flask login failure events

[gnufede]

Checklist

• Change(s) are motivated and described in the PR description
• Testing strategy is described if automated tests are not included in the PR
• Risks are described (performance impact, potential for breakage, maintainability)
• Change is maintainable (easy to change, telemetry, documentation)
• Library release note guidelines are followed or label changelog/no-changelog is set
• Documentation is included (in-code, generated user docs, public corp docs)
• Backport labels are set (if applicable)
• If this PR changes the public interface, I've notified @DataDog/apm-tees.
• If change touches code that signs or publishes builds or packages, or handles credentials of any kind, I've requested a review from @DataDog/security-design-and-guidance.

Reviewer Checklist

• Title is accurate
• All changes are related to the pull request's stated goal
• Description motivates each change
• Avoids breaking API changes
• Testing strategy adequately addresses listed risks
• Change is maintainable (easy to change, telemetry, documentation)
• Release note makes sense to a user of the library
• Author has acknowledged and discussed the performance implications of this PR as reported in the benchmarks PR comment
• Backport labels are set in a manner that is consistent with the release branch maintenance policy

[datadog-dd-trace-py-rkomorn]

Datadog Report

Branch report: gnufede/flask-login-failure-event
Commit report: 0f9706b
Test service: dd-trace-py

❌ 1 Failed (0 Known Flaky), 1020 Passed, 12 Skipped, 0s Wall Time

❌ Failed Tests (1)

• test_flask_login_failure_user_doesnt_exists - test_flask_login_appsec.py - Details

  Expand for error

   assert None == 'true'
    +  where None = <bound method Span.get_tag of <Span(id=17918103577237213788,trace_id=135589725773687656528241632068786840511,parent_id=None,name=flask.request)>>(('appsec.events.users.login' + '.failure.track'))
    +    where <bound method Span.get_tag of <Span(id=17918103577237213788,trace_id=135589725773687656528241632068786840511,parent_id=None,name=flask.request)>> = <Span(id=17918103577237213788,trace_id=135589725773687656528241632068786840511,parent_id=None,name=flask.request)>.get_tag
    +    and   'appsec.events.users.login' = APPSEC.USER_LOGIN_EVENT_PREFIX_PUBLIC