[aduth]

🎫 Ticket

LG-15559

🛠 Summary of changes

Adds the ability to generate email reports for A/B test results to be sent to a team contact email on a regular basis.

This is intended to help:

• Ensure accountability to create queries ahead of an A/B test being active in production, to guarantee that we're able to produce usable analytics for the test
• Reduce manual engineer effort to actively monitor an A/B test after a few hours and on subsequent days of a test being active to make sure that the data being reported is in line with expected values
• Be able to report data directly to relevant stakeholders automatically without additional involvement from an engineer
• Improve visibility of ongoing A/B test progress to an entire team and other stakeholders

📜 Testing Plan

End-to-end testing is difficult, but you can verify that the report generates with expected tabular data with AWS-authenticated manual script execution.

Example:

$ aws-vault exec sandbox-readonly -- rails c

require 'reporting/ab_tests_report'
query = AbTest::ReportQueryConfig.new(
  title: 'Sign in success rate by mobile',
  query: "fields properties.browser_mobile as `Device` " \
         "| filter name = 'Email and Password Authentication' " \
         "| stats avg(properties.event_properties.success) as `Success Percent` by `Device` " \
         "| sort `Device`",
  row_labels: ['Mobile', 'Desktop'],
)
report = Reporting::AbTestsReport.new(
  queries: [query],
  time_range: Time.zone.now.yesterday..Time.zone.now,
)
report.send(:cloudwatch_client).instance_variable_set(:@log_group_name, 'int_/srv/idp/shared/log/events.log')
report.as_tables
# Example:
# [[["Device", "Success Percent"], ["Mobile", "0.80%"], ["Desktop", "0.60%"]]]

Observe:

• Returned fields as table columns
• Customizable row labels (first cell)
• Table columns including "percent" are formatted as percentages

Verify that running the job class's perform method does not produce any errors. There are currently on A/B tests configured to use this feature, so no queries should be expected to be run.

$ rails c
Reports::AbTestsReport.new.perform(Time.zone.now)
# []

[matthinz]

This is super cool!