Aug 27 - Add MySQL optimize and security check

tests/test_sla_candidate_query.py

@@ -0,0 +1,165 @@
+"""
+Equivalence test for the SQL prefilter in send_sla_alerts().
+
+The cron used to read EVERY open issue and decide in Python which ones deserved
+a notification. It now narrows to candidates in SQL first.
+
+The contract is a CONSERVATIVE SUPERSET, not equality:
+
+  * Nothing the old loop would have notified may be missed. This is the safety
+    property -- a miss is a silently unsent SLA alert.
+  * The SQL may return extra rows, because it deliberately does not replicate
+    the "already notified at_risk and still only at_risk" skip (that would mean
+    writing the per-severity deadline arithmetic a second time, in SQL). The
+    Python loop still applies that skip, so no extra notification is ever sent
+    -- only a handful of extra rows are read.
+
+The reference predicate below is the old loop's skip logic, written out.
+"""
+from datetime import timedelta
+
+import pytest
+
+from app import db
+from app.models.issue import Issue
+from app.utils.sla import SLA_HOURS, AT_RISK_THRESHOLD, sla_status
+from app.utils.time_utils import now_eastern
+
+
+def _candidate_query():
+    """The prefilter exactly as send_sla_alerts() builds it."""
+    now = now_eastern()
+    age_clauses = [
+        db.and_(
+            Issue.severity == severity,
+            Issue.reported_at <= now - timedelta(hours=hours * AT_RISK_THRESHOLD),
+        )
+        for severity, hours in SLA_HOURS.items()
+    ]
+    return Issue.query.filter(
+        Issue.status.in_(['open', 'in_progress', 'pending_verification']),
+        Issue.reported_at.isnot(None),
+        db.or_(Issue.sla_notified.is_(None), Issue.sla_notified != 'breached'),
+        db.or_(*age_clauses),
+    )
+
+
+def _old_loop_would_act(issue):
+    """The pre-change Python logic: which rows survived to send a notification."""
+    if issue.status not in ('open', 'in_progress', 'pending_verification'):
+        return False
+    if issue.reported_at is None:
+        return False          # would have raised TypeError -- see the NULL test
+    status = sla_status(issue)
+    if status not in ('at_risk', 'breached'):
+        return False
+    already = issue.sla_notified
+    if already == 'breached':
+        return False
+    if already == 'at_risk' and status == 'at_risk':
+        return False
+    return True
+
+
+def _add(severity, hours_ago, status='open', sla_notified=None):
+    issue = Issue(
+        severity=severity,
+        description='x',
+        status=status,
+        sla_notified=sla_notified,
+        reported_at=now_eastern() - timedelta(hours=hours_ago),
+    )
+    db.session.add(issue)
+    return issue
+
+
+@pytest.fixture
+def population(app):
+    """One issue per interesting combination of severity / age / state."""
+    rows = []
+    for severity, window in SLA_HOURS.items():
+        at_risk_at = window * AT_RISK_THRESHOLD
+        rows += [
+            _add(severity, 0),                       # fresh -> ok
+            _add(severity, at_risk_at * 0.5),        # halfway -> ok
+            _add(severity, at_risk_at + 1),          # at risk
+            _add(severity, window + 1),              # breached
+            # already-notified variants
+            _add(severity, at_risk_at + 1, sla_notified='at_risk'),
+            _add(severity, window + 1, sla_notified='at_risk'),
+            _add(severity, window + 1, sla_notified='breached'),
+            # non-actionable / other statuses
+            _add(severity, window + 1, status='resolved'),
+            _add(severity, window + 1, status='in_progress'),
+            _add(severity, window + 1, status='pending_verification'),
+        ]
+    db.session.commit()
+    return rows
+
+
+def test_prefilter_never_misses_an_actionable_issue(population):
+    """Safety property: every row the old loop notified is still selected."""
+    expected = {i.id for i in population if _old_loop_would_act(i)}
+    actual = {i.id for i in _candidate_query().all()}
+
+    assert expected, 'fixture built no actionable issues -- test is vacuous'
+    assert expected <= actual, (
+        'the prefilter drops issues the old loop would have alerted on: '
+        f'{sorted(expected - actual)}'
+    )
+
+
+def test_prefilter_extras_are_all_skipped_by_the_loop(population):
+    """The extra rows the SQL lets through produce no extra notifications.
+
+    Each must be a row the Python loop independently skips, so the set of alerts
+    actually sent is unchanged.
+    """
+    by_id = {i.id: i for i in population}
+    expected = {i.id for i in population if _old_loop_would_act(i)}
+    extras = {i.id for i in _candidate_query().all()} - expected
+
+    for iid in extras:
+        issue = by_id[iid]
+        assert not _old_loop_would_act(issue)
+        # and the only reason it is allowed through is the at_risk bookkeeping
+        assert issue.sla_notified == 'at_risk' and sla_status(issue) == 'at_risk', (
+            f'issue {iid} is an unexplained extra: status={issue.status} '
+            f'severity={issue.severity} sla_notified={issue.sla_notified} '
+            f'sla_status={sla_status(issue)}'
+        )
+
+
+def test_prefilter_excludes_the_bulk_of_open_issues(population):
+    """The point of the change: most open issues are never read."""
+    total_open = Issue.query.filter(
+        Issue.status.in_(['open', 'in_progress', 'pending_verification'])
+    ).count()
+    candidates = _candidate_query().count()
+    assert candidates < total_open
+
+
+def test_null_reported_at_is_excluded_not_crashed(app):
+    """reported_at is nullable and sla_status() raises TypeError on NULL.
+
+    Before the prefilter one such row aborted the whole cron run; it must now be
+    excluded in SQL instead.
+    """
+    issue = Issue(severity='high', description='x', status='open')
+    db.session.add(issue)
+    db.session.commit()
+
+    # The column carries default=now_eastern, so an ORM insert can never leave
+    # it NULL -- the row has to be forced, which is exactly how a legacy or
+    # raw-SQL-inserted row would look.
+    db.session.execute(
+        db.text('UPDATE issues SET reported_at = NULL WHERE id = :i'),
+        {'i': issue.id},
+    )
+    db.session.commit()
+    db.session.expire(issue)
+
+    assert issue.reported_at is None
+    assert issue.id not in {i.id for i in _candidate_query().all()}
+    with pytest.raises(TypeError):
+        sla_status(issue)      # confirms the crash the filter is avoiding