Plan 04 Summary: Auto-Pause by Consecutive Failures

What Was Built

Added a consecutive_fetch_failures counter to Source that tracks consecutive fetch failures and automatically pauses sources after 5 consecutive failures. The counter resets on any successful fetch (200 or 304). When auto-pause triggers, the source is paused with update_columns (fast, no callbacks), a fetch log entry records the event, and a toast notification is broadcast to the UI.

Tasks Completed

1. Migration: Added consecutive_fetch_failures integer column (default 0, NOT NULL) with partial index on sourcemon_sources
2. Counter logic in SourceUpdater: Reset to 0 on success/304, increment on failure
3. Auto-pause trigger: check_consecutive_failure_auto_pause! fires after 5 consecutive failures, sets auto_paused_until, auto_paused_at, health_status, backoff_until, next_fetch_at
4. Notification: Creates fetch log entry with error_class: "SourceMonitor::AutoPause" and broadcasts warning toast
5. SourceHealthMonitor integration: Resume path clears consecutive_fetch_failures to 0
6. Tests: 11 new tests (10 in consecutive_failures_test.rb, 1 in source_health_monitor_test.rb)

Files Modified

• db/migrate/20260307120000_add_consecutive_fetch_failures_to_sources.rb (created)
• lib/source_monitor/fetching/feed_fetcher/source_updater.rb (modified)
• lib/source_monitor/health/source_health_monitor.rb (modified)
• test/lib/source_monitor/fetching/consecutive_failures_test.rb (created)
• test/lib/source_monitor/health/source_health_monitor_test.rb (modified)
• test/dummy/db/schema.rb (auto-updated by migration)

Commits

• 1ab10db feat(migration): add consecutive_fetch_failures column to sources
• 310f95d feat(fetching): add consecutive failure counter and auto-pause trigger
• da55bb8 feat(health): reset consecutive_fetch_failures on health monitor resume
• 114cf91 test(fetching): add tests for consecutive failure auto-pause

Deviations

• Notification approach: Used fetch_logs.create! instead of LogEntry.create! for the auto-pause notification. LogEntry uses delegated_type and requires a loggable (FetchLog/ScrapeLog/HealthCheckLog), so creating a fetch_log entry directly was simpler and consistent with the existing pattern. The fetch log entry uses error_class: "SourceMonitor::AutoPause" to distinguish auto-pause events from actual fetch failures.
• No source_updater_test.rb modifications: The plan suggested modifying a source_updater_test.rb file, but that file doesn't exist. The existing tests are split across source_updater_error_category_test.rb and source_updater_favicon_test.rb. The new consecutive_failures_test.rb comprehensively covers all SourceUpdater counter behavior.

Validation

• bin/rubocop on all modified files: 0 offenses
• bin/rails test: 1325 runs, 4022 assertions, 0 failures, 0 errors